#!/usr/bin/env node

/**
 * Destructive mutation tests isolated in the operating-system temp directory.
 * The checked-out repository is never modified.
 */

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 here = path.dirname(fileURLToPath(import.meta.url));
const root = path.resolve(here, "..");
const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), "agency-transfer-hardening-"));
const results = [];

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

async function fixture(name) {
  const target = path.join(tempRoot, name);
  await fs.cp(root, target, {
    recursive: true,
    filter: (source) => {
      const relative = path.relative(root, source);
      if (!relative) return true;
      const first = relative.split(path.sep)[0];
      return ![".git", "release"].includes(first) && !first.startsWith(".parquet-build-") && !first.startsWith(".parquet-backup-");
    }
  });
  return target;
}

function run(repo, script, args = []) {
  return spawnSync(process.execPath, [path.join(repo, "scripts", script), ...args], {
    cwd: repo,
    encoding: "utf8",
    maxBuffer: 32 * 1024 * 1024
  });
}

function errorCodes(result) {
  try {
    return JSON.parse(result.stdout).integrity.errors.map((item) => item.code);
  } catch {
    return [];
  }
}

function assert(condition, message) {
  if (!condition) throw new Error(message);
}

try {
  if (!(await fs.stat(path.join(root, "node_modules", "parquetjs-lite")).catch(() => null))) {
    throw new Error("node_modules/parquetjs-lite is required. Run npm ci before npm run test:hardening.");
  }
  const baseline = run(root, "validate-data.mjs");
  assert(baseline.status === 0, `Baseline validation must pass before mutation tests.\n${baseline.stdout || baseline.stderr}`);

  // 1. A forged Parquet manifest must not be accepted.
  {
    const repo = await fixture("parquet-manifest");
    const manifestPath = path.join(repo, "parquet", "manifest.json");
    const manifest = JSON.parse(await fs.readFile(manifestPath, "utf8"));
    manifest.tables[0].sha256 = "0".repeat(64);
    await fs.writeFile(manifestPath, `${JSON.stringify(manifest, null, 2)}\n`);
    const validation = run(repo, "validate-data.mjs");
    const codes = errorCodes(validation);
    assert(validation.status !== 0 && codes.includes("PARQUET_FILE_HASH_MISMATCH"), "Mutated Parquet manifest was not rejected by file hash");
    results.push({ mutation: "parquet_manifest_hash", status: "rejected", code: "PARQUET_FILE_HASH_MISMATCH" });
  }

  // 2. Two byte-identical but stale audit files must still fail.
  {
    const repo = await fixture("stale-audit");
    const auditPath = path.join(repo, "data", "audit.json");
    const audit = JSON.parse(await fs.readFile(auditPath, "utf8"));
    audit.summary.table_row_counts.cases += 1;
    const stale = `${JSON.stringify(audit, null, 2)}\n`;
    await fs.writeFile(auditPath, stale);
    await fs.writeFile(path.join(repo, "data", "audit-v03.json"), stale);
    const validation = run(repo, "validate-data.mjs");
    const codes = errorCodes(validation);
    assert(
      validation.status !== 0 && codes.includes("STORED_AUDIT_ROW_COUNT_MISMATCH") && codes.includes("STORED_AUDIT_STALE"),
      "Byte-identical stale audits were not rejected"
    );
    results.push({ mutation: "stored_audit_count", status: "rejected", codes: ["STORED_AUDIT_ROW_COUNT_MISMATCH", "STORED_AUDIT_STALE"] });
  }

