<?php

namespace Illuminate\Database\Eloquent;

use DateTime;
use Exception;
use ArrayAccess;
use Carbon\Carbon;
use LogicException;
use JsonSerializable;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use Illuminate\Contracts\Support\Jsonable;
use Illuminate\Contracts\Events\Dispatcher;
use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Contracts\Routing\UrlRoutable;
use Illuminate\Contracts\Queue\QueueableEntity;
use Illuminate\Database\Eloquent\Relations\Pivot;
use Illuminate\Database\Eloquent\Relations\HasOne;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\Relations\MorphTo;
use Illuminate\Database\Eloquent\Relations\MorphOne;
use Illuminate\Database\Eloquent\Relations\Relation;
use Illuminate\Support\Collection as BaseCollection;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\MorphMany;
use Illuminate\Database\Query\Builder as QueryBuilder;
use Illuminate\Database\Eloquent\Relations\MorphToMany;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasManyThrough;
use Illuminate\Database\ConnectionResolverInterface as Resolver;

abstract class Model implements ArrayAccess, Arrayable, Jsonable, JsonSerializable, QueueableEntity, UrlRoutable
{
    /**
     * The connection name for the model.
     *
     * @var string
     */
    protected $connection;

    /**
     * The table associated with the model.
     *
     * @var string
     */
    protected $table;

    /**
     * The primary key for the model.
     *
     * @var string
     */
    protected $primaryKey = 'id';

    /**
     * The number of models to return for pagination.
     *
     * @var int
     */
    protected $perPage = 15;

    /**
     * Indicates if the IDs are auto-incrementing.
     *
     * @var bool
     */
    public $incrementing = true;

    /**
     * Indicates if the model should be timestamped.
     *
     * @var bool
     */
    public $timestamps = true;

    /**
     * The model's attributes.
     *
     * @var array
     */
    protected $attributes = [];

    /**
     * The model attribute's original state.
     *
     * @var array
     */
    protected $original = [];

    /**
     * The loaded relationships for the model.
     *
     * @var array
     */
    protected $relations = [];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [];

    /**
     * The attributes that should be visible in arrays.
     *
     * @var array
     */
    protected $visible = [];

    /**
     * The accessors to append to the model's array form.
     *
     * @var array
     */
    protected $appends = [];

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [];

    /**
     * The attributes that aren't mass assignable.
     *
     * @var array
     */
    protected $guarded = ['*'];

    /**
     * The attributes that should be mutated to dates.
     *
     * @var array
     */
    protected $dates = [];

    /**
     * The storage format of the model's date columns.
     *
     * @var string
     */
    protected $dateFormat;

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [];

    /**
     * The relationships that should be touched on save.
     *
     * @var array
     */
    protected $touches = [];

    /**
     * User exposed observable events.
     *
     * @var array
     */
    protected $observables = [];

    /**
     * The relations to eager load on every query.
     *
     * @var array
     */
    protected $with = [];

    /**
     * The class name to be used in polymorphic relations.
     *
     * @var string
     */
    protected $morphClass;

    /**
     * Indicates if the model exists.
     *
     * @var bool
     */
    public $exists = false;

    /**
     * Indicates if the model was inserted during the current request lifecycle.
     *
     * @var bool
     */
    public $wasRecentlyCreated = false;

    /**
     * Indicates whether attributes are snake cased on arrays.
     *
     * @var bool
     */
    public static $snakeAttributes = true;

    /**
     * The connection resolver instance.
     *
     * @var \Illuminate\Database\ConnectionResolverInterface
     */
    protected static $resolver;

    /**
     * The event dispatcher instance.
     *
     * @var \Illuminate\Contracts\Events\Dispatcher
     */
    protected static $dispatcher;

    /**
     * The array of booted models.
     *
     * @var array
     */
    protected static $booted = [];

    /**
     * The array of global scopes on the model.
     *
     * @var array
     */
    protected static $globalScopes = [];

    /**
     * Indicates if all mass assignment is enabled.
     *
     * @var bool
     */
    protected static $unguarded = false;

    /**
     * The cache of the mutated attributes for each class.
     *
     * @var array
     */
    protected static $mutatorCache = [];

    /**
     * The many to many relationship methods.
     *
     * @var array
     */
    public static $manyMethods = ['belongsToMany', 'morphToMany', 'morphedByMany'];

    /**
     * The name of the "created at" column.
     *
     * @var string
     */
    const CREATED_AT = 'created_at';

    /**
     * The name of the "updated at" column.
     *
     * @var string
     */
    const UPDATED_AT = 'updated_at';

    /**
     * Create a new Eloquent model instance.
     *
     * @param  array  $attributes
     * @return void
     */
    public function __construct(array $attributes = [])
    {
        $this->bootIfNotBooted();

        $this->syncOriginal();

        $this->fill($attributes);
    }

    /**
     * Check if the model needs to be booted and if so, do it.
     *
     * @return void
     */
    protected function bootIfNotBooted()
    {
        $class = get_class($this);

        if (! isset(static::$booted[$class])) {
            static::$booted[$class] = true;

            $this->fireModelEvent('booting', false);

            static::boot();

            $this->fireModelEvent('booted', false);
        }
    }

    /**
     * The "booting" method of the model.
     *
     * @return void
     */
    protected static function boot()
    {
        static::bootTraits();
    }

    /**
     * Boot all of the bootable traits on the model.
     *
     * @return void
     */
    protected static function bootTraits()
    {
        foreach (class_uses_recursive(get_called_class()) as $trait) {
            if (method_exists(get_called_class(), $method = 'boot'.class_basename($trait))) {
                forward_static_call([get_called_class(), $method]);
            }
        }
    }

    /**
     * Clear the list of booted models so they will be re-booted.
     *
     * @return void
     */
    public static function clearBootedModels()
    {
        static::$booted = [];
    }

    /**
     * Register a new global scope on the model.
     *
     * @param  \Illuminate\Database\Eloquent\ScopeInterface  $scope
     * @return void
     */
    public static function addGlobalScope(ScopeInterface $scope)
    {
        static::$globalScopes[get_called_class()][get_class($scope)] = $scope;
    }

    /**
     * Determine if a model has a global scope.
     *
     * @param  \Illuminate\Database\Eloquent\ScopeInterface  $scope
     * @return bool
     */
    public static function hasGlobalScope($scope)
    {
        return ! is_null(static::getGlobalScope($scope));
    }

    /**
     * Get a global scope registered with the model.
     *
     * @param  \Illuminate\Database\Eloquent\ScopeInterface  $scope
     * @return \Illuminate\Database\Eloquent\ScopeInterface|null
     */
    public static function getGlobalScope($scope)
    {
        return Arr::first(static::$globalScopes[get_called_class()], function ($key, $value) use ($scope) {
            return $scope instanceof $value;
        });
    }

    /**
     * Get the global scopes for this class instance.
     *
     * @return array
     */
    public function getGlobalScopes()
    {
        return Arr::get(static::$globalScopes, get_class($this), []);
    }

    /**
     * Register an observer with the Model.
     *
     * @param  object|string  $class
     * @param  int  $priority
     * @return void
     */
    public static function observe($class, $priority = 0)
    {
        $instance = new static;

        $className = is_string($class) ? $class : get_class($class);

        // When registering a model observer, we will spin through the possible events
        // and determine if this observer has that method. If it does, we will hook
        // it into the model's event system, making it convenient to watch these.
        foreach ($instance->getObservableEvents() as $event) {
            if (method_exists($class, $event)) {
                static::registerModelEvent($event, $className.'@'.$event, $priority);
            }
        }
    }

    /**
     * Fill the model with an array of attributes.
     *
     * @param  array  $attributes
     * @return $this
     *
     * @throws \Illuminate\Database\Eloquent\MassAssignmentException
     */
    public function fill(array $attributes)
    {
        $totallyGuarded = $this->totallyGuarded();

        foreach ($this->fillableFromArray($attributes) as $key => $value) {
            $key = $this->removeTableFromKey($key);

            // The developers may choose to place some attributes in the "fillable"
            // array, which means only those attributes may be set through mass
            // assignment to the model, and all others will just be ignored.
            if ($this->isFillable($key)) {
                $this->setAttribute($key, $value);
            } elseif ($totallyGuarded) {
                throw new MassAssignmentException($key);
            }
        }

        return $this;
    }

    /**
     * Fill the model with an array of attributes. Force mass assignment.
     *
     * @param  array  $attributes
     * @return $this
     */
    public function forceFill(array $attributes)
    {
        // Since some versions of PHP have a bug that prevents it from properly
        // binding the late static context in a closure, we will first store
        // the model in a variable, which we will then use in the closure.
        $model = $this;

        return static::unguarded(function () use ($model, $attributes) {
            return $model->fill($attributes);
        });
    }

