/**
 * blocks-check — the mechanical guard of the blocks tier's B contract
 * (docs/architecture/blocks.md). Small on purpose: blocks are exempt from the
 * acceptance matrix, NOT from discipline.
 *
 * Checks:
 *   B-2      no raw interactive natives (`<button/input/select/textarea/a>`)
 *            in block `.svelte` files — every interactive element is a canon
 *            eidos component.
 *   B-4/B-1  import direction: blocks never import `$packs` or `$uix/sema`;
 *            nothing in the canon (`src/uix/{morfo,soma,sema,eidos,
 *            active-uix,langs}`) nor in `src/{arts,libs,packs}` imports the
 *            blocks tier.
 *   B-4      import allowlist (hard boundary 1): a block imports only `$uix`,
 *            the public arts, `$libs/forms`, `svelte` and its own relatives.
 *            Anything else is the boundary being crossed, not a new need.
 *   B-10     a block never imports another block (declared exception: the
 *            shells allowlist).
 *   D-BLK.2  no `.css` files under the tier; a scoped `<style>` requires a
 *            `justified:` comment marker (layout-components-first).
 *   B-9      every block folder ships `README.md` and a demo route at
 *            `web/routes/blocks/{kebab}/+page.svelte`.
 *   B-9      the README carries the template's four sections, and the block
 *            has a shipped entry in the demo catalog (`_lib/catalog.ts`) —
 *            the single list the rail and the gallery read.
 *   B-8      the README declares its landmark + heading hierarchy: which
 *            sectioning element and which levels the block emits.
 *
 * Self-testing: the detectors are asserted against inline fixtures on every
 * run (a raw `<button>` fixture MUST be flagged, a `<Button>` fixture must
 * not, …), so a silently-broken regex fails the guard itself.
 */

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

const REPO = process.cwd();
const BLOCKS_DIR = join(REPO, 'src', 'uix', 'blocks');
const DEMO_DIR = join(REPO, 'web', 'routes', 'blocks');
const CATALOG_FILE = join(DEMO_DIR, '_lib', 'catalog.ts');
const ARTS_DIR = join(REPO, 'src', 'arts');

// B-10 declared exception: the shells compose F1 pieces and blocks by design.
const SHELL_ALLOWLIST = new Set(['app-shell', 'docs-shell']);

// The public arts a block may import, DERIVED from the tree (`$name` →
// `src/arts/name`) — a hand-written list falls behind the day an art lands.
const PUBLIC_ARTS = new Set(
	existsSync(ARTS_DIR)
		? readdirSync(ARTS_DIR).filter((entry) => statSync(join(ARTS_DIR, entry)).isDirectory())
		: []
);

// The four sections the B-9 template requires of every block README.
/**
 * The B-9 template. `## Equivalencias` joined it when the wave's stretch B
 * landed: the tier's claim is «variants as typed props instead of N dumps», and
 * that claim is only worth something if each block SHOWS which composition of
 * ours reaches each variant of theirs — and names what it does not reach. The
 * rule is switched on LAST on purpose: turning it on before the tables existed
 * would have painted every README red for the length of the wave.
 */
const README_SECTIONS = [
	'## Function',
	'## Composition map',
	'## Decisions',
	'## Equivalencias',
	'## Gaps'
];

// Trees that must never import the blocks tier (B-4).
const OUTSIDE_ROOTS = [
	join(REPO, 'src', 'arts'),
	join(REPO, 'src', 'libs'),
	join(REPO, 'src', 'packs'),
	join(REPO, 'src', 'uix', 'morfo'),
	join(REPO, 'src', 'uix', 'soma'),
	join(REPO, 'src', 'uix', 'sema'),
	join(REPO, 'src', 'uix', 'eidos'),
	join(REPO, 'src', 'uix', 'active-uix'),
	join(REPO, 'src', 'uix', 'langs')
];

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

const RAW_NATIVE_RE = /<(button|input|select|textarea|a)\b/;
const IMPORT_RE = /(?:from|import)\s*['"]([^'"]+)['"]/g;

function norm(path: string): string {
	return path.replace(/\\/g, '/');
}

/**
 * Blank out comments, keeping every line break so line numbers survive. The
 * entry points document their own usage with an `// import { Cta } from
 * '$blocks/cta'` example, and an allowlist that reads prose as code flags it.
 */
function stripComments(src: string): string {
	const blank = (match: string): string => match.replace(/[^\n]/g, ' ');
	return src
		.replace(/\/\*[\s\S]*?\*\//g, blank)
		.replace(/<!--[\s\S]*?-->/g, blank)
		.replace(/(?<!:)\/\/[^\n]*/g, blank);
}

