import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath, pathToFileURL } from 'node:url';

export const REQUIRED_PACKAGE_MANAGER = 'npm@10.9.7';

export const REQUIRED_WORKSPACES = Object.freeze([
  'apps/admin-web',
  'apps/ai-game-creator-shell',
  'apps/desktop-shell',
  'apps/mobile-shell',
  'apps/preview-deployer-web',
  'packages/image-canvas-core',
  'packages/image-canvas-react',
  'packages/shared',
  'tools/spine-json-export-validator',
]);

const WORKSPACE_NAMES = Object.freeze({
  'apps/admin-web': '@genarrative/admin-web',
  'apps/ai-game-creator-shell': '@genarrative/ai-game-creator-shell',
  'apps/desktop-shell': '@genarrative/desktop-shell',
  'apps/mobile-shell': '@genarrative/mobile-shell',
  'apps/preview-deployer-web': '@genarrative/preview-deployer-web',
  'packages/image-canvas-core': '@genarrative/image-canvas-core',
  'packages/image-canvas-react': '@genarrative/image-canvas-react',
  'packages/shared': '@genarrative/shared',
  'tools/spine-json-export-validator':
    '@genarrative/spine-json-export-validator',
});

const REQUIRED_LOCAL_DEPENDENCIES = Object.freeze({
  'package.json': [
    '@genarrative/image-canvas-core',
    '@genarrative/image-canvas-react',
    '@genarrative/shared',
  ],
  'apps/admin-web/package.json': ['@genarrative/shared'],
  'apps/ai-game-creator-shell/package.json': [
    '@genarrative/image-canvas-core',
    '@genarrative/image-canvas-react',
    '@genarrative/shared',
  ],
  'apps/mobile-shell/package.json': ['@genarrative/shared'],
  'packages/image-canvas-react/package.json': [
    '@genarrative/image-canvas-core',
  ],
});

const DEPENDENCY_FIELDS = Object.freeze([
  'dependencies',
  'devDependencies',
  'optionalDependencies',
  'peerDependencies',
]);

const IGNORED_NESTED_DIRECTORIES = new Set([
  '.git',
  '.vite',
  'build',
  'dist',
  'node_modules',
  'target',
]);

const HOIST_SENSITIVE_CONFIGS = Object.freeze([
  'vite.config.ts',
  'vitest.config.ts',
  'apps/ai-game-creator-shell/vite.config.ts',
]);

const FORBIDDEN_WORKSPACE_NODE_MODULES_PATH =
  'apps/ai-game-creator-shell/node_modules/';

function readJson(rootDir, relativePath, errors) {
  const absolutePath = path.join(rootDir, relativePath);
  try {
    return JSON.parse(fs.readFileSync(absolutePath, 'utf8'));
  } catch (error) {
    errors.push(`${relativePath}: cannot read valid JSON (${error.message})`);
    return null;
  }
}

function normalizeWorkspaceLink(value) {
  return typeof value === 'string'
    ? value.replace(/^\.\//u, '').replaceAll('\\', '/')
    : value;
}

function findNestedLockfiles(rootDir, workspacePath) {
  const matches = [];
  const pending = [path.join(rootDir, workspacePath)];

  while (pending.length > 0) {
    const directory = pending.pop();
    let entries;
    try {
      entries = fs.readdirSync(directory, { withFileTypes: true });
    } catch {
      continue;
    }

    for (const entry of entries) {
      if (entry.isSymbolicLink()) {
        continue;
      }
      const entryPath = path.join(directory, entry.name);
      if (entry.isDirectory()) {
        if (!IGNORED_NESTED_DIRECTORIES.has(entry.name)) {
          pending.push(entryPath);
        }
        continue;
      }
      if (
        entry.name === 'package-lock.json' ||
        entry.name === 'npm-shrinkwrap.json'
      ) {
        matches.push(path.relative(rootDir, entryPath).replaceAll('\\', '/'));
      }
    }
  }

  return matches.sort();
}

export function collectNpmWorkspaceErrors(rootDir) {
  const errors = [];
  const rootPackage = readJson(rootDir, 'package.json', errors);
  const lockfile = readJson(rootDir, 'package-lock.json', errors);
  if (!rootPackage || !lockfile) {
    return errors;
  }

  for (const configPath of HOIST_SENSITIVE_CONFIGS) {
    const absolutePath = path.join(rootDir, configPath);
    if (
      fs.existsSync(absolutePath) &&
      fs
        .readFileSync(absolutePath, 'utf8')
        .includes(FORBIDDEN_WORKSPACE_NODE_MODULES_PATH)
    ) {
      errors.push(
        `${configPath}: resolve dependencies from the workspace manifest instead of hard-coding ${FORBIDDEN_WORKSPACE_NODE_MODULES_PATH}`,
      );
    }
  }