    /**
     * Get the fillable attributes of a given array.
     *
     * @param  array  $attributes
     * @return array
     */
    protected function fillableFromArray(array $attributes)
    {
        if (count($this->fillable) > 0 && ! static::$unguarded) {
            return array_intersect_key($attributes, array_flip($this->fillable));
        }

        return $attributes;
    }

    /**
     * Create a new instance of the given model.
     *
     * @param  array  $attributes
     * @param  bool  $exists
     * @return static
     */
    public function newInstance($attributes = [], $exists = false)
    {
        // This method just provides a convenient way for us to generate fresh model
        // instances of this current model. It is particularly useful during the
        // hydration of new objects via the Eloquent query builder instances.
        $model = new static((array) $attributes);

        $model->exists = $exists;

        return $model;
    }

    /**
     * Create a new model instance that is existing.
     *
     * @param  array  $attributes
     * @param  string|null  $connection
     * @return static
     */
    public function newFromBuilder($attributes = [], $connection = null)
    {
        $model = $this->newInstance([], true);

        $model->setRawAttributes((array) $attributes, true);

        $model->setConnection($connection ?: $this->connection);

        return $model;
    }

    /**
     * Create a collection of models from plain arrays.
     *
     * @param  array  $items
     * @param  string|null  $connection
     * @return \Illuminate\Database\Eloquent\Collection
     */
    public static function hydrate(array $items, $connection = null)
    {
        $instance = (new static)->setConnection($connection);

        $items = array_map(function ($item) use ($instance) {
            return $instance->newFromBuilder($item);
        }, $items);

        return $instance->newCollection($items);
    }

    /**
     * Create a collection of models from a raw query.
     *
     * @param  string  $query
     * @param  array  $bindings
     * @param  string|null  $connection
     * @return \Illuminate\Database\Eloquent\Collection
     */
    public static function hydrateRaw($query, $bindings = [], $connection = null)
    {
        $instance = (new static)->setConnection($connection);

        $items = $instance->getConnection()->select($query, $bindings);

        return static::hydrate($items, $connection);
    }

    /**
     * Save a new model and return the instance.
     *
     * @param  array  $attributes
     * @return static
     */
    public static function create(array $attributes = [])
    {
        $model = new static($attributes);

        $model->save();

        return $model;
    }

    /**
     * Save a new model and return the instance. Allow mass-assignment.
     *
     * @param  array  $attributes
     * @return static
     */
    public static function forceCreate(array $attributes)
    {
        // Since some versions of PHP have a bug that prevents it from properly
        // binding the late static context in a closure, we will first store
        // the model in a variable, which we will then use in the closure.
        $model = new static;

        return static::unguarded(function () use ($model, $attributes) {
            return $model->create($attributes);
        });
    }

    /**
     * Begin querying the model.
     *
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public static function query()
    {
        return (new static)->newQuery();
    }

    /**
     * Begin querying the model on a given connection.
     *
     * @param  string|null  $connection
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public static function on($connection = null)
    {
        // First we will just create a fresh instance of this model, and then we can
        // set the connection on the model so that it is be used for the queries
        // we execute, as well as being set on each relationship we retrieve.
        $instance = new static;

        $instance->setConnection($connection);

        return $instance->newQuery();
    }

    /**
     * Begin querying the model on the write connection.
     *
     * @return \Illuminate\Database\Query\Builder
     */
    public static function onWriteConnection()
    {
        $instance = new static;

        return $instance->newQuery()->useWritePdo();
    }

    /**
     * Get all of the models from the database.
     *
     * @param  array|mixed  $columns
     * @return \Illuminate\Database\Eloquent\Collection|static[]
     */
    public static function all($columns = ['*'])
    {
        $columns = is_array($columns) ? $columns : func_get_args();

        $instance = new static;

        return $instance->newQuery()->get($columns);
    }

    /**
     * Reload a fresh model instance from the database.
     *
     * @param  array  $with
     * @return static|null
     */
    public function fresh(array $with = [])
    {
        if (! $this->exists) {
            return;
        }

        $key = $this->getKeyName();

        return static::with($with)->where($key, $this->getKey())->first();
    }

    /**
     * Eager load relations on the model.
     *
     * @param  array|string  $relations
     * @return $this
     */
    public function load($relations)
    {
        if (is_string($relations)) {
            $relations = func_get_args();
        }

        $query = $this->newQuery()->with($relations);

        $query->eagerLoadRelations([$this]);

        return $this;
    }

    /**
     * Begin querying a model with eager loading.
     *
     * @param  array|string  $relations
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public static function with($relations)
    {
        if (is_string($relations)) {
            $relations = func_get_args();
        }

        $instance = new static;

        return $instance->newQuery()->with($relations);
    }

    /**
     * Append attributes to query when building a query.
     *
     * @param  array|string  $attributes
     * @return $this
     */
    public function append($attributes)
    {
        if (is_string($attributes)) {
            $attributes = func_get_args();
        }

        $this->appends = array_unique(
            array_merge($this->appends, $attributes)
        );

        return $this;
    }

    /**
     * Define a one-to-one relationship.
     *
     * @param  string  $related
     * @param  string  $foreignKey
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasOne
     */
    public function hasOne($related, $foreignKey = null, $localKey = null)
    {
        $foreignKey = $foreignKey ?: $this->getForeignKey();

        $instance = new $related;

        $localKey = $localKey ?: $this->getKeyName();

        return new HasOne($instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey);
    }

    /**
     * Define a polymorphic one-to-one relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphOne
     */
    public function morphOne($related, $name, $type = null, $id = null, $localKey = null)
    {
        $instance = new $related;

        list($type, $id) = $this->getMorphs($name, $type, $id);

        $table = $instance->getTable();

        $localKey = $localKey ?: $this->getKeyName();

        return new MorphOne($instance->newQuery(), $this, $table.'.'.$type, $table.'.'.$id, $localKey);
    }

    /**
     * Define an inverse one-to-one or many relationship.
     *
     * @param  string  $related
     * @param  string  $foreignKey
     * @param  string  $otherKey
     * @param  string  $relation
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function belongsTo($related, $foreignKey = null, $otherKey = null, $relation = null)
    {
        // If no relation name was given, we will use this debug backtrace to extract
        // the calling method's name and use that as the relationship name as most
        // of the time this will be what we desire to use for the relationships.
        if (is_null($relation)) {
            list($current, $caller) = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);

            $relation = $caller['function'];
        }

        // If no foreign key was supplied, we can use a backtrace to guess the proper
        // foreign key name by using the name of the relationship function, which
        // when combined with an "_id" should conventionally match the columns.
        if (is_null($foreignKey)) {
            $foreignKey = Str::snake($relation).'_id';
        }

        $instance = new $related;

        // Once we have the foreign key names, we'll just create a new Eloquent query
        // for the related models and returns the relationship instance which will
        // actually be responsible for retrieving and hydrating every relations.
        $query = $instance->newQuery();

        $otherKey = $otherKey ?: $instance->getKeyName();

        return new BelongsTo($query, $this, $foreignKey, $otherKey, $relation);
    }

    /**
     * Define a polymorphic, inverse one-to-one or many relationship.
     *
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
     */
    public function morphTo($name = null, $type = null, $id = null)
    {
        // If no name is provided, we will use the backtrace to get the function name
        // since that is most likely the name of the polymorphic interface. We can
        // use that to get both the class and foreign key that will be utilized.
        if (is_null($name)) {
            list($current, $caller) = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);

            $name = Str::snake($caller['function']);
        }

        list($type, $id) = $this->getMorphs($name, $type, $id);

        // If the type value is null it is probably safe to assume we're eager loading
        // the relationship. In this case we'll just pass in a dummy query where we
        // need to remove any eager loads that may already be defined on a model.
        if (empty($class = $this->$type)) {
            return new MorphTo(
                $this->newQuery()->setEagerLoads([]), $this, $id, null, $type, $name
            );
        }

        // If we are not eager loading the relationship we will essentially treat this
        // as a belongs-to style relationship since morph-to extends that class and
        // we will pass in the appropriate values so that it behaves as expected.
        else {
            $class = $this->getActualClassNameForMorph($class);

            $instance = new $class;

            return new MorphTo(
                $instance->newQuery(), $this, $id, $instance->getKeyName(), $type, $name
            );
        }
    }

    /**
     * Retrieve the fully qualified class name from a slug.
     *
     * @param  string  $class
     * @return string
     */
    public function getActualClassNameForMorph($class)
    {
        return Arr::get(Relation::morphMap(), $class, $class);
    }

    /**
     * Define a one-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $foreignKey
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasMany
     */
    public function hasMany($related, $foreignKey = null, $localKey = null)
    {
        $foreignKey = $foreignKey ?: $this->getForeignKey();

        $instance = new $related;

        $localKey = $localKey ?: $this->getKeyName();

        return new HasMany($instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey);
    }

    /**
     * Define a has-many-through relationship.
     *
     * @param  string  $related
     * @param  string  $through
     * @param  string|null  $firstKey
     * @param  string|null  $secondKey
     * @param  string|null  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasManyThrough
     */
    public function hasManyThrough($related, $through, $firstKey = null, $secondKey = null, $localKey = null)
    {
        $through = new $through;

        $firstKey = $firstKey ?: $this->getForeignKey();

