import { BaseRegistry } from '../core/classes.baseregistry.js';
import { RegistryStorage } from '../core/classes.registrystorage.js';
import { AuthManager } from '../core/classes.authmanager.js';
import type { IRequestContext, IResponse, IAuthToken } from '../core/interfaces.core.js';
import type {
  IPackument,
  INpmVersion,
  IPublishRequest,
  ISearchResponse,
  ISearchResult,
  ITokenListResponse,
  ITokenCreateRequest,
  IUserAuthRequest,
  INpmError,
} from './interfaces.npm.js';

/**
 * NPM Registry implementation
 * Compliant with npm registry API
 */
export class NpmRegistry extends BaseRegistry {
  private storage: RegistryStorage;
  private authManager: AuthManager;
  private basePath: string = '/npm';
  private registryUrl: string;

  constructor(
    storage: RegistryStorage,
    authManager: AuthManager,
    basePath: string = '/npm',
    registryUrl: string = 'http://localhost:5000/npm'
  ) {
    super();
    this.storage = storage;
    this.authManager = authManager;
    this.basePath = basePath;
    this.registryUrl = registryUrl;
  }

  public async init(): Promise<void> {
    // NPM registry initialization
  }

  public getBasePath(): string {
    return this.basePath;
  }

  public async handleRequest(context: IRequestContext): Promise<IResponse> {
    const path = context.path.replace(this.basePath, '');

    // Extract token from Authorization header
    const authHeader = context.headers['authorization'] || context.headers['Authorization'];
    const tokenString = authHeader?.replace(/^Bearer\s+/i, '');
    const token = tokenString ? await this.authManager.validateToken(tokenString, 'npm') : null;

    // Registry root
    if (path === '/' || path === '') {
      return this.handleRegistryInfo();
    }

    // Search: /-/v1/search
    if (path.startsWith('/-/v1/search')) {
      return this.handleSearch(context.query);
    }

    // User authentication: /-/user/org.couchdb.user:{username}
    const userMatch = path.match(/^\/-\/user\/org\.couchdb\.user:(.+)$/);
    if (userMatch) {
      return this.handleUserAuth(context.method, userMatch[1], context.body, token);
    }

    // Token operations: /-/npm/v1/tokens
    if (path.startsWith('/-/npm/v1/tokens')) {
      return this.handleTokens(context.method, path, context.body, token);
    }

    // Dist-tags: /-/package/{package}/dist-tags
    const distTagsMatch = path.match(/^\/-\/package\/(@?[^\/]+(?:\/[^\/]+)?)\/dist-tags(?:\/(.+))?$/);
    if (distTagsMatch) {
      const [, packageName, tag] = distTagsMatch;
      return this.handleDistTags(context.method, packageName, tag, context.body, token);
    }

    // Tarball download: /{package}/-/{filename}.tgz
    const tarballMatch = path.match(/^\/(@?[^\/]+(?:\/[^\/]+)?)\/-\/(.+\.tgz)$/);
    if (tarballMatch) {
      const [, packageName, filename] = tarballMatch;
      return this.handleTarballDownload(packageName, filename, token);
    }

    // Package operations: /{package}
    const packageMatch = path.match(/^\/(@?[^\/]+(?:\/[^\/]+)?)$/);
    if (packageMatch) {
      const packageName = packageMatch[1];
      return this.handlePackage(context.method, packageName, context.body, context.query, token);
    }

    // Package version: /{package}/{version}
    const versionMatch = path.match(/^\/(@?[^\/]+(?:\/[^\/]+)?)\/([^\/]+)$/);
    if (versionMatch) {
      const [, packageName, version] = versionMatch;
      return this.handlePackageVersion(packageName, version, token);
    }

    return {
      status: 404,
      headers: { 'Content-Type': 'application/json' },
      body: this.createError('E404', 'Not found'),
    };
  }

  protected async checkPermission(
    token: IAuthToken | null,
    resource: string,
    action: string
  ): Promise<boolean> {
    if (!token) return false;
    return this.authManager.authorize(token, `npm:package:${resource}`, action);
  }

