#!/usr/bin/env node
/**
 * Sync the vendored shared core in a plugin repo against the canonical
 * obsidian-plugin-core checkout.
 *
 * Run from a plugin repo root (each plugin vendors a copy of this script):
 *   node scripts/sync-shared.mjs           # copy canonical -> src/shared/
 *   node scripts/sync-shared.mjs --check   # exit 1 if the vendored copy drifted
 *
 * Run from obsidian-plugin-core itself:
 *   node scripts/sync-shared.mjs --manifest   # regenerate shared/MANIFEST.sha256
 *
 * THE DRIFT GATE HAS TO WORK WITHOUT THE CANONICAL REPO. This script used to exit 0 from
 * `--check` whenever ../obsidian-plugin-core was absent — which is ALWAYS true in CI and in a
 * fresh clone. So `npm test`'s drift check enforced nothing on any pull request, and a
 * hand-edited `src/shared/verifyLicense.mjs` merged green: exactly the drift class this repo
 * exists to prevent, and exactly how two divergent copies of the verifier happened.
 *
 * So `sync:shared` also writes MANIFEST.sha256 — the SHA-256 of every synced file — INTO the
 * vendored tree, and `--check` validates the vendored files against that manifest when the
 * canonical repo is not around. Editing a vendored file now fails the check on any machine,
 * with or without the canonical checkout; editing the manifest to match is a deliberate act
 * that shows up in the diff of a file whose header says not to.
 */
import crypto from "node:crypto";
import fs from "node:fs";
import path from "node:path";
import { pathToFileURL } from "node:url";

/** [canonical-relative, plugin-relative] pairs kept in sync. */
const FILES = [
	["shared/verifyLicense.mjs", "src/shared/verifyLicense.mjs"],
	["shared/verifyLicense.d.mts", "src/shared/verifyLicense.d.mts"],
	["shared/suiteLicense.mjs", "src/shared/suiteLicense.mjs"],
	["shared/suiteLicense.d.mts", "src/shared/suiteLicense.d.mts"],
	["shared/revokedLicenses.mjs", "src/shared/revokedLicenses.mjs"],
	["shared/revokedLicenses.d.mts", "src/shared/revokedLicenses.d.mts"],
	["shared/licenseTransition.mjs", "src/shared/licenseTransition.mjs"],
	["shared/licenseTransition.d.mts", "src/shared/licenseTransition.d.mts"],
	["shared/featureGates.mjs", "src/shared/featureGates.mjs"],
	["shared/featureGates.d.mts", "src/shared/featureGates.d.mts"],
	["shared/hash.mjs", "src/shared/hash.mjs"],
	["shared/hash.d.mts", "src/shared/hash.d.mts"],
	["shared/engine/protocol.mjs", "src/shared/engine/protocol.mjs"],
	["shared/engine/protocol.d.mts", "src/shared/engine/protocol.d.mts"],
	["shared/engine/chunk.mjs", "src/shared/engine/chunk.mjs"],
	["shared/engine/chunk.d.mts", "src/shared/engine/chunk.d.mts"],
	["shared/engine/installPlan.mjs", "src/shared/engine/installPlan.mjs"],
	["shared/engine/installPlan.d.mts", "src/shared/engine/installPlan.d.mts"],
	["shared/engine/engineRelease.mjs", "src/shared/engine/engineRelease.mjs"],
	["shared/engine/engineRelease.d.mts", "src/shared/engine/engineRelease.d.mts"],
	["shared/engine/EngineHost.ts", "src/shared/engine/EngineHost.ts"],
	["shared/engine/EngineBroker.ts", "src/shared/engine/EngineBroker.ts"],
	["shared/engine/EngineInstallModal.ts", "src/shared/engine/EngineInstallModal.ts"],
	["shared/signals/signalsAggregate.mjs", "src/shared/signals/signalsAggregate.mjs"],
	["shared/signals/signalsAggregate.d.mts", "src/shared/signals/signalsAggregate.d.mts"],
	["shared/signals/SignalStore.ts", "src/shared/signals/SignalStore.ts"],
	["shared/signals/SignalsBroker.ts", "src/shared/signals/SignalsBroker.ts"],
	["scripts/sync-shared.mjs", "scripts/sync-shared.mjs"],
];

