function read(done) {
    require("fs").readFile('./input', 'utf8', (err, data) => {
        var map = new Map(),
            line = 0;
        data.split("\n").forEach((l) => {
            if (l && l.length) {
                while (true) {
                    var reg = /[\^><v]/.exec(l);
                    if (!reg)
                        break;
                    if (reg[0] == ">" || reg[0] == "<")
                        l = l.replace(reg[0], "-");
                    else
                        l = l.replace(reg[0], "|");
                    map.carts.push(new Cart(reg.index, line, reg[0]));
                }
                map.push(l);
                ++line;
            }
        });
        done(map);
    });
}

function Map() {
    this.world = [];
    this.carts = [];
}

Map.prototype.show = function() {
    var data = [];
    this.world.forEach(row => {
        var str = "";
        row.forEach(c => str += (c == '|' || c == '-' ? ' ' : c));
        data.push(str);
    });
    this.carts.forEach(c => {
        if (!data[c.py] || c.px >= data[c.py].length) return;
        data[c.py] = data[c.py].substring(0, c.px) +'x' +data[c.py].substring(c.px +1);
    });
    data.forEach(row => {
        console.log(row);
    });
    for (var i =data[0].length; i > 0; --i)
        process.stdout.write('-');
    process.stdout.write("\n");
}

Map.prototype.tick = function() {
    this.carts.sort((a, b) => {
        if (a.py == b.py)
            return a.px -b.px;
        return a.py -b.py;
    });
    this.carts.some(c => {
        if (c.colided)
            return;
        c.move(this);
        var colide = this.colision(c.px, c.py);
        if (colide) {
            colide.forEach(c => c.colided = true);
        }
    });
}

Map.prototype.nbCartAlive = function() {
    var live = 0;
    this.carts.forEach(c => c.colided ? live : ++live);
    return live;
}

Map.prototype.colision = function(px, py) {
    var colided = [];
    this.carts.forEach(c => {
        if (c.px == px && c.py == py && !c.colided)
            colided.push(c);
    });
    return colided.length > 1 ? colided : null;
}

Map.prototype.isCross = function(px, py) {
    var c = this.world[py][px];
    return c == '/' || c == '\\' || c == '+' ? c : null;
}

Map.prototype.push = function(line) {
    var l = [];
    for (var i =0, len = line.length; i < len; ++i)
        l[i] = line.charAt(i);
    this.world.push(l);
}

function Cart(px, py, direction) {
    this.px = px;
    this.py = py;
    this.colided = false;
    this.nextTurn = 0;
    this.id = px +"x" +py;
    switch (direction) {
        case '>':
            this.direction = [1, 0];
            break;
        case '<':
            this.direction = [-1, 0];
            break;
        case '^':
            this.direction = [0, -1];
            break;
        case 'v':
            this.direction = [0, 1];
            break;
    }
}

Cart.prototype.move = function(map) {
    this.px += this.direction[0];
    this.py += this.direction[1];
    var cross = map.isCross(this.px, this.py);
    if (!cross)
        return;
    if (cross == '+') {
        if (this.nextTurn == 0)
            this.direction = [ this.direction[1], -this.direction[0] ];
        else if (this.nextTurn == 2)
            this.direction = [ -this.direction[1], this.direction[0] ];
        this.nextTurn = (this.nextTurn +1) %3;
    } else {
        var factor = cross == '/' ? -1 : 1;
        this.direction = [ this.direction[1] *factor, this.direction[0] *factor ];
    }
}

function ex1() {
    read(map => {
        while (map.nbCartAlive() == map.carts.length)
            map.tick();
        map.carts.some(c => c.colided ? (console.log(c) || true) : null);
    });
}

function ex2() {
    read(map => {
        while (map.nbCartAlive() > 1)
            map.tick();
        map.carts.some(c => c.colided ? null : (console.log(c) || true));
    });
}

ex1();
ex2();