  // ========================================================================
  // REQUEST HANDLERS
  // ========================================================================

  private handleRegistryInfo(): IResponse {
    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: {
        db_name: 'registry',
        doc_count: 0,
        doc_del_count: 0,
        update_seq: 0,
        purge_seq: 0,
        compact_running: false,
        disk_size: 0,
        data_size: 0,
        instance_start_time: Date.now().toString(),
        disk_format_version: 0,
        committed_update_seq: 0,
      },
    };
  }

  private async handlePackage(
    method: string,
    packageName: string,
    body: any,
    query: Record<string, string>,
    token: IAuthToken | null
  ): Promise<IResponse> {
    switch (method) {
      case 'GET':
        return this.getPackument(packageName, token, query);
      case 'PUT':
        return this.publishPackage(packageName, body, token);
      case 'DELETE':
        return this.unpublishPackage(packageName, token);
      default:
        return {
          status: 405,
          headers: {},
          body: this.createError('EBADREQUEST', 'Method not allowed'),
        };
    }
  }

  private async getPackument(
    packageName: string,
    token: IAuthToken | null,
    query: Record<string, string>
  ): Promise<IResponse> {
    const packument = await this.storage.getNpmPackument(packageName);
    if (!packument) {
      return {
        status: 404,
        headers: { 'Content-Type': 'application/json' },
        body: this.createError('E404', `Package '${packageName}' not found`),
      };
    }

    // Check if abbreviated version requested
    const accept = query['accept'] || '';
    if (accept.includes('application/vnd.npm.install-v1+json')) {
      // Return abbreviated packument
      const abbreviated = {
        name: packument.name,
        modified: packument.time?.modified || new Date().toISOString(),
        'dist-tags': packument['dist-tags'],
        versions: packument.versions,
      };

      return {
        status: 200,
        headers: { 'Content-Type': 'application/vnd.npm.install-v1+json' },
        body: abbreviated,
      };
    }

    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: packument,
    };
  }

  private async handlePackageVersion(
    packageName: string,
    version: string,
    token: IAuthToken | null
  ): Promise<IResponse> {
    const packument = await this.storage.getNpmPackument(packageName);
    if (!packument) {
      return {
        status: 404,
        headers: { 'Content-Type': 'application/json' },
        body: this.createError('E404', 'Package not found'),
      };
    }

    // Resolve version (could be "latest" or actual version)
    let actualVersion = version;
    if (version === 'latest') {
      actualVersion = packument['dist-tags']?.latest;
      if (!actualVersion) {
        return {
          status: 404,
          headers: {},
          body: this.createError('E404', 'No latest version'),
        };
      }
    }

    const versionData = packument.versions[actualVersion];
    if (!versionData) {
      return {
        status: 404,
        headers: {},
        body: this.createError('E404', 'Version not found'),
      };
    }

    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: versionData,
    };
  }

  private async publishPackage(
    packageName: string,
    body: IPublishRequest,
    token: IAuthToken | null
  ): Promise<IResponse> {
    if (!await this.checkPermission(token, packageName, 'write')) {
      return {
        status: 401,
        headers: {},
        body: this.createError('EUNAUTHORIZED', 'Unauthorized'),
      };
    }

    if (!body || !body.versions || !body._attachments) {
      return {
        status: 400,
        headers: {},
        body: this.createError('EBADREQUEST', 'Invalid publish request'),
      };
    }

    // Get existing packument or create new one
    let packument = await this.storage.getNpmPackument(packageName);
    const isNew = !packument;

    if (isNew) {
      packument = {
        _id: packageName,
        name: packageName,
        description: body.description,
        'dist-tags': body['dist-tags'] || { latest: Object.keys(body.versions)[0] },
        versions: {},
        time: {
          created: new Date().toISOString(),
          modified: new Date().toISOString(),
        },
        maintainers: body.maintainers || [],
        readme: body.readme,
      };
    }

    // Process each new version
    for (const [version, versionData] of Object.entries(body.versions)) {
      // Check if version already exists
      if (packument.versions[version]) {
        return {
          status: 403,
          headers: {},
          body: this.createError('EPUBLISHCONFLICT', `Version ${version} already exists`),
        };
      }

      // Find attachment for this version
      const attachmentKey = Object.keys(body._attachments).find(key =>
        key.includes(version)
      );

      if (!attachmentKey) {
        return {
          status: 400,
          headers: {},
          body: this.createError('EBADREQUEST', `No tarball for version ${version}`),
        };
      }

      const attachment = body._attachments[attachmentKey];

      // Decode base64 tarball
      const tarballBuffer = Buffer.from(attachment.data, 'base64');

      // Calculate shasum
      const crypto = await import('crypto');
      const shasum = crypto.createHash('sha1').update(tarballBuffer).digest('hex');
      const integrity = `sha512-${crypto.createHash('sha512').update(tarballBuffer).digest('base64')}`;

      // Store tarball
      await this.storage.putNpmTarball(packageName, version, tarballBuffer);