/**
 * Hard boundary 1 (B-4): what a block is allowed to import. `$uix/sema`,
 * `$packs` and cross-block imports are rejected earlier with their own rule,
 * so this is the catch-all for everything the boundary never named.
 */
function isAllowedSpec(spec: string): boolean {
	if (spec.startsWith('./') || spec.startsWith('../')) return true;
	if (spec === 'svelte' || spec === 'svelte/elements') return true;
	if (spec === '$uix' || spec.startsWith('$uix/')) return true;
	if (spec === '$blocks' || spec.startsWith('$blocks/')) return true;
	if (spec === '$libs/forms' || spec.startsWith('$libs/forms/')) return true;
	const art = /^\$([a-z0-9-]+)(?:\/|$)/.exec(spec);
	return art !== null && PUBLIC_ARTS.has(art[1]);
}

function isUnder(abs: string, root: string): boolean {
	return norm(abs).startsWith(norm(root) + '/');
}

/** Resolve an import specifier to an absolute path when it targets the repo. */
function resolveSpec(fileAbs: string, spec: string): string | null {
	if (spec.startsWith('./') || spec.startsWith('../')) return resolve(dirname(fileAbs), spec);
	if (spec === '$blocks' || spec.startsWith('$blocks/'))
		return join(BLOCKS_DIR, spec.slice('$blocks'.length + 1));
	if (spec === '$packs' || spec.startsWith('$packs/'))
		return join(REPO, 'src', 'packs', spec.slice('$packs'.length + 1));
	if (spec.startsWith('$uix/')) return join(REPO, 'src', 'uix', spec.slice('$uix/'.length));
	if (spec.startsWith('@/')) return join(REPO, 'src', spec.slice(2));
	return null;
}

/** The block folder a path belongs to, or null. */
function blockOf(abs: string): string | null {
	if (!isUnder(abs, BLOCKS_DIR)) return null;
	return norm(relative(BLOCKS_DIR, abs)).split('/')[0] ?? null;
}

/** Scan one file INSIDE the tier. Pure — safe for self-test fixtures. */
export function scanBlockFile(fileAbs: string, rel: string, src: string): Violation[] {
	const out: Violation[] = [];
	const ownBlock = blockOf(fileAbs);
	const lines = src.split('\n');

	if (fileAbs.endsWith('.svelte')) {
		// B-2 reads CODE, never prose. It used to strip only single-line `<!-- … -->`
		// on each line, so a MULTI-line comment explaining why a native is not used
		// («`interactive` would turn the card into a `<button>`») was flagged as the
		// native itself. `stripComments` already handles every comment shape and
		// keeps the line breaks, which is why line numbers still point true — the
		// same lesson phase 5 applied to the import allowlist, one rule late.
		const codeLines = stripComments(src).split('\n');
		codeLines.forEach((code, i) => {
			if (RAW_NATIVE_RE.test(code)) {
				out.push({
					rule: 'B-2',
					file: rel,
					line: i + 1,
					detail: `raw interactive native — compose the canon component (${code.trim().slice(0, 60)}…)`
				});
			}
		});
		if (/<style\b/.test(src) && !/justified:/.test(src)) {
			out.push({
				rule: 'D-BLK.2',
				file: rel,
				line: lines.findIndex((l) => /<style\b/.test(l)) + 1,
				detail: 'scoped <style> without a `/* justified: … */` marker — layout-components-first'
			});
		}
	}

	const withoutComments = stripComments(src);
	for (const match of withoutComments.matchAll(IMPORT_RE)) {
		const spec = match[1];
		const line = withoutComments.slice(0, match.index).split('\n').length;
		const target = resolveSpec(fileAbs, spec);
		if (spec.startsWith('$packs') || (target && isUnder(target, join(REPO, 'src', 'packs')))) {
			out.push({
				rule: 'B-4',
				file: rel,
				line,
				detail: `a block must not import the packs tier (${spec})`
			});
			continue;
		}
		if (
			spec.startsWith('$uix/sema') ||
			(target && isUnder(target, join(REPO, 'src', 'uix', 'sema')))
		) {
			out.push({
				rule: 'B-1',
				file: rel,
				line,
				detail: `a block must not import sema — perception belongs to the canon (${spec})`
			});
			continue;
		}
		if (target) {
			const targetBlock = blockOf(target);
			if (targetBlock && ownBlock && targetBlock !== ownBlock && !SHELL_ALLOWLIST.has(ownBlock)) {
				out.push({
					rule: 'B-10',
					file: rel,
					line,
					detail: `block "${ownBlock}" imports block "${targetBlock}" — share via canon or duplicate consciously`
				});
				continue;
			}
		}
		if (!isAllowedSpec(spec)) {
			out.push({
				rule: 'B-4',
				file: rel,
				line,
				detail: `import outside hard boundary 1 (${spec}) — a block imports $uix, the public arts, $libs/forms and svelte; anything else is promoted or the app's`
			});
		}
	}
	return out;
}

