import * as plugins from '../plugins.js';
import { BaseUpstream } from '../upstream/classes.baseupstream.js';
import type {
  IProtocolUpstreamConfig,
  IUpstreamFetchContext,
  IUpstreamRegistryConfig,
} from '../upstream/interfaces.upstream.js';

/**
 * Composer-specific upstream implementation.
 *
 * Handles:
 * - Package metadata fetching (packages.json, provider-includes)
 * - Package version metadata (p2/{vendor}/{package}.json)
 * - Dist file (zip) proxying
 * - Packagist v2 API support
 */
export class ComposerUpstream extends BaseUpstream {
  protected readonly protocolName = 'composer';

  constructor(
    config: IProtocolUpstreamConfig,
    logger?: plugins.smartlog.Smartlog,
  ) {
    super(config, logger);
  }

  /**
   * Fetch the root packages.json from upstream.
   */
  public async fetchPackagesJson(): Promise<any | null> {
    const context: IUpstreamFetchContext = {
      protocol: 'composer',
      resource: '*',
      resourceType: 'root',
      path: '/packages.json',
      method: 'GET',
      headers: {
        'accept': 'application/json',
      },
      query: {},
    };

    const result = await this.fetch(context);

    if (!result || !result.success) {
      return null;
    }

    if (Buffer.isBuffer(result.body)) {
      return JSON.parse(result.body.toString('utf8'));
    }

    return result.body;
  }

  /**
   * Fetch package metadata using v2 API (p2/{vendor}/{package}.json).
   */
  public async fetchPackageMetadata(vendor: string, packageName: string): Promise<any | null> {
    const fullName = `${vendor}/${packageName}`;
    const path = `/p2/${vendor}/${packageName}.json`;

    const context: IUpstreamFetchContext = {
      protocol: 'composer',
      resource: fullName,
      resourceType: 'metadata',
      path,
      method: 'GET',
      headers: {
        'accept': 'application/json',
      },
      query: {},
    };

    const result = await this.fetch(context);

    if (!result || !result.success) {
      return null;
    }

    if (Buffer.isBuffer(result.body)) {
      return JSON.parse(result.body.toString('utf8'));
    }

    return result.body;
  }

  /**
   * Fetch package metadata with dev versions (p2/{vendor}/{package}~dev.json).
   */
  public async fetchPackageDevMetadata(vendor: string, packageName: string): Promise<any | null> {
    const fullName = `${vendor}/${packageName}`;
    const path = `/p2/${vendor}/${packageName}~dev.json`;

    const context: IUpstreamFetchContext = {
      protocol: 'composer',
      resource: fullName,
      resourceType: 'metadata-dev',
      path,
      method: 'GET',
      headers: {
        'accept': 'application/json',
      },
      query: {},
    };

    const result = await this.fetch(context);

    if (!result || !result.success) {
      return null;
    }

    if (Buffer.isBuffer(result.body)) {
      return JSON.parse(result.body.toString('utf8'));
    }

    return result.body;
  }

  /**
   * Fetch a provider-includes file.
   */
  public async fetchProviderIncludes(path: string): Promise<any | null> {
    const context: IUpstreamFetchContext = {
      protocol: 'composer',
      resource: '*',
      resourceType: 'provider',
      path: path.startsWith('/') ? path : `/${path}`,
      method: 'GET',
      headers: {
        'accept': 'application/json',
      },
      query: {},
    };

    const result = await this.fetch(context);

    if (!result || !result.success) {
      return null;
    }

    if (Buffer.isBuffer(result.body)) {
      return JSON.parse(result.body.toString('utf8'));
    }

    return result.body;
  }

  /**
   * Fetch a dist file (zip) from upstream.
   */
  public async fetchDist(url: string): Promise<Buffer | null> {
    // Parse the URL to get the path
    let path: string;
    try {
      const parsed = new URL(url);
      path = parsed.pathname;
    } catch {
      path = url;
    }

    const context: IUpstreamFetchContext = {
      protocol: 'composer',
      resource: '*',
      resourceType: 'dist',
      path,
      method: 'GET',
      headers: {
        'accept': 'application/zip, application/octet-stream',
      },
      query: {},
    };

    const result = await this.fetch(context);

    if (!result || !result.success) {
      return null;
    }

    return Buffer.isBuffer(result.body) ? result.body : Buffer.from(result.body);
  }

  /**
   * Override URL building for Composer-specific handling.
   */
  protected buildUpstreamUrl(
    upstream: IUpstreamRegistryConfig,
    context: IUpstreamFetchContext,
  ): string {
    let baseUrl = upstream.url;

    // Remove trailing slash
    if (baseUrl.endsWith('/')) {
      baseUrl = baseUrl.slice(0, -1);
    }

    return `${baseUrl}${context.path}`;
  }
}