        $secondKey = $secondKey ?: $through->getForeignKey();

        $localKey = $localKey ?: $this->getKeyName();

        return new HasManyThrough((new $related)->newQuery(), $this, $through, $firstKey, $secondKey, $localKey);
    }

    /**
     * Define a polymorphic one-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphMany
     */
    public function morphMany($related, $name, $type = null, $id = null, $localKey = null)
    {
        $instance = new $related;

        // Here we will gather up the morph type and ID for the relationship so that we
        // can properly query the intermediate table of a relation. Finally, we will
        // get the table and create the relationship instances for the developers.
        list($type, $id) = $this->getMorphs($name, $type, $id);

        $table = $instance->getTable();

        $localKey = $localKey ?: $this->getKeyName();

        return new MorphMany($instance->newQuery(), $this, $table.'.'.$type, $table.'.'.$id, $localKey);
    }

    /**
     * Define a many-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $table
     * @param  string  $foreignKey
     * @param  string  $otherKey
     * @param  string  $relation
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function belongsToMany($related, $table = null, $foreignKey = null, $otherKey = null, $relation = null)
    {
        // If no relationship name was passed, we will pull backtraces to get the
        // name of the calling function. We will use that function name as the
        // title of this relation since that is a great convention to apply.
        if (is_null($relation)) {
            $relation = $this->getBelongsToManyCaller();
        }

        // First, we'll need to determine the foreign key and "other key" for the
        // relationship. Once we have determined the keys we'll make the query
        // instances as well as the relationship instances we need for this.
        $foreignKey = $foreignKey ?: $this->getForeignKey();

        $instance = new $related;

        $otherKey = $otherKey ?: $instance->getForeignKey();

        // If no table name was provided, we can guess it by concatenating the two
        // models using underscores in alphabetical order. The two model names
        // are transformed to snake case from their default CamelCase also.
        if (is_null($table)) {
            $table = $this->joiningTable($related);
        }

        // Now we're ready to create a new query builder for the related model and
        // the relationship instances for the relation. The relations will set
        // appropriate query constraint and entirely manages the hydrations.
        $query = $instance->newQuery();

        return new BelongsToMany($query, $this, $table, $foreignKey, $otherKey, $relation);
    }

    /**
     * Define a polymorphic many-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string  $table
     * @param  string  $foreignKey
     * @param  string  $otherKey
     * @param  bool  $inverse
     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
     */
    public function morphToMany($related, $name, $table = null, $foreignKey = null, $otherKey = null, $inverse = false)
    {
        $caller = $this->getBelongsToManyCaller();

        // First, we will need to determine the foreign key and "other key" for the
        // relationship. Once we have determined the keys we will make the query
        // instances, as well as the relationship instances we need for these.
        $foreignKey = $foreignKey ?: $name.'_id';

        $instance = new $related;

        $otherKey = $otherKey ?: $instance->getForeignKey();

        // Now we're ready to create a new query builder for this related model and
        // the relationship instances for this relation. This relations will set
        // appropriate query constraints then entirely manages the hydrations.
        $query = $instance->newQuery();

        $table = $table ?: Str::plural($name);

        return new MorphToMany(
            $query, $this, $name, $table, $foreignKey,
            $otherKey, $caller, $inverse
        );
    }

    /**
     * Define a polymorphic, inverse many-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string  $table
     * @param  string  $foreignKey
     * @param  string  $otherKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
     */
    public function morphedByMany($related, $name, $table = null, $foreignKey = null, $otherKey = null)
    {
        $foreignKey = $foreignKey ?: $this->getForeignKey();

        // For the inverse of the polymorphic many-to-many relations, we will change
        // the way we determine the foreign and other keys, as it is the opposite
        // of the morph-to-many method since we're figuring out these inverses.
        $otherKey = $otherKey ?: $name.'_id';

        return $this->morphToMany($related, $name, $table, $foreignKey, $otherKey, true);
    }

    /**
     * Get the relationship name of the belongs to many.
     *
     * @return string
     */
    protected function getBelongsToManyCaller()
    {
        $self = __FUNCTION__;

        $caller = Arr::first(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS), function ($key, $trace) use ($self) {
            $caller = $trace['function'];

            return ! in_array($caller, Model::$manyMethods) && $caller != $self;
        });

        return ! is_null($caller) ? $caller['function'] : null;
    }

    /**
     * Get the joining table name for a many-to-many relation.
     *
     * @param  string  $related
     * @return string
     */
    public function joiningTable($related)
    {
        // The joining table name, by convention, is simply the snake cased models
        // sorted alphabetically and concatenated with an underscore, so we can
        // just sort the models and join them together to get the table name.
        $base = Str::snake(class_basename($this));

        $related = Str::snake(class_basename($related));

        $models = [$related, $base];

        // Now that we have the model names in an array we can just sort them and
        // use the implode function to join them together with an underscores,
        // which is typically used by convention within the database system.
        sort($models);

        return strtolower(implode('_', $models));
    }

    /**
     * Destroy the models for the given IDs.
     *
     * @param  array|int  $ids
     * @return int
     */
    public static function destroy($ids)
    {
        // We'll initialize a count here so we will return the total number of deletes
        // for the operation. The developers can then check this number as a boolean
        // type value or get this total count of records deleted for logging, etc.
        $count = 0;

        $ids = is_array($ids) ? $ids : func_get_args();

        $instance = new static;

        // We will actually pull the models from the database table and call delete on
        // each of them individually so that their events get fired properly with a
        // correct set of attributes in case the developers wants to check these.
        $key = $instance->getKeyName();

        foreach ($instance->whereIn($key, $ids)->get() as $model) {
            if ($model->delete()) {
                $count++;
            }
        }

        return $count;
    }

    /**
     * Delete the model from the database.
     *
     * @return bool|null
     *
     * @throws \Exception
     */
    public function delete()
    {
        if (is_null($this->getKeyName())) {
            throw new Exception('No primary key defined on model.');
        }

        if ($this->exists) {
            if ($this->fireModelEvent('deleting') === false) {
                return false;
            }

            // Here, we'll touch the owning models, verifying these timestamps get updated
            // for the models. This will allow any caching to get broken on the parents
            // by the timestamp. Then we will go ahead and delete the model instance.
            $this->touchOwners();

            $this->performDeleteOnModel();

            $this->exists = false;

            // Once the model has been deleted, we will fire off the deleted event so that
            // the developers may hook into post-delete operations. We will then return
            // a boolean true as the delete is presumably successful on the database.
            $this->fireModelEvent('deleted', false);

            return true;
        }
    }

    /**
     * Force a hard delete on a soft deleted model.
     *
     * This method protects developers from running forceDelete when trait is missing.
     *
     * @return bool|null
     */
    public function forceDelete()
    {
        return $this->delete();
    }

    /**
     * Perform the actual delete query on this model instance.
     *
     * @return void
     */
    protected function performDeleteOnModel()
    {
        $this->setKeysForSaveQuery($this->newQueryWithoutScopes())->delete();
    }

    /**
     * Register a saving model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function saving($callback, $priority = 0)
    {
        static::registerModelEvent('saving', $callback, $priority);
    }

    /**
     * Register a saved model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function saved($callback, $priority = 0)
    {
        static::registerModelEvent('saved', $callback, $priority);
    }

    /**
     * Register an updating model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function updating($callback, $priority = 0)
    {
        static::registerModelEvent('updating', $callback, $priority);
    }

    /**
     * Register an updated model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function updated($callback, $priority = 0)
    {
        static::registerModelEvent('updated', $callback, $priority);
    }

    /**
     * Register a creating model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function creating($callback, $priority = 0)
    {
        static::registerModelEvent('creating', $callback, $priority);
    }

    /**
     * Register a created model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function created($callback, $priority = 0)
    {
        static::registerModelEvent('created', $callback, $priority);
    }

    /**
     * Register a deleting model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function deleting($callback, $priority = 0)
    {
        static::registerModelEvent('deleting', $callback, $priority);
    }

    /**
     * Register a deleted model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    public static function deleted($callback, $priority = 0)
    {
        static::registerModelEvent('deleted', $callback, $priority);
    }

    /**
     * Remove all of the event listeners for the model.
     *
     * @return void
     */
    public static function flushEventListeners()
    {
        if (! isset(static::$dispatcher)) {
            return;
        }

        $instance = new static;

        foreach ($instance->getObservableEvents() as $event) {
            static::$dispatcher->forget("eloquent.{$event}: ".get_called_class());
        }
    }

    /**
     * Register a model event with the dispatcher.
     *
     * @param  string  $event
     * @param  \Closure|string  $callback
     * @param  int  $priority
     * @return void
     */
    protected static function registerModelEvent($event, $callback, $priority = 0)
    {
        if (isset(static::$dispatcher)) {
            $name = get_called_class();

            static::$dispatcher->listen("eloquent.{$event}: {$name}", $callback, $priority);
        }
    }

