package overflow_gateway_websocket

import (
	"net/http"
	"sync"

	"git.loafle.net/overflow/overflow_gateway_websocket/websocket"
	"github.com/valyala/fasthttp"
)

type ()

type Server interface {
	ListenAndServe(addr string) error
	HandleSocket(pattern string, o *SocketOptions)
}

type server struct {
	_option         *ServerOptions
	_upgrader       *websocket.Upgrader
	_handlers       map[string]*SocketOptions
	_sockets        map[string]Socket
	_socketsMtx     sync.Mutex
	_addSocketCh    chan Socket
	_removeSocketCh chan Socket
}

func NewServer(o *ServerOptions) Server {
	s := &server{
		_option:         o.Validate(),
		_handlers:       make(map[string]*SocketOptions, 1),
		_sockets:        make(map[string]Socket, 100),
		_addSocketCh:    make(chan Socket),
		_removeSocketCh: make(chan Socket),
	}

	s._upgrader = &websocket.Upgrader{
		HandshakeTimeout:  s._option.HandshakeTimeout,
		ReadBufferSize:    s._option.ReadBufferSize,
		WriteBufferSize:   s._option.WriteBufferSize,
		CheckOrigin:       s._option.OnCheckOrigin,
		Error:             s.onError,
		EnableCompression: s._option.EnableCompression,
	}

	return s
}

func (s *server) addSocket(soc Socket) {
	s._addSocketCh <- soc
}

func (s *server) removeSocket(soc Socket) {
	s._removeSocketCh <- soc
}

func (s *server) onError(ctx *fasthttp.RequestCtx, status int, reason error) {
	ctx.Response.Header.Set("Sec-Websocket-Version", "13")
	ctx.Error(http.StatusText(status), status)

	s._option.OnError(ctx, status, reason)
}

func (s *server) onDisconnected(soc Socket) {
	s.removeSocket(soc)
	s._option.OnDisconnected(soc)
}

func (s *server) onConnection(ctx *fasthttp.RequestCtx) {
	path := string(ctx.Path())
	co, ok := s._handlers[path]
	if !ok {
		s.onError(ctx, fasthttp.StatusNotFound, nil)
		return
	}

	s._upgrader.Upgrade(ctx, nil, func(conn *websocket.Conn, err error) {
		if err != nil {
			s.onError(ctx, fasthttp.StatusInternalServerError, err)
			return
		}
		id := s._option.IDGenerator(ctx)
		soc := NewSocket(id, path, co, conn)
		s.addSocket(soc)
		s._option.OnConnection(soc)

		soc.run()
	})
}

func (s *server) listenHandler() {
	for {
		select {
		// Add new a socket
		case soc := <-s._addSocketCh:
			s._socketsMtx.Lock()
			s._sockets[soc.ID()] = soc
			s._socketsMtx.Unlock()

		// remove a socket
		case soc := <-s._removeSocketCh:
			s._socketsMtx.Lock()
			delete(s._sockets, soc.ID())
			s._socketsMtx.Unlock()
		}
	}
}

func (s *server) Sockets() map[string]Socket {
	return s._sockets
}

func (s *server) HandleSocket(pattern string, o *SocketOptions) {
	o.onDisconnected = s.onDisconnected

	s._handlers[pattern] = o.Validate()
}

func (s *server) ListenAndServe(addr string) error {
	go s.listenHandler()

	return fasthttp.ListenAndServe(addr, s.onConnection)
}