package main

import (
	// Standard
	"encoding/binary"
	"fmt"
	"net"
)

const (
	RUN_COMMAND       = 0
	GET_WORKSPACES    = 1
	SUBSCRIBE         = 2
	GET_OUTPUTS       = 3
	GET_TREE          = 4
	GET_MARKS         = 5
	GET_BAR_CONFIG    = 6
	GET_VERSION       = 7
	GET_BINDING_MODES = 8
	GET_CONFIG        = 9
	SEND_TICK         = 10
	SYNC              = 11
)

func NewI3Socket(filename string) (I3Socket, error) {
	var i3Socket I3Socket
	var err error

	i3Socket.conn, err = net.Dial("unix", filename)
	if err != nil {
		return i3Socket, err
	}

	return i3Socket, nil
}

func (sock I3Socket) Close() error {
	return sock.conn.Close()
}

func I3ReadMessage(sock I3Socket) (msg []byte, err error) {
	buf := make([]byte, 6)
	if _, err = sock.conn.Read(buf); err != nil {
		return nil, err
	}
	if string(buf) != "i3-ipc" {
		return nil, fmt.Errorf("Invalid i3 IPC answer")
	}

	// LE encoded length
	buf = make([]byte, 4)
	if _, err = sock.conn.Read(buf); err != nil {
		return nil, err
	}
	msgLength := binary.LittleEndian.Uint32(buf)

	// LE encoded msg type
	buf = make([]byte, 4)
	if _, err = sock.conn.Read(buf); err != nil {
		return nil, err
	}

	// Requested data
	buf = make([]byte, msgLength)
	if _, err = sock.conn.Read(buf); err != nil {
		return nil, err
	}
	msg = buf

	return
}

func (sock I3Socket) Request(typ int, message string) ([]byte, error) {
	header := []byte("i3-ipc")
	buf := make([]byte, 8)
	binary.LittleEndian.PutUint32(buf, uint32(len(message)))
	binary.LittleEndian.PutUint32(buf[4:], uint32(typ))
	msg := append(header, buf...)
	msg = append(msg, ([]byte(message))...)

	_, err := sock.conn.Write(msg)
	if err != nil {
		return nil, err
	}

	buf, err = I3ReadMessage(sock)
	if err != nil {
		return nil, err
	}
	return buf, nil
}