package main

import (
	"encoding/json"
	"fmt"
	"log"
	"math"

	"golang.org/x/net/websocket"
)

type Position struct {
	X, Y int
}

type player struct {
	Position Position `json:"position"`
	Name     string   `json:"name"`
	ws       *websocket.Conn
	send     chan *player
}

func (p *player) validMove(next Position) (r bool) {
	r = true
	if math.Abs(float64(p.Position.X-next.X)) > 1 {
		r = false
	}
	if math.Abs(float64(p.Position.Y-next.Y)) > 1 {
		r = false
	}
	return
}

func (p *player) sender() {
	for pinfo := range p.send {
		err := websocket.JSON.Send(p.ws, pinfo)
		if err != nil {
			break
		}
	}
	p.ws.Close()
}

func (p *player) recv() {
	for {
		var msg string
		err := websocket.Message.Receive(p.ws, &msg)
		if err != nil {
			break
		}
		// XXX: the danger!
		var pos Position
		err = json.Unmarshal([]byte(msg), &pos)
		if err != nil {
			break
		}
		if !p.validMove(pos) {
			break
		}
		p.Position = pos
		g.broadcast <- p
	}
	p.ws.Close()
}

func addPlayer(ws *websocket.Conn) {
	var name string
	err := websocket.Message.Receive(ws, &name)
	if err != nil {
		log.Fatal("trouble parsing username")
	}
	p := &player{
		Name: name,
		send: make(chan *player, 256),
		ws:   ws,
	}
	g.register <- p
	defer func() {
		g.unregister <- p
	}()
	go p.sender()
	p.recv()
	fmt.Printf("%v has been disconnect from this game\n", p)
}