"use strict";

let tetris = function () {
    const grid_x = 10;
    const grid_y = 30;
    const tetrimonios = [
        /*'I'*/{ mR:2,
              r:[
                    [ [0,0],[0,1],[0,2],[0,3] ],
                    [ [0,0],[1,0],[2,0],[3,0] ]
                ]
            },
        /*'O':*/{ mR:1,
              r:[
                    [ [0,0],[0,1],[1,0],[1,1] ]
                ]
            },
        /*'L':*/{ mR:4,
              r:[
                    [ [0,0],[0,1],[0,2],[1,2] ],
                    [ [0,0],[1,0],[2,0],[0,1] ],
                    [ [0,0],[1,0],[1,1],[1,2] ],
                    [ [2,0],[2,1],[1,1],[0,1] ]
                ]
            },
        /*'L2':*/{ mR:4,
              r:[
                    [ [1,0],[1,1],[1,2],[0,2] ],
                    [ [0,0],[0,1],[1,1],[2,1] ],
                    [ [1,0],[0,0],[0,1],[0,2] ],
                    [ [0,0],[1,0],[2,0],[2,1] ]
                ]
            },
        /*'Z':*/{ mR:2, 
              r:[
                    [ [0,0],[1,0],[1,1],[2,1] ],
                    [ [1,0],[1,1],[0,1],[0,2] ]
                ]
            },
        /*'Z2':*/{ mR:2,
              r:[
                    [ [0,1],[1,1],[1,0],[2,0] ],
                    [ [0,0],[0,1],[1,1],[1,2] ]
                ]
            }
    ];

    let timer, canvas, ctx, bs;
    let next_t;
    
    let board;
    let t = {t:null,x:0,y:0,r:0};


    function control(e) {
        switch(e.key) {
            case 'r': clean(t); newGame();  break;
            case 'a': clean(t); nextT();  break;
            case 'ArrowUp':     moveUp(t);   break;
            case 'ArrowDown':   moveDown(t); break;
            case 'ArrowLeft':   moveLeft(t); break;
            case 'ArrowRight':  moveRight(t);break;
        }
    }

    function clean(p) { ctx.fillStyle = "#FFFFFF"; drawBlocks(p,drawBlock_clean); }
    function draw(p) { ctx.fillStyle = "#666666"; drawBlocks(p,drawBlock_filled); }
    function drawBlocks(p, drawBlock) {
        p.t.r[p.r].forEach(b => drawBlock(p.x + b[0], p.y + b[1]));
    }
    function drawBlock_clean(x,y) {
        ctx.fillRect(bs*(1+x), bs*(1+y), bs, bs);
    }
    function drawBlock_filled(x,y) {
        ctx.fillRect(bs*(1+x), bs*(1+y), bs, bs);
    }


    function moveUp(p) {
        clean(t);
        let r = p.r;
        p.r = (++p.r)% p.t.mR;
        if ( collision(p) ) p.r = r;
        draw(t);
    }

    function moveDown(p) {
        clean(t);
        p.y++;
        if ( collision(p) ) {
            p.y--;
            glue(p);
        }
        draw(t);
    }

    function moveLeft(p) {
        clean(t);
        p.x--;
        if ( collision(p) ) p.x++;
        draw(t);
    }

    function moveRight(p) {
        clean(t);
        p.x++;
        if ( collision(p) ) p.x--;
        draw(t);
    }

    function glue(p) {
        p.t.r[p.r].forEach(b => { board[p.x+b[0]][p.y+b[1]]=1; } );
        draw(t);
        dropShape(t);
    }

    function collision(p) {
        if ( p.x<0 || p.x>=grid_x || p.y<0 || p.y>=grid_y ) return true;
        if ( p.t.r[p.r].filter(b => ( p.x+b[0]>=grid_x || p.y+b[1]>=grid_y || board[p.x+b[0]][p.y+b[1]]==1 ) ).length>0 ) return true;
        return false
    }

    function getNextT() {
        let tNum = Math.floor(Math.random() * tetrimonios.length);
        return tetrimonios[ tNum ];
    }

    function dropShape(p) {
        p.t = next_t;
        p.x = grid_x/2 - 1;
        p.y = 0;
        p.r = 0;
        
        next_t = getNextT();
    }

    function newGame() {
        ctx.fillStyle = "#FFFFFF";
        ctx.fillRect(0,0,canvas.getBoundingClientRect().width,canvas.getBoundingClientRect().height);

        board = Array.from(Array(grid_x), () => new Array(grid_y));
        next_t = getNextT();
        dropShape( t );
        if (!timer) timer = setInterval(()=>moveDown(t), 1000);
    }

    function getBlockSize() {
        const space_top = 5;
        const space_right = 20;
        
        const { width, height } = canvas.getBoundingClientRect();
        return Math.floor( Math.min( height / (space_top + grid_y), width / (space_right + grid_x) ) );
    }

    function init() {
        canvas = document.getElementById("app");
        canvas.width = window.innerWidth
        canvas.height = window.innerHeight

        ctx = canvas.getContext("2d");
        bs = getBlockSize();

        document.addEventListener('keydown', control);
        newGame();
    }
    init();

}


document.addEventListener('DOMContentLoaded', tetris );