package gtp

import (
	"errors"
	"fmt"
	"git.noahlan.cn/noahlan/ntool/narr"
	"git.noahlan.cn/noahlan/ntool/ncmd"
	"git.noahlan.cn/noahlan/ntool/nlog"
	"git.noahlan.cn/noahlan/ntool/nmath"
	"git.noahlan.cn/noahlan/ntool/nstr"
	"git.noahlan.cn/noahlan/ntool/nsys/atomic"
	"strings"
	"sync"
	"time"
)

var (
	DefaultMaxMessageId uint = 999
	DefaultTimeout           = 3 * time.Second
)

var ErrTimeout = errors.New("timeout")

type (
	Options struct {
		DevMode      bool          `json:",default=false"` // 开发模式
		MaxMessageId uint          `json:",default=999"`   // 最大消息ID
		Timeout      time.Duration `json:""`               // 单条命令最大等待时间，默认3s
	}
	Option func(options *Options)

	pendingMsg struct {
		chWait chan struct{}
		resp   *GTPResponse
	}

	GtpEngine struct {
		*Options

		Cmd        *ncmd.Cmd
		serializer *GTPSerializer
		mid        *atomic.AtomicInt64

		pendingMsg map[string]*pendingMsg

		mu sync.RWMutex
	}
)

func NewGtpEngine(opts ...Option) *GtpEngine {
	serializer := NewGTPSerializer()
	ret := &GtpEngine{
		Options: &Options{
			DevMode: false,
		},
		mid:        atomic.NewAtomicInt64(),
		pendingMsg: make(map[string]*pendingMsg),

		mu: sync.RWMutex{},
	}

	for _, opt := range opts {
		opt(ret.Options)
	}

	if ret.MaxMessageId == 0 {
		ret.MaxMessageId = DefaultMaxMessageId
	}
	if ret.Timeout == 0 {
		ret.Timeout = DefaultTimeout
	}

	ret.serializer = serializer
	ret.Cmd = ncmd.NewCmd(ncmd.WithOptions(&ncmd.Options{
		Marshaler:      serializer,
		Buffered:       false,
		CombinedOutput: false,
		Streaming:      true,
		LineBufferSize: ncmd.DEFAULT_LINE_BUFFER_SIZE,
		DevMode:        ret.DevMode,
	}))

	return ret
}

// Bind 绑定实例到id
func (e *GtpEngine) Bind(id int64) {
	e.Cmd.Session.SetId(id)
	// Set in_use flag
	e.Cmd.Session.SetAttribute(KeyInUse, true)
}

// Release 释放示例，以便其它调用
func (e *GtpEngine) Release() {
	e.Cmd.Session.SetId(0)
	e.Cmd.Session.SetAttribute(KeyInUse, false)
}

func (e *GtpEngine) Session() *ncmd.Session {
	return e.Cmd.Session
}

func (e *GtpEngine) StartSafe(name string, args ...string) <-chan ncmd.Status {
	ret := e.Cmd.StatusChan()
	if !e.Cmd.Started() {
		if !e.Cmd.Stopped() {
			ret = e.Start(name, args...)
		} else {
			// 被停止
			e.Cmd = e.Cmd.Clone()
			ret = e.Start(name, args...)
		}
	}

	return ret
}

func (e *GtpEngine) Start(name string, args ...string) <-chan ncmd.Status {
	statusChan := e.Cmd.Start(name, args...)

	go e.handleMessage()

	return statusChan
}

func (e *GtpEngine) Send(id, command string, args ...string) (*GTPResponse, error) {
	if len(id) == 0 || len(id) > 3 {
		id = e.nextId()
	}

	pMsg := &pendingMsg{
		chWait: make(chan struct{}, 1),
	}
	e.mu.Lock()
	e.pendingMsg[id] = pMsg
	e.mu.Unlock()

	err := e.Cmd.Send(&GTPCommand{
		ID:   id,
		Cmd:  command,
		Args: args,
	})
	if err != nil {
		return nil, err
	}

	// waiting pending message with timeout
	timer := time.NewTimer(e.Timeout)

	select {
	case <-timer.C:
		// error
		e.mu.Lock()
		delete(e.pendingMsg, id)
		e.mu.Unlock()

		return nil, ErrTimeout
	case <-pMsg.chWait:
		return pMsg.resp, nil
	}
}

func (e *GtpEngine) nextId() string {
	idInt := e.mid.IncrementAndGet()
	if idInt > int64(e.MaxMessageId) {
		e.mid.Reset()
		idInt = e.mid.IncrementAndGet()
	}
	return nstr.SafeString(idInt)
}

func (e *GtpEngine) handleMessage() {
	for e.Cmd.Stdout != nil || e.Cmd.Stderr != nil {
		select {
		case line, open := <-e.Cmd.Stdout:
			if !open {
				e.Cmd.Stdout = nil
				continue
			}
			//if e.DevMode {
			//	nlog.Debugf("接收单条消息: %s", line)
			//}

			resp, ok := e.serializer.Unmarshal(line)
			if !ok {
				continue
			}
			if e.DevMode {
				nlog.Debugf("接收完整消息: %+v", resp)
			}

			e.mu.RLock()
			pMsg, ok := e.pendingMsg[resp.ID]
			e.mu.RUnlock()
			if !ok {
				continue
			}

			pMsg.resp = resp
			pMsg.chWait <- struct{}{}
		case line, open := <-e.Cmd.Stderr:
			if !open {
				e.Cmd.Stdout = nil
				continue
			}
			nlog.Errorf("错误消息: %s\n", line)
		}
	}
}

// Name 查看gtp软件名称
func (e *GtpEngine) Name() string {
	cmd := "name"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return "unknown"
	}
	return resp.Content
}