/** Generated, not synced: it is the checksum OF the synced files. */
const MANIFEST = ["shared/MANIFEST.sha256", "src/shared/MANIFEST.sha256"];

const MANIFEST_HEADER = [
	"# SHA-256 of every file in the vendored shared tree, keyed by its canonical path.",
	"# GENERATED by scripts/sync-shared.mjs. Do not edit, and do not edit a shared file",
	"# without re-running `npm run sync:shared` — `npm test` verifies this manifest even",
	"# when the canonical obsidian-plugin-core checkout is not present (i.e. in CI).",
];

/** Compare content, not line endings — git autocrlf checkouts differ per OS. */
const normalize = (text) => text.replace(/\r\n/g, "\n");

const sha256 = (text) => crypto.createHash("sha256").update(normalize(text), "utf8").digest("hex");

/**
 * @param {string} root  repo root
 * @param {(pair: string[]) => string} pick  canonical-relative or plugin-relative
 * @returns {string} the manifest body
 */
export function buildManifest(root, pick) {
	const lines = [...MANIFEST_HEADER];
	for (const pair of FILES) {
		const file = path.join(root, pick(pair));
		if (!fs.existsSync(file)) throw new Error(`sync-shared: cannot hash a missing file: ${file}`);
		lines.push(`${sha256(fs.readFileSync(file, "utf8"))}  ${pair[0]}`);
	}
	return lines.join("\n") + "\n";
}

const canonicalManifest = (root) => buildManifest(root, ([from]) => from);
const vendoredManifest = (root) => buildManifest(root, ([, to]) => to);

/** Write `body` to `file` only when it would change it. Returns true when it wrote. */
function writeIfChanged(file, body) {
	const have = fs.existsSync(file) ? fs.readFileSync(file, "utf8") : null;
	if (have !== null && normalize(have) === normalize(body)) return false;
	fs.mkdirSync(path.dirname(file), { recursive: true });
	fs.writeFileSync(file, body);
	return true;
}

/** The vendored tree, checked against the manifest that shipped with it. No canonical repo
 *  needed — this is the check that actually runs on a pull request. */
function checkAgainstManifest(repoRoot) {
	const manifestPath = path.join(repoRoot, MANIFEST[1]);
	if (!fs.existsSync(manifestPath)) {
		console.error(
			`sync-shared: ${MANIFEST[1]} is missing — the vendored tree cannot be verified.\n` +
				'Run "npm run sync:shared" against the canonical obsidian-plugin-core checkout.'
		);
		return 1;
	}

	let want;
	try {
		want = vendoredManifest(repoRoot);
	} catch (error) {
		console.error(String(error instanceof Error ? error.message : error));
		return 1;
	}

	const have = fs.readFileSync(manifestPath, "utf8");
	if (normalize(have) === normalize(want)) {
		console.log(`sync-shared: vendored tree matches ${MANIFEST[1]} (${FILES.length} files).`);
		return 0;
	}

	// Name the files, not just the mismatch — the whole point is to say what was hand-edited.
	const expected = new Map(
		normalize(have)
			.split("\n")
			.filter((line) => line && !line.startsWith("#"))
			.map((line) => {
				const [hash, file] = line.split(/\s+/);
				return [file, hash];
			})
	);
	let drifted = 0;
	for (const [from, to] of FILES) {
		const file = path.join(repoRoot, to);
		const actual = fs.existsSync(file) ? sha256(fs.readFileSync(file, "utf8")) : "<missing>";
		if (expected.get(from) !== actual) {
			console.error(`sync-shared: DRIFT in ${to} (does not match ${MANIFEST[1]})`);
			drifted++;
		}
	}
	if (drifted === 0) {
		console.error(`sync-shared: ${MANIFEST[1]} does not match the files it lists — it was edited by hand.`);
		drifted = 1;
	}
	console.error(
		`sync-shared: ${drifted} file(s) drifted from the canonical shared tree. Edit them in ` +
			'obsidian-plugin-core and run "npm run sync:shared" — never in this repo.'
	);
	return 1;
}