    /**
     * Get the observable event names.
     *
     * @return array
     */
    public function getObservableEvents()
    {
        return array_merge(
            [
                'creating', 'created', 'updating', 'updated',
                'deleting', 'deleted', 'saving', 'saved',
                'restoring', 'restored',
            ],
            $this->observables
        );
    }

    /**
     * Set the observable event names.
     *
     * @param  array  $observables
     * @return $this
     */
    public function setObservableEvents(array $observables)
    {
        $this->observables = $observables;

        return $this;
    }

    /**
     * Add an observable event name.
     *
     * @param  array|mixed  $observables
     * @return void
     */
    public function addObservableEvents($observables)
    {
        $observables = is_array($observables) ? $observables : func_get_args();

        $this->observables = array_unique(array_merge($this->observables, $observables));
    }

    /**
     * Remove an observable event name.
     *
     * @param  array|mixed  $observables
     * @return void
     */
    public function removeObservableEvents($observables)
    {
        $observables = is_array($observables) ? $observables : func_get_args();

        $this->observables = array_diff($this->observables, $observables);
    }

    /**
     * Increment a column's value by a given amount.
     *
     * @param  string  $column
     * @param  int  $amount
     * @return int
     */
    protected function increment($column, $amount = 1)
    {
        return $this->incrementOrDecrement($column, $amount, 'increment');
    }

    /**
     * Decrement a column's value by a given amount.
     *
     * @param  string  $column
     * @param  int  $amount
     * @return int
     */
    protected function decrement($column, $amount = 1)
    {
        return $this->incrementOrDecrement($column, $amount, 'decrement');
    }

    /**
     * Run the increment or decrement method on the model.
     *
     * @param  string  $column
     * @param  int  $amount
     * @param  string  $method
     * @return int
     */
    protected function incrementOrDecrement($column, $amount, $method)
    {
        $query = $this->newQuery();

        if (! $this->exists) {
            return $query->{$method}($column, $amount);
        }

        $this->incrementOrDecrementAttributeValue($column, $amount, $method);

        return $query->where($this->getKeyName(), $this->getKey())->{$method}($column, $amount);
    }

    /**
     * Increment the underlying attribute value and sync with original.
     *
     * @param  string  $column
     * @param  int  $amount
     * @param  string  $method
     * @return void
     */
    protected function incrementOrDecrementAttributeValue($column, $amount, $method)
    {
        $this->{$column} = $this->{$column} + ($method == 'increment' ? $amount : $amount * -1);

        $this->syncOriginalAttribute($column);
    }

    /**
     * Update the model in the database.
     *
     * @param  array  $attributes
     * @return bool|int
     */
    public function update(array $attributes = [])
    {
        if (! $this->exists) {
            return false;
        }

        return $this->fill($attributes)->save();
    }

    /**
     * Save the model and all of its relationships.
     *
     * @return bool
     */
    public function push()
    {
        if (! $this->save()) {
            return false;
        }

        // To sync all of the relationships to the database, we will simply spin through
        // the relationships and save each model via this "push" method, which allows
        // us to recurse into all of these nested relations for the model instance.
        foreach ($this->relations as $models) {
            $models = $models instanceof Collection
                        ? $models->all() : [$models];

            foreach (array_filter($models) as $model) {
                if (! $model->push()) {
                    return false;
                }
            }
        }

        return true;
    }

    /**
     * Save the model to the database.
     *
     * @param  array  $options
     * @return bool
     */
    public function save(array $options = [])
    {
        $query = $this->newQueryWithoutScopes();

        // If the "saving" event returns false we'll bail out of the save and return
        // false, indicating that the save failed. This provides a chance for any
        // listeners to cancel save operations if validations fail or whatever.
        if ($this->fireModelEvent('saving') === false) {
            return false;
        }

        // If the model already exists in the database we can just update our record
        // that is already in this database using the current IDs in this "where"
        // clause to only update this model. Otherwise, we'll just insert them.
        if ($this->exists) {
            $saved = $this->performUpdate($query, $options);
        }

        // If the model is brand new, we'll insert it into our database and set the
        // ID attribute on the model to the value of the newly inserted row's ID
        // which is typically an auto-increment value managed by the database.
        else {
            $saved = $this->performInsert($query, $options);
        }

        if ($saved) {
            $this->finishSave($options);
        }

        return $saved;
    }

    /**
     * Save the model to the database using transaction.
     *
     * @param  array  $options
     * @return bool
     *
     * @throws \Throwable
     */
    public function saveOrFail(array $options = [])
    {
        return $this->getConnection()->transaction(function () use ($options) {
            return $this->save($options);
        });
    }

    /**
     * Finish processing on a successful save operation.
     *
     * @param  array  $options
     * @return void
     */
    protected function finishSave(array $options)
    {
        $this->fireModelEvent('saved', false);

        $this->syncOriginal();

        if (Arr::get($options, 'touch', true)) {
            $this->touchOwners();
        }
    }

    /**
     * Perform a model update operation.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  array  $options
     * @return bool
     */
    protected function performUpdate(Builder $query, array $options = [])
    {
        $dirty = $this->getDirty();

        if (count($dirty) > 0) {
            // If the updating event returns false, we will cancel the update operation so
            // developers can hook Validation systems into their models and cancel this
            // operation if the model does not pass validation. Otherwise, we update.
            if ($this->fireModelEvent('updating') === false) {
                return false;
            }

            // First we need to create a fresh query instance and touch the creation and
            // update timestamp on the model which are maintained by us for developer
            // convenience. Then we will just continue saving the model instances.
            if ($this->timestamps && Arr::get($options, 'timestamps', true)) {
                $this->updateTimestamps();
            }

            // Once we have run the update operation, we will fire the "updated" event for
            // this model instance. This will allow developers to hook into these after
            // models are updated, giving them a chance to do any special processing.
            $dirty = $this->getDirty();

            if (count($dirty) > 0) {
                $numRows = $this->setKeysForSaveQuery($query)->update($dirty);

                $this->fireModelEvent('updated', false);
            }
        }

        return true;
    }

    /**
     * Perform a model insert operation.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  array  $options
     * @return bool
     */
    protected function performInsert(Builder $query, array $options = [])
    {
        if ($this->fireModelEvent('creating') === false) {
            return false;
        }

        // First we'll need to create a fresh query instance and touch the creation and
        // update timestamps on this model, which are maintained by us for developer
        // convenience. After, we will just continue saving these model instances.
        if ($this->timestamps && Arr::get($options, 'timestamps', true)) {
            $this->updateTimestamps();
        }

        // If the model has an incrementing key, we can use the "insertGetId" method on
        // the query builder, which will give us back the final inserted ID for this
        // table from the database. Not all tables have to be incrementing though.
        $attributes = $this->attributes;

        if ($this->incrementing) {
            $this->insertAndSetId($query, $attributes);
        }

        // If the table isn't incrementing we'll simply insert these attributes as they
        // are. These attribute arrays must contain an "id" column previously placed
        // there by the developer as the manually determined key for these models.
        else {
            $query->insert($attributes);
        }

        // We will go ahead and set the exists property to true, so that it is set when
        // the created event is fired, just in case the developer tries to update it
        // during the event. This will allow them to do so and run an update here.
        $this->exists = true;

        $this->wasRecentlyCreated = true;

        $this->fireModelEvent('created', false);

        return true;
    }

    /**
     * Insert the given attributes and set the ID on the model.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  array  $attributes
     * @return void
     */
    protected function insertAndSetId(Builder $query, $attributes)
    {
        $id = $query->insertGetId($attributes, $keyName = $this->getKeyName());

        $this->setAttribute($keyName, $id);
    }

    /**
     * Touch the owning relations of the model.
     *
     * @return void
     */
    public function touchOwners()
    {
        foreach ($this->touches as $relation) {
            $this->$relation()->touch();

            if ($this->$relation instanceof self) {
                $this->$relation->fireModelEvent('saved', false);

                $this->$relation->touchOwners();
            } elseif ($this->$relation instanceof Collection) {
                $this->$relation->each(function (Model $relation) {
                    $relation->touchOwners();
                });
            }
        }
    }

    /**
     * Determine if the model touches a given relation.
     *
     * @param  string  $relation
     * @return bool
     */
    public function touches($relation)
    {
        return in_array($relation, $this->touches);
    }

    /**
     * Fire the given event for the model.
     *
     * @param  string  $event
     * @param  bool  $halt
     * @return mixed
     */
    protected function fireModelEvent($event, $halt = true)
    {
        if (! isset(static::$dispatcher)) {
            return true;
        }

        // We will append the names of the class to the event to distinguish it from
        // other model events that are fired, allowing us to listen on each model
        // event set individually instead of catching event for all the models.
        $event = "eloquent.{$event}: ".get_class($this);

