package websocket

import (
	"bytes"
	"encoding/json"
	"net/http"
	"primesys_command_producer/src/data"
	"primesys_command_producer/src/logger"
	. "primesys_command_producer/src/types"
	"time"

	"github.com/gorilla/websocket"
)

const (
	// Time allowed to write a message to peer
	writeWait = 10 * time.Second

	// Time allowed to read the next pong message from the peer
	pongWait = 60 * time.Second

	pingPeriod = (pongWait * 9) / 10

	maxMessageSize = 10485760

	sendBufferSize = 16
)

var (
	newline = []byte{'\n'}
	space   = []byte{' '}
)

// to upgrade connection from http to socket
var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin:     func(r *http.Request) bool { return true },
}

type Client struct {
	// file path in which pending commands are there
	FilePath string
	// user who opened the connection
	UserID string

	ServerFlag string
	// hub in which all client will be registered
	hub *Hub

	// socket connection
	conn *websocket.Conn

	send chan []byte
}

func (c *Client) readPump() {

	defer func() {
		c.hub.unregister <- c
		c.conn.Close()
	}()

	logger.Info("msg size ")

	c.conn.SetReadLimit(maxMessageSize)
	c.conn.SetReadDeadline(time.Now().Add(pongWait))
	c.conn.SetPongHandler(func(string) error { c.conn.SetReadDeadline(time.Now().Add(pongWait)); return nil })

	for {
		_, message, err := c.conn.ReadMessage()

		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				logger.Error("userId=%s socket error: %v", c.UserID, err)
			}
			break
		}

		message = bytes.TrimSpace(bytes.ReplaceAll(message, newline, space))
		logger.Info("message came %d", len(message))

		c.handleMessage(message)
	}
}

func (c *Client) reply(response CommandResponse) {
	data, err := json.Marshal(response)
	if err != nil {
		logger.Error("userId=%s response marshal failed: %v", c.UserID, err)
		return
	}

	select {
	case c.send <- data:
	default:
		logger.Warn("userId=%s send buffer full, response dropped", c.UserID)
	}
}

func (c *Client) writePump() {
	ticker := time.NewTicker(pingPeriod)
	defer func() {
		ticker.Stop()
		c.conn.Close()
	}()

	for {
		select {
		case message, ok := <-c.send:
			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
			if !ok {
				c.conn.WriteMessage(websocket.CloseMessage, []byte{})
				return
			}

			w, err := c.conn.NextWriter(websocket.TextMessage)
			if err != nil {
				logger.Error("userId=%s error in message writing: %v", c.UserID, err)
				return
			}
			w.Write(message)

			n := len(c.send)
			for i := 0; i < n; i++ {
				w.Write(newline)
				w.Write(<-c.send)
			}

			if err := w.Close(); err != nil {
				return
			}
		case <-ticker.C:
			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
			if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
				return
			}
		}
	}
}

func serveWs(userId string, hub *Hub, w http.ResponseWriter, r *http.Request) {
	serverFlag, err := data.GetServerFlag(userId)
	if err != nil {
		logger.Error("userId=%s unauthorized: %v", userId, err)
		http.Error(w, err.Error(), http.StatusUnauthorized)
		return
	}

	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		logger.Error("Socket upgrade failed: %v", err)
		return
	}

	client := &Client{
		UserID:     userId,
		ServerFlag: serverFlag,
		hub:        hub,
		conn:       conn,
		send:       make(chan []byte, sendBufferSize),
	}
	client.hub.register <- client

	go client.writePump()
	go client.readPump()
}