import { access, readFile } from "node:fs/promises";
import { createHash } from "node:crypto";
import { basename, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const frontendDir = fileURLToPath(new URL("../", import.meta.url));
const packageInfo = JSON.parse(await readFile(resolve(frontendDir, "package.json"), "utf8"));
const failures = [];

const args = process.argv.slice(2);
const optionValue = (name) => {
  const index = args.indexOf(name);
  return index >= 0 ? args[index + 1] : undefined;
};

const feedPath = resolve(
  frontendDir,
  optionValue("--feed") || process.env.DESKTOP_UPDATE_FEED || "src-tauri/target/release/bundle/latest.json",
);
const artifactDir = optionValue("--artifacts-dir") || process.env.DESKTOP_UPDATE_ARTIFACTS_DIR;
const expectedBaseUrl = optionValue("--base-url") || process.env.DESKTOP_UPDATE_BASE_URL;
const checksumManifestPath =
  optionValue("--checksum-manifest") ||
  process.env.DESKTOP_UPDATE_CHECKSUM_MANIFEST ||
  (artifactDir ? resolve(artifactDir, "SHA256SUMS.txt") : undefined);

const fail = (message) => failures.push(message);
const assert = (condition, message) => {
  if (!condition) fail(message);
};

const assertFileExists = async (path, description) => {
  try {
    await access(path);
  } catch {
    fail(`${description} does not exist: ${path}`);
  }
};

const sha256 = async (path) => createHash("sha256").update(await readFile(path)).digest("hex");

const readChecksumManifest = async () => {
  if (!checksumManifestPath) return undefined;
  try {
    const source = await readFile(checksumManifestPath, "utf8");
    const checksums = new Map();
    for (const line of source.split(/\r?\n/)) {
      const trimmed = line.trim();
      if (!trimmed) continue;
      const match = trimmed.match(/^([a-f0-9]{64})\s+\*?(.+)$/i);
      if (!match) {
        fail(`Checksum manifest contains an invalid line: ${line}`);
        continue;
      }
      checksums.set(basename(match[2]), match[1].toLowerCase());
    }
    return checksums;
  } catch (error) {
    fail(`Cannot read checksum manifest ${checksumManifestPath}: ${error.message}`);
    return undefined;
  }
};

const assertChecksum = async (checksums, path, description) => {
  if (!checksums) return;
  const name = basename(path);
  const expected = checksums.get(name);
  assert(Boolean(expected), `Checksum manifest must include ${description}: ${name}`);
  if (expected) {
    const actual = await sha256(path);
    assert(actual === expected, `${description} checksum mismatch for ${name}.`);
  }
};

const assertManifestEntries = async (checksums) => {
  if (!checksums || !artifactDir) return;
  for (const [name, expected] of checksums.entries()) {
    const path = resolve(artifactDir, name);
    await assertFileExists(path, `checksum manifest entry ${name}`);
    try {
      const actual = await sha256(path);
      assert(actual === expected, `Checksum manifest entry mismatch for ${name}.`);
    } catch (error) {
      fail(`Cannot verify checksum manifest entry ${name}: ${error.message}`);
    }
  }
};

let feed;
try {
  feed = JSON.parse(await readFile(feedPath, "utf8"));
} catch (error) {
  fail(`Cannot read desktop update feed ${feedPath}: ${error.message}`);
}

if (feed) {
  const checksums = await readChecksumManifest();
  await assertManifestEntries(checksums);
  const normalizedFeedVersion = String(feed.version || "").replace(/^v/, "");
  const platforms = feed.platforms || {};
  const darwinArm = platforms["darwin-aarch64"];
  const darwinIntel = platforms["darwin-x86_64"];

  assert(normalizedFeedVersion === packageInfo.version, `latest.json version must match package version ${packageInfo.version}.`);
  assert(Boolean(feed.pub_date || feed.pubDate), "latest.json must include a publication date.");
  assert(Boolean(darwinArm), "latest.json must include darwin-aarch64.");
  assert(Boolean(darwinIntel), "latest.json must include darwin-x86_64.");

  const entries = [
    ["darwin-aarch64", darwinArm],
    ["darwin-x86_64", darwinIntel],
  ];

  for (const [platform, entry] of entries) {
    const rawUrl = entry?.url;
    const signature = entry?.signature;
    assert(typeof signature === "string" && signature.length > 80, `${platform} must include an updater signature.`);
    assert(typeof rawUrl === "string" && rawUrl.length > 0, `${platform} must include an artifact URL.`);
    if (!rawUrl) continue;

    let url;
    try {
      url = new URL(rawUrl);
    } catch {
      fail(`${platform} artifact URL is invalid: ${rawUrl}`);
      continue;
    }

    assert(url.protocol === "https:", `${platform} artifact URL must use HTTPS.`);
    assert(!/[?&]token=/i.test(url.search), `${platform} artifact URL must not contain token query parameters.`);
    assert(!url.pathname.endsWith("/latest.json"), `${platform} artifact URL must point to an immutable artifact, not latest.json.`);
    assert(url.pathname.includes(packageInfo.version), `${platform} artifact URL must include version ${packageInfo.version}.`);
    if (expectedBaseUrl) {
      assert(rawUrl.startsWith(expectedBaseUrl), `${platform} artifact URL must start with ${expectedBaseUrl}.`);
    }

    if (artifactDir) {
      const artifactPath = resolve(artifactDir, basename(url.pathname));
      const signaturePath = `${artifactPath}.sig`;
      await assertFileExists(artifactPath, `${platform} updater artifact`);
      await assertFileExists(signaturePath, `${platform} updater artifact signature`);
      await assertChecksum(checksums, artifactPath, `${platform} updater artifact`);
      await assertChecksum(checksums, signaturePath, `${platform} updater artifact signature`);
    }
  }

  if (darwinArm?.url && darwinIntel?.url) {
    assert(darwinArm.url === darwinIntel.url, "Universal macOS latest.json must point both darwin architectures at the same artifact.");
  }

  if (artifactDir) {
    await assertChecksum(checksums, feedPath, "latest.json");
  }
}

if (failures.length > 0) {
  console.error(`Desktop update feed check failed:\n${failures.map((item) => `  - ${item}`).join("\n")}`);
  process.exitCode = 1;
} else {
  console.log("Desktop update feed check passed.");
}