  if (rootPackage.packageManager !== REQUIRED_PACKAGE_MANAGER) {
    errors.push(
      `package.json: packageManager must be ${REQUIRED_PACKAGE_MANAGER}, received ${String(rootPackage.packageManager)}`,
    );
  }
  if (
    JSON.stringify(rootPackage.workspaces) !==
    JSON.stringify(REQUIRED_WORKSPACES)
  ) {
    errors.push(
      `package.json: workspaces must be the explicit ordered list ${JSON.stringify(REQUIRED_WORKSPACES)}`,
    );
  }

  const manifests = new Map([['package.json', rootPackage]]);
  for (const workspacePath of REQUIRED_WORKSPACES) {
    const manifestPath = `${workspacePath}/package.json`;
    const manifest = readJson(rootDir, manifestPath, errors);
    if (!manifest) {
      continue;
    }
    manifests.set(manifestPath, manifest);
    if (manifest.name !== WORKSPACE_NAMES[workspacePath]) {
      errors.push(
        `${manifestPath}: name must be ${WORKSPACE_NAMES[workspacePath]}, received ${String(manifest.name)}`,
      );
    }
    if (workspacePath === 'apps/ai-game-creator-shell') {
      if (!/^\d+\.\d+\.\d+$/u.test(manifest.version ?? '')) {
        errors.push(
          `${manifestPath}: workspace version must be a three-part semver`,
        );
      }
    } else if (manifest.version !== '0.1.0') {
      errors.push(`${manifestPath}: workspace version must be 0.1.0`);
    }

    for (const nestedLockfile of findNestedLockfiles(rootDir, workspacePath)) {
      errors.push(
        `${nestedLockfile}: nested npm lockfiles are forbidden inside workspaces`,
      );
    }
  }

  const localPackageNames = new Set(Object.values(WORKSPACE_NAMES));
  for (const [manifestPath, manifest] of manifests) {
    for (const dependencyField of DEPENDENCY_FIELDS) {
      for (const [dependencyName, dependencySpec] of Object.entries(
        manifest[dependencyField] ?? {},
      )) {
        if (
          typeof dependencySpec === 'string' &&
          dependencySpec.startsWith('workspace:')
        ) {
          errors.push(
            `${manifestPath}: ${dependencyField}.${dependencyName} must not use the unsupported workspace: protocol`,
          );
        }
        if (
          localPackageNames.has(dependencyName) &&
          dependencySpec !== '0.1.0'
        ) {
          errors.push(
            `${manifestPath}: ${dependencyField}.${dependencyName} must use exact version 0.1.0`,
          );
        }
      }
    }
  }

  for (const [manifestPath, requiredDependencies] of Object.entries(
    REQUIRED_LOCAL_DEPENDENCIES,
  )) {
    const manifest = manifests.get(manifestPath);
    if (!manifest) {
      continue;
    }
    for (const dependencyName of requiredDependencies) {
      if (manifest.dependencies?.[dependencyName] !== '0.1.0') {
        errors.push(
          `${manifestPath}: dependencies.${dependencyName} must be declared as exact version 0.1.0`,
        );
      }
    }
  }

  const lockPackages = lockfile.packages;
  if (!lockPackages || typeof lockPackages !== 'object') {
    errors.push('package-lock.json: packages map is required');
    return errors;
  }
  if (
    JSON.stringify(lockPackages['']?.workspaces) !==
    JSON.stringify(REQUIRED_WORKSPACES)
  ) {
    errors.push(
      'package-lock.json: root package entry must contain the explicit workspace list',
    );
  }

  for (const workspacePath of REQUIRED_WORKSPACES) {
    const expectedName = WORKSPACE_NAMES[workspacePath];
    const workspaceEntry = lockPackages[workspacePath];
    if (!workspaceEntry || workspaceEntry.name !== expectedName) {
      errors.push(
        `package-lock.json: packages[${JSON.stringify(workspacePath)}] must describe ${expectedName}`,
      );
    }

    const linkKey = `node_modules/${expectedName}`;
    const linkEntry = lockPackages[linkKey];
    if (
      !linkEntry ||
      linkEntry.link !== true ||
      normalizeWorkspaceLink(linkEntry.resolved) !== workspacePath
    ) {
      errors.push(
        `package-lock.json: packages[${JSON.stringify(linkKey)}] must link to ${workspacePath}`,
      );
    }
  }

  return errors;
}

export function checkNpmWorkspaces(rootDir) {
  const errors = collectNpmWorkspaceErrors(rootDir);
  if (errors.length > 0) {
    throw new Error(
      `npm workspace validation failed:\n- ${errors.join('\n- ')}`,
    );
  }
}

const isMainModule =
  process.argv[1] &&
  pathToFileURL(path.resolve(process.argv[1])).href === import.meta.url;

if (isMainModule) {
  const rootDir = path.resolve(
    path.dirname(fileURLToPath(import.meta.url)),
    '..',
  );
  try {
    checkNpmWorkspaces(rootDir);
    console.log('[check:npm-workspaces] OK');
  } catch (error) {
    console.error(error.message);
    process.exitCode = 1;
  }
}