        $method = $halt ? 'until' : 'fire';

        return static::$dispatcher->$method($event, $this);
    }

    /**
     * Set the keys for a save update query.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @return \Illuminate\Database\Eloquent\Builder
     */
    protected function setKeysForSaveQuery(Builder $query)
    {
        $query->where($this->getKeyName(), '=', $this->getKeyForSaveQuery());

        return $query;
    }

    /**
     * Get the primary key value for a save query.
     *
     * @return mixed
     */
    protected function getKeyForSaveQuery()
    {
        if (isset($this->original[$this->getKeyName()])) {
            return $this->original[$this->getKeyName()];
        }

        return $this->getAttribute($this->getKeyName());
    }

    /**
     * Update the model's update timestamp.
     *
     * @return bool
     */
    public function touch()
    {
        if (! $this->timestamps) {
            return false;
        }

        $this->updateTimestamps();

        return $this->save();
    }

    /**
     * Update the creation and update timestamps.
     *
     * @return void
     */
    protected function updateTimestamps()
    {
        $time = $this->freshTimestamp();

        if (! $this->isDirty(static::UPDATED_AT)) {
            $this->setUpdatedAt($time);
        }

        if (! $this->exists && ! $this->isDirty(static::CREATED_AT)) {
            $this->setCreatedAt($time);
        }
    }

    /**
     * Set the value of the "created at" attribute.
     *
     * @param  mixed  $value
     * @return $this
     */
    public function setCreatedAt($value)
    {
        $this->{static::CREATED_AT} = $value;

        return $this;
    }

    /**
     * Set the value of the "updated at" attribute.
     *
     * @param  mixed  $value
     * @return $this
     */
    public function setUpdatedAt($value)
    {
        $this->{static::UPDATED_AT} = $value;

        return $this;
    }

    /**
     * Get the name of the "created at" column.
     *
     * @return string
     */
    public function getCreatedAtColumn()
    {
        return static::CREATED_AT;
    }

    /**
     * Get the name of the "updated at" column.
     *
     * @return string
     */
    public function getUpdatedAtColumn()
    {
        return static::UPDATED_AT;
    }

    /**
     * Get a fresh timestamp for the model.
     *
     * @return \Carbon\Carbon
     */
    public function freshTimestamp()
    {
        return new Carbon;
    }

    /**
     * Get a fresh timestamp for the model.
     *
     * @return string
     */
    public function freshTimestampString()
    {
        return $this->fromDateTime($this->freshTimestamp());
    }

    /**
     * Get a new query builder for the model's table.
     *
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public function newQuery()
    {
        $builder = $this->newQueryWithoutScopes();

        return $this->applyGlobalScopes($builder);
    }

    /**
     * Get a new query instance without a given scope.
     *
     * @param  \Illuminate\Database\Eloquent\ScopeInterface  $scope
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public function newQueryWithoutScope($scope)
    {
        $this->getGlobalScope($scope)->remove($builder = $this->newQuery(), $this);

        return $builder;
    }

    /**
     * Get a new query builder that doesn't have any global scopes.
     *
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function newQueryWithoutScopes()
    {
        $builder = $this->newEloquentBuilder(
            $this->newBaseQueryBuilder()
        );

        // Once we have the query builders, we will set the model instances so the
        // builder can easily access any information it may need from the model
        // while it is constructing and executing various queries against it.
        return $builder->setModel($this)->with($this->with);
    }

    /**
     * Apply all of the global scopes to an Eloquent builder.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $builder
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public function applyGlobalScopes($builder)
    {
        foreach ($this->getGlobalScopes() as $scope) {
            $scope->apply($builder, $this);
        }

        return $builder;
    }

    /**
     * Remove all of the global scopes from an Eloquent builder.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $builder
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public function removeGlobalScopes($builder)
    {
        foreach ($this->getGlobalScopes() as $scope) {
            $scope->remove($builder, $this);
        }

        return $builder;
    }

    /**
     * Create a new Eloquent query builder for the model.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function newEloquentBuilder($query)
    {
        return new Builder($query);
    }

    /**
     * Get a new query builder instance for the connection.
     *
     * @return \Illuminate\Database\Query\Builder
     */
    protected function newBaseQueryBuilder()
    {
        $conn = $this->getConnection();

        $grammar = $conn->getQueryGrammar();

        return new QueryBuilder($conn, $grammar, $conn->getPostProcessor());
    }

    /**
     * Create a new Eloquent Collection instance.
     *
     * @param  array  $models
     * @return \Illuminate\Database\Eloquent\Collection
     */
    public function newCollection(array $models = [])
    {
        return new Collection($models);
    }

    /**
     * Create a new pivot model instance.
     *
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  array  $attributes
     * @param  string  $table
     * @param  bool  $exists
     * @return \Illuminate\Database\Eloquent\Relations\Pivot
     */
    public function newPivot(Model $parent, array $attributes, $table, $exists)
    {
        return new Pivot($parent, $attributes, $table, $exists);
    }

    /**
     * Get the table associated with the model.
     *
     * @return string
     */
    public function getTable()
    {
        if (isset($this->table)) {
            return $this->table;
        }

        return str_replace('\\', '', Str::snake(Str::plural(class_basename($this))));
    }

    /**
     * Set the table associated with the model.
     *
     * @param  string  $table
     * @return $this
     */
    public function setTable($table)
    {
        $this->table = $table;

        return $this;
    }

    /**
     * Get the value of the model's primary key.
     *
     * @return mixed
     */
    public function getKey()
    {
        return $this->getAttribute($this->getKeyName());
    }

    /**
     * Get the queueable identity for the entity.
     *
     * @return mixed
     */
    public function getQueueableId()
    {
        return $this->getKey();
    }

    /**
     * Get the primary key for the model.
     *
     * @return string
     */
    public function getKeyName()
    {
        return $this->primaryKey;
    }

    /**
     * Set the primary key for the model.
     *
     * @param  string  $key
     * @return $this
     */
    public function setKeyName($key)
    {
        $this->primaryKey = $key;

        return $this;
    }

    /**
     * Get the table qualified key name.
     *
     * @return string
     */
    public function getQualifiedKeyName()
    {
        return $this->getTable().'.'.$this->getKeyName();
    }

    /**
     * Get the value of the model's route key.
     *
     * @return mixed
     */
    public function getRouteKey()
    {
        return $this->getAttribute($this->getRouteKeyName());
    }

    /**
     * Get the route key for the model.
     *
     * @return string
     */
    public function getRouteKeyName()
    {
        return $this->getKeyName();
    }

    /**
     * Determine if the model uses timestamps.
     *
     * @return bool
     */
    public function usesTimestamps()
    {
        return $this->timestamps;
    }

    /**
     * Get the polymorphic relationship columns.
     *
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @return array
     */
    protected function getMorphs($name, $type, $id)
    {
        $type = $type ?: $name.'_type';

        $id = $id ?: $name.'_id';

        return [$type, $id];
    }

    /**
     * Get the class name for polymorphic relations.
     *
     * @return string
     */
    public function getMorphClass()
    {
        $morphMap = Relation::morphMap();

        $class = get_class($this);

        if (! empty($morphMap) && in_array($class, $morphMap)) {
            return array_search($class, $morphMap, true);
        }

        return $this->morphClass ?: $class;
    }

    /**
     * Get the number of models to return per page.
     *
     * @return int
     */
    public function getPerPage()
    {
        return $this->perPage;
    }

    /**
     * Set the number of models to return per page.
     *
     * @param  int  $perPage
     * @return $this
     */
    public function setPerPage($perPage)
    {
        $this->perPage = $perPage;

        return $this;
    }

    /**
     * Get the default foreign key name for the model.
     *
     * @return string
     */
    public function getForeignKey()
    {
        return Str::snake(class_basename($this)).'_id';
    }

    /**
     * Get the hidden attributes for the model.
     *
     * @return array
     */
    public function getHidden()
    {
        return $this->hidden;
    }

    /**
     * Set the hidden attributes for the model.
     *
     * @param  array  $hidden
     * @return $this
     */
    public function setHidden(array $hidden)
    {
        $this->hidden = $hidden;

        return $this;
    }

    /**
     * Add hidden attributes for the model.
     *
     * @param  array|string|null  $attributes
     * @return void
     */
    public function addHidden($attributes = null)
    {
        $attributes = is_array($attributes) ? $attributes : func_get_args();

        $this->hidden = array_merge($this->hidden, $attributes);
    }

    /**
     * Make the given, typically hidden, attributes visible.
     *
     * @param  array|string  $attributes
     * @return $this
     */
    public function withHidden($attributes)
    {
        $this->hidden = array_diff($this->hidden, (array) $attributes);

        return $this;
    }

    /**
     * Get the visible attributes for the model.
     *
     * @return array
     */
    public function getVisible()
    {
        return $this->visible;
    }

    /**
     * Set the visible attributes for the model.
     *
     * @param  array  $visible
     * @return $this
     */
    public function setVisible(array $visible)
    {
        $this->visible = $visible;

        return $this;
    }

    /**
     * Add visible attributes for the model.
     *
     * @param  array|string|null  $attributes
     * @return void
     */
    public function addVisible($attributes = null)
    {
        $attributes = is_array($attributes) ? $attributes : func_get_args();

