package client

import (
	"errors"
	"fmt"
	"git.bvbej.com/bvbej/base-golang/pkg/websocket/client/service"
	"git.bvbej.com/bvbej/base-golang/pkg/websocket/codec"
	_ "git.bvbej.com/bvbej/base-golang/pkg/websocket/codec/json"
	_ "git.bvbej.com/bvbej/base-golang/pkg/websocket/codec/protobuf"
	"git.bvbej.com/bvbej/base-golang/tool/assist"
	"github.com/gorilla/websocket"
	"go.uber.org/zap"
	"net/http"
	"net/url"
	"reflect"
	"sync/atomic"
	"time"
)

const (
	writeWait          = 20 * time.Second
	pongWait           = 60 * time.Second
	reconnectWait      = 3 * time.Second
	pingPeriod         = (pongWait * 9) / 10
	maxFrameMessageLen = 16 * 1024
	maxSendBuffer      = 32
)

var (
	_                   Client = (*client)(nil)
	ErrBrokenPipe              = errors.New("send to broken pipe")
	ErrBufferPoolExceed        = errors.New("send buffer exceed")
)

type Client interface {
	readLoop()
	writeLoop()
	ping()
	onReceive(msg []byte) error
	onSend(msg []byte) error
	connect() error

	Send(router string, data any) error
	Connect(requestHeader http.Header) error
	OnReceiveError() <-chan error
	OnReconnect(f func())
}

type client struct {
	url           url.URL
	requestHeader http.Header
	logger        *zap.Logger
	session       *service.Session
	isConnected   *atomic.Bool
	routerCodec   codec.Codec
	send          chan []byte
	handlers      map[string]*service.Handler // 注册的方法列表
	onReceiveChan chan error
	pingTicker    *time.Ticker
	onReconnect   func()
}

func New(logger *zap.Logger, url url.URL, decoder string, handlers interface{}) (Client, error) {
	if !assist.InArray(url.Scheme, []string{"ws", "wss"}) {
		return nil, errors.New(`param: scheme not supported`)
	}

	routerCodec := codec.GetCodec(decoder)
	if routerCodec == nil {
		return nil, errors.New(`param: codec not supported`)
	}

	components := service.RegisterHandler(handlers)
	if len(components) == 0 {
		return nil, errors.New(`param: handlers unqualified`)
	}

	c := &client{
		logger:        logger,
		isConnected:   new(atomic.Bool),
		routerCodec:   routerCodec,
		url:           url,
		send:          make(chan []byte, maxSendBuffer),
		handlers:      components,
		onReceiveChan: make(chan error, maxSendBuffer),
		pingTicker:    time.NewTicker(pingPeriod),
	}
	return c, nil
}

func (c *client) readLoop() {
	_ = c.session.Conn.SetReadDeadline(time.Now().Add(pongWait))
	c.session.Conn.SetPongHandler(func(string) error {
		_ = c.session.Conn.SetReadDeadline(time.Now().Add(pongWait))
		return nil
	})

	for {
		_, data, err := c.session.Conn.ReadMessage()
		if err != nil {
			c.isConnected.Store(false)
			for c.connect() != nil {
				time.Sleep(reconnectWait)
			}
			if c.onReconnect != nil {
				c.onReconnect()
			}
			continue
		}
		err = c.onReceive(data)
		if err != nil {
			c.onReceiveChan <- err
		}
	}
}

func (c *client) writeLoop() {
	for {
		msg := <-c.send
		_ = c.session.Conn.SetWriteDeadline(time.Now().Add(writeWait))
		if err := c.session.Conn.WriteMessage(websocket.BinaryMessage, msg); err != nil {
			continue
		}
	}
}

func (c *client) ping() {
	for range c.pingTicker.C {
		_ = c.session.Conn.SetWriteDeadline(time.Now().Add(writeWait))
		if err := c.session.Conn.WriteMessage(websocket.PingMessage, nil); err != nil {
			for c.connect() != nil {
				time.Sleep(reconnectWait)
			}
		}
	}
}

func (c *client) connect() error {
	conn, _, err := websocket.DefaultDialer.Dial(c.url.String(), c.requestHeader)
	if err != nil {
		return fmt.Errorf("dial: %s", err)
	}

	c.session = service.NewSession(conn)
	c.isConnected.Store(true)

	return nil
}

func (c *client) onReceive(msg []byte) error {
	_, msgPack, err := c.routerCodec.Unmarshal(msg)
	if err != nil {
		return fmt.Errorf("onreceive: %v", err)
	}
	router, ok := msgPack.Router.(string)
	if !ok {
		return fmt.Errorf("onreceive: invalid router:%v", msgPack.Router)
	}
	s, ok := c.handlers[router]
	if !ok {
		return fmt.Errorf("onreceive: function not registed router:%s err:%v", msgPack.Router, err)
	}

	if msgPack.Err != nil {
		return fmt.Errorf("%s:%s", router, msgPack.Err)
	}

	var args = []reflect.Value{s.Receiver, reflect.ValueOf(c.session), reflect.ValueOf(msgPack.DataPtr)}
	s.Method.Func.Call(args)

	return nil
}

func (c *client) onSend(msg []byte) (err error) {
	defer func() {
		if e := recover(); e != nil {
			err = ErrBrokenPipe
		}
	}()

	if !c.isConnected.Load() {
		return ErrBrokenPipe
	}

	if len(c.send) >= maxSendBuffer {
		return ErrBufferPoolExceed
	}

	if len(msg) > maxFrameMessageLen {
		return
	}

	c.send <- msg

	return nil
}

func (c *client) Connect(requestHeader http.Header) error {
	c.requestHeader = requestHeader

	err := c.connect()
	if err != nil {
		return err
	}

	go c.ping()
	go c.writeLoop()
	go c.readLoop()

	return nil
}

func (c *client) Send(router string, data any) error {
	rb, err := c.routerCodec.Marshal(router, data, nil)
	if err != nil {
		return fmt.Errorf("service: %v", err)
	}
	return c.onSend(rb)
}

func (c *client) OnReceiveError() <-chan error {
	return c.onReceiveChan
}

func (c *client) OnReconnect(f func()) {
	c.onReconnect = f
}