/**
 * Hugging Face Hub Storage Integration
 * 
 * NOTE: This still goes through Vercel serverless functions,
 * so it won't bypass Vercel's 4.5MB/50MB request size limits.
 * For true 2GB uploads, you need direct client uploads (S3, R2, etc.)
 */

export interface HuggingFaceFileResult {
  file_id: string;
  file_url: string;
  repo_path: string;
}

const HF_API_BASE = 'https://huggingface.co/api';

/**
 * Upload a file to Hugging Face Hub using the commit endpoint
 */
export async function uploadToHuggingFace(
  file: Blob,
  fileName: string,
  fileId: string
): Promise<HuggingFaceFileResult> {
  const token = process.env.HF_TOKEN;
  const repoId = process.env.HF_REPO_ID;
  const repoType = process.env.HF_REPO_TYPE || 'dataset';

  if (!token || !repoId) {
    throw new Error('Hugging Face credentials not configured. Set HF_TOKEN and HF_REPO_ID');
  }

  // Convert Blob to base64 for the commit API
  const arrayBuffer = await file.arrayBuffer();
  const buffer = Buffer.from(arrayBuffer);
  const base64Content = buffer.toString('base64');

  // Determine file extension
  const ext = fileName.split('.').pop() || 'bin';
  const pathInRepo = `files/${fileId}.${ext}`;

  // Use the commit endpoint (new API)
  // Format: POST /api/{repo_type}s/{repo_id}/commit/{revision}
  const repoTypePlural = repoType === 'dataset' ? 'datasets' : 'models';
  const commitUrl = `${HF_API_BASE}/${repoTypePlural}/${repoId}/commit/main`;

  // The commit API expects operations in a specific format
  const commitData = {
    operations: [
      {
        operation: 'add',
        path: pathInRepo,
        content: base64Content,
      }
    ],
    commit_message: `Upload ${fileName}`,
  };

  const response = await fetch(commitUrl, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${token}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(commitData),
  });

  if (!response.ok) {
    const errorText = await response.text();
    throw new Error(`Hugging Face API error: ${response.status} - ${errorText}`);
  }

  // Get the public URL
  const fileUrl = `https://huggingface.co/${repoType === 'dataset' ? 'datasets' : repoType}/${repoId}/resolve/main/${pathInRepo}`;
  
  // Alternative CDN URL (may be faster)
  const cdnUrl = `https://cdn.huggingface.co/${repoId}/main/${pathInRepo}`;

  return {
    file_id: fileId,
    file_url: cdnUrl, // Use CDN URL for faster access
    repo_path: pathInRepo,
  };
}

/**
 * Get file URL from Hugging Face Hub
 */
export async function getHuggingFaceUrl(
  fileId: string,
  extension: string = 'jpg'
): Promise<string> {
  const repoId = process.env.HF_REPO_ID;
  const repoType = process.env.HF_REPO_TYPE || 'dataset';
  const pathInRepo = `files/${fileId}.${extension}`;

  // Try CDN first (faster)
  return `https://cdn.huggingface.co/${repoId}/main/${pathInRepo}`;
}

/**
 * Check if Hugging Face is configured
 */
export function isHuggingFaceConfigured(): boolean {
  return !!(process.env.HF_TOKEN && process.env.HF_REPO_ID);
}