import { execFile } from "node:child_process";
import { mkdir, mkdtemp, readdir, readFile, realpath, rm, stat } from "node:fs/promises";
import { homedir, tmpdir } from "node:os";
import path from "node:path";
import process from "node:process";
import { fileURLToPath, pathToFileURL } from "node:url";
import { promisify } from "node:util";

/**
 * The public module-development package set (ADR 0053), and the release check that packs it.
 *
 *   node scripts/pack-public-packages.ts --out <directory>
 *
 * Rebuilds each public package from clean output, packs it with `pnpm pack`, and inspects every
 * tarball before anything may consume it: only the package's built files, its declarations, and a
 * `LICENSE`; a manifest with no `workspace:` range, no install-time lifecycle script, the explicit
 * distribution marker, and the one coordinated version. It publishes nothing.
 */

const execFileAsync = promisify(execFile);
const repositoryRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");

export type PublicPackageRole = "author-api" | "tooling" | "pre-1.0" | "implementation";

export interface PublicPackage {
  readonly name: string;
  /** Relative to the repository root. */
  readonly directory: string;
  readonly role: PublicPackageRole;
}

/** ADR 0053's public set. Every other workspace package is private and never published. */
export const PUBLIC_PACKAGES: readonly PublicPackage[] = Object.freeze([
  { directory: "packages/module-sdk", name: "@ekklesia/module-sdk", role: "author-api" },
  { directory: "packages/module-database", name: "@ekklesia/module-database", role: "author-api" },
  { directory: "packages/module-ui-sdk", name: "@ekklesia/module-ui-sdk", role: "author-api" },
  { directory: "packages/design-tokens", name: "@ekklesia/design-tokens", role: "author-api" },
  { directory: "packages/module-ui-build", name: "@ekklesia/module-ui-build", role: "tooling" },
  { directory: "packages/module-pack", name: "@ekklesia/module-pack", role: "tooling" },
  {
    directory: "packages/typescript-config",
    name: "@ekklesia/typescript-config",
    role: "tooling",
  },
  { directory: "packages/ui", name: "@ekklesia/ui", role: "pre-1.0" },
  // A dependency of the packages above, never a supported direct module-author dependency.
  { directory: "packages/contracts", name: "@ekklesia/contracts", role: "implementation" },
]);

/** `ekklesia.distribution` in a public package's manifest: the identity the canonical packager
 * recognizes an installed Ekklesia package by (`packages/module-pack/src/packages.ts`). */
export const PUBLIC_PACKAGE_DISTRIBUTION = "module-development";

/** Scripts a package manager runs on a consumer's machine when it installs, packs, or publishes. */
const LIFECYCLE_SCRIPTS = Object.freeze([
  "preinstall",
  "install",
  "postinstall",
  "prepare",
  "prepack",
  "postpack",
  "prepublish",
  "prepublishOnly",
  "publish",
  "postpublish",
]);

/** The fields a consumer's install resolves. `devDependencies` are never installed from a published
 * package, so a tooling package's test-only use of a private package is not a problem there. */
const INSTALLED_DEPENDENCY_FIELDS = Object.freeze([
  "dependencies",
  "peerDependencies",
  "optionalDependencies",
]);

function isRecord(value: unknown): value is Readonly<Record<string, unknown>> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