      // Update version data with dist info
      const safeName = packageName.replace('@', '').replace('/', '-');
      versionData.dist = {
        tarball: `${this.registryUrl}/${packageName}/-/${safeName}-${version}.tgz`,
        shasum,
        integrity,
        fileCount: 0,
        unpackedSize: tarballBuffer.length,
      };

      versionData._id = `${packageName}@${version}`;
      versionData._npmUser = token ? { name: token.userId, email: '' } : undefined;

      // Add version to packument
      packument.versions[version] = versionData;
      if (packument.time) {
        packument.time[version] = new Date().toISOString();
        packument.time.modified = new Date().toISOString();
      }
    }

    // Update dist-tags
    if (body['dist-tags']) {
      packument['dist-tags'] = { ...packument['dist-tags'], ...body['dist-tags'] };
    }

    // Save packument
    await this.storage.putNpmPackument(packageName, packument);

    return {
      status: 201,
      headers: { 'Content-Type': 'application/json' },
      body: { ok: true, id: packageName, rev: packument._rev || '1-' + Date.now() },
    };
  }

  private async unpublishPackage(
    packageName: string,
    token: IAuthToken | null
  ): Promise<IResponse> {
    if (!await this.checkPermission(token, packageName, 'delete')) {
      return {
        status: 401,
        headers: {},
        body: this.createError('EUNAUTHORIZED', 'Unauthorized'),
      };
    }

    const packument = await this.storage.getNpmPackument(packageName);
    if (!packument) {
      return {
        status: 404,
        headers: {},
        body: this.createError('E404', 'Package not found'),
      };
    }

    // Delete all tarballs
    for (const version of Object.keys(packument.versions)) {
      await this.storage.deleteNpmTarball(packageName, version);
    }

    // Delete packument
    await this.storage.deleteNpmPackument(packageName);

    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: { ok: true },
    };
  }

  private async handleTarballDownload(
    packageName: string,
    filename: string,
    token: IAuthToken | null
  ): Promise<IResponse> {
    // Extract version from filename: package-name-1.0.0.tgz
    const versionMatch = filename.match(/-([\d.]+(?:-[a-z0-9.]+)?)\.tgz$/);
    if (!versionMatch) {
      return {
        status: 400,
        headers: {},
        body: this.createError('EBADREQUEST', 'Invalid tarball filename'),
      };
    }

    const version = versionMatch[1];
    const tarball = await this.storage.getNpmTarball(packageName, version);

    if (!tarball) {
      return {
        status: 404,
        headers: {},
        body: this.createError('E404', 'Tarball not found'),
      };
    }

    return {
      status: 200,
      headers: {
        'Content-Type': 'application/octet-stream',
        'Content-Length': tarball.length.toString(),
      },
      body: tarball,
    };
  }

  private async handleSearch(query: Record<string, string>): Promise<IResponse> {
    const text = query.text || '';
    const size = parseInt(query.size || '20', 10);
    const from = parseInt(query.from || '0', 10);

    // Simple search implementation (in production, use proper search index)
    const results: ISearchResult[] = [];

    // For now, return empty results
    // In production, implement full-text search across packuments

    const response: ISearchResponse = {
      objects: results,
      total: results.length,
      time: new Date().toISOString(),
    };

    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: response,
    };
  }

  private async handleUserAuth(
    method: string,
    username: string,
    body: IUserAuthRequest,
    token: IAuthToken | null
  ): Promise<IResponse> {
    if (method !== 'PUT') {
      return {
        status: 405,
        headers: {},
        body: this.createError('EBADREQUEST', 'Method not allowed'),
      };
    }

    if (!body || !body.name || !body.password) {
      return {
        status: 400,
        headers: {},
        body: this.createError('EBADREQUEST', 'Invalid request'),
      };
    }

    // Authenticate user
    const userId = await this.authManager.authenticate({
      username: body.name,
      password: body.password,
    });

    if (!userId) {
      return {
        status: 401,
        headers: {},
        body: this.createError('EUNAUTHORIZED', 'Invalid credentials'),
      };
    }

    // Create NPM token
    const npmToken = await this.authManager.createNpmToken(userId, false);

    return {
      status: 201,
      headers: { 'Content-Type': 'application/json' },
      body: {
        ok: true,
        id: `org.couchdb.user:${username}`,
        rev: '1-' + Date.now(),
        token: npmToken,
      },
    };
  }

  private async handleTokens(
    method: string,
    path: string,
    body: any,
    token: IAuthToken | null
  ): Promise<IResponse> {
    if (!token) {
      return {
        status: 401,
        headers: {},
        body: this.createError('EUNAUTHORIZED', 'Unauthorized'),
      };
    }

