#!/usr/bin/env node

import { execFile } from "node:child_process";
import { lstat, mkdir, mkdtemp, readdir, rm, stat } from "node:fs/promises";
import path from "node:path";
import process from "node:process";
import { promisify } from "node:util";

type Options = {
  dryRun: boolean;
  outputDirectory: string;
  sourceDirectory: string;
  temporaryDirectory: string;
};

const execFileAsync = promisify(execFile);

function usage(): void {
  console.log(`Usage: pnpm extract-archives [options] <output-directory>

Recursively extracts every ZIP from catalog into the output directory. Category and
program paths are preserved; each archive is extracted into a directory named after it.
Existing destination directories and files are skipped.

  --dry-run          list operations without extracting files
  --source <path>    read ZIP archives from a directory other than catalog
  --temp-dir <path>  use a specific directory for temporary files
  --help             show this help message`);
}

function parseArguments(args: string[]): Options {
  const positional: string[] = [];
  let dryRun = false;
  let sourceDirectory = path.resolve("catalog");
  let temporaryDirectory = "/tmp/codex/extract-archives";

  for (let index = 0; index < args.length; index += 1) {
    const argument = args[index];
    if (argument === "--help" || argument === "-h") {
      usage();
      process.exit(0);
    } else if (argument === "--dry-run") {
      dryRun = true;
    } else if (argument === "--source") {
      const value = args[index + 1];
      if (value === undefined) {
        throw new Error("--source requires a path");
      }
      sourceDirectory = path.resolve(value);
      index += 1;
    } else if (argument === "--temp-dir") {
      const value = args[index + 1];
      if (value === undefined) {
        throw new Error("--temp-dir requires a path");
      }
      temporaryDirectory = path.resolve(value);
      index += 1;
    } else if (argument.startsWith("-")) {
      throw new Error(`Unknown option: ${argument}`);
    } else {
      positional.push(argument);
    }
  }

  if (positional.length !== 1) {
    throw new Error("Expected one output directory path");
  }

  return {
    dryRun,
    outputDirectory: path.resolve(positional[0]),
    sourceDirectory,
    temporaryDirectory,
  };
}

async function run(command: string, args: string[]): Promise<string> {
  const { stdout } = await execFileAsync(command, args, {
    encoding: "utf8",
    maxBuffer: 32 * 1024 * 1024,
  });
  return stdout;
}

async function collectArchives(directory: string): Promise<string[]> {
  const archives: string[] = [];

  async function visit(currentDirectory: string): Promise<void> {
    const entries = await readdir(currentDirectory, { withFileTypes: true });
    entries.sort((left, right) => left.name.localeCompare(right.name, "en"));

    for (const entry of entries) {
      const entryPath = path.join(currentDirectory, entry.name);
      if (entry.isDirectory()) {
        await visit(entryPath);
      } else if (entry.isFile() && path.extname(entry.name).toLowerCase() === ".zip") {
        archives.push(entryPath);
      }
    }
  }

  await visit(directory);
  return archives;
}

function destinationFor(archive: string, sourceDirectory: string, outputDirectory: string): string {
  const basename = path.basename(archive);
  const stem = basename.slice(0, -path.extname(basename).length);
  if (stem.length === 0) {
    throw new Error(`Archive has no usable name: ${archive}`);
  }

  const relativeArchive = path.relative(sourceDirectory, archive);
  if (
    relativeArchive === ".." ||
    relativeArchive.startsWith(`..${path.sep}`) ||
    path.isAbsolute(relativeArchive)
  ) {
    throw new Error(`Archive is outside the source directory: ${archive}`);
  }

  let relativeParent = path.dirname(relativeArchive);
  if (path.basename(relativeParent) === "files") {
    relativeParent = path.dirname(relativeParent);
  }
  return path.join(outputDirectory, relativeParent, stem);
}

async function pathExists(target: string): Promise<boolean> {
  try {
    await lstat(target);
    return true;
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
      return false;
    }
    throw error;
  }
}

