import { randomUUID } from 'node:crypto';
import {
  cpSync,
  existsSync,
  lstatSync,
  mkdirSync,
  readFileSync,
  renameSync,
  rmSync,
  unlinkSync,
  writeFileSync,
} from 'node:fs';
import { isAbsolute, join, relative, resolve, sep } from 'node:path';
import { retryTransientFilesystemOperation } from './filesystem-retry';

export interface BundledSuperpowersPathInput {
  isPackaged: boolean;
  resourcesPath: string;
  appPath: string;
}

export interface EnsureBundledSuperpowersOptions {
  managedConfigDir: string;
  sourceDir?: string;
}

export interface EnsureBundledCourseSkillsOptions {
  managedConfigDir: string;
  sourceDir?: string;
}

const WRAPPER_PLUGIN_NAME = 'superpowers-niancode.js';
const SUPERPOWERS_REPO_DIR = 'superpowers';
const SUPERPOWERS_BUNDLES_DIR = 'superpowers-bundles';
const SUPERPOWERS_ACTIVE_MANIFEST = 'superpowers-active.json';
export const BUNDLED_COURSE_SKILL_IDS = [
  'deploy-publish-check',
  'designer-design-spec',
  'dev-build-test',
  'game-assets',
  'marketing-launch-story',
  'nianxxgame-skill',
  'partner-agent-showcase',
  'pm-project-plan',
  'product-demo-prototype',
  'ui-ux-course-quality',
  'youth-plain-language',
  'youth-ai-product-course',
] as const;
const RETIRED_COURSE_SKILL_IDS = ['course-stage-review', 'student-growth-logger'] as const;

export function resolveBundledSuperpowersDir(input: BundledSuperpowersPathInput): string {
  const resourcesDir = input.isPackaged
    ? join(input.resourcesPath, 'resources')
    : join(input.appPath, 'resources');

  return join(resourcesDir, 'skills', SUPERPOWERS_REPO_DIR);
}

export function resolveBundledCourseSkillsDir(input: BundledSuperpowersPathInput): string {
  return input.isPackaged
    ? join(input.resourcesPath, 'course-skills')
    : join(input.appPath, '.opencode', 'skills');
}

export function getManagedOpencodeConfigDir(userDataDir: string): string {
  return join(userDataDir, 'opencode', 'niancode-config');
}

function readBundledSuperpowersVersion(sourceDir: string): string {
  const packagePath = join(sourceDir, 'package.json');
  const packageJson = JSON.parse(retryTransientFilesystemOperation(
    () => readFileSync(packagePath, 'utf8'),
  )) as { version?: unknown };
  if (typeof packageJson.version !== 'string' || !packageJson.version.trim()) {
    throw new Error(`Bundled Superpowers package has no valid version: ${packagePath}`);
  }
  return packageJson.version.trim();
}

function toSafeBundleName(version: string): string {
  const safeVersion = version.replace(/[^A-Za-z0-9._-]+/g, '-').replace(/^-+|-+$/g, '');
  if (!safeVersion) {
    throw new Error(`Bundled Superpowers version cannot form a safe directory name: ${version}`);
  }
  return safeVersion;
}

function isCompleteBundle(bundleDir: string, expectedVersion: string): boolean {
  try {
    if (!existsSync(join(bundleDir, '.opencode', 'plugins', 'superpowers.js'))
      || !existsSync(join(bundleDir, 'skills', 'using-superpowers', 'SKILL.md'))) {
      return false;
    }
    return readBundledSuperpowersVersion(bundleDir) === expectedVersion;
  } catch {
    return false;
  }
}

function resolveManifestBundle(
  managedConfigDir: string,
  bundlesDir: string,
  expectedVersion: string,
): string | null {
  try {
    const manifest = JSON.parse(retryTransientFilesystemOperation(
      () => readFileSync(join(managedConfigDir, SUPERPOWERS_ACTIVE_MANIFEST), 'utf8'),
    )) as { version?: unknown; directory?: unknown };
    if (manifest.version !== expectedVersion || typeof manifest.directory !== 'string') {
      return null;
    }

    const bundlesRoot = resolve(bundlesDir);
    const bundleDir = resolve(bundlesDir, manifest.directory);
    const relativeBundlePath = relative(bundlesRoot, bundleDir);
    if (!relativeBundlePath
      || relativeBundlePath === '..'
      || relativeBundlePath.startsWith(`..${sep}`)
      || isAbsolute(relativeBundlePath)) {
      return null;
    }
    return isCompleteBundle(bundleDir, expectedVersion) ? bundleDir : null;
  } catch {
    return null;
  }
}

