// Programmatic POSITIONING + HIGHLIGHT test for the win7 context menu.
//
//   bun scripts/menu-probe.ts
//
// Why this exists: 7.css declares `position: relative` on ul[role=menu] (it
// needs it for the gutter stripe and submenus), and the `skin` layer outranks
// `utilities` — so Tailwind's `.fixed` on the app's own menu lost, its
// [style.left/top.px] became FLOW offsets, and every right-click menu rendered
// below the viewport of the h-screen frame. Nothing about the idle window
// changes when that breaks, so the screenshot harness (scripts/shot.ts) cannot
// see it, and hover-probe.ts tests a different axis. This script renders the
// menu markup at declared coordinates and pixel-scans whether it actually
// landed there.
//
// It carries its own control: a second menu WITHOUT the `w7-ctx` marker class,
// i.e. the bug verbatim. That one must stay invisible — if it ever shows up,
// 7.css stopped forcing `relative` and this probe's premise is stale.
//
// It also checks the item HIGHLIGHT, using hover-probe.ts's trick (`:hover`
// rewritten to a `.simhover` class, since headless Firefox has no pointer):
// 7.css paints hovered items with a translucent gradient wash, and this app
// wants one flat colour. A gradient is detectable as vertical colour spread
// down a text-free strip of the item, so "is it flat?" is a measurement, not
// an opinion. What canNOT be measured here is the 1s afterglow fade — a
// temporal effect — but its cause is structural (`button::before` still has
// `content`), and this probe would show the glow's colour if the pseudo ever
// came back.
//
// Inherits shot.ts's constraints: dedicated Firefox profile (a running Firefox
// holds the default profile's lock), and the page must be written INTO the
// dist folder or strict_origin_policy silently unstyles it.
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 WORK = path.join(ROOT, ".shot");

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

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`);

// Hover as a CLASS: same rewrite hover-probe.ts uses, for the same reason —
// `--screenshot` has no pointer. `:hover` has no partial-token hazard.
const css = await Bun.file(path.join(DIST, styles)).text();
const PROBE_CSS = "_menu-probe.css";
await Bun.write(path.join(DIST, PROBE_CSS), css.replaceAll(":hover", ".simhover"));

// ---- the probe page ----

// Geometry (CSS px = image px; headless Firefox applies no DPR scaling).
const MENU_X = 200;
const MENU_Y = 100;
const CONTROL_X = 560;
const MENU_W = 200;

// Mirrors ui/src/app/skins/7like/context-menu.ts EXACTLY where it matters:
// ul[role=menu] > li[role=menuitem] > button, the `w7-ctx fixed` class pair,
// and left/top as inline pixel styles. `w7-ctx` is what the skinfix rule in
// 7like.css keys on; the control deliberately omits it.
const menu = (x: number, marker: boolean) => `
  <ul role="menu" tabindex="-1"
      class="${marker ? "w7-ctx " : ""}fixed z-50 outline-none"
      style="left: ${x}px; top: ${MENU_Y}px; width: ${MENU_W}px">
    <li role="menuitem"><button type="button"${marker ? ' class="simhover"' : ""}>Send to Other Panel</button></li>
    <li role="menuitem" class="has-divider"><button type="button">Rename</button></li>
    <li role="menuitem"><button type="button">Copy Path</button></li>
    <li role="menuitem" aria-disabled="true"><button type="button">Delete</button></li>
  </ul>`;

// The frame reproduces the app's: .window.w7-frame is a 100vh flex column and
// <app-context-menu> is one of its LAST children, so a menu that falls back to
// static flow lands past the bottom edge — which is the whole bug.
// The body gets an explicit white background (inline, so no layer can touch
// it) purely so "is anything drawn here?" is an unambiguous question.
const page = `<!doctype html>
<html class="win7" lang="en">
<head><meta charset="utf-8"><link rel="stylesheet" href="${PROBE_CSS}">
</head>
<body>
  <div class="window glass w7-frame active" style="display: flex; flex-direction: column; height: 100vh">
    <div class="title-bar">
      <div class="title-bar-text">miniSCP</div>
      <div class="title-bar-controls"><button aria-label="Close"></button></div>
    </div>
    <div class="window-body" style="flex: 1; min-height: 0; background: #fff"></div>
    ${menu(MENU_X, true)}
    ${menu(CONTROL_X, false)}
  </div>
</body></html>`;

const pagePath = path.join(DIST, "_menu-probe.html");
await Bun.write(pagePath, page);

// ---- shoot ----

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

const out = path.join(WORK, "menu-probe.png");
const proc = Bun.spawnSync(
	["firefox", "--headless", "--profile", profile, "--screenshot", out, "--window-size", "800,400", `file://${pagePath}`],
	{ cwd: ROOT, stdout: "pipe", stderr: "pipe" },
);
if (!existsSync(out)) {
	console.error(proc.stderr.toString().trim());
	fail("firefox produced no image");
}

