// Repaint the cream moon discs (and their tan rim) with the background colour, in the given x-ranges only.
const sharp = require("module").createRequire("/home/ubuntu/kalki-cli/projects/mybazaar-web/package.json")("sharp");
const [, , input, output, ...ranges] = process.argv;
(async () => {
	const { data, info } = await sharp(input).removeAlpha().raw().toBuffer({ resolveWithObject: true });
	const { width, height } = info;
	const spans = ranges.map((r) => r.split("-").map(Number));
	const inSpan = (x) => spans.some(([a, b]) => x >= a && x <= b);
	const bg = [data[0], data[1], data[2]];
	const warm = (i) => data[i] - data[i + 2];
	const mask = new Uint8Array(width * height);
	for (let y = 0; y < height; y++) for (let x = 0; x < width; x++) {
		const i = (y * width + x) * 3;
		if (inSpan(x) && warm(i) > 28 && data[i] > 170) mask[y * width + x] = 1;
	}
	// Grow the mask four times over faintly warm pixels: the anti-aliased rim is up to four pixels wide.
	for (let pass = 0; pass < 4; pass++) {
		const grow = mask.slice();
		for (let y = 1; y < height - 1; y++) for (let x = 1; x < width - 1; x++) {
			const p = y * width + x;
			if (mask[p] || !inSpan(x)) continue;
			const i = p * 3;
			if (warm(i) > 3 && data[i] > 150 && (mask[p - 1] || mask[p + 1] || mask[p - width] || mask[p + width])) grow[p] = 1;
		}
		mask.set(grow);
	}
	// One flat fill in the corner colour, which is exactly what remove-background samples and clears.
	let n = 0;
	for (let p = 0; p < mask.length; p++) if (mask[p]) { data.set(bg, p * 3); n++; }
	await sharp(data, { raw: { width, height, channels: 3 } }).png().toFile(output);
	console.log(`repainted ${n} px`);
})();