// Version 查看gtp软件版本
func (e *GtpEngine) Version() string {
	cmd := "version"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return "0"
	}
	return resp.Content
}

// ProtocolVersion 查看gtp协议版本
func (e *GtpEngine) ProtocolVersion() string {
	cmd := "protocol_version"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return "1"
	}
	return resp.Content
}

// ListCommands 列举gtp软件可用命令列表
func (e *GtpEngine) ListCommands() []string {
	cmd := "list_commands"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return []string{}
	}
	return strings.Split(resp.Content, "\n")
}

// KnowCommand 判断命令是否支持
func (e *GtpEngine) KnowCommand(cmd string) bool {
	command := fmt.Sprintf("known_command %s", cmd)
	resp, err := e.Send(e.nextId(), command)
	if !e.Check(resp, err, command) {
		return false
	}
	if strings.ToLower(strings.TrimSpace(resp.Content)) != "true" {
		return false
	}
	return true
}

// Komi 设置贴目
func (e *GtpEngine) Komi(komi float64) bool {
	cmd := fmt.Sprintf("komi %.1f", komi)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// BoardSize 设置棋盘大小
func (e *GtpEngine) BoardSize(size int) bool {
	cmd := fmt.Sprintf("boardsize %d", size)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// ClearBoard 清理棋盘
func (e *GtpEngine) ClearBoard() bool {
	cmd := "clear_board"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// Play 下棋 color: B/W vex: A1
func (e *GtpEngine) Play(color, vex string) bool {
	cmd := fmt.Sprintf("play %s %s", color, vex)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// GenMove 生成一手棋 color: B/W
func (e *GtpEngine) GenMove(color string) string {
	cmd := fmt.Sprintf("genmove %s", color)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return ""
	}
	return resp.Content
}

// SetFreeHandicap 设置自由的让子点位
func (e *GtpEngine) SetFreeHandicap(vexArr ...string) bool {
	if len(vexArr) < 2 {
		return true
	}
	cmd := fmt.Sprintf("set_free_handicap %s", strings.Join(vexArr, " "))
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// Sync 同步
// handicaps: points of all handicaps
// plays: [][2]string -> [["B","A1"]]
func (e *GtpEngine) Sync(size int, komi float64, handicaps []string, plays [][]string) bool {
	// 1. komi
	// 2. boardsize
	// 3. clear_board
	// 4. set_free_handicap pos1 pos2 ...
	// 5~n. play X XX

	playAllFn := func() bool {
		return narr.Every(plays, func(_ int, v []string) bool {
			if len(v) < 2 {
				return false
			}
			color, pos := v[0], v[1]
			return e.Play(color, pos)
		})
	}

	return e.Komi(komi) &&
		e.BoardSize(size) &&
		e.ClearBoard() &&
		e.SetFreeHandicap(handicaps...) &&
		playAllFn()
}

// LoadSgf 加载SGF文件
func (e *GtpEngine) LoadSgf(file string) bool {
	cmd := fmt.Sprintf("loadsgf %s", file)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// FinalStatusList 获取当前盘面形势判断
func (e *GtpEngine) FinalStatusList(cmd string) string {
	command := fmt.Sprintf("final_status_list %s", cmd)
	resp, err := e.Send(e.nextId(), command)
	if !e.Check(resp, err, command) {
		return ""
	}
	return resp.Content
}

// SetLevel 设置AI级别
func (e *GtpEngine) SetLevel(level int) bool {
	cmd := fmt.Sprintf("level %d", level)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// SetRandomSeed 设置AI随机数
func (e *GtpEngine) SetRandomSeed(seed int) bool {
	cmd := fmt.Sprintf("set_random_seed %d", seed)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// ShowBoard 显示棋盘
func (e *GtpEngine) ShowBoard() string {
	cmd := "showboard"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return ""
	}
	return resp.Content
}

// PrintSgf 打印SGF
func (e *GtpEngine) PrintSgf() string {
	cmd := "printsgf"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return ""
	}
	return resp.Content
}

// TimeSetting 设置时间规则
func (e *GtpEngine) TimeSetting(baseTime, byoTime, byoStones int) bool {
	cmd := fmt.Sprintf("time_settings %d %d %d", baseTime, byoTime, byoStones)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// KGSTimeSetting 设置KGS time
func (e *GtpEngine) KGSTimeSetting(mainTime, readTime, readLimit int) bool {
	cmd := fmt.Sprintf("kgs-time_settings byoyomi %d %d %d", mainTime, readTime, readLimit)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// FinalScore 获取结果
// returns winner, score, ok
func (e *GtpEngine) FinalScore() (string, float64, bool) {
	cmd := "final_score"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return "", 0, false
	}
	splited := strings.Split(resp.Content, "+")
	if len(splited) < 2 {
		return "", 0, false
	}
	score, _ := nmath.Float(splited[1])
	return splited[0], score, true
}

// Undo 悔棋
func (e *GtpEngine) Undo() bool {
	cmd := "undo"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// TimeLeft 设置时间
func (e *GtpEngine) TimeLeft(color string, mainTime, stones int) bool {
	cmd := fmt.Sprintf("time_left %s %d %d", color, mainTime, stones)
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	return true
}

// Quit 退出
func (e *GtpEngine) Quit() bool {
	cmd := "quit"
	resp, err := e.Send(e.nextId(), cmd)
	if !e.Check(resp, err, cmd) {
		return false
	}
	_ = e.Cmd.Stop()

	return true
}

func (e *GtpEngine) Check(resp *GTPResponse, err error, cmd string) bool {
	if err != nil {
		nlog.Errorf("发送命令[%s]失败 %v", cmd, err)
		return false
	}
	if resp.Err != nil {
		nlog.Errorf("接收到GTP错误消息 %v", resp.Err)
		return false
	}
	return true
}