  // 3. Invalid boolean input must block the builder without touching Parquet.
  {
    const repo = await fixture("invalid-coercion");
    const casesPath = path.join(repo, "data", "cases.csv");
    const original = await fs.readFile(casesPath, "utf8");
    const lines = original.split("\n");
    const headers = lines[0].split(",");
    const anchorIndex = headers.indexOf("anchor_case");
    assert(anchorIndex >= 0, "cases.csv lacks anchor_case fixture column");
    const cells = lines[1].split(",");
    assert(cells[anchorIndex] === "true" || cells[anchorIndex] === "false", "Unexpected quoted/complex anchor_case fixture value");
    cells[anchorIndex] = "truthy";
    lines[1] = cells.join(",");
    await fs.writeFile(casesPath, lines.join("\n"));
    const statsPath = path.join(repo, "data", "stats.json");
    const stats = JSON.parse(await fs.readFile(statsPath, "utf8"));
    stats._integrity.file_sha256["cases.csv"] = sha256(await fs.readFile(casesPath));
    await fs.writeFile(statsPath, `${JSON.stringify(stats, null, 2)}\n`);
    const parquetPath = path.join(repo, "parquet", "cases.parquet");
    const before = sha256(await fs.readFile(parquetPath));
    const build = run(repo, "build-parquet.mjs");
    const after = sha256(await fs.readFile(parquetPath));
    assert(
      build.status !== 0 && /FIELD_TYPE_INVALID|invalid boolean/i.test(`${build.stdout}\n${build.stderr}`),
      `Invalid boolean coercion did not block the build as expected.\n${build.stdout}\n${build.stderr}`
    );
    assert(before === after, "Failed Parquet build modified the existing output");
    results.push({ mutation: "invalid_boolean_coercion", status: "rejected", existing_parquet_preserved: true });
  }

  // 4. Invalid numeric input is rejected rather than parsed or omitted.
  {
    const repo = await fixture("invalid-numeric-coercion");
    const csvPath = path.join(repo, "data", "coverage_summary.csv");
    const lines = (await fs.readFile(csvPath, "utf8")).split("\n");
    const headers = lines[0].split(",");
    const countIndex = headers.indexOf("included_case_count");
    assert(countIndex >= 0, "coverage_summary.csv lacks included_case_count fixture column");
    const cells = lines[1].split(",");
    cells[countIndex] = "12records";
    lines[1] = cells.join(",");
    await fs.writeFile(csvPath, lines.join("\n"));
    const statsPath = path.join(repo, "data", "stats.json");
    const stats = JSON.parse(await fs.readFile(statsPath, "utf8"));
    stats._integrity.file_sha256["coverage_summary.csv"] = sha256(await fs.readFile(csvPath));
    await fs.writeFile(statsPath, `${JSON.stringify(stats, null, 2)}\n`);
    const parquetPath = path.join(repo, "parquet", "coverage_summary.parquet");
    const before = sha256(await fs.readFile(parquetPath));
    const build = run(repo, "build-parquet.mjs");
    const after = sha256(await fs.readFile(parquetPath));
    assert(
      build.status !== 0 && /FIELD_TYPE_INVALID|invalid integer/i.test(`${build.stdout}\n${build.stderr}`),
      `Invalid numeric coercion did not block the build as expected.\n${build.stdout}\n${build.stderr}`
    );
    assert(before === after, "Failed numeric Parquet build modified the existing output");
    results.push({ mutation: "invalid_numeric_coercion", status: "rejected", existing_parquet_preserved: true });
  }