        $this->visible = array_merge($this->visible, $attributes);
    }

    /**
     * Set the accessors to append to model arrays.
     *
     * @param  array  $appends
     * @return $this
     */
    public function setAppends(array $appends)
    {
        $this->appends = $appends;

        return $this;
    }

    /**
     * Get the fillable attributes for the model.
     *
     * @return array
     */
    public function getFillable()
    {
        return $this->fillable;
    }

    /**
     * Set the fillable attributes for the model.
     *
     * @param  array  $fillable
     * @return $this
     */
    public function fillable(array $fillable)
    {
        $this->fillable = $fillable;

        return $this;
    }

    /**
     * Get the guarded attributes for the model.
     *
     * @return array
     */
    public function getGuarded()
    {
        return $this->guarded;
    }

    /**
     * Set the guarded attributes for the model.
     *
     * @param  array  $guarded
     * @return $this
     */
    public function guard(array $guarded)
    {
        $this->guarded = $guarded;

        return $this;
    }

    /**
     * Disable all mass assignable restrictions.
     *
     * @param  bool  $state
     * @return void
     */
    public static function unguard($state = true)
    {
        static::$unguarded = $state;
    }

    /**
     * Enable the mass assignment restrictions.
     *
     * @return void
     */
    public static function reguard()
    {
        static::$unguarded = false;
    }

    /**
     * Determine if current state is "unguarded".
     *
     * @return bool
     */
    public static function isUnguarded()
    {
        return static::$unguarded;
    }

    /**
     * Run the given callable while being unguarded.
     *
     * @param  callable  $callback
     * @return mixed
     */
    public static function unguarded(callable $callback)
    {
        if (static::$unguarded) {
            return $callback();
        }

        static::unguard();

        try {
            return $callback();
        } finally {
            static::reguard();
        }
    }

    /**
     * Determine if the given attribute may be mass assigned.
     *
     * @param  string  $key
     * @return bool
     */
    public function isFillable($key)
    {
        if (static::$unguarded) {
            return true;
        }

        // If the key is in the "fillable" array, we can of course assume that it's
        // a fillable attribute. Otherwise, we will check the guarded array when
        // we need to determine if the attribute is black-listed on the model.
        if (in_array($key, $this->fillable)) {
            return true;
        }

        if ($this->isGuarded($key)) {
            return false;
        }

        return empty($this->fillable) && ! Str::startsWith($key, '_');
    }

    /**
     * Determine if the given key is guarded.
     *
     * @param  string  $key
     * @return bool
     */
    public function isGuarded($key)
    {
        return in_array($key, $this->guarded) || $this->guarded == ['*'];
    }

    /**
     * Determine if the model is totally guarded.
     *
     * @return bool
     */
    public function totallyGuarded()
    {
        return count($this->fillable) == 0 && $this->guarded == ['*'];
    }

    /**
     * Remove the table name from a given key.
     *
     * @param  string  $key
     * @return string
     */
    protected function removeTableFromKey($key)
    {
        if (! Str::contains($key, '.')) {
            return $key;
        }

        return last(explode('.', $key));
    }

    /**
     * Get the relationships that are touched on save.
     *
     * @return array
     */
    public function getTouchedRelations()
    {
        return $this->touches;
    }

    /**
     * Set the relationships that are touched on save.
     *
     * @param  array  $touches
     * @return $this
     */
    public function setTouchedRelations(array $touches)
    {
        $this->touches = $touches;

        return $this;
    }

    /**
     * Get the value indicating whether the IDs are incrementing.
     *
     * @return bool
     */
    public function getIncrementing()
    {
        return $this->incrementing;
    }

    /**
     * Set whether IDs are incrementing.
     *
     * @param  bool  $value
     * @return $this
     */
    public function setIncrementing($value)
    {
        $this->incrementing = $value;

        return $this;
    }

    /**
     * Convert the model instance to JSON.
     *
     * @param  int  $options
     * @return string
     */
    public function toJson($options = 0)
    {
        return json_encode($this->jsonSerialize(), $options);
    }

    /**
     * Convert the object into something JSON serializable.
     *
     * @return array
     */
    public function jsonSerialize()
    {
        return $this->toArray();
    }

    /**
     * Convert the model instance to an array.
     *
     * @return array
     */
    public function toArray()
    {
        $attributes = $this->attributesToArray();

        return array_merge($attributes, $this->relationsToArray());
    }

    /**
     * Convert the model's attributes to an array.
     *
     * @return array
     */
    public function attributesToArray()
    {
        $attributes = $this->getArrayableAttributes();

        // If an attribute is a date, we will cast it to a string after converting it
        // to a DateTime / Carbon instance. This is so we will get some consistent
        // formatting while accessing attributes vs. arraying / JSONing a model.
        foreach ($this->getDates() as $key) {
            if (! isset($attributes[$key])) {
                continue;
            }

            $attributes[$key] = $this->serializeDate(
                $this->asDateTime($attributes[$key])
            );
        }

        $mutatedAttributes = $this->getMutatedAttributes();

        // We want to spin through all the mutated attributes for this model and call
        // the mutator for the attribute. We cache off every mutated attributes so
        // we don't have to constantly check on attributes that actually change.
        foreach ($mutatedAttributes as $key) {
            if (! array_key_exists($key, $attributes)) {
                continue;
            }

            $attributes[$key] = $this->mutateAttributeForArray(
                $key, $attributes[$key]
            );
        }

        // Next we will handle any casts that have been setup for this model and cast
        // the values to their appropriate type. If the attribute has a mutator we
        // will not perform the cast on those attributes to avoid any confusion.
        foreach ($this->casts as $key => $value) {
            if (! array_key_exists($key, $attributes) ||
                in_array($key, $mutatedAttributes)) {
                continue;
            }

            $attributes[$key] = $this->castAttribute(
                $key, $attributes[$key]
            );
        }

        // Here we will grab all of the appended, calculated attributes to this model
        // as these attributes are not really in the attributes array, but are run
        // when we need to array or JSON the model for convenience to the coder.
        foreach ($this->getArrayableAppends() as $key) {
            $attributes[$key] = $this->mutateAttributeForArray($key, null);
        }

        return $attributes;
    }

    /**
     * Get an attribute array of all arrayable attributes.
     *
     * @return array
     */
    protected function getArrayableAttributes()
    {
        return $this->getArrayableItems($this->attributes);
    }

    /**
     * Get all of the appendable values that are arrayable.
     *
     * @return array
     */
    protected function getArrayableAppends()
    {
        if (! count($this->appends)) {
            return [];
        }

        return $this->getArrayableItems(
            array_combine($this->appends, $this->appends)
        );
    }

    /**
     * Get the model's relationships in array form.
     *
     * @return array
     */
    public function relationsToArray()
    {
        $attributes = [];

        foreach ($this->getArrayableRelations() as $key => $value) {
            // If the values implements the Arrayable interface we can just call this
            // toArray method on the instances which will convert both models and
            // collections to their proper array form and we'll set the values.
            if ($value instanceof Arrayable) {
                $relation = $value->toArray();
            }

            // If the value is null, we'll still go ahead and set it in this list of
            // attributes since null is used to represent empty relationships if
            // if it a has one or belongs to type relationships on the models.
            elseif (is_null($value)) {
                $relation = $value;
            }

            // If the relationships snake-casing is enabled, we will snake case this
            // key so that the relation attribute is snake cased in this returned
            // array to the developers, making this consistent with attributes.
            if (static::$snakeAttributes) {
                $key = Str::snake($key);
            }

            // If the relation value has been set, we will set it on this attributes
            // list for returning. If it was not arrayable or null, we'll not set
            // the value on the array because it is some type of invalid value.
            if (isset($relation) || is_null($value)) {
                $attributes[$key] = $relation;
            }

            unset($relation);
        }

        return $attributes;
    }

    /**
     * Get an attribute array of all arrayable relations.
     *
     * @return array
     */
    protected function getArrayableRelations()
    {
        return $this->getArrayableItems($this->relations);
    }

    /**
     * Get an attribute array of all arrayable values.
     *
     * @param  array  $values
     * @return array
     */
    protected function getArrayableItems(array $values)
    {
        if (count($this->getVisible()) > 0) {
            return array_intersect_key($values, array_flip($this->getVisible()));
        }

        return array_diff_key($values, array_flip($this->getHidden()));
    }

    /**
     * Get an attribute from the model.
     *
     * @param  string  $key
     * @return mixed
     */
    public function getAttribute($key)
    {
        if (array_key_exists($key, $this->attributes) || $this->hasGetMutator($key)) {
            return $this->getAttributeValue($key);
        }

        return $this->getRelationValue($key);
    }

    /**
     * Get a plain attribute (not a relationship).
     *
     * @param  string  $key
     * @return mixed
     */
    public function getAttributeValue($key)
    {
        $value = $this->getAttributeFromArray($key);

        // If the attribute has a get mutator, we will call that then return what
        // it returns as the value, which is useful for transforming values on
        // retrieval from the model to a form that is more useful for usage.
        if ($this->hasGetMutator($key)) {
            return $this->mutateAttribute($key, $value);
        }

