/*
Copyright (c) 2025 WuJingrun（吴京润）

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
 */
package f_util

import std.collection.{HashMap, ArrayList}
import f_exception.IllegalAccessException

/*
 * 策略模式的接口，所有策略都要实现此接口
 * N 是策略的标识，需要用N找到对应的策略，
 * S 是策略的具体实现，N与S需要一一对应
 * A 是执行策略的参数
 * R 是执行策略的结果
 */
public interface Strategy<N, A, R> where N <: Hashable & Equatable<N> {
    /**
     * 返回策略标识
     */
    prop name: N

    /**
     * 执行策略
     */
    func execute(arg: A): R
}

/*策略的集合*/
public class Strategies<N, A, R> where N <: Hashable & Equatable<N> {
    private let strategies = HashMap<N, Strategy<N, A, R>>()
    public init() {}

    /** 把指定策略注册进来*/
    public func register(strategy: Strategy<N, A, R>): Strategies<N, A, R> {
        strategies[strategy.name] = strategy
        this
    }
    public func register<S>(strategies: Iterable<S>): Unit where S <: Strategy<N, A, R> {
        for (s in strategies) {
            this.strategies[s.name] = s
        }
    }

    /**
     * 用指定的标识和参数执行策略，如果没有找到标识是name的策略会抛出base.IllegalAccessException
     */
    public func execute(name: N, arg: A): R {
        match (strategies.get(name)) {
            case Some(s) => s.execute(arg)
            case _ => throw IllegalAccessException("there is no strategy to match current condition")
        }
    }
}