/** Scan a block README against B-9's template and B-8's landmark duty. Pure. */
export function scanReadme(rel: string, src: string): Violation[] {
	const out: Violation[] = [];
	for (const section of README_SECTIONS) {
		if (!src.split('\n').some((line) => line.trim() === section)) {
			out.push({
				rule: 'B-9',
				file: rel,
				line: 1,
				detail: `README without the "${section}" section of the B-9 template`
			});
		}
	}
	if (!/^\*\*Landmark\b/m.test(src)) {
		out.push({
			rule: 'B-8',
			file: rel,
			line: 1,
			detail:
				'README without a `**Landmark + headings**` declaration — which sectioning element and which heading levels the block emits, and how the app adjusts them'
		});
	}
	return out;
}

/** slug → shipped, read from the demo catalog. Pure. */
export function parseCatalog(src: string): Map<string, boolean> {
	const out = new Map<string, boolean>();
	for (const match of src.matchAll(/\{\s*slug:\s*'([^']+)'[^}]*?shipped:\s*(true|false)\s*\}/g)) {
		out.set(match[1], match[2] === 'true');
	}
	return out;
}

/**
 * Cross-check the live tree against the demo catalog, BOTH ways: a block the
 * catalog does not ship is invisible to the rail and the gallery; a slug it
 * ships without a block behind it is a dead link. Pure.
 */
export function scanCatalog(
	blocks: string[],
	catalog: Map<string, boolean>,
	rel: string
): Violation[] {
	const out: Violation[] = [];
	const live = new Set(blocks);
	for (const block of blocks) {
		if (catalog.get(block) === true) continue;
		out.push({
			rule: 'B-9',
			file: rel,
			line: 1,
			detail: catalog.has(block)
				? `block "${block}" ships but its catalog entry says shipped: false`
				: `block "${block}" has no entry in the demo catalog`
		});
	}
	for (const [slug, shipped] of catalog) {
		if (shipped && !live.has(slug)) {
			out.push({
				rule: 'B-9',
				file: rel,
				line: 1,
				detail: `the catalog ships "${slug}" but there is no block at src/uix/blocks/${slug}`
			});
		}
	}
	return out;
}

/** Scan one file OUTSIDE the tier for imports INTO it. Pure. */
export function scanOutsideFile(fileAbs: string, rel: string, src: string): Violation[] {
	const out: Violation[] = [];
	for (const match of src.matchAll(IMPORT_RE)) {
		const spec = match[1];
		const target = resolveSpec(fileAbs, spec);
		if (
			spec === '$blocks' ||
			spec.startsWith('$blocks/') ||
			(target && (target === BLOCKS_DIR || isUnder(target, BLOCKS_DIR)))
		) {
			out.push({
				rule: 'B-4',
				file: rel,
				line: src.slice(0, match.index).split('\n').length,
				detail: `the canon must not import the blocks tier (${spec})`
			});
		}
	}
	return out;
}

function walk(dir: string, exts: RegExp, out: string[] = []): string[] {
	for (const entry of readdirSync(dir)) {
		const path = join(dir, entry);
		if (statSync(path).isDirectory()) walk(path, exts, out);
		else if (exts.test(entry)) out.push(path);
	}
	return out;
}

/** Assert the detectors against inline fixtures — the permanent negative test. */
function selfTest(): string[] {
	const failures: string[] = [];
	const inHero = join(BLOCKS_DIR, 'hero', 'hero.svelte');
	const inShell = join(BLOCKS_DIR, 'app-shell', 'app-shell.svelte');
	const expectRules = (name: string, got: Violation[], want: string[]) => {
		const gotRules = got.map((v) => v.rule).sort();
		if (JSON.stringify(gotRules) !== JSON.stringify([...want].sort()))
			failures.push(`${name}: expected [${want}], got [${gotRules}]`);
	};