        // If the attribute exists within the cast array, we will convert it to
        // an appropriate native PHP type dependant upon the associated value
        // given with the key in the pair. Dayle made this comment line up.
        if ($this->hasCast($key)) {
            $value = $this->castAttribute($key, $value);
        }

        // If the attribute is listed as a date, we will convert it to a DateTime
        // instance on retrieval, which makes it quite convenient to work with
        // date fields without having to create a mutator for each property.
        elseif (in_array($key, $this->getDates())) {
            if (! is_null($value)) {
                return $this->asDateTime($value);
            }
        }

        return $value;
    }

    /**
     * Get a relationship.
     *
     * @param  string  $key
     * @return mixed
     */
    public function getRelationValue($key)
    {
        // If the key already exists in the relationships array, it just means the
        // relationship has already been loaded, so we'll just return it out of
        // here because there is no need to query within the relations twice.
        if ($this->relationLoaded($key)) {
            return $this->relations[$key];
        }

        // If the "attribute" exists as a method on the model, we will just assume
        // it is a relationship and will load and return results from the query
        // and hydrate the relationship's value on the "relationships" array.
        if (method_exists($this, $key)) {
            return $this->getRelationshipFromMethod($key);
        }
    }

    /**
     * Get an attribute from the $attributes array.
     *
     * @param  string  $key
     * @return mixed
     */
    protected function getAttributeFromArray($key)
    {
        if (array_key_exists($key, $this->attributes)) {
            return $this->attributes[$key];
        }
    }

    /**
     * Get a relationship value from a method.
     *
     * @param  string  $method
     * @return mixed
     *
     * @throws \LogicException
     */
    protected function getRelationshipFromMethod($method)
    {
        $relations = $this->$method();

        if (! $relations instanceof Relation) {
            throw new LogicException('Relationship method must return an object of type '
                .'Illuminate\Database\Eloquent\Relations\Relation');
        }

        return $this->relations[$method] = $relations->getResults();
    }

    /**
     * Determine if a get mutator exists for an attribute.
     *
     * @param  string  $key
     * @return bool
     */
    public function hasGetMutator($key)
    {
        return method_exists($this, 'get'.Str::studly($key).'Attribute');
    }

    /**
     * Get the value of an attribute using its mutator.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function mutateAttribute($key, $value)
    {
        return $this->{'get'.Str::studly($key).'Attribute'}($value);
    }

    /**
     * Get the value of an attribute using its mutator for array conversion.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function mutateAttributeForArray($key, $value)
    {
        $value = $this->mutateAttribute($key, $value);

        return $value instanceof Arrayable ? $value->toArray() : $value;
    }

    /**
     * Determine whether an attribute should be cast to a native type.
     *
     * @param  string  $key
     * @return bool
     */
    protected function hasCast($key)
    {
        return array_key_exists($key, $this->casts);
    }

    /**
     * Determine whether a value is Date / DateTime castable for inbound manipulation.
     *
     * @param  string  $key
     * @return bool
     */
    protected function isDateCastable($key)
    {
        return $this->hasCast($key) &&
               in_array($this->getCastType($key), ['date', 'datetime'], true);
    }

    /**
     * Determine whether a value is JSON castable for inbound manipulation.
     *
     * @param  string  $key
     * @return bool
     */
    protected function isJsonCastable($key)
    {
        return $this->hasCast($key) &&
               in_array($this->getCastType($key), ['array', 'json', 'object', 'collection'], true);
    }

    /**
     * Get the type of cast for a model attribute.
     *
     * @param  string  $key
     * @return string
     */
    protected function getCastType($key)
    {
        return trim(strtolower($this->casts[$key]));
    }

    /**
     * Cast an attribute to a native PHP type.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function castAttribute($key, $value)
    {
        if (is_null($value)) {
            return $value;
        }

        switch ($this->getCastType($key)) {
            case 'int':
            case 'integer':
                return (int) $value;
            case 'real':
            case 'float':
            case 'double':
                return (float) $value;
            case 'string':
                return (string) $value;
            case 'bool':
            case 'boolean':
                return (bool) $value;
            case 'object':
                return $this->fromJson($value, true);
            case 'array':
            case 'json':
                return $this->fromJson($value);
            case 'collection':
                return new BaseCollection($this->fromJson($value));
            case 'date':
            case 'datetime':
                return $this->asDateTime($value);
            default:
                return $value;
        }
    }

    /**
     * Set a given attribute on the model.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return $this
     */
    public function setAttribute($key, $value)
    {
        // First we will check for the presence of a mutator for the set operation
        // which simply lets the developers tweak the attribute as it is set on
        // the model, such as "json_encoding" an listing of data for storage.
        if ($this->hasSetMutator($key)) {
            $method = 'set'.Str::studly($key).'Attribute';

            return $this->{$method}($value);
        }

        // If an attribute is listed as a "date", we'll convert it from a DateTime
        // instance into a form proper for storage on the database tables using
        // the connection grammar's date format. We will auto set the values.
        elseif ($value && (in_array($key, $this->getDates()) || $this->isDateCastable($key))) {
            $value = $this->fromDateTime($value);
        }

        if ($this->isJsonCastable($key) && ! is_null($value)) {
            $value = $this->asJson($value);
        }

        $this->attributes[$key] = $value;

        return $this;
    }

    /**
     * Determine if a set mutator exists for an attribute.
     *
     * @param  string  $key
     * @return bool
     */
    public function hasSetMutator($key)
    {
        return method_exists($this, 'set'.Str::studly($key).'Attribute');
    }

    /**
     * Get the attributes that should be converted to dates.
     *
     * @return array
     */
    public function getDates()
    {
        $defaults = [static::CREATED_AT, static::UPDATED_AT];

        return $this->timestamps ? array_merge($this->dates, $defaults) : $this->dates;
    }

    /**
     * Convert a DateTime to a storable string.
     *
     * @param  \DateTime|int  $value
     * @return string
     */
    public function fromDateTime($value)
    {
        $format = $this->getDateFormat();

        $value = $this->asDateTime($value);

        return $value->format($format);
    }

    /**
     * Return a timestamp as DateTime object.
     *
     * @param  mixed  $value
     * @return \Carbon\Carbon
     */
    protected function asDateTime($value)
    {
        // If this value is already a Carbon instance, we shall just return it as is.
        // This prevents us having to reinstantiate a Carbon instance when we know
        // it already is one, which wouldn't be fulfilled by the DateTime check.
        if ($value instanceof Carbon) {
            return $value;
        }

        // If the value is already a DateTime instance, we will just skip the rest of
        // these checks since they will be a waste of time, and hinder performance
        // when checking the field. We will just return the DateTime right away.
        if ($value instanceof DateTime) {
            return Carbon::instance($value);
        }

        // If this value is an integer, we will assume it is a UNIX timestamp's value
        // and format a Carbon object from this timestamp. This allows flexibility
        // when defining your date fields as they might be UNIX timestamps here.
        if (is_numeric($value)) {
            return Carbon::createFromTimestamp($value);
        }

        // If the value is in simply year, month, day format, we will instantiate the
        // Carbon instances from that format. Again, this provides for simple date
        // fields on the database, while still supporting Carbonized conversion.
        if (preg_match('/^(\d{4})-(\d{2})-(\d{2})$/', $value)) {
            return Carbon::createFromFormat('Y-m-d', $value)->startOfDay();
        }

        // Finally, we will just assume this date is in the format used by default on
        // the database connection and use that format to create the Carbon object
        // that is returned back out to the developers after we convert it here.
        return Carbon::createFromFormat($this->getDateFormat(), $value);
    }

    /**
     * Prepare a date for array / JSON serialization.
     *
     * @param  \DateTime  $date
     * @return string
     */
    protected function serializeDate(DateTime $date)
    {
        return $date->format($this->getDateFormat());
    }

    /**
     * Get the format for database stored dates.
     *
     * @return string
     */
    protected function getDateFormat()
    {
        return $this->dateFormat ?: $this->getConnection()->getQueryGrammar()->getDateFormat();
    }

    /**
     * Set the date format used by the model.
     *
     * @param  string  $format
     * @return $this
     */
    public function setDateFormat($format)
    {
        $this->dateFormat = $format;

        return $this;
    }

    /**
     * Encode the given value as JSON.
     *
     * @param  mixed  $value
     * @return string
     */
    protected function asJson($value)
    {
        return json_encode($value);
    }

    /**
     * Decode the given JSON back into an array or object.
     *
     * @param  string  $value
     * @param  bool  $asObject
     * @return mixed
     */
    public function fromJson($value, $asObject = false)
    {
        return json_decode($value, ! $asObject);
    }

    /**
     * Clone the model into a new, non-existing instance.
     *
     * @param  array|null  $except
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function replicate(array $except = null)
    {
        $except = $except ?: [
            $this->getKeyName(),
            $this->getCreatedAtColumn(),
            $this->getUpdatedAtColumn(),
        ];

        $attributes = Arr::except($this->attributes, $except);

        with($instance = new static)->setRawAttributes($attributes);

        return $instance->setRelations($this->relations);
    }

    /**
     * Get all of the current attributes on the model.
     *
     * @return array
     */
    public function getAttributes()
    {
        return $this->attributes;
    }