function copyDirectorySync(sourceDir: string, targetDir: string): void {
  cpSync(sourceDir, targetDir, {
    recursive: true,
    force: true,
    filter: (sourcePath, targetPath) => {
      // Node 24.14's Windows override path can corrupt non-ASCII destinations
      // when replacing a file. Public unlink keeps force-overwrite semantics.
      if (lstatSync(sourcePath).isFile() && existsSync(targetPath)) {
        unlinkSync(targetPath);
      }
      return true;
    },
  });
}

function installImmutableBundle(
  sourceDir: string,
  bundlesDir: string,
  safeBundleName: string,
  expectedVersion: string,
): string {
  retryTransientFilesystemOperation(() => mkdirSync(bundlesDir, { recursive: true }));
  const stagingDir = join(
    bundlesDir,
    `.staging-${safeBundleName}-${process.pid}-${randomUUID()}`,
  );

  try {
    retryTransientFilesystemOperation(() => copyDirectorySync(sourceDir, stagingDir));
    if (!isCompleteBundle(stagingDir, expectedVersion)) {
      throw new Error(`Bundled Superpowers staging copy is incomplete: ${stagingDir}`);
    }

    const preferredDir = join(bundlesDir, safeBundleName);
    if (isCompleteBundle(preferredDir, expectedVersion)) {
      return preferredDir;
    }

    const selectedDir = existsSync(preferredDir)
      ? join(bundlesDir, `${safeBundleName}-${randomUUID()}`)
      : preferredDir;
    try {
      retryTransientFilesystemOperation(() => renameSync(stagingDir, selectedDir));
    } catch (error) {
      if (!isCompleteBundle(selectedDir, expectedVersion)) {
        throw error;
      }
    }
    return selectedDir;
  } finally {
    if (existsSync(stagingDir)) {
      try {
        retryTransientFilesystemOperation(() => rmSync(stagingDir, {
          recursive: true,
          force: true,
        }));
      } catch {
        // Startup cleanup is best-effort; preserve the installation result or error.
      }
    }
  }
}

function writeSelectedBundleFiles(
  managedConfigDir: string,
  bundlesDir: string,
  bundleDir: string,
  version: string,
): void {
  const targetPluginsDir = join(managedConfigDir, 'plugins');
  retryTransientFilesystemOperation(() => mkdirSync(targetPluginsDir, { recursive: true }));

  const pluginPath = join(bundleDir, '.opencode', 'plugins', 'superpowers.js');
  let pluginImport = relative(targetPluginsDir, pluginPath).split(sep).join('/');
  if (!pluginImport.startsWith('.')) pluginImport = `./${pluginImport}`;

  retryTransientFilesystemOperation(() => writeFileSync(
    join(targetPluginsDir, WRAPPER_PLUGIN_NAME),
    `export { SuperpowersPlugin } from '${pluginImport}';\n`,
    'utf8',
  ));
  retryTransientFilesystemOperation(() => writeFileSync(
    join(managedConfigDir, SUPERPOWERS_ACTIVE_MANIFEST),
    `${JSON.stringify({
      version,
      directory: relative(bundlesDir, bundleDir),
    }, null, 2)}\n`,
    'utf8',
  ));
}

export function ensureBundledSuperpowersPlugin(options: EnsureBundledSuperpowersOptions): boolean {
  const sourceDir = options.sourceDir?.trim();
  if (!sourceDir) {
    return false;
  }

  const sourcePluginPath = join(sourceDir, '.opencode', 'plugins', 'superpowers.js');
  const sourceSkillsDir = join(sourceDir, 'skills');
  if (!existsSync(sourcePluginPath) || !existsSync(sourceSkillsDir)) {
    return false;
  }

  const version = readBundledSuperpowersVersion(sourceDir);
  const safeBundleName = toSafeBundleName(version);
  const bundlesDir = join(options.managedConfigDir, SUPERPOWERS_BUNDLES_DIR);
  const preferredDir = join(bundlesDir, safeBundleName);
  const bundleDir = resolveManifestBundle(
    options.managedConfigDir,
    bundlesDir,
    version,
  ) ?? (isCompleteBundle(preferredDir, version)
    ? preferredDir
    : installImmutableBundle(sourceDir, bundlesDir, safeBundleName, version));

  writeSelectedBundleFiles(
    options.managedConfigDir,
    bundlesDir,
    bundleDir,
    version,
  );

  return true;
}

export function ensureBundledCourseSkills(options: EnsureBundledCourseSkillsOptions): boolean {
  const sourceDir = options.sourceDir?.trim();
  if (!sourceDir || !existsSync(sourceDir)) {
    return false;
  }

  const targetSkillsDir = join(options.managedConfigDir, 'skills');
  mkdirSync(targetSkillsDir, { recursive: true });
  for (const skillId of RETIRED_COURSE_SKILL_IDS) {
    rmSync(join(targetSkillsDir, skillId), { recursive: true, force: true });
  }
  copyDirectorySync(sourceDir, targetSkillsDir);

  return true;
}