package hysteria

import (
	"encoding/binary"
	"io"
	"sync"
	"time"

	"github.com/apernet/quic-go"
	"github.com/apernet/quic-go/quicvarint"
	"github.com/xtls/xray-core/common/net"
	"github.com/xtls/xray-core/common/protocol"
)

type interConn struct {
	stream *quic.Stream
	local  net.Addr
	remote net.Addr

	client bool
	mutex  sync.Mutex

	user *protocol.MemoryUser
}

func (i *interConn) User() *protocol.MemoryUser {
	return i.user
}

func (i *interConn) Read(b []byte) (int, error) {
	return i.stream.Read(b)
}

func (i *interConn) Write(b []byte) (int, error) {
	if i.client {
		i.mutex.Lock()
		defer i.mutex.Unlock()
		if i.client {
			buf := make([]byte, 0, quicvarint.Len(FrameTypeTCPRequest)+len(b))
			buf = quicvarint.Append(buf, FrameTypeTCPRequest)
			buf = append(buf, b...)
			_, err := i.stream.Write(buf)
			if err != nil {
				return 0, err
			}
			i.client = false
			return len(b), nil
		}
	}

	return i.stream.Write(b)
}

func (i *interConn) Close() error {
	i.stream.CancelRead(0)
	return i.stream.Close()
}

func (i *interConn) LocalAddr() net.Addr {
	return i.local
}

func (i *interConn) RemoteAddr() net.Addr {
	return i.remote
}

func (i *interConn) SetDeadline(t time.Time) error {
	return i.stream.SetDeadline(t)
}

func (i *interConn) SetReadDeadline(t time.Time) error {
	return i.stream.SetReadDeadline(t)
}

func (i *interConn) SetWriteDeadline(t time.Time) error {
	return i.stream.SetWriteDeadline(t)
}

type InterUdpConn struct {
	conn   *quic.Conn
	local  net.Addr
	remote net.Addr

	id uint32
	ch chan []byte

	closed    bool
	closeFunc func()

	last  time.Time
	mutex sync.Mutex

	user *protocol.MemoryUser
}

func (i *InterUdpConn) User() *protocol.MemoryUser {
	return i.user
}

func (i *InterUdpConn) SetLast() {
	i.mutex.Lock()
	defer i.mutex.Unlock()

	i.last = time.Now()
}

func (i *InterUdpConn) GetLast() time.Time {
	i.mutex.Lock()
	defer i.mutex.Unlock()

	return i.last
}

func (i *InterUdpConn) Read(p []byte) (int, error) {
	b, ok := <-i.ch
	if !ok {
		return 0, io.EOF
	}
	n := copy(p, b)
	if n != len(b) {
		return 0, io.ErrShortBuffer
	}

	i.SetLast()
	return n, nil
}

func (i *InterUdpConn) Write(p []byte) (int, error) {
	i.SetLast()

	binary.BigEndian.PutUint32(p, i.id)
	if err := i.conn.SendDatagram(p); err != nil {
		return 0, err
	}
	return len(p), nil
}

func (i *InterUdpConn) Close() error {
	i.closeFunc()
	return nil
}

func (i *InterUdpConn) LocalAddr() net.Addr {
	return i.local
}

func (i *InterUdpConn) RemoteAddr() net.Addr {
	return i.remote
}

func (i *InterUdpConn) SetDeadline(t time.Time) error {
	return nil
}

func (i *InterUdpConn) SetReadDeadline(t time.Time) error {
	return nil
}

func (i *InterUdpConn) SetWriteDeadline(t time.Time) error {
	return nil
}