  // 5. Release artifacts are accepted only with a matching manifest/SHA file.
  {
    const repo = await fixture("release-artifact");
    const releaseDir = path.join(repo, "release");
    await fs.mkdir(releaseDir, { recursive: true });
    const zipName = "agency-transfer-election-cases-v0.4.0.zip";
    const workbookName = "agency-transfer-election-evidence-index-v0.4.0.xlsx";
    await fs.writeFile(path.join(releaseDir, workbookName), "external-runtime workbook fixture\n");
    const packageBuild = run(repo, "build-package.mjs");
    assert(packageBuild.status === 0, `Deterministic package fixture build failed.\n${packageBuild.stdout}\n${packageBuild.stderr}`);
    const firstZipHash = sha256(await fs.readFile(path.join(releaseDir, zipName)));
    const packageRebuild = run(repo, "build-package.mjs");
    const secondZipHash = sha256(await fs.readFile(path.join(releaseDir, zipName)));
    assert(packageRebuild.status === 0 && firstZipHash === secondZipHash, "Repeated package build was not byte-deterministic");
    const packageVerification = run(repo, "verify-package.mjs");
    assert(packageVerification.status === 0, `Package member verification failed.\n${packageVerification.stdout}\n${packageVerification.stderr}`);
    const initialCheckoutParity = run(repo, "verify-package.mjs", ["--checkout-parity"]);
    assert(initialCheckoutParity.status === 0, `Fresh package must match its checkout.\n${initialCheckoutParity.stdout}\n${initialCheckoutParity.stderr}`);
    const manifestBuild = run(repo, "build-release-manifest.mjs");
    assert(manifestBuild.status === 0, `Release manifest fixture build failed.\n${manifestBuild.stdout}\n${manifestBuild.stderr}`);
    const cleanValidation = run(repo, "validate-data.mjs");
    assert(cleanValidation.status === 0, `Matching release manifest fixture did not validate.\n${cleanValidation.stdout}\n${cleanValidation.stderr}`);
    const releaseManifestPath = path.join(releaseDir, "release-manifest.json");
    const cleanReleaseManifest = await fs.readFile(releaseManifestPath, "utf8");
    const duplicateManifest = JSON.parse(cleanReleaseManifest);
    duplicateManifest.package_files[1] = { ...duplicateManifest.package_files[0] };
    await fs.writeFile(releaseManifestPath, `${JSON.stringify(duplicateManifest, null, 2)}\n`);
    const duplicateValidation = run(repo, "validate-data.mjs");
    assert(
      duplicateValidation.status !== 0 && errorCodes(duplicateValidation).includes("RELEASE_PACKAGE_FILE_DUPLICATE"),
      "Duplicate release package-file entries were not rejected"
    );
    await fs.writeFile(releaseManifestPath, cleanReleaseManifest);
    const manifestBeforeCheckoutChange = sha256(await fs.readFile(releaseManifestPath));
    await fs.appendFile(path.join(repo, "README.md"), "\nPost-release mutable-main documentation fixture.\n");
    const frozenVerification = run(repo, "verify-package.mjs");
    assert(frozenVerification.status === 0, `Mutable checkout incorrectly invalidated the frozen package.\n${frozenVerification.stdout}\n${frozenVerification.stderr}`);
    const changedCheckoutParity = run(repo, "verify-package.mjs", ["--checkout-parity"]);
    assert(
      changedCheckoutParity.status !== 0 && /differs from current checkout/i.test(`${changedCheckoutParity.stdout}\n${changedCheckoutParity.stderr}`),
      "Explicit checkout-parity verification did not reject mutable-main drift"
    );
    const manifestRebuild = run(repo, "build-release-manifest.mjs");
    const manifestAfterCheckoutChange = sha256(await fs.readFile(releaseManifestPath));
    assert(
      manifestRebuild.status === 0 && manifestBeforeCheckoutChange === manifestAfterCheckoutChange,
      "Release manifest changed when only the mutable checkout diverged from the frozen ZIP"
    );
    const mutableMainValidation = run(repo, "validate-data.mjs");
    assert(
      mutableMainValidation.status === 0,
      `Mutable-main documentation incorrectly invalidated the frozen release.\n${mutableMainValidation.stdout}\n${mutableMainValidation.stderr}`
    );
    await fs.appendFile(path.join(releaseDir, zipName), "tampered\n");
    const tamperedValidation = run(repo, "validate-data.mjs");
    const codes = errorCodes(tamperedValidation);
    assert(
      tamperedValidation.status !== 0 && codes.includes("RELEASE_ARTIFACT_HASH_MISMATCH"),
      "Tampered release artifact was not rejected"
    );
    results.push({
      mutation: "release_artifact_after_manifest", status: "rejected",
      code: "RELEASE_ARTIFACT_HASH_MISMATCH", deterministic_package_rebuild: true,
      package_member_verification: "pass", mutable_main_release_verification: "pass",
      explicit_checkout_parity_after_drift: "rejected", duplicate_package_file_entry: "rejected"
    });
  }

  process.stdout.write(`${JSON.stringify({ status: "pass", isolated_temp_root: tempRoot, tests: results }, null, 2)}\n`);
} finally {
  await fs.rm(tempRoot, { recursive: true, force: true });
}