/**
 * packs-check — the mechanical guard of the pack tier's P contract
 * (docs/architecture/packs.md). Small on purpose: packs are exempt from the
 * acceptance matrix, NOT from discipline.
 *
 * Checks (all error-level):
 *   P-3  no raw platform APIs in `src/packs/` — everything goes through the
 *        injected ports (`SceneDom` etc.). Raw `requestAnimationFrame`,
 *        `new ResizeObserver/IntersectionObserver/MutationObserver`,
 *        `addEventListener`, `setTimeout/setInterval`, `matchMedia` = error.
 *   S-1  no scoped `<style>` blocks in pack `.svelte` files — the consumer
 *        styles the host via class/style; the pack never competes with eidos.
 *   R-1  every `effects/*.ts` module registers its effect AND merges its
 *        params type (`registerAmbientEffect` + `declare module`), so the
 *        typed registry can't drift from the runtime one.
 *
 * P-1/P-2/P-5/P-6 are enforced structurally by `EngineScene` (type-required
 * `reduce`, handle teardown, aria-hidden canvas, IO pause + budget) — no
 * static check needed here.
 */

import { readdirSync, readFileSync, statSync } from 'node:fs';
import { join, relative } from 'node:path';

const REPO = process.cwd();
const PACKS_DIR = join(REPO, 'src', 'packs');

interface Violation {
	rule: string;
	file: string;
	line: number;
	detail: string;
}

const RAW_API_RE =
	/\brequestAnimationFrame\s*\(|\bcancelAnimationFrame\s*\(|new\s+(ResizeObserver|IntersectionObserver|MutationObserver)\b|\baddEventListener\s*\(|\bsetTimeout\s*\(|\bsetInterval\s*\(|\bmatchMedia\s*\(/;

function walk(dir: string, out: string[] = []): string[] {
	for (const entry of readdirSync(dir)) {
		const path = join(dir, entry);
		if (statSync(path).isDirectory()) walk(path, out);
		else if (/\.(ts|svelte)$/.test(entry) && !/\.test\./.test(entry)) out.push(path);
	}
	return out;
}

function main(): void {
	const violations: Violation[] = [];
	let files: string[] = [];
	try {
		files = walk(PACKS_DIR);
	} catch {
		console.error('packs-check: cannot scan src/packs/');
		process.exitCode = 1;
		return;
	}
	if (files.length === 0) {
		console.error('packs-check: empty source corpus under src/packs/');
		process.exitCode = 1;
		return;
	}

	for (const file of files) {
		const rel = relative(REPO, file);
		const src = readFileSync(file, 'utf8');
		const lines = src.split('\n');

		lines.forEach((line, i) => {
			// Comments may NAME the raw APIs (docs of what the port replaces).
			const code = line.replace(/\/\/.*$/, '').replace(/^\s*\*.*$/, '');
			if (RAW_API_RE.test(code)) {
				violations.push({
					rule: 'P-3',
					file: rel,
					line: i + 1,
					detail: `raw platform API — use the injected port (${code.trim().slice(0, 60)}…)`
				});
			}
		});

		if (file.endsWith('.svelte') && /<style\b/.test(src)) {
			violations.push({
				rule: 'S-1',
				file: rel,
				line: lines.findIndex((l) => /<style\b/.test(l)) + 1,
				detail: 'scoped <style> in a pack component — style the host via class/style'
			});
		}

		if (/[\\/]effects[\\/][^\\/]+\.ts$/.test(file)) {
			if (!src.includes('registerAmbientEffect(')) {
				violations.push({
					rule: 'R-1',
					file: rel,
					line: 1,
					detail: 'effect module does not register its effect (registerAmbientEffect)'
				});
			}
			if (!src.includes('declare module')) {
				violations.push({
					rule: 'R-1',
					file: rel,
					line: 1,
					detail: 'effect module does not merge its params type (declare module …/registry)'
				});
			}
		}
	}

	if (violations.length > 0) {
		for (const v of violations) {
			console.error(`ERROR [${v.rule}] ${v.file}:${v.line} — ${v.detail}`);
		}
		console.error(`\npacks-check: ${violations.length} error(s) across ${files.length} files`);
		process.exit(1);
	}
	console.log(`packs-check: 0 error(s) across ${files.length} files`);
}

main();