	expectRules(
		'raw <button> flagged',
		scanBlockFile(inHero, 'fixture', '<button onclick={x}>go</button>'),
		['B-2']
	);
	expectRules(
		'canon <Button> + <aside> clean',
		scanBlockFile(inHero, 'fixture', '<aside>\n<Button onclick={x}>go</Button>\n</aside>'),
		[]
	);
	expectRules(
		'packs import flagged',
		scanBlockFile(inHero, 'fixture', "import { mesh } from '$packs/ambient';"),
		['B-4']
	);
	expectRules(
		'sema import flagged',
		scanBlockFile(inHero, 'fixture', "import { pack } from '$uix/sema/components/dialog';"),
		['B-1']
	);
	expectRules(
		'unjustified <style> flagged',
		scanBlockFile(inHero, 'fixture', '<div />\n<style>.x{color:red}</style>'),
		['D-BLK.2']
	);
	expectRules(
		'justified <style> clean',
		scanBlockFile(inHero, 'fixture', '<div />\n<style>/* justified: demo glue */ .x{}</style>'),
		[]
	);
	expectRules(
		'cross-block import flagged',
		scanBlockFile(inHero, 'fixture', "import Pricing from '$blocks/pricing';"),
		['B-10']
	);
	expectRules(
		'shell composing a block allowed',
		scanBlockFile(inShell, 'fixture', "import Hero from '../hero/index.ts';"),
		[]
	);
	expectRules(
		'canon importing $blocks flagged',
		scanOutsideFile(
			join(REPO, 'src', 'uix', 'eidos', 'x.ts'),
			'fixture',
			"import H from '$blocks/hero';"
		),
		['B-4']
	);
	expectRules(
		'canon relative import into blocks flagged',
		scanOutsideFile(
			join(REPO, 'src', 'uix', 'eidos', 'x.ts'),
			'fixture',
			"import H from '../blocks/hero/index.ts';"
		),
		['B-4']
	);
	expectRules(
		'import outside the boundary flagged',
		scanBlockFile(inHero, 'fixture', "import { z } from 'zod';"),
		['B-4']
	);
	expectRules(
		'a lib that is not $libs/forms flagged',
		scanBlockFile(inHero, 'fixture', "import { toDate } from '$libs/days';"),
		['B-4']
	);
	expectRules(
		'the sanctioned imports clean',
		scanBlockFile(
			inHero,
			'fixture',
			"import { Stack } from '$uix/eidos/components/stack';\n" +
				"import { createForm } from '$libs/forms';\n" +
				"import { getWindow } from '$adom';\n" +
				"import { object } from '$sium/core';\n" +
				"import type { Snippet } from 'svelte';\n" +
				"import type { HTMLAttributes } from 'svelte/elements';\n" +
				"import type { HeroProps } from './types';"
		),
		[]
	);
	expectRules(
		'an example import inside a comment is prose, not code',
		scanBlockFile(inHero, 'fixture', "//   import { Pricing } from '$blocks/pricing';"),
		[]
	);
	expectRules(
		'a native named inside a MULTI-line comment is prose, not code',
		scanBlockFile(
			inHero,
			'fixture',
			'<!--\n\tinteractive would turn the card into a <button>, and the action already holds one.\n-->\n<Button>go</Button>'
		),
		[]
	);
	expectRules(
		'a real native BELOW a multi-line comment is still flagged',
		scanBlockFile(
			inHero,
			'fixture',
			'<!--\n\ta note about <button> semantics\n-->\n<button onclick={x}>go</button>'
		),
		['B-2']
	);
	expectRules(
		'README without the landmark declaration flagged',
		scanReadme(
			'fixture',
			'# Hero\n\n## Function\n\n## Composition map\n\n## Decisions\n\n## Equivalencias\n\n## Gaps\n'
		),
		['B-8']
	);
	expectRules(
		'README without the equivalence matrix flagged',
		scanReadme(
			'fixture',
			'# Hero\n\n## Function\n\n## Composition map\n\n**Landmark + headings**: a section.\n\n## Decisions\n\n## Gaps\n'
		),
		['B-9']
	);
	expectRules(
		'README missing a template section flagged',
		scanReadme(
			'fixture',
			'# Hero\n\n## Function\n\n**Landmark + headings**: a `<section>`.\n\n## Gaps\n'
		),
		['B-9', 'B-9', 'B-9']
	);
	expectRules(
		'a complete README clean',
		scanReadme(
			'fixture',
			'# Hero\n\n## Function\n\n## Composition map\n\n**Landmark + headings**: a `<section>`.\n\n## Decisions\n\n## Equivalencias\n\n## Gaps\n'
		),
		[]
	);

