sussyKey = null;
isShift = false;
isAlt = false;

document.addEventListener("keydown", function(modifierDownListener) {
    // User presses shift
    if (modifierDownListener.keyCode == 16) {
        isShift = true;
    }
    // User presses alt
    if (modifierDownListener.keyCode == 18) {
        isAlt = true;
    }
});

document.addEventListener("keyup", function(modifierUpListener) {
    // User releases shift
    if (modifierUpListener.keyCode == 16) {
        isShift = false;
    }
    // User releases alt
    if (modifierUpListener.keyCode == 18) {
        isAlt = false;
    }
});

document.addEventListener("keyup", function(sussyListener) {
    switch (sussyListener.keyCode) {
        case 87:
            sussyKey = "W";
            break;
        case 65:
            sussyKey = "A";
            break;
        case 83:
            sussyKey = "S";
            break;
        case 68:
            sussyKey = "D";
            break;
        case 81:
            sussyKey = "Q";
            break;
        case 88:
            sussyKey = "X";
            break;
        case 90:
            sussyKey = "Z";
            break;
        case 72:
            sussyKey = "H";
            break;
    };
});

function tryCreatePixel(_element,_x,_y) {
    if(!elements[_element]) {
        throw new Error("Element " + _element + " doesn't exist!");
    };
    if(isEmpty(_x,_y)) {
        createPixel(_element,_x,_y);
        return true;
    } else {
        return false;
    }
}

function controllablePixelTryCreatePixelNullCheck(_element,_x,_y) {
    if(!elements[_element]) { //catch the null
        return false;
    };
    if(isEmpty(_x,_y)) {
        tryCreatePixel(_element,_x,_y);
        return true;
    } else {
        return false;
    }
}

elements.controllable_pixel = {
    color: "#FFFFFF",
    colorOn: "#FFFF00",
    behavior: behaviors.WALL,
    state: "solid",
    density: 2000,
    maxSize: 1,
    conduct: 1,
    hardness: 1,
    tick: function(pixel) {
        var xx = pixel.x;
        var yy = pixel.y;
        userElement = currentElement;
        if(userElement === pixel.element) {
            userElement = null;
        };
        if(isShift && !isAlt) {
            sussyKey === "Z" ? pixel.color = "rgb(255,191,127)" : pixel.color = "rgb(255,127,127)";
        }
        if(isAlt && !isShift) {
            sussyKey === "Z" ? pixel.color = "rgb(191,255,127)" : pixel.color = "rgb(127,255,127)";
        }
        if(isAlt && isShift) {
            sussyKey === "Z" ? pixel.color = "rgb(255,255,0)" : pixel.color = "rgb(255,255,127)";
        }
        if(!isAlt && !isShift) {
            sussyKey === "Z" ? pixel.color = "rgb(255,255,191)" : pixel.color = "rgb(255,255,255)";
        }
        if(sussyKey !== null) {
            switch (sussyKey) {
                case "W":
                    isAlt ? controllablePixelTryCreatePixelNullCheck(userElement,xx,yy-1) : tryMove(pixel,xx,yy-1);
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "A":
                    isAlt ? controllablePixelTryCreatePixelNullCheck(userElement,xx-1,yy) : tryMove(pixel,xx-1,yy);
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "S":
                    isAlt ? controllablePixelTryCreatePixelNullCheck(userElement,xx,yy+1) : tryMove(pixel,xx,yy+1);
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "D":
                    tryMove(pixel,xx+1,yy);
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "H": //Alt+D is something else in some browsers.
                    if(isAlt) {
                        controllablePixelTryCreatePixelNullCheck(userElement,xx+1,yy);
                    };
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "X":
                    explodeAt(xx,yy,5)
                    if(!isShift) {
                        sussyKey = null;
                    }
                    break;
                case "Z":
                    if (!pixel.charge && !pixel.chargeCD && !isEmpty(pixel.x,pixel.y,true)) {
                        pixel.charge = 1;
                    }
                    if(!isShift === 0) {
                        sussyKey = null;
                    }
                    break;
                case "Q": //Use if a key gets stuck
                    sussyKey = null;
                    isShift = null;
                    isAlt = null;
                    break;
            }
        }
    },
}