// Transcript fetching utility
import fetch from "node-fetch";

export interface TranscriptFetchResult {
  success: boolean;
  content?: string;
  error?: string;
}

/**
 * Fetch transcript content from a URL
 * @param url The transcript URL
 * @param username Optional username for authentication
 * @param password Optional password for authentication
 * @returns Promise with fetch result
 */
export async function fetchTranscriptContent(
  url: string,
  username?: string,
  password?: string
): Promise<TranscriptFetchResult> {
  try {
    if (!url || !url.trim()) {
      return {
        success: false,
        error: 'No transcript URL provided',
      };
    }

    // Prepare authentication header if credentials provided
    const authHeader =
      username && password
        ? "Basic " + Buffer.from(`${username}:${password}`).toString("base64")
        : undefined;

    const headers: Record<string, string> = {
      'User-Agent': 'LiveDash-Transcript-Fetcher/1.0',
    };

    if (authHeader) {
      headers.Authorization = authHeader;
    }

    // Fetch the transcript with timeout
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), 30000); // 30 second timeout

    const response = await fetch(url, {
      method: 'GET',
      headers,
      signal: controller.signal,
    });

    clearTimeout(timeoutId);

    if (!response.ok) {
      return {
        success: false,
        error: `HTTP ${response.status}: ${response.statusText}`,
      };
    }

    const content = await response.text();

    if (!content || content.trim().length === 0) {
      return {
        success: false,
        error: 'Empty transcript content',
      };
    }

    return {
      success: true,
      content: content.trim(),
    };

  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : String(error);

    // Handle common network errors
    if (errorMessage.includes('ENOTFOUND')) {
      return {
        success: false,
        error: 'Domain not found',
      };
    }

    if (errorMessage.includes('ECONNREFUSED')) {
      return {
        success: false,
        error: 'Connection refused',
      };
    }

    if (errorMessage.includes('timeout')) {
      return {
        success: false,
        error: 'Request timeout',
      };
    }

    return {
      success: false,
      error: errorMessage,
    };
  }
}

/**
 * Validate if a URL looks like a valid transcript URL
 * @param url The URL to validate
 * @returns boolean indicating if URL appears valid
 */
export function isValidTranscriptUrl(url: string): boolean {
  if (!url || typeof url !== 'string') {
    return false;
  }

  try {
    const parsedUrl = new URL(url);
    return parsedUrl.protocol === 'http:' || parsedUrl.protocol === 'https:';
  } catch {
    return false;
  }
}

/**
 * Extract session ID from transcript content if possible
 * This is a helper function that can be enhanced based on transcript format
 * @param content The transcript content
 * @returns Extracted session ID or null
 */
export function extractSessionIdFromTranscript(content: string): string | null {
  if (!content) return null;

  // Look for common session ID patterns
  const patterns = [
    /session[_-]?id[:\s]*([a-zA-Z0-9-]+)/i,
    /id[:\s]*([a-zA-Z0-9-]{8,})/i,
    /^([a-zA-Z0-9-]{8,})/m, // First line might be session ID
  ];

  for (const pattern of patterns) {
    const match = content.match(pattern);
    if (match && match[1]) {
      return match[1].trim();
    }
  }

  return null;
}