import type { Framebuffer } from "./Framebuffer.ts";

interface TextureImageData {
	data: Uint8ClampedArray;
	width: number;
	height: number;
}

/** Clears the framebuffer and depth buffer to initial state. */
export class FramebufferClear {
	clear(framebuffer: Framebuffer, r = 0, g = 0, b = 0, a = 255): void {
		// ImageData is RGBA byte order; on little-endian Uint32Array reads ABGR.
		const packed = (a << 24) | (b << 16) | (g << 8) | r;
		framebuffer.u32.fill(packed);
	}

	clearTexture(framebuffer: Framebuffer, texture: TextureImageData): void {
		const src = texture.data;
		const srcWidth = texture.width;
		const srcHeight = texture.height;
		if (srcWidth <= 0 || srcHeight <= 0) return;

		const dst = framebuffer.data;
		const dstWidth = framebuffer.width;
		const dstHeight = framebuffer.height;
		for (let y = 0; y < dstHeight; y++) {
			const srcY = ((y * srcHeight) / dstHeight) | 0;
			for (let x = 0; x < dstWidth; x++) {
				const srcX = ((x * srcWidth) / dstWidth) | 0;
				const srcIndex = (srcY * srcWidth + srcX) << 2;
				const dstIndex = (y * dstWidth + x) << 2;
				dst[dstIndex] = src[srcIndex];
				dst[dstIndex + 1] = src[srcIndex + 1];
				dst[dstIndex + 2] = src[srcIndex + 2];
				dst[dstIndex + 3] = src[srcIndex + 3];
			}
		}
	}
}