import { NextRequest, NextResponse } from 'next/server';
import { RecommendationService, RecommendationAlgorithm } from '@/lib/recommendation-service';

export async function GET(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url);
    
    const algorithm = (searchParams.get('algorithm') || 'unwatched_first') as RecommendationAlgorithm;
    const limit = Math.min(parseInt(searchParams.get('limit') || '20'), 100);
    const excludeRecentDays = parseInt(searchParams.get('exclude_recent_days') || '30');
    
    // Validate parameters
    if (limit < 1 || limit > 100) {
      return NextResponse.json(
        { error: 'Limit must be between 1 and 100' },
        { status: 400 }
      );
    }
    
    if (excludeRecentDays < 0) {
      return NextResponse.json(
        { error: 'Exclude recent days must be non-negative' },
        { status: 400 }
      );
    }
    
    const service = new RecommendationService();
    const recommendations = await service.getRecommendations({
      algorithm,
      limit,
      excludeRecentDays
    });
    
    return NextResponse.json({
      recommendations,
      algorithm,
      total_videos: recommendations.length,
      total_recommended: recommendations.length
    });
    
  } catch (error: any) {
    console.error('Recommendation error:', error);
    return NextResponse.