function validateArchivePaths(archive: string, listing: string): void {
  for (const originalEntry of listing.split(/\r?\n/)) {
    if (originalEntry.length === 0) {
      continue;
    }
    const entry = originalEntry.replaceAll("\\", "/");
    const parts = entry.split("/");
    if (
      entry.startsWith("/") ||
      /^[a-z]:($|\/)/i.test(entry) ||
      parts.includes("..")
    ) {
      throw new Error(`${archive}: unsafe path in ZIP: ${originalEntry}`);
    }
  }
}

async function validateExtractedTree(directory: string): Promise<void> {
  for (const entry of await readdir(directory, { withFileTypes: true })) {
    const entryPath = path.join(directory, entry.name);
    const entryStat = await lstat(entryPath);
    if (entryStat.isSymbolicLink()) {
      throw new Error(`ZIP contains a symbolic link: ${entryPath}`);
    }
    if (entryStat.isDirectory()) {
      await validateExtractedTree(entryPath);
    } else if (!entryStat.isFile()) {
      throw new Error(`ZIP contains an unsupported special file: ${entryPath}`);
    }
  }
}

async function extractArchive(archive: string, destination: string, temporaryRoot: string): Promise<void> {
  await run("7z", ["t", archive, "-bso0", "-bsp0"]);
  validateArchivePaths(archive, await run("zipinfo", ["-1", archive]));

  const temporaryDirectory = await mkdtemp(path.join(temporaryRoot, "archive-"));
  let destinationCreated = false;
  try {
    await run("7z", ["x", archive, `-o${temporaryDirectory}`, "-y", "-bso0", "-bsp0"]);
    await validateExtractedTree(temporaryDirectory);
    await mkdir(path.dirname(destination), { recursive: true });
    await mkdir(destination);
    destinationCreated = true;
    await run("cp", ["-a", "--", `${temporaryDirectory}${path.sep}.`, destination]);
  } catch (error) {
    if (destinationCreated) {
      await rm(destination, { recursive: true, force: true });
    }
    throw error;
  } finally {
    await rm(temporaryDirectory, { recursive: true, force: true });
  }
}

async function main(): Promise<void> {
  const options = parseArguments(process.argv.slice(2));
  const rootStat = await stat(options.sourceDirectory);
  if (!rootStat.isDirectory()) {
    throw new Error(`Expected a source directory: ${options.sourceDirectory}`);
  }

  const relativeOutput = path.relative(options.sourceDirectory, options.outputDirectory);
  if (
    relativeOutput === "" ||
    (!relativeOutput.startsWith(`..${path.sep}`) && relativeOutput !== ".." && !path.isAbsolute(relativeOutput))
  ) {
    throw new Error("Output directory must not be inside the source directory");
  }

  const archives = await collectArchives(options.sourceDirectory);
  if (archives.length === 0) {
    console.log(`No ZIP archives found in ${options.sourceDirectory}`);
    return;
  }

  if (!options.dryRun) {
    await mkdir(options.outputDirectory, { recursive: true });
    await mkdir(options.temporaryDirectory, { recursive: true });
  }

  let extracted = 0;
  let failed = 0;
  let skipped = 0;

  for (const archive of archives) {
    try {
      const destination = destinationFor(
        archive,
        options.sourceDirectory,
        options.outputDirectory,
      );
      if (await pathExists(destination)) {
        skipped += 1;
        console.log(`Skipped: ${archive} (destination exists: ${destination})`);
      } else if (options.dryRun) {
        console.log(`Would extract: ${archive} -> ${destination}`);
      } else {
        await extractArchive(archive, destination, options.temporaryDirectory);
        extracted += 1;
        console.log(`Extracted: ${archive} -> ${destination}`);
      }
    } catch (error) {
      failed += 1;
      const message = error instanceof Error ? error.message : String(error);
      console.error(`Failed: ${archive}: ${message}`);
    }
  }

  console.log(
    `Done. Archives: ${archives.length}; extracted: ${extracted}; skipped: ${skipped}; failed: ${failed}`,
  );
  if (failed > 0) {
    process.exitCode = 1;
  }
}

try {
  await main();
} catch (error) {
  const message = error instanceof Error ? error.message : String(error);
  console.error(`Error: ${message}`);
  process.exitCode = 1;
}