/** TODO LIST FOR LAYERS
    - move the tmp layer so that it's always right below the active layer
    - when the move tool is selected (to move a selection), the tmp layer must be put right above the 
        active layer to show a preview
*/


/** Handler class for a single canvas (a single layer)
 *
 * @param width Canvas width
 * @param height Canvas height
 * @param canvas HTML canvas element
 */
function Layer(width, height, canvas) {
    this.canvasSize = [width, height],
    this.canvas = canvas,
    this.context = this.canvas.getContext("2d"),
    // Initializes the canvas
    this.initialize = function() {
        var maxHorizontalZoom = Math.floor(window.innerWidth/this.canvasSize[0]*0.75);
        var maxVerticalZoom = Math.floor(window.innerHeight/this.canvasSize[1]*0.75);

        zoom = Math.min(maxHorizontalZoom,maxVerticalZoom);
        if (zoom < 1) zoom = 1;

        //resize canvas
        this.canvas.width = this.canvasSize[0];
        this.canvas.height = this.canvasSize[1];
        this.canvas.style.width = (this.canvas.width*zoom)+'px';
        this.canvas.style.height = (this.canvas.height*zoom)+'px';

        //unhide canvas
        this.canvas.style.display = 'block';

        //center canvas in window
        this.canvas.style.left = 64+canvasView.clientWidth/2-(this.canvasSize[0]*zoom/2)+'px';
        this.canvas.style.top = 48+canvasView.clientHeight/2-(this.canvasSize[1]*zoom/2)+'px';
    },
    // Resizes canvas
    this.resize = function() {
        let newWidth = (this.canvas.width * zoom) + 'px';
        let newHeight = (this.canvas.height *zoom)+ 'px';

        this.canvas.style.width = newWidth;
        this.canvas.style.height = newHeight;
    },
    // Copies the otherCanvas' position and size
    this.copyData = function(otherCanvas) {
        this.canvas.style.width = otherCanvas.canvas.style.width;
        this.canvas.style.height = otherCanvas.canvas.style.height;

        this.canvas.style.left = otherCanvas.canvas.style.left;
        this.canvas.style.top = otherCanvas.canvas.style.top;
    }
}