package server

import (
	"encoding/json"
	"regexp"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"github.com/mitchellh/mapstructure"
	"github.com/rotisserie/eris"
	"gorm.io/gorm"
	"sikey.com/websocket/models"
	"sikey.com/websocket/repositories"
	"sikey.com/websocket/utils/gid"
	"sikey.com/websocket/utils/zlog"
)

type Client struct {
	ctx            *gin.Context
	UserId         string
	hub            *Hub
	UnderlyingConn *websocket.Conn
	online         *models.Online

	isSimpleMsg   bool   // isSimpleMsg 是否是简单消息
	localization  string // localization 国际码
	firebaseToken string // firebaseToken FCM 推送的 token

	// Send message channel 发送消息
	// 当用户在线时会通过 Send channel 发送在线消息 但如果用户不在线,
	Send chan *Message

	readWait  time.Duration // readWait 读超时
	writeWait time.Duration // writeWait 写超时
	pingWait  time.Duration // pingWait 心跳超时

	repos *repositories.Repositories
}

func (c *Client) reader() {
	defer func() {
		c.hub.Disconnect <- c
		c.Close()
		zlog.Debugf("Close client %s", c.UserId)
	}()

	c.UnderlyingConn.SetReadDeadline(time.Now().Add(c.readWait))
	for {
		_, bytes, err := c.UnderlyingConn.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				zlog.Errorf("error: %v", eris.Wrap(err, c.UserId))
			} else {
				zlog.Errorf("error: %v", eris.Wrap(err, c.UserId))
			}
			// Close connect
			// _ = c.repos.OnlineRepository.Offline(c.ctx, c.online)
			return
		}

		message := deserializeMessage(bytes)
		switch message.Type {
		case MessageTypePingPong:
			zlog.Debugf("receive ping message from %s", c.UserId)
			_ = c.repos.OnlineRepository.Heartbeat(c.ctx, c.online)
		case MessageTypeUpChating, MessageTypeDownChating:
			// Chat dialogue messages
			chatingContent := message.Content.(ChatingContent)

			// Save message to database
			messageId := gid.GetMessageId()
			chatingContent.MessageId = messageId
			chatingContent.SessionId = chatingContent.Receiver
			err = c.saveMessage(messageId, message.Type, &chatingContent)
			if err != nil {
				c.writeError(message.RequestId, err)
				continue
			}

			// Receiver ID format determines whether the receiver is an account or a session
			zlog.Debugf("message receiver: %s", chatingContent.Receiver)
			users := c.getReceiverUserIds(chatingContent.Receiver)
			zlog.Debugf("users: %s", users)
			for _, id := range users {
				var messaging = *message
				messaging.Receiver = id
				messaging.Content = chatingContent
				zlog.Infof("Send message %s to %s", c.UserId, id)

				// Check if the user is online
				if c.firebaseToken != "" {
					var online bool
					if online, err = c.repos.OnlineRepository.Is(c.ctx, id); err != nil {
						zlog.Error(eris.Wrap(err, "unable to find online user"))
						continue
					} else {
						if !online {
							// Send FCM message
						}
					}
				}
				c.hub.Message <- &messaging
			}

			// Reply message id
			message.Content = &ContentReply{MessageId: messageId}
		}

		// Reply message
		// zlog.Debugf("reply message %s to %s", message.RequestId, c.UserId)
		if message.IsNeedReply() {
			c.Send <- newReplyMessage(message)

			// Reset read deadline, prevent Reader from shutting down
			// zlog.Debugf("reset read deadline for %s", c.UserId)
			c.UnderlyingConn.SetReadDeadline(time.Now().Add(c.pingWait))
		}
	}
}

func (c *Client) writer() {
	ticker := time.NewTicker(c.pingWait)
	defer func() {
		ticker.Stop()
		c.Close()
	}()

	for {
		select {
		case message, ok := <-c.Send:
			c.UnderlyingConn.SetWriteDeadline(time.Now().Add(c.writeWait))
			if !ok {
				// The hub closed the channel.
				c.UnderlyingConn.WriteMessage(websocket.CloseMessage, []byte{})
				return
			}

			var err error
			err = c.UnderlyingConn.WriteMessage(websocket.TextMessage, serializationMessage(message))
			if err != nil {
				return
			}

			// Received modification message status
			switch message.Type {
			case MessageTypeUpChating, MessageTypeDownChating:
				// Chat dialogue messages
				if chatingContent, ok := message.Content.(ChatingContent); ok {
					if msg, err := c.repos.SessionRepository.FindMessageById(c.ctx, chatingContent.MessageId); err == nil {
						msg.Received = true
						c.repos.SessionRepository.UpdateMessage(c.ctx, msg)
					} else {
						if eris.Is(err, gorm.ErrRecordNotFound) {
							break
						}
						zlog.Error(err)
					}
				}
			}

			buf, _ := message.MarshalBinary()
			zlog.Debugf("send message %s to %s content: %v", message.RequestId, c.UserId, string(buf))
		case <-ticker.C:
			// 到时间发送 ping 信号
			c.UnderlyingConn.SetWriteDeadline(time.Now().Add(c.writeWait))
			if err := c.UnderlyingConn.WriteMessage(websocket.PingMessage, nil); err != nil {
				return
			}
		}
	}
}

func (c *Client) writeError(requestId string, err error) {
	c.Send <- &Message{
		RequestId: requestId,
		Type:      MessageTypeError,
		Content:   ContentError{Err: err.Error()},
	}
}

func (c *Client) saveMessage(messageId string, messageType int8, content *ChatingContent) error {
	// Standardized structure, This is not an unnecessary step!!!
	// Filter out excess fields.
	var err error
	switch content.PayloadType {
	case ChatingContentTypeText:
		var textContent ContentText
		err = mapstructure.Decode(content.Payload, &textContent)
		content.Payload = textContent
	case ChatingContentTypeMetadata:
		var contentMetadata ContentMetadata
		err = mapstructure.Decode(content.Payload, &contentMetadata)
		content.Payload = contentMetadata
	}
	if err != nil {
		return eris.Wrap(err, "unable to decode message content")
	}
	payload, _ := json.Marshal(content.Payload)
	return c.repos.SessionRepository.CreateMessage(c.ctx, &models.SessionMessage{
		ID:          messageId,
		SessionId:   content.Receiver,
		Receiver:    content.Receiver,
		Sender:      c.UserId,
		Type:        messageType,
		ContentType: content.PayloadType,
		Content:     payload,
		IsRead:      false,
	})
}

// getReceiverUserIds 通过 receiver 获取接收者的用户ID
// 使用正则表达式验证ID 是否是 account_id 或 session_id
// session_id 的话需要查询 session_member 表获取 session 的成员
func (c *Client) getReceiverUserIds(receiver string) []string {
	reg, _ := regexp.Compile(`[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}`)
	if reg.Match([]byte(receiver)) {
		return []string{receiver}
	}

	members, err := c.repos.SessionRepository.GetSessionMembersRemoveOneself(
		c.ctx, receiver, c.UserId)
	if err != nil {
		return []string{}
	}

	var ms = make([]string, len(members))
	for i, memb := range members {
		ms[i] = memb.RefId
	}
	return ms
}

// Close websocket connection
func (c *Client) Close() {
	c.UnderlyingConn.Close()
	online := &models.Online{UserId: c.UserId, ServerId: c.hub.serverId}
	c.repos.OnlineRepository.Offline(c.ctx, online)
}