	const catalog = parseCatalog(
		"[{ slug: 'hero', label: 'Hero', shipped: true }, { slug: 'kanban', label: 'Kanban', shipped: false }]"
	);
	if (catalog.get('hero') !== true || catalog.get('kanban') !== false || catalog.size !== 2)
		failures.push(`catalog parse: expected hero=true kanban=false, got ${[...catalog]}`);
	if (parseCatalog("[{ label: 'Hero', shipped: true }]").size !== 0)
		failures.push('catalog parse: an entry without a slug must not become a row');

	expectRules(
		'block without a catalog entry flagged',
		scanCatalog(['hero'], new Map(), 'fixture'),
		['B-9']
	);
	expectRules(
		'block whose entry says shipped: false flagged',
		scanCatalog(['hero'], new Map([['hero', false]]), 'fixture'),
		['B-9']
	);
	expectRules(
		'catalog shipping a block that does not exist flagged',
		scanCatalog([], new Map([['ghost', true]]), 'fixture'),
		['B-9']
	);
	expectRules(
		'tree and catalog in agreement clean',
		scanCatalog(
			['hero'],
			new Map([
				['hero', true],
				['kanban', false]
			]),
			'fixture'
		),
		[]
	);
	return failures;
}

function main(): void {
	const selfFailures = selfTest();
	if (selfFailures.length > 0) {
		for (const f of selfFailures) console.error(`SELF-TEST FAIL — ${f}`);
		console.error(`\nblocks-check: the guard's own detectors are broken (${selfFailures.length})`);
		process.exit(1);
	}

	const violations: Violation[] = [];
	let blockFiles: string[] = [];
	let blockDirs: string[] = [];
	if (existsSync(BLOCKS_DIR)) {
		blockFiles = walk(BLOCKS_DIR, /\.(ts|svelte|css)$/);
		blockDirs = readdirSync(BLOCKS_DIR).filter((e) => statSync(join(BLOCKS_DIR, e)).isDirectory());
	}

	for (const file of blockFiles) {
		const rel = relative(REPO, file);
		if (file.endsWith('.css')) {
			violations.push({
				rule: 'D-BLK.2',
				file: rel,
				line: 1,
				detail: 'a block ships no .css file — layout-components-first'
			});
			continue;
		}
		if (/\.test\./.test(file)) continue;
		violations.push(...scanBlockFile(file, rel, readFileSync(file, 'utf8')));
	}

	const catalog = existsSync(CATALOG_FILE)
		? parseCatalog(readFileSync(CATALOG_FILE, 'utf8'))
		: null;
	if (catalog === null) {
		violations.push({
			rule: 'B-9',
			file: relative(REPO, CATALOG_FILE),
			line: 1,
			detail: 'the demo catalog is missing — the rail and the gallery read it as their single list'
		});
	}
	const shippedBlocks = new Set<string>();

	for (const dir of blockDirs) {
		const hasCode = walk(join(BLOCKS_DIR, dir), /\.(ts|svelte)$/).length > 0;
		if (!hasCode) continue;
		shippedBlocks.add(dir);
		const readme = join(BLOCKS_DIR, dir, 'README.md');
		if (!existsSync(readme)) {
			violations.push({
				rule: 'B-9',
				file: `src/uix/blocks/${dir}`,
				line: 1,
				detail: 'block folder without README.md (Function · Composition map · Decisions · Gaps)'
			});
		} else {
			violations.push(...scanReadme(relative(REPO, readme), readFileSync(readme, 'utf8')));
		}
		if (!existsSync(join(DEMO_DIR, dir, '+page.svelte'))) {
			violations.push({
				rule: 'B-9',
				file: `src/uix/blocks/${dir}`,
				line: 1,
				detail: `block without a demo route (web/routes/blocks/${dir}/+page.svelte)`
			});
		}
	}

	if (catalog !== null) {
		violations.push(...scanCatalog([...shippedBlocks], catalog, relative(REPO, CATALOG_FILE)));
	}

	let outsideCount = 0;
	for (const root of OUTSIDE_ROOTS) {
		if (!existsSync(root)) continue;
		for (const file of walk(root, /\.(ts|svelte)$/)) {
			outsideCount++;
			violations.push(...scanOutsideFile(file, relative(REPO, file), readFileSync(file, 'utf8')));
		}
	}

	if (violations.length > 0) {
		for (const v of violations) {
			console.error(`ERROR [${v.rule}] ${v.file}:${v.line} — ${v.detail}`);
		}
		console.error(
			`\nblocks-check: ${violations.length} error(s) across ${blockDirs.length} block(s)`
		);
		process.exit(1);
	}
	console.log(
		`blocks-check: self-test OK · 0 error(s) across ${blockDirs.length} block(s) (${blockFiles.length} files; ${outsideCount} canon/arts/libs/packs files scanned for direction)`
	);
}

main();