/** What is wrong with a packed `package.json`, or nothing. */
export function packedManifestProblems(
  manifest: Readonly<Record<string, unknown>>,
  expected: { readonly name: string; readonly version: string },
): string[] {
  const problems: string[] = [];
  if (manifest.name !== expected.name) problems.push(`is named ${String(manifest.name)}`);
  if (manifest.version !== expected.version) {
    problems.push(
      `has version ${String(manifest.version)}, not the coordinated ${expected.version}`,
    );
  }
  if (manifest.private !== undefined) problems.push("declares private");
  if (manifest.license !== "AGPL-3.0-or-later") problems.push("does not declare its licence");
  if (JSON.stringify(manifest).includes("workspace:")) problems.push("keeps a workspace: range");
  const ekklesia = manifest.ekklesia;
  if (!isRecord(ekklesia) || ekklesia.distribution !== PUBLIC_PACKAGE_DISTRIBUTION) {
    problems.push("lacks the module-development distribution marker");
  }
  const scripts = isRecord(manifest.scripts) ? manifest.scripts : {};
  for (const script of LIFECYCLE_SCRIPTS) {
    if (Object.hasOwn(scripts, script)) problems.push(`runs a ${script} script`);
  }
  const publicNames = new Set(PUBLIC_PACKAGES.map((entry) => entry.name));
  for (const field of INSTALLED_DEPENDENCY_FIELDS) {
    const dependencies = manifest[field];
    if (!isRecord(dependencies)) continue;
    for (const [name, range] of Object.entries(dependencies)) {
      if (!name.startsWith("@ekklesia/")) continue;
      if (!publicNames.has(name)) problems.push(`${field} names the private ${name}`);
      else if (range !== expected.version) {
        problems.push(`${field} names ${name}@${String(range)}, not ${expected.version}`);
      }
    }
  }
  return problems;
}

const BUILT_FILE = /^dist\/(.+?)(?:\.d\.ts|\.js)(?:\.map)?$/u;

/**
 * What is wrong with a tarball's file list, or nothing. Every file is `package.json`, `LICENSE`, or
 * under one of the manifest's `files` entries; nothing is a source, test, or configuration file; and
 * every built file has the source it was compiled from, so stale output from a deleted source fails.
 */
export function tarballFileProblems(
  files: readonly string[],
  manifest: Readonly<Record<string, unknown>>,
  hasSource: (relativeWithoutExtension: string) => boolean,
): string[] {
  const problems: string[] = [];
  const declared = Array.isArray(manifest.files) ? manifest.files.map(String) : [];
  if (!files.includes("LICENSE")) problems.push("has no LICENSE");
  if (!files.includes("package.json")) problems.push("has no package.json");
  for (const file of files) {
    if (file === "package.json" || file === "LICENSE") continue;
    if (!declared.some((entry) => file === entry || file.startsWith(`${entry}/`))) {
      problems.push(`ships ${file}, which its files field does not name`);
      continue;
    }
    if (
      /(?:^|\/)(?:src|tests?|node_modules)\//u.test(file) ||
      /\.test\.[cm]?[jt]sx?$/u.test(file)
    ) {
      problems.push(`ships ${file}`);
      continue;
    }
    const built = BUILT_FILE.exec(file);
    if (file.startsWith("dist/") && (built === null || !hasSource(built[1] ?? ""))) {
      problems.push(`ships ${file}, which no source produces`);
    }
  }
  return problems;
}

async function readJson(file: string): Promise<Record<string, unknown>> {
  return JSON.parse(await readFile(file, "utf8")) as Record<string, unknown>;
}

async function filesUnder(directory: string): Promise<string[]> {
  const entries = await readdir(directory, { recursive: true, withFileTypes: true });
  return entries
    .filter((entry) => entry.isFile())
    .map((entry) =>
      path.relative(directory, path.join(entry.parentPath, entry.name)).split(path.sep).join("/"),
    )
    .sort();
}

async function sourceExists(packageDirectory: string, relative: string): Promise<boolean> {
  for (const extension of [".ts", ".tsx"]) {
    try {
      await stat(path.join(packageDirectory, "src", `${relative}${extension}`));
      return true;
    } catch {}
  }
  return false;
}

export interface PackedPackage {
  readonly name: string;
  readonly tarball: string;
  readonly files: number;
  readonly bytes: number;
}

async function pnpm(arguments_: readonly string[], cwd: string): Promise<string> {
  const { stdout } = await execFileAsync("pnpm", [...arguments_], {
    cwd,
    maxBuffer: 64 * 1024 * 1024,
  });
  return stdout;
}

