class CanvasRenderer {
  
	constructor(w, h) {
		const canvas = document.createElement("canvas");
		this.w = canvas.width = w;
		this.h = canvas.height = h;
		this.view = canvas;
		this.ctx = canvas.getContext("2d");
		this.ctx.textBaseLine = "top";
	}

	setPixelated() {
		this.ctx["imageSmoothingEnabled"] = false;       /* standard */
		this.ctx["mozImageSmoothingEnabled"] = false;    /* Firefox */
		this.ctx["oImageSmoothingEnabled"] = false;      /* Opera */
		this.ctx["webkitImageSmoothingEnabled"] = false; /* Safari */
		this.ctx["msImageSmoothingEnabled"] = false;     /* IE */
	}

	render(container, clear = true) {
		const { ctx } = this;
		function renderRec(container) {
			// Render container children
			container.children.forEach(child => {
				if (child.visible == false) {
					return;
				}

				ctx.save();

				if (child.pos) {
					ctx.translate(Math.round(child.pos.x), Math.round(child.pos.y));
				}

				if (child.anchor) {
					ctx.translate(child.anchor.x, child.anchor.y);
				}

				if (child.scale) {
					ctx.scale(child.scale.x, child.scale.y);
				}

				if (child.rotation) {
					const px = child.pivot ? child.pivot.x : 0;
					const py = child.pivot ? child.pivot.y : 0;
					ctx.translate(px, py);
					ctx.rotate(child.rotation);
					ctx.translate(-px, -py);
				}

				if (child.text) {
					const { font, fill, align } = child.style;
					if (font) ctx.font = font;
					if (fill) ctx.fillStyle = fill;
					if (align) ctx.textAlign = align;
					ctx.fillText(child.text, 0, 0);
				}

				else if (child.texture) {
					const img = child.texture.img;
					if (child.tileW && child.tileH) {
						ctx.drawImage(
							img,
							child.frame.x * child.tileW,
							child.frame.y * child.tileH,
							child.tileW, child.tileH,
							0, 0,
							child.tileW, child.tileH
						);
					} else if (child.imgPos && child.width && child.height) {
						ctx.drawImage(
							img,
							child.imgPos.x,
							child.imgPos.y,
							child.width, child.height,
							0, 0,
							child.width, child.height
						);
					} else {
						ctx.drawImage(img, 0, 0);
					}
				} else if (child.style && child.w && child.h) {
					ctx.fillStyle = child.style.fill;
					ctx.fillRect(0, 0, child.w, child.h);
				} else if (child.style && child.radius) {
					var gradient = ctx.createRadialGradient(0, 0, 50, 0, 0, 50);
					gradient.addColorStop(0, child.style.start);
					gradient.addColorStop(1, child.style.stop);

					ctx.arc(0, 0, child.radius, 0, 2 * Math.PI);
					ctx.fillStyle = gradient;

					ctx.fill();
				} else if (child.style && child.target) {
                  	ctx.beginPath();
					ctx.moveTo(0,0);
					ctx.lineTo(child.target.x, child.target.y);
					ctx.strokeStyle = child.style;
					ctx.stroke();
				}

				// Handle children with children
				if (child.children) {
					renderRec(child);
				}
				ctx.restore();
			});
		}
		if (clear) {
			ctx.clearRect(0, 0, this.w, this.h);
		}
		renderRec(container);
	}
}
module.exports = CanvasRenderer;