// Headless screenshot of the skin harness, so the Win7 look can be reviewed
// visually during development rather than inferred from a clean build log.
//
//   bun scripts/shot.ts [--dark] [--width 1200] [--height 1400] [--out path.png]
//   bun scripts/shot.ts --url http://localhost:4200   (any page, not just the harness)
//
// Firefox is used because it ships on this machine and has a built-in
// --screenshot mode; no Chromium/puppeteer download is needed. Two constraints
// it imposes:
//   - a DEDICATED PROFILE is mandatory. A running Firefox holds a lock on the
//     default profile and the headless run aborts with "Firefox is already
//     running, but is not responding".
//   - it renders with Gecko, NOT the WebKitGTK engine the app actually uses.
//     Good enough for skin fidelity (layout, colour, gradients, borders);
//     useless for engine-specific behaviour or native window transparency.
//     Real confirmation is still `bun run start`.
//
// The harness links the REAL hashed stylesheet from ui/dist (produced by the
// normal `bun run build:ui`), so there is no second build pipeline to keep in
// sync.
//
// The composed page is written INTO that same dist folder, and this is not
// incidental: Firefox's security.fileuri.strict_origin_policy stops a file://
// document from loading a stylesheet that lives in a different directory. Host
// the page elsewhere and it renders completely unstyled — which looks exactly
// like "the skin is broken" rather than "the CSS never loaded". Keeping them
// co-located also lets media/ fonts resolve.
import { existsSync, mkdirSync, readdirSync, rmSync } from "node:fs";
import path from "node:path";

const ROOT = path.join(import.meta.dir, "..");
const DIST = path.join(ROOT, "ui", "dist", "ui", "browser");
const HARNESS = path.join(ROOT, "ui", "dev", "harness.html");
const WORK = path.join(ROOT, ".shot");

function arg(name: string): string | undefined {
	const i = process.argv.indexOf(`--${name}`);
	return i >= 0 ? process.argv[i + 1] : undefined;
}
const flag = (name: string) => process.argv.includes(`--${name}`);

function fail(message: string): never {
	console.error(`[shot] ERROR: ${message}`);
	process.exit(1);
}

// ---- resolve the built stylesheet ----

if (!existsSync(DIST)) fail(`no build output at ${DIST} — run: bun run build:ui`);
const styles = readdirSync(DIST).find((f) => f.startsWith("styles-") && f.endsWith(".css"));
if (!styles) fail(`no styles-*.css in ${DIST} — run: bun run build:ui`);

// ---- compose the page ----

mkdirSync(WORK, { recursive: true });
const profile = path.join(WORK, "profile");
mkdirSync(profile, { recursive: true });

const url = arg("url");
let target: string;

if (url) {
	target = url;
} else {
	const dark = flag("dark");
	let html = await Bun.file(HARNESS).text();
	// replaceAll, not replace: the harness documents its own {{STYLES}} token in
	// a header comment that precedes the <link>, so a first-match replace
	// substitutes the comment and silently leaves the stylesheet unlinked.
	html = html.replaceAll("{{STYLES}}", styles); // relative: page sits next to it
	// The preload bakes these attributes in the real app; do it by hand here.
	if (dark) html = html.replace('<html class="win7"', '<html class="win7" data-theme="dark"');
	const page = path.join(DIST, dark ? "_harness.dark.html" : "_harness.light.html");
	await Bun.write(page, html);
	target = `file://${page}`;
}

// ---- shoot ----

const out = path.resolve(arg("out") ?? path.join(WORK, flag("dark") ? "dark.png" : "light.png"));
const width = arg("width") ?? "1200";
const height = arg("height") ?? "1500";

// A stale lock from a killed run makes every later shot fail confusingly.
rmSync(path.join(profile, "parent.lock"), { force: true });

const proc = Bun.spawnSync(
	[
		"firefox",
		"--headless",
		"--profile",
		profile,
		"--screenshot",
		out,
		"--window-size",
		`${width},${height}`,
		target,
	],
	{ cwd: ROOT, stdout: "pipe", stderr: "pipe" },
);

if (!existsSync(out)) {
	console.error(proc.stderr.toString().trim());
	fail("firefox produced no image (see stderr above)");
}
console.log(`[shot] ${out}`);