    /**
     * Set the array of model attributes. No checking is done.
     *
     * @param  array  $attributes
     * @param  bool  $sync
     * @return $this
     */
    public function setRawAttributes(array $attributes, $sync = false)
    {
        $this->attributes = $attributes;

        if ($sync) {
            $this->syncOriginal();
        }

        return $this;
    }

    /**
     * Get the model's original attribute values.
     *
     * @param  string|null  $key
     * @param  mixed  $default
     * @return array
     */
    public function getOriginal($key = null, $default = null)
    {
        return Arr::get($this->original, $key, $default);
    }

    /**
     * Sync the original attributes with the current.
     *
     * @return $this
     */
    public function syncOriginal()
    {
        $this->original = $this->attributes;

        return $this;
    }

    /**
     * Sync a single original attribute with its current value.
     *
     * @param  string  $attribute
     * @return $this
     */
    public function syncOriginalAttribute($attribute)
    {
        $this->original[$attribute] = $this->attributes[$attribute];

        return $this;
    }

    /**
     * Determine if the model or given attribute(s) have been modified.
     *
     * @param  array|string|null  $attributes
     * @return bool
     */
    public function isDirty($attributes = null)
    {
        $dirty = $this->getDirty();

        if (is_null($attributes)) {
            return count($dirty) > 0;
        }

        if (! is_array($attributes)) {
            $attributes = func_get_args();
        }

        foreach ($attributes as $attribute) {
            if (array_key_exists($attribute, $dirty)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Get the attributes that have been changed since last sync.
     *
     * @return array
     */
    public function getDirty()
    {
        $dirty = [];

        foreach ($this->attributes as $key => $value) {
            if (! array_key_exists($key, $this->original)) {
                $dirty[$key] = $value;
            } elseif ($value !== $this->original[$key] &&
                                 ! $this->originalIsNumericallyEquivalent($key)) {
                $dirty[$key] = $value;
            }
        }

        return $dirty;
    }

    /**
     * Determine if the new and old values for a given key are numerically equivalent.
     *
     * @param  string  $key
     * @return bool
     */
    protected function originalIsNumericallyEquivalent($key)
    {
        $current = $this->attributes[$key];

        $original = $this->original[$key];

        return is_numeric($current) && is_numeric($original) && strcmp((string) $current, (string) $original) === 0;
    }

    /**
     * Get all the loaded relations for the instance.
     *
     * @return array
     */
    public function getRelations()
    {
        return $this->relations;
    }

    /**
     * Get a specified relationship.
     *
     * @param  string  $relation
     * @return mixed
     */
    public function getRelation($relation)
    {
        return $this->relations[$relation];
    }

    /**
     * Determine if the given relation is loaded.
     *
     * @param  string  $key
     * @return bool
     */
    public function relationLoaded($key)
    {
        return array_key_exists($key, $this->relations);
    }

    /**
     * Set the specific relationship in the model.
     *
     * @param  string  $relation
     * @param  mixed  $value
     * @return $this
     */
    public function setRelation($relation, $value)
    {
        $this->relations[$relation] = $value;

        return $this;
    }

    /**
     * Set the entire relations array on the model.
     *
     * @param  array  $relations
     * @return $this
     */
    public function setRelations(array $relations)
    {
        $this->relations = $relations;

        return $this;
    }

    /**
     * Get the database connection for the model.
     *
     * @return \Illuminate\Database\Connection
     */
    public function getConnection()
    {
        return static::resolveConnection($this->connection);
    }

    /**
     * Get the current connection name for the model.
     *
     * @return string
     */
    public function getConnectionName()
    {
        return $this->connection;
    }

    /**
     * Set the connection associated with the model.
     *
     * @param  string  $name
     * @return $this
     */
    public function setConnection($name)
    {
        $this->connection = $name;

        return $this;
    }

    /**
     * Resolve a connection instance.
     *
     * @param  string|null  $connection
     * @return \Illuminate\Database\Connection
     */
    public static function resolveConnection($connection = null)
    {
        return static::$resolver->connection($connection);
    }

    /**
     * Get the connection resolver instance.
     *
     * @return \Illuminate\Database\ConnectionResolverInterface
     */
    public static function getConnectionResolver()
    {
        return static::$resolver;
    }

    /**
     * Set the connection resolver instance.
     *
     * @param  \Illuminate\Database\ConnectionResolverInterface  $resolver
     * @return void
     */
    public static function setConnectionResolver(Resolver $resolver)
    {
        static::$resolver = $resolver;
    }

    /**
     * Unset the connection resolver for models.
     *
     * @return void
     */
    public static function unsetConnectionResolver()
    {
        static::$resolver = null;
    }

    /**
     * Get the event dispatcher instance.
     *
     * @return \Illuminate\Contracts\Events\Dispatcher
     */
    public static function getEventDispatcher()
    {
        return static::$dispatcher;
    }

    /**
     * Set the event dispatcher instance.
     *
     * @param  \Illuminate\Contracts\Events\Dispatcher  $dispatcher
     * @return void
     */
    public static function setEventDispatcher(Dispatcher $dispatcher)
    {
        static::$dispatcher = $dispatcher;
    }

    /**
     * Unset the event dispatcher for models.
     *
     * @return void
     */
    public static function unsetEventDispatcher()
    {
        static::$dispatcher = null;
    }

    /**
     * Get the mutated attributes for a given instance.
     *
     * @return array
     */
    public function getMutatedAttributes()
    {
        $class = get_class($this);

        if (! isset(static::$mutatorCache[$class])) {
            static::cacheMutatedAttributes($class);
        }

        return static::$mutatorCache[$class];
    }

    /**
     * Extract and cache all the mutated attributes of a class.
     *
     * @param  string  $class
     * @return void
     */
    public static function cacheMutatedAttributes($class)
    {
        $mutatedAttributes = [];

        // Here we will extract all of the mutated attributes so that we can quickly
        // spin through them after we export models to their array form, which we
        // need to be fast. This'll let us know the attributes that can mutate.
        if (preg_match_all('/(?<=^|;)get([^;]+?)Attribute(;|$)/', implode(';', get_class_methods($class)), $matches)) {
            foreach ($matches[1] as $match) {
                if (static::$snakeAttributes) {
                    $match = Str::snake($match);
                }

                $mutatedAttributes[] = lcfirst($match);
            }
        }

        static::$mutatorCache[$class] = $mutatedAttributes;
    }

    /**
     * Dynamically retrieve attributes on the model.
     *
     * @param  string  $key
     * @return mixed
     */
    public function __get($key)
    {
        return $this->getAttribute($key);
    }

    /**
     * Dynamically set attributes on the model.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return void
     */
    public function __set($key, $value)
    {
        $this->setAttribute($key, $value);
    }

    /**
     * Determine if the given attribute exists.
     *
     * @param  mixed  $offset
     * @return bool
     */
    public function offsetExists($offset)
    {
        return isset($this->$offset);
    }

    /**
     * Get the value for a given offset.
     *
     * @param  mixed  $offset
     * @return mixed
     */
    public function offsetGet($offset)
    {
        return $this->$offset;
    }

    /**
     * Set the value for a given offset.
     *
     * @param  mixed  $offset
     * @param  mixed  $value
     * @return void
     */
    public function offsetSet($offset, $value)
    {
        $this->$offset = $value;
    }

    /**
     * Unset the value for a given offset.
     *
     * @param  mixed  $offset
     * @return void
     */
    public function offsetUnset($offset)
    {
        unset($this->$offset);
    }

    /**
     * Determine if an attribute or relation exists on the model.
     *
     * @param  string  $key
     * @return bool
     */
    public function __isset($key)
    {
        if (isset($this->attributes[$key]) || isset($this->relations[$key])) {
            return true;
        }

        if (method_exists($this, $key) && $this->$key && isset($this->relations[$key])) {
            return true;
        }

        return $this->hasGetMutator($key) && ! is_null($this->getAttributeValue($key));
    }

    /**
     * Unset an attribute on the model.
     *
     * @param  string  $key
     * @return void
     */
    public function __unset($key)
    {
        unset($this->attributes[$key], $this->relations[$key]);
    }

    /**
     * Handle dynamic method calls into the model.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        if (in_array($method, ['increment', 'decrement'])) {
            return call_user_func_array([$this, $method], $parameters);
        }

        $query = $this->newQuery();

        return call_user_func_array([$query, $method], $parameters);
    }

    /**
     * Handle dynamic static method calls into the method.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public static function __callStatic($method, $parameters)
    {
        $instance = new static;

        return call_user_func_array([$instance, $method], $parameters);
    }

    /**
     * Convert the model to its string representation.
     *
     * @return string
     */
    public function __toString()
    {
        return $this->toJson();
    }

    /**
     * When a model is being unserialized, check if it needs to be booted.
     *
     * @return void
     */
    public function __wakeup()
    {
        $this->bootIfNotBooted();
    }
}