package client

import (
	"fmt"
	"io"
	"net"
	"net/http"
	"sync"
	"time"

	"git.loafle.net/commons_go/logging"
	cuc "git.loafle.net/commons_go/util/context"
	"git.loafle.net/commons_go/websocket_fasthttp/websocket"
)

type Socket interface {
	Context() SocketContext

	// Subprotocol returns the negotiated protocol for the connection.
	Subprotocol() string

	// Close closes the underlying network connection without sending or waiting for a close frame.
	Close() error

	// LocalAddr returns the local network address.
	LocalAddr() net.Addr

	// RemoteAddr returns the remote network address.
	RemoteAddr() net.Addr

	// WriteControl writes a control message with the given deadline. The allowed
	// message types are CloseMessage, PingMessage and PongMessage.
	WriteControl(messageType int, data []byte, deadline time.Time) error

	// NextWriter returns a writer for the next message to send. The writer's Close
	// method flushes the complete message to the network.
	//
	// There can be at most one open writer on a connection. NextWriter closes the
	// previous writer if the application has not already done so.
	NextWriter(messageType int) (io.WriteCloser, error)

	// WritePreparedMessage writes prepared message into connection.
	WritePreparedMessage(pm *websocket.PreparedMessage) error

	// WriteMessage is a helper method for getting a writer using NextWriter,
	// writing the message and closing the writer.
	WriteMessage(messageType int, data []byte) error

	// SetWriteDeadline sets the write deadline on the underlying network
	// connection. After a write has timed out, the websocket state is corrupt and
	// all future writes will return an error. A zero value for t means writes will
	// not time out.
	SetWriteDeadline(t time.Time) error

	// NextReader returns the next data message received from the peer. The
	// returned messageType is either TextMessage or BinaryMessage.
	//
	// There can be at most one open reader on a connection. NextReader discards
	// the previous message if the application has not already consumed it.
	//
	// Applications must break out of the application's read loop when this method
	// returns a non-nil error value. Errors returned from this method are
	// permanent. Once this method returns a non-nil error, all subsequent calls to
	// this method return the same error.
	NextReader() (messageType int, r io.Reader, err error)

	// ReadMessage is a helper method for getting a reader using NextReader and
	// reading from that reader to a buffer.
	ReadMessage() (messageType int, p []byte, err error)

	// SetReadDeadline sets the read deadline on the underlying network connection.
	// After a read has timed out, the websocket connection state is corrupt and
	// all future reads will return an error. A zero value for t means reads will
	// not time out.
	SetReadDeadline(t time.Time) error

	// SetReadLimit sets the maximum size for a message read from the peer. If a
	// message exceeds the limit, the connection sends a close frame to the peer
	// and returns ErrReadLimit to the application.
	SetReadLimit(limit int64)

	// CloseHandler returns the current close handler
	CloseHandler() func(code int, text string) error

	// SetCloseHandler sets the handler for close messages received from the peer.
	// The code argument to h is the received close code or CloseNoStatusReceived
	// if the close message is empty. The default close handler sends a close frame
	// back to the peer.
	//
	// The application must read the connection to process close messages as
	// described in the section on Control Frames above.
	//
	// The connection read methods return a CloseError when a close frame is
	// received. Most applications should handle close messages as part of their
	// normal error handling. Applications should only set a close handler when the
	// application must perform some action before sending a close frame back to
	// the peer.
	SetCloseHandler(h func(code int, text string) error)

	// PingHandler returns the current ping handler
	PingHandler() func(appData string) error

	// SetPingHandler sets the handler for ping messages received from the peer.
	// The appData argument to h is the PING frame application data. The default
	// ping handler sends a pong to the peer.
	//
	// The application must read the connection to process ping messages as
	// described in the section on Control Frames above.
	SetPingHandler(h func(appData string) error)

	// PongHandler returns the current pong handler
	PongHandler() func(appData string) error

