import { execFileSync } from "node:child_process";
import { readFileSync } from "node:fs";
import { join } from "node:path";

const ROOT = new URL("..", import.meta.url).pathname.replace(/\/$/, "");
const RUN_LINE_RE = /^\s*run:\s*(.+?)\s*$/;

/** @param {string} path */
const read = (path) => readFileSync(join(ROOT, path), "utf-8");

/**
 * Gates must invoke `pnpm oxlint` with no extra arguments: pnpm forwards them
 * after `--`, where oxlint reads them as file paths and lints nothing.
 * @param {Record<string, string>} scripts
 */
function findGatesWithOwnFlags(scripts) {
	const commands = Object.entries(scripts)
		.filter(([name]) => name !== "oxlint")
		.flatMap(([name, body]) =>
			body.split("&&").map((c) => [`scripts.${name}`, c.trim()]),
		);
	for (const line of read("lefthook.yml").split("\n")) {
		const command = RUN_LINE_RE.exec(line)?.[1];
		if (command) commands.push(["lefthook.yml", command]);
	}
	return commands
		.filter(([, c]) => c.includes("oxlint") && c !== "pnpm oxlint")
		.map(([source, c]) => `${source} runs "${c}" instead of "pnpm oxlint"`);
}

/**
 * Runs the configured command with one rule forced to warn. A working gate
 * exits non-zero; exiting 0 means it lints nothing, or does not fail on
 * warnings.
 * @param {string} oxlintScript
 */
function failsOnWarnings(oxlintScript) {
	const args = [...oxlintScript.split(" ").slice(1), "-W", "no-console"];
	try {
		execFileSync(join(ROOT, "node_modules/.bin/oxlint"), args, {
			cwd: ROOT,
			stdio: "ignore",
		});
		return false;
	} catch {
		return true;
	}
}

/**
 * Reports ways a quality gate could pass without checking anything, which is
 * indistinguishable from a clean run.
 * @returns {string[]}
 */
export function checkGates() {
	/** @type {Record<string, string>} */
	const scripts = JSON.parse(read("package.json")).scripts;
	const violations = findGatesWithOwnFlags(scripts);

	// Vitest defaults to failing when no test file matches. Setting this puts
	// the test gate back to exiting 0 if the include globs ever stop matching.
	if (read("vitest.config.ts").includes("passWithNoTests")) {
		violations.push("vitest.config.ts sets passWithNoTests");
	}

	// jscpd's pattern is a single glob string. An array matches no files, and
	// the run then reports success having read nothing.
	if (Array.isArray(JSON.parse(read(".jscpd.json")).pattern)) {
		violations.push(".jscpd.json sets pattern to an array, not a glob string");
	}

	// The canary rule below is not type-aware, so the probe alone cannot
	// detect type-aware rules being switched off.
	if (!scripts.oxlint.includes("--type-aware")) {
		violations.push("scripts.oxlint is missing --type-aware");
	}
	if (!failsOnWarnings(scripts.oxlint)) {
		violations.push(
			`scripts.oxlint exits 0 despite no-console violations: "${scripts.oxlint}"`,
		);
	}
	return violations;
}