function main(argv) {
	const repoRoot = process.cwd();
	const canonical = process.env.PLUGIN_CORE_PATH || path.resolve(repoRoot, "..", "obsidian-plugin-core");
	const check = argv.includes("--check");
	const manifestOnly = argv.includes("--manifest");

	// Regenerate the canonical manifest in obsidian-plugin-core itself. Its own test suite
	// runs this in --check mode, so a shared file edited without regenerating fails there too.
	if (manifestOnly) {
		const file = path.join(repoRoot, MANIFEST[0]);
		const body = canonicalManifest(repoRoot);
		if (check) {
			const have = fs.existsSync(file) ? fs.readFileSync(file, "utf8") : "";
			if (normalize(have) !== normalize(body)) {
				console.error(`sync-shared: ${MANIFEST[0]} is stale — run "npm run manifest:shared".`);
				return 1;
			}
			console.log(`sync-shared: ${MANIFEST[0]} is current.`);
			return 0;
		}
		console.log(writeIfChanged(file, body) ? `sync-shared: wrote ${MANIFEST[0]}.` : `sync-shared: ${MANIFEST[0]} is current.`);
		return 0;
	}

	if (!fs.existsSync(canonical)) {
		// No canonical checkout: CI, or a fresh clone. This is the case the old script treated
		// as "nothing to do", which is what made the gate decorative. The vendored manifest is
		// the authority here.
		if (check) return checkAgainstManifest(repoRoot);
		console.log(`sync-shared: canonical repo not found at ${canonical} — nothing to copy.`);
		return 0;
	}

	let drifted = 0;
	for (const [from, to] of FILES) {
		const src = path.join(canonical, from);
		const dest = path.join(repoRoot, to);
		if (!fs.existsSync(src)) {
			console.error(`sync-shared: missing canonical file ${src}`);
			return 1;
		}
		const want = fs.readFileSync(src, "utf8");
		const have = fs.existsSync(dest) ? fs.readFileSync(dest, "utf8") : null;
		if (have !== null && normalize(want) === normalize(have)) continue;
		if (check) {
			console.error(`sync-shared: DRIFT in ${to} (canonical: ${from})`);
			drifted++;
		} else {
			fs.mkdirSync(path.dirname(dest), { recursive: true });
			fs.writeFileSync(dest, want);
			console.log(`sync-shared: updated ${to}`);
		}
	}

	if (check) {
		if (drifted > 0) {
			console.error(`sync-shared: ${drifted} file(s) drifted — run "npm run sync:shared" to update.`);
			return 1;
		}
		// The files match the canonical tree; the manifest must match them too, or CI (which
		// has no canonical tree and can only consult the manifest) would disagree with us.
		return checkAgainstManifest(repoRoot);
	}

	// Keep both manifests honest: the canonical one, so obsidian-plugin-core's own test passes,
	// and the vendored one, which is the only thing CI can check.
	const body = canonicalManifest(canonical);
	if (writeIfChanged(path.join(canonical, MANIFEST[0]), body)) {
		console.log(`sync-shared: refreshed ${MANIFEST[0]} in the canonical repo`);
	}
	if (writeIfChanged(path.join(repoRoot, MANIFEST[1]), body)) console.log(`sync-shared: updated ${MANIFEST[1]}`);
	console.log("sync-shared: done.");
	return 0;
}

// Importable (obsidian-plugin-core's own manifest test uses buildManifest) and runnable.
if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
	process.exit(main(process.argv.slice(2)));
}

export { FILES, MANIFEST, main };