	// SetPongHandler sets the handler for pong messages received from the peer.
	// The appData argument to h is the PONG frame application data. The default
	// pong handler does nothing.
	//
	// The application must read the connection to process ping messages as
	// described in the section on Control Frames above.
	SetPongHandler(h func(appData string) error)

	// UnderlyingConn returns the internal net.Conn. This can be used to further
	// modifications to connection specific flags.
	UnderlyingConn() net.Conn

	// EnableWriteCompression enables and disables write compression of
	// subsequent text and binary messages. This function is a noop if
	// compression was not negotiated with the peer.
	EnableWriteCompression(enable bool)

	// SetCompressionLevel sets the flate compression level for subsequent text and
	// binary messages. This function is a noop if compression was not negotiated
	// with the peer. See the compress/flate package for a description of
	// compression levels.
	SetCompressionLevel(level int) error

	// Header returns header by key
	Header(key string) (value string)

	// Headers returns the RequestHeader struct
	Headers() http.Header
}

func NewSocket(sb SocketBuilder, parentContext cuc.Context) (Socket, error) {
	if nil == sb {
		logging.Logger().Panicf("Client Socket: SocketBuilder must be specified")
	}
	sb.Validate()

	sc := sb.SocketContext(parentContext)
	if nil == sc {
		logging.Logger().Panicf("Client Socket: SocketContext must be specified")
	}

	sh := sb.GetSocketHandler()

	d := &websocket.Dialer{}
	d.NetDial = sb.Dial
	d.Proxy = sb.UseProxy
	d.TLSClientConfig = sb.GetTLSConfig()
	d.HandshakeTimeout = sb.GetHandshakeTimeout()
	d.ReadBufferSize = sb.GetReadBufferSize()
	d.WriteBufferSize = sb.GetWriteBufferSize()
	d.Subprotocols = sb.GetSubProtocols()
	d.EnableCompression = sb.IsEnableCompression()
	d.Jar = sb.GetRequestCookie()

	url := sb.GetURL()
	if "" == url {
		return nil, fmt.Errorf("Client Socket: URL of server must be specified")
	}
	reqHeader := sb.GetRequestHeader()

	conn, res, err := d.Dial(url, reqHeader)
	if nil != err {
		return nil, err
	}

	sh.OnConnect(sc, res)

	s := retainSocket()
	s.Conn = conn
	s.ctx = sc
	s.sh = sh
	s.resHeader = res.Header

	return s, nil
}

type fasthttpWebSocket struct {
	*websocket.Conn

	ctx SocketContext
	sh  SocketHandler

	resHeader http.Header
}

func (s *fasthttpWebSocket) Context() SocketContext {
	return s.ctx
}

func (s *fasthttpWebSocket) NextWriter(messageType int) (io.WriteCloser, error) {
	if 0 < s.sh.GetWriteTimeout() {
		s.SetWriteDeadline(time.Now().Add(s.sh.GetWriteTimeout() * time.Second))
	}

	return s.Conn.NextWriter(messageType)
}

func (s *fasthttpWebSocket) WriteMessage(messageType int, data []byte) error {
	if 0 < s.sh.GetWriteTimeout() {
		s.SetWriteDeadline(time.Now().Add(s.sh.GetWriteTimeout() * time.Second))
	}

	return s.Conn.WriteMessage(messageType, data)
}

func (s *fasthttpWebSocket) Header(key string) (value string) {
	if nil == s.resHeader {
		return ""
	}
	return s.resHeader.Get(key)
}

func (s *fasthttpWebSocket) Headers() http.Header {
	return s.resHeader
}

func (s *fasthttpWebSocket) Close() error {
	err := s.Conn.Close()
	s.sh.OnDisconnect(s)
	releaseSocket(s)
	return err
}

var socketPool sync.Pool

func retainSocket() *fasthttpWebSocket {
	v := socketPool.Get()
	if v == nil {
		return &fasthttpWebSocket{}
	}
	return v.(*fasthttpWebSocket)
}

func releaseSocket(s *fasthttpWebSocket) {
	s.sh = nil
	s.ctx = nil

	socketPool.Put(s)
}