async function packOne(
  entry: PublicPackage,
  version: string,
  outDirectory: string,
  scratch: string,
): Promise<{ packed: PackedPackage; problems: string[] }> {
  const directory = path.join(repositoryRoot, entry.directory);
  const report = JSON.parse(
    await pnpm(["pack", "--json", "--pack-destination", outDirectory], directory),
  ) as { filename: string };
  const tarball = report.filename;
  const extracted = path.join(scratch, entry.name.replace("/", "+"));
  await mkdir(extracted, { recursive: true });
  await execFileAsync("tar", ["-xzf", tarball, "-C", extracted]);
  const root = path.join(extracted, "package");
  const files = await filesUnder(root);
  const manifest = await readJson(path.join(root, "package.json"));

  const sources = new Map<string, boolean>();
  for (const file of files) {
    const built = BUILT_FILE.exec(file)?.[1];
    if (built !== undefined && !sources.has(built)) {
      sources.set(built, await sourceExists(directory, built));
    }
  }
  const problems = [
    ...packedManifestProblems(manifest, { name: entry.name, version }),
    ...tarballFileProblems(files, manifest, (relative) => sources.get(relative) === true),
  ];
  // Nothing the package says may name the machine or checkout it was packed on.
  for (const file of files) {
    const text = (await readFile(path.join(root, file))).toString("latin1");
    for (const local of [repositoryRoot, homedir()]) {
      if (text.includes(local)) problems.push(`${file} names a local path`);
    }
  }
  return {
    packed: { bytes: (await stat(tarball)).size, files: files.length, name: entry.name, tarball },
    problems: [...new Set(problems)],
  };
}

/** Rebuilds the public set from clean output, packs it into `outDirectory`, and inspects it. */
export async function packPublicPackages(outDirectory: string): Promise<{
  readonly packed: readonly PackedPackage[];
  readonly problems: readonly string[];
}> {
  const version = String((await readJson(path.join(repositoryRoot, "package.json"))).version);
  await mkdir(outDirectory, { recursive: true });
  const out = await realpath(outDirectory);

  // Stale output from a deleted source would otherwise ship: the build only ever adds files, and
  // Turbo's cache would restore whatever an earlier build left behind.
  for (const entry of PUBLIC_PACKAGES) {
    await rm(path.join(repositoryRoot, entry.directory, "dist"), { force: true, recursive: true });
  }
  await pnpm(
    [
      "exec",
      "turbo",
      "run",
      "build",
      "--force",
      "--output-logs=errors-only",
      ...PUBLIC_PACKAGES.map((entry) => `--filter=${entry.name}`),
    ],
    repositoryRoot,
  );

  const scratch = await mkdtemp(path.join(tmpdir(), "ekklesia-public-packages-"));
  try {
    const packed: PackedPackage[] = [];
    const problems: string[] = [];
    for (const entry of PUBLIC_PACKAGES) {
      const result = await packOne(entry, version, out, scratch);
      packed.push(result.packed);
      problems.push(...result.problems.map((problem) => `${entry.name} ${problem}.`));
    }
    return { packed, problems };
  } finally {
    await rm(scratch, { force: true, recursive: true });
  }
}

async function main(argv: readonly string[]): Promise<number> {
  if (argv.length !== 2 || argv[0] !== "--out" || !argv[1]) {
    process.stderr.write("Usage: node scripts/pack-public-packages.ts --out <directory>\n");
    return 64;
  }
  try {
    const { packed, problems } = await packPublicPackages(path.resolve(argv[1]));
    for (const entry of packed) {
      process.stdout.write(
        `${path.basename(entry.tarball)}: ${entry.files} files, ${entry.bytes} bytes\n`,
      );
    }
    if (problems.length > 0) {
      for (const problem of problems) process.stderr.write(`${problem}\n`);
      return 1;
    }
    process.stdout.write(`Packed and inspected ${packed.length} public packages.\n`);
    return 0;
  } catch {
    process.stderr.write("Packing the public packages failed while building or packing.\n");
    return 1;
  }
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  process.exitCode = await main(process.argv.slice(2));
}