package events

import (
	"errors"
	"net/http"
	"time"

	"git.quimbo.fr/odwrtw/canape/backend/auth"
	"git.quimbo.fr/odwrtw/canape/backend/users"
	"git.quimbo.fr/odwrtw/canape/backend/web"
	"github.com/gorilla/websocket"
)

const (
	// Ping every 30 seconds, must be less than pongWait
	pingWait = 30 * time.Second
	// Time allowed to read the next pong message from the client
	pongWait = 35 * time.Second
	// Time allowed to write to the client
	writeWait = 30 * time.Second
)

// WsHandler handles the websockets messages
func WsHandler(env *web.Env, w http.ResponseWriter, r *http.Request) error {
	// Get the user
	v := auth.GetCurrentUser(r, env.Log)
	user, ok := v.(*users.User)
	if !ok {
		return env.RenderError(w, errors.New("invalid user type"))
	}

	upgrader := websocket.Upgrader{
		ReadBufferSize:  1024,
		WriteBufferSize: 1024,
	}

	// Upgrade the request for websockets
	ws, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		env.Log.Warnf("got error upgrading request: %+v", err)
		if _, ok := err.(websocket.HandshakeError); !ok {
			env.Log.Warn("handshake error")
		}
		return err
	}
	defer ws.Close()

	// The pong handler only postpone the read deadline
	ws.SetPongHandler(func(string) error {
		ws.SetReadDeadline(time.Now().Add(pongWait))
		return nil
	})

	// Channel where the eventers will write events to
	serverEventStream := make(chan ServerEvent)
	// Channel where the eventers will write errors to
	serverErrorStream := make(chan ServerError)

	events := map[string]Eventer{
		"torrents": &TorrentNotifier{
			Notifier: NewNotifier(serverEventStream, serverErrorStream),
			user:     user,
			log:      env.Log,
		},
	}

	c := channel{
		serverEventStream: serverEventStream,
		serverErrorStream: serverErrorStream,
		done:              make(chan struct{}, 1),
		conn:              ws,
		log:               env.Log,
		events:            events,
	}

	// Launch the go routine responsible for writing events in the websocket
	go c.writer()
	// Launch the reader responsible for reading events from the websocket
	c.reader()

	return nil
}