#!/usr/bin/env node

/**
 * Build the deterministic v0.4.0 ZIP package.
 *
 * CSV and Parquet are canonical. The XLSX is copied as a frozen, checksum-only
 * convenience artifact because its external runtime is not in package.json.
 */

import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { createHash } from "node:crypto";
import { spawnSync } from "node:child_process";
import { fileURLToPath } from "node:url";

const VERSION = "0.4.0";
const FIXED_TIME = new Date("2026-08-15T00:00:00.000Z");
const here = path.dirname(fileURLToPath(import.meta.url));
const root = path.resolve(here, "..");
const packageName = `agency-transfer-election-cases-v${VERSION}`;
const workbookName = `agency-transfer-election-evidence-index-v${VERSION}.xlsx`;
const releaseDir = path.join(root, "release");
const workbookPath = path.join(releaseDir, workbookName);
const outputPath = path.join(releaseDir, `${packageName}.zip`);
const atomicOutputPath = path.join(releaseDir, `.${packageName}.zip.${process.pid}.tmp`);
const rootFiles = [
  ".gitignore", "CHANGELOG.md", "CITATION.cff", "CONTRIBUTING.md", "LICENSE",
  "README.md", "package-lock.json", "package.json", "requirements-validation.txt"
];
const sourceDirs = ["data", "docs", "parquet", "research", "scripts"];

function sha256(buffer) {
  return createHash("sha256").update(buffer).digest("hex");
}

async function filesBelow(base, relative = "") {
  const directory = path.join(base, relative);
  const entries = await fs.readdir(directory, { withFileTypes: true });
  const files = [];
  for (const entry of entries.sort((a, b) => a.name.localeCompare(b.name))) {
    const child = path.join(relative, entry.name);
    if (entry.isSymbolicLink()) throw new Error(`Symlink is not allowed in release package: ${child}`);
    if (entry.isDirectory()) files.push(...await filesBelow(base, child));
    else if (entry.isFile()) files.push(child.split(path.sep).join("/"));
    else throw new Error(`Unsupported release entry: ${child}`);
  }
  return files;
}

await fs.mkdir(releaseDir, { recursive: true });
await fs.access(workbookPath);
const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), `${packageName}-`));
const stage = path.join(tempRoot, packageName);
const tempZip = path.join(tempRoot, `${packageName}.zip`);

try {
  await fs.mkdir(stage, { recursive: true });
  for (const filename of rootFiles) {
    await fs.copyFile(path.join(root, filename), path.join(stage, filename));
  }
  for (const dirname of sourceDirs) {
    await fs.cp(path.join(root, dirname), path.join(stage, dirname), { recursive: true, dereference: false });
  }
  await fs.mkdir(path.join(stage, "workbook"));
  await fs.copyFile(workbookPath, path.join(stage, "workbook", workbookName));

  const payloadFiles = (await filesBelow(stage)).sort();
  const entries = [];
  for (const filename of payloadFiles) {
    const buffer = await fs.readFile(path.join(stage, filename));
    entries.push({ path: filename, bytes: buffer.byteLength, sha256: sha256(buffer) });
  }
  const manifest = {
    manifest_version: 1,
    dataset_version: VERSION,
    package_root: packageName,
    frozen_at: FIXED_TIME.toISOString(),
    file_count: entries.length,
    files: entries
  };
  await fs.writeFile(path.join(stage, "PACKAGE-MANIFEST.json"), `${JSON.stringify(manifest, null, 2)}\n`);
  await fs.writeFile(
    path.join(stage, "PACKAGE-SHA256SUMS"),
    `${entries.map((entry) => `${entry.sha256}  ${entry.path}`).join("\n")}\n`
  );

  const allFiles = (await filesBelow(stage)).sort();
  const allDirs = new Set([stage]);
  for (const filename of allFiles) {
    let current = path.dirname(path.join(stage, filename));
    while (current.startsWith(stage)) {
      allDirs.add(current);
      if (current === stage) break;
      current = path.dirname(current);
    }
    await fs.utimes(path.join(stage, filename), FIXED_TIME, FIXED_TIME);
  }
  for (const directory of [...allDirs].sort((a, b) => b.length - a.length)) {
    await fs.utimes(directory, FIXED_TIME, FIXED_TIME);
  }

  const zipEntries = allFiles.map((filename) => `${packageName}/${filename}`);
  const result = spawnSync("zip", ["-X", "-q", tempZip, "-@"], {
    cwd: tempRoot,
    input: `${zipEntries.join("\n")}\n`,
    encoding: "utf8",
    env: { ...process.env, TZ: "UTC" }
  });
  if (result.error) throw result.error;
  if (result.status !== 0) throw new Error(`zip failed (${result.status}): ${String(result.stderr || result.stdout).trim()}`);
  // The staging directory may be mounted on a different filesystem than the
  // repository. Copy to a same-directory temporary file, then rename atomically.
  await fs.copyFile(tempZip, atomicOutputPath);
  await fs.rename(atomicOutputPath, outputPath);
  const output = await fs.readFile(outputPath);
  process.stdout.write(`${JSON.stringify({
    version: VERSION,
    file: path.relative(root, outputPath),
    bytes: output.byteLength,
    sha256: sha256(output),
    packaged_files: entries.length
  })}\n`);
} finally {
  await fs.rm(atomicOutputPath, { force: true });
  await fs.rm(tempRoot, { recursive: true, force: true });
}