// Copyright 2017 Google LLC. All Rights Reserved.
//
// 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 main contains the implementation and entry point for the createtree
// command.
//
// Example usage:
// $ ./createtree --admin_server=host:port
//
// The command outputs the tree ID of the created tree to stdout, or an error to
// stderr in case of failure. The output is minimal to allow for easy usage in
// automated scripts.
//
// Several flags are provided to configure the create tree, most of which try to
// assume reasonable defaults.
package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"time"

	"github.com/google/trillian"
	"github.com/google/trillian/client"
	"github.com/google/trillian/client/rpcflags"
	"github.com/google/trillian/cmd"
	"google.golang.org/grpc"
	"google.golang.org/protobuf/types/known/durationpb"
	"k8s.io/klog/v2"
)

var (
	adminServerAddr = flag.String("admin_server", "", "Address of the gRPC Trillian Admin Server (host:port)")
	rpcDeadline     = flag.Duration("rpc_deadline", time.Second*10, "Deadline for RPC requests")

	treeState       = flag.String("tree_state", trillian.TreeState_ACTIVE.String(), "State of the new tree")
	treeType        = flag.String("tree_type", trillian.TreeType_LOG.String(), "Type of the new tree")
	displayName     = flag.String("display_name", "", "Display name of the new tree")
	description     = flag.String("description", "", "Description of the new tree")
	maxRootDuration = flag.Duration("max_root_duration", time.Hour, "Interval after which a new signed root is produced despite no submissions; zero means never")

	configFile = flag.String("config", "", "Config file containing flags, file contents can be overridden by command line flags")

	errAdminAddrNotSet = errors.New("empty --admin_server, please provide the Admin server host:port")
)

// TODO(Martin2112): Pass everything needed into this and don't refer to flags.
func createTree(ctx context.Context) (*trillian.Tree, error) {
	if *adminServerAddr == "" {
		return nil, errAdminAddrNotSet
	}

	req, err := newRequest()
	if err != nil {
		return nil, err
	}

	dialOpts, err := rpcflags.NewClientDialOptionsFromFlags()
	if err != nil {
		return nil, fmt.Errorf("failed to determine dial options: %v", err)
	}

	conn, err := grpc.Dial(*adminServerAddr, dialOpts...)
	if err != nil {
		return nil, fmt.Errorf("failed to dial %v: %v", *adminServerAddr, err)
	}
	defer func() {
		if err := conn.Close(); err != nil {
			klog.Errorf("Close(): %v", err)
		}
	}()

	adminClient := trillian.NewTrillianAdminClient(conn)
	logClient := trillian.NewTrillianLogClient(conn)

	return client.CreateAndInitTree(ctx, req, adminClient, logClient)
}

func newRequest() (*trillian.CreateTreeRequest, error) {
	ts, ok := trillian.TreeState_value[*treeState]
	if !ok {
		return nil, fmt.Errorf("unknown TreeState: %v", *treeState)
	}

	tt, ok := trillian.TreeType_value[*treeType]
	if !ok {
		return nil, fmt.Errorf("unknown TreeType: %v", *treeType)
	}

	ctr := &trillian.CreateTreeRequest{Tree: &trillian.Tree{
		TreeState:       trillian.TreeState(ts),
		TreeType:        trillian.TreeType(tt),
		DisplayName:     *displayName,
		Description:     *description,
		MaxRootDuration: durationpb.New(*maxRootDuration),
	}}
	klog.Infof("Creating tree %+v", ctr.Tree)

	return ctr, nil
}

func main() {
	klog.InitFlags(nil)
	flag.Parse()
	defer klog.Flush()

	if *configFile != "" {
		if err := cmd.ParseFlagFile(*configFile); err != nil {
			klog.Exitf("Failed to load flags from config file %q: %s", *configFile, err)
		}
	}

	ctx, cancel := context.WithTimeout(context.Background(), *rpcDeadline)
	defer cancel()
	tree, err := createTree(ctx)
	if err != nil {
		klog.Exitf("Failed to create tree: %v", err)
	}

	// DO NOT change the output format, scripts are meant to depend on it.
	// If you really want to change it, provide an output_format flag and
	// keep the default as-is.
	fmt.Println(tree.TreeId)
}