/*
	Author: 林水溶
	英文名：shuiRongLin
	博客: https://shuirong.github.io

	！-------转载请保留上面作者信息-------！人最起码的东西得有是吧。
	
	思路：不管是这个1024游戏还是其他任何程序，思路最重要，用代码写出来反而是次要的东西！

	程序流程：打开页面，程序运行-->先随机出个4-->人操作（上下左右）-->(根据人的按键)对棋盘进行解析，
	该合并合并，该不动不动，该移动的移动，同时随机再出个4-->重复上一步-->在人按了512步之后，每次人按之后判断2048出现了没

	PS:之所以512步之前不判断赢了没，是因为最快赢需要512步，但实际情况下不太可能。之前判断没必要
*/

var checkerBoard = [
					[0,0,0,0],
					[0,0,0,0],
					[0,0,0,0],
					[0,0,0,0]
				]  // 初始化游戏棋盘，0就是什么都没有，
var checkerBoardId = [
					['0-0','0-1','0-2','0-3'],
					['1-0','1-1','1-2','1-3'],
					['2-0','2-1','2-2','2-3'],
					['3-0','3-1','3-2','3-3']
				]//棋盘对应位置的元素id，方便后面用
var color = {
	'2': '#eee4da',
	'4': '#ede0c8',
	'8': '#f2b179',
	'16': '#f59563',
	'32': '#f67c5f',
	'64': '#f65e3b',
	'128': '#edcf72',
	'256': '#edcc61',
	'512': '#edc850',
	'1024': '#edc53f',
	'2048': '#edc22e',
}
var score = 0; //记录分数

window.onload = function(){
	start();
}

//主函数
function start(){
	randomTwo();
	randomTwo();
	//给键盘的上下左右绑定监听事件  上 下 左 右--38 40 37 39
	$(document).keyup(function(event){
		if(event.which>=37&&event.which<=40){
			judge(event.which);//把用户的按键行为传进去
		}
	});
}

//在棋盘上随机出现2
function randomTwo(){
	let status = false;//随机4是不是搞定了
	while(!status){//随机xy直到棋盘上对应位置的值是0
		let x = Math.floor(Math.random()*4);
		let y = Math.floor(Math.random()*4);
		if(checkerBoard[x][y]===0){
			checkerBoard[x][y]=2;
			status = true;
		}
	}
	render();
}

//根据用户的按键对棋盘上现有的棋子依照游戏规则进行计算，将结果体现在全局变量checkerBoard上
// 上下左右不管哪个，棋盘上的棋子每个都有三种可能，拿上举例。1：它上面是0或者是边缘。2：它上面有数字且不一样
//3：上面有数字且一样。这就12中情况，得想办法抽象化，代码重用。
function judge(button){
	
	if(button==38){ //上
		for(var j=0; j<4; j++){
			for(var i=1; i<4;i++){
				if(checkerBoard[i][j]!==0){ //第一排的话，不用动，所以从第二排开始计算
					for(var m=0; m<i; m++){
						if(checkerBoard[m][j]==0&&!shuCanMove(j,i,m)){
							checkerBoard[m][j] = checkerBoard[i][j];
							checkerBoard[i][j] = 0;
						}else if(checkerBoard[m][j]==checkerBoard[i][j]&&!shuCanMove(j,i,m)){
							checkerBoard[m][j] = (checkerBoard[m][j] * 2);
							checkerBoard[i][j] = 0;
							score += checkerBoard[m][j];
						}
					}
				}
			}	
		}
	}else if(button==40){ //下
		for(var j=0; j<4; j++){
			for(var i=2; i>=0;i--){
				if(checkerBoard[i][j]!==0){
					for(var m=3; m>i;m--){
						if(checkerBoard[m][j]==0&&!shuCanMove(j,i,m)){
							checkerBoard[m][j] = checkerBoard[i][j];
							checkerBoard[i][j] = 0;
						}else if(checkerBoard[m][j] == checkerBoard[i][j] && !shuCanMove(j,i,m)){
							checkerBoard[m][j] = (checkerBoard[m][j] * 2);
							checkerBoard[i][j] = 0;
							score += checkerBoard[m][j];
						}
					}
				}
			}
		}
	}else if(button == 37){
		for(var i=0; i<4; i++){
			for(var j=1; j<4; j++){
				if(checkerBoard[i][j]!=0){
					for(var m=0; m<j; m++){
						if(checkerBoard[i][m]==0 && !hengCanMove(i,j,m)){
							checkerBoard[i][m] = checkerBoard[i][j];
							checkerBoard[i][j] = 0;
						}else if(checkerBoard[i][m] == checkerBoard[i][j]&&!hengCanMove(i,j,m)){
							checkerBoard[i][m] = (checkerBoard[i][m]*2);
							checkerBoard[i][j] = 0;
							score += checkerBoard[i][m];
						}
					}
				}
			}
		}
	}else if(button == 39){
		for(var i=0; i<4; i++){
			for(var j=2; j>=0; j--){
				if(checkerBoard[i][j]!=0){
					for(var m=3; m>j; m--){
						if(checkerBoard[i][m]==0&&!hengCanMove(i,j,m)){
							checkerBoard[i][m] = checkerBoard[i][j];
							checkerBoard[i][j] = 0;
						}else if(checkerBoard[i][m] == checkerBoard[i][j]&&!hengCanMove(i,j,m)){
							checkerBoard[i][m] = (checkerBoard[i][m]*2);
							checkerBoard[i][j] = 0;	
							score += checkerBoard[i][m];
						}
					}
				}
			}
		}
	}
	render();
	randomTwo();
}

//根据checkerBoard将棋盘的值重新渲染一遍
function render(){
	checkerBoard.forEach(function(x,xIndex){
		x.forEach(function(y,yIndex){
			if(y!==0){
				text(checkerBoardId[xIndex][yIndex],y);
			}else{
				text(checkerBoardId[xIndex][yIndex],'');
			}
		})
	});
	document.getElementById('realScore').innerText = score;
}

//不知道为何 $(id).text(123) 和 $(id).html(123) 不能用了，不管它，自己造了个
function text(id,text){
	let ele = document.getElementById(id);
	ele.innerText = text;
	ele.setAttribute('style','background:'+color[text]);	
}

function conso(){
	console.log(checkerBoard[0][0],checkerBoard[0][1],checkerBoard[0][2],checkerBoard[0][3]);
	console.log(checkerBoard[1][0],checkerBoard[1][1],checkerBoard[1][2],checkerBoard[1][3]);
	console.log(checkerBoard[2][0],checkerBoard[2][1],checkerBoard[2][2],checkerBoard[2][3]);
	console.log(checkerBoard[3][0],checkerBoard[3][1],checkerBoard[3][2],checkerBoard[3][3]);	
	console.log('-----------------------');
}

function shuCanMove(j,i,m){
	var from,to;
	if(i>m){
		from = m;
		to = i;
	}else{
		from = i;
		to = m;
	}
	for(var n=from+1; n<to;n++){
		if(checkerBoard[n][j]!=0){
			return true;
		}
	}
	return false;
}

function hengCanMove(j,i,m){
	var from,to;
	if(i>m){
		from = m;
		to = i;
	}else{
		from = i;
		to = m;
	}

	for(var n=from+1;n<to;n++){
		if(checkerBoard[j][n]!=0){
			return true;
		}
	}
	return false;

}