(function() {
    var Keyboard;
    window.Game = window.Game || {};
    window.Keyboard = window.Game.Keyboard = Keyboard = {};

    var keyMap = {
        27: "ESC", 32: "SPACE",
        37: "LEFT", 38: "UP", 39: "RIGHT", 40: "DOWN",
        65: "A", 66: "B", 67: "C", 68: "D", 69: "E",
        70: "F", 71: "G", 72: "H", 73: "I", 74: "J",
        75: "K", 76: "L", 77: "M", 78: "N", 79: "O",
        80: "P", 81: "Q", 82: "R", 83: "S", 84: "T",
        85: "U", 86: "V", 87: "W", 88: "X", 89: "Y", 90: "Z",
    };

    // TODO: probably should use hasOwnProperty
    for (i in keyMap) {
        Keyboard[keyMap[i]] = {
            down: false,
            up: true,
            pressed: false,
        };
    }

    Keyboard.init = function() {
        document.addEventListener("keydown", Keyboard.onKeyDown);
        document.addEventListener("keyup", Keyboard.onKeyUp);
    };

    Keyboard.onKeyDown = function(e) {
        var keyName = keyMap[e.keyCode];
        var key = Keyboard[keyName];
        if (!key) return;
        if (!key.down) {
            key.pressed = true;
        }
        key.down = true;
        key.up = false;
    };

    Keyboard.onKeyUp = function(e) {
        var keyName = keyMap[e.keyCode];
        var key = Keyboard[keyName];
        if (!key) return;
        key.down = false;
        key.pressed = false;
        key.up = true;
    };

    Keyboard.update = function() {
        for (i in keyMap) {
            Keyboard[keyMap[i]].pressed = false;
        }
    };

}());