import * as plugins from './plugins.js';
import * as types from './types.js';
import { CoreResponse as AbstractCoreResponse } from '../core_base/response.js';

/**
 * Node.js implementation of Core Response class that provides a fetch-like API
 */
export class CoreResponse<T = any>
  extends AbstractCoreResponse<T>
  implements types.INodeResponse<T>
{
  private incomingMessage: plugins.http.IncomingMessage;
  private bodyBufferPromise: Promise<Buffer> | null = null;
  private _autoDrainTimeout: NodeJS.Immediate | null = null;

  // Public properties
  public readonly ok: boolean;
  public readonly status: number;
  public readonly statusText: string;
  public readonly headers: plugins.http.IncomingHttpHeaders;
  public readonly url: string;

  constructor(
    incomingMessage: plugins.http.IncomingMessage,
    url: string,
    options: types.ICoreRequestOptions = {},
  ) {
    super();
    this.incomingMessage = incomingMessage;
    this.url = url;
    this.status = incomingMessage.statusCode || 0;
    this.statusText = incomingMessage.statusMessage || '';
    this.ok = this.status >= 200 && this.status < 300;
    this.headers = incomingMessage.headers;

    // Auto-drain unconsumed streams to prevent socket hanging
    // This prevents keep-alive sockets from timing out when response bodies aren't consumed
    // Default to true if not specified
    if (options.autoDrain !== false) {
      this._autoDrainTimeout = setImmediate(() => {
        if (!this.consumed && !this.incomingMessage.readableEnded) {
          console.log(
            `Auto-draining unconsumed response body for ${this.url} (status: ${this.status})`,
          );
          this.incomingMessage.resume(); // Drain without processing
        }
      });
    }
  }

  /**
   * Override to also cancel auto-drain when body is consumed
   */
  protected ensureNotConsumed(): void {
    // Cancel auto-drain since we're consuming the body
    if (this._autoDrainTimeout) {
      clearImmediate(this._autoDrainTimeout);
      this._autoDrainTimeout = null;
    }

    super.ensureNotConsumed();
  }

  /**
   * Collects the body as a buffer
   */
  private async collectBody(): Promise<Buffer> {
    this.ensureNotConsumed();

    if (this.bodyBufferPromise) {
      return this.bodyBufferPromise;
    }

    this.bodyBufferPromise = new Promise<Buffer>((resolve, reject) => {
      const chunks: Buffer[] = [];

      this.incomingMessage.on('data', (chunk: Buffer) => {
        chunks.push(chunk);
      });

      this.incomingMessage.on('end', () => {
        resolve(Buffer.concat(chunks));
      });

      this.incomingMessage.on('error', reject);
    });

    return this.bodyBufferPromise;
  }

  /**
   * Parse response as JSON
   */
  async json(): Promise<T> {
    const buffer = await this.collectBody();
    const text = buffer.toString('utf-8');

    try {
      return JSON.parse(text);
    } catch (error) {
      throw new Error(`Failed to parse JSON: ${error.message}`);
    }
  }

  /**
   * Get response as text
   */
  async text(): Promise<string> {
    const buffer = await this.collectBody();
    return buffer.toString('utf-8');
  }

  /**
   * Get response as ArrayBuffer
   */
  async arrayBuffer(): Promise<ArrayBuffer> {
    const buffer = await this.collectBody();
    const sliced = buffer.buffer.slice(
      buffer.byteOffset,
      buffer.byteOffset + buffer.byteLength,
    );
    // Ensure we return ArrayBuffer, not SharedArrayBuffer
    return sliced instanceof ArrayBuffer ? sliced : new ArrayBuffer(0);
  }

  /**
   * Get response as a web-style ReadableStream
   */
  stream(): ReadableStream<Uint8Array> | null {
    this.ensureNotConsumed();

    // Convert Node.js stream to web stream using Readable.toWeb()
    // This creates a proper Node.js-compatible web stream that works with Readable.fromWeb()
    if (this.incomingMessage.readableEnded || this.incomingMessage.destroyed) {
      return null;
    }

    // Use Readable.toWeb() to convert Node.js stream to web stream (Node.js 16.5+)
    // The returned type is automatically Node.js ReadableStream which is compatible with Readable.fromWeb()
    return plugins.stream.Readable.toWeb(this.incomingMessage) as any;
  }

  /**
   * Get the raw IncomingMessage (for legacy compatibility)
   */
  raw(): plugins.http.IncomingMessage {
    return this.incomingMessage;
  }
}