// ---- pixel scan ----

/**
 * Count pixels that are visibly NOT the white window body: the menu's border
 * (#0006 over white ≈ #999), its shadow and its black item text all qualify.
 * A menu that rendered where it was told fills this with hundreds of them; an
 * empty white region scores 0.
 */
async function inkCount(img: string, x: number, y: number, w: number, h: number): Promise<number> {
	const p = Bun.spawnSync(["magick", img, "-crop", `${w}x${h}+${x}+${y}`, "+repage", "txt:"], {
		stdout: "pipe",
		stderr: "pipe",
	});
	let count = 0;
	for (const line of p.stdout.toString().split("\n").slice(1)) {
		const m = /\((\d+),(\d+),(\d+)/.exec(line);
		if (!m) continue;
		const [r, g, b] = [Number(m[1]), Number(m[2]), Number(m[3])];
		if (Math.max(r, g, b) < 200) count++;
	}
	return count;
}

/**
 * Colour spread down a text-free strip of the first (force-hovered) item: the
 * ul's own 2px padding + the item's 1px border put the item's background at
 * x >= menu+3, and its 32px left padding keeps label text out to menu+32. So a
 * column at menu+5..menu+26 is pure fill — except for the gutter stripe, which
 * 7.css puts at left: 28px. A flat colour reads 0 spread; a gradient does not.
 */
async function fillSpread(
	img: string,
	x: number,
	y: number,
	w: number,
	h: number,
): Promise<{ spread: number; mean: [number, number, number] }> {
	const p = Bun.spawnSync(["magick", img, "-crop", `${w}x${h}+${x}+${y}`, "+repage", "txt:"], {
		stdout: "pipe",
		stderr: "pipe",
	});
	const lo: number[] = [255, 255, 255];
	const hi: number[] = [0, 0, 0];
	const sum = [0, 0, 0];
	let n = 0;
	for (const line of p.stdout.toString().split("\n").slice(1)) {
		const m = /\((\d+),(\d+),(\d+)/.exec(line);
		if (!m) continue;
		for (let c = 0; c < 3; c++) {
			const v = Number(m[c + 1]);
			lo[c] = Math.min(lo[c], v);
			hi[c] = Math.max(hi[c], v);
			sum[c] += v;
		}
		n++;
	}
	if (!n) return { spread: -1, mean: [0, 0, 0] };
	return {
		spread: Math.max(hi[0] - lo[0], hi[1] - lo[1], hi[2] - lo[2]),
		mean: [Math.round(sum[0] / n), Math.round(sum[1] / n), Math.round(sum[2] / n)],
	};
}

// Inset by 2px so the scan cannot straddle the region's own edge.
const BOX = { w: MENU_W - 4, h: 60 };
const placed = await inkCount(out, MENU_X + 2, MENU_Y + 2, BOX.w, BOX.h);
const control = await inkCount(out, CONTROL_X + 2, MENU_Y + 2, BOX.w, BOX.h);

console.log("[menu-probe] ink at the declared coordinates:\n");
console.log("  menu                        px  verdict");
console.log(
	`  w7-ctx (position: fixed)${String(placed).padStart(6)}  ${placed > 0 ? "placed" : "MISSING: menu did not render where it was told"}`,
);
console.log(
	`  control (no marker)     ${String(control).padStart(6)}  ${control > 0 ? "NOTE: 7.css no longer forces relative — premise stale" : "off-viewport, as expected"}`,
);
// The force-hovered first item: fill strip, and the same strip on the item
// below it as a not-hovered reference (which must stay the menu surface).
const FILL = { x: MENU_X + 5, w: 21, h: 14 };
const hovered = await fillSpread(out, FILL.x, MENU_Y + 7, FILL.w, FILL.h);
const resting = await fillSpread(out, FILL.x, MENU_Y + 34, FILL.w, FILL.h);
const FLAT_MAX = 6; // antialiasing tolerance; 7.css's wash spreads far wider

console.log("\n[menu-probe] item highlight (force-hovered vs resting):\n");
console.log("  item                    mean rgb        spread  verdict");
console.log(
	`  hovered (.simhover)     ${hovered.mean.join(",").padEnd(15)} ${String(hovered.spread).padStart(6)}  ${
		hovered.spread <= FLAT_MAX ? "flat" : "GRADIENT: highlight is not a flat colour"
	}`,
);
console.log(`  resting                 ${resting.mean.join(",").padEnd(15)} ${String(resting.spread).padStart(6)}  reference`);

console.log(`\n[menu-probe] image: ${out}`);

let failed = false;
if (placed === 0) {
	console.log("[menu-probe] the context menu is positioned in FLOW again — see 7like.css .w7-ctx");
	failed = true;
}
if (hovered.spread > FLAT_MAX) {
	console.log("[menu-probe] the item highlight regained a gradient — see the menu block in 7like.css");
	failed = true;
}
if (hovered.mean.join(",") === resting.mean.join(",")) {
	console.log("[menu-probe] hovered and resting items are identical — the highlight is not painting at all");
	failed = true;
}
if (failed) process.exit(2);
console.log("[menu-probe] clean");