    // List tokens: GET /-/npm/v1/tokens
    if (path === '/-/npm/v1/tokens' && method === 'GET') {
      return this.listTokens(token);
    }

    // Create token: POST /-/npm/v1/tokens
    if (path === '/-/npm/v1/tokens' && method === 'POST') {
      return this.createToken(body, token);
    }

    // Delete token: DELETE /-/npm/v1/tokens/token/{key}
    const deleteMatch = path.match(/^\/-\/npm\/v1\/tokens\/token\/(.+)$/);
    if (deleteMatch && method === 'DELETE') {
      return this.deleteToken(deleteMatch[1], token);
    }

    return {
      status: 404,
      headers: {},
      body: this.createError('E404', 'Not found'),
    };
  }

  private async listTokens(token: IAuthToken): Promise<IResponse> {
    const tokens = await this.authManager.listUserTokens(token.userId);

    const response: ITokenListResponse = {
      objects: tokens.map(t => ({
        token: '********',
        key: t.key,
        readonly: t.readonly,
        created: t.created,
        updated: t.created,
      })),
      total: tokens.length,
      urls: {},
    };

    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: response,
    };
  }

  private async createToken(body: ITokenCreateRequest, token: IAuthToken): Promise<IResponse> {
    if (!body || !body.password) {
      return {
        status: 400,
        headers: {},
        body: this.createError('EBADREQUEST', 'Password required'),
      };
    }

    // Verify password (simplified - in production, verify against stored password)
    const readonly = body.readonly || false;
    const newToken = await this.authManager.createNpmToken(token.userId, readonly);

    return {
      status: 201,
      headers: { 'Content-Type': 'application/json' },
      body: {
        token: newToken,
        key: 'sha512-' + newToken.substring(0, 16) + '...',
        cidr_whitelist: body.cidr_whitelist || [],
        readonly,
        created: new Date().toISOString(),
        updated: new Date().toISOString(),
      },
    };
  }

  private async deleteToken(key: string, token: IAuthToken): Promise<IResponse> {
    // In production, lookup token by key hash and delete
    return {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
      body: { ok: true },
    };
  }

  private async handleDistTags(
    method: string,
    packageName: string,
    tag: string | undefined,
    body: any,
    token: IAuthToken | null
  ): Promise<IResponse> {
    const packument = await this.storage.getNpmPackument(packageName);
    if (!packument) {
      return {
        status: 404,
        headers: {},
        body: this.createError('E404', 'Package not found'),
      };
    }

    // GET /-/package/{package}/dist-tags
    if (method === 'GET' && !tag) {
      return {
        status: 200,
        headers: { 'Content-Type': 'application/json' },
        body: packument['dist-tags'] || {},
      };
    }

    // PUT /-/package/{package}/dist-tags/{tag}
    if (method === 'PUT' && tag) {
      if (!await this.checkPermission(token, packageName, 'write')) {
        return {
          status: 401,
          headers: {},
          body: this.createError('EUNAUTHORIZED', 'Unauthorized'),
        };
      }

      if (typeof body !== 'string') {
        return {
          status: 400,
          headers: {},
          body: this.createError('EBADREQUEST', 'Version string required'),
        };
      }

      packument['dist-tags'] = packument['dist-tags'] || {};
      packument['dist-tags'][tag] = body;
      await this.storage.putNpmPackument(packageName, packument);

      return {
        status: 200,
        headers: { 'Content-Type': 'application/json' },
        body: { ok: true },
      };
    }

    // DELETE /-/package/{package}/dist-tags/{tag}
    if (method === 'DELETE' && tag) {
      if (!await this.checkPermission(token, packageName, 'write')) {
        return {
          status: 401,
          headers: {},
          body: this.createError('EUNAUTHORIZED', 'Unauthorized'),
        };
      }

      if (tag === 'latest') {
        return {
          status: 403,
          headers: {},
          body: this.createError('EFORBIDDEN', 'Cannot delete latest tag'),
        };
      }

      if (packument['dist-tags'] && packument['dist-tags'][tag]) {
        delete packument['dist-tags'][tag];
        await this.storage.putNpmPackument(packageName, packument);
      }

      return {
        status: 200,
        headers: { 'Content-Type': 'application/json' },
        body: { ok: true },
      };
    }

    return {
      status: 405,
      headers: {},
      body: this.createError('EBADREQUEST', 'Method not allowed'),
    };
  }

  // ========================================================================
  // HELPER METHODS
  // ========================================================================

  private createError(code: string, message: string): INpmError {
    return {
      error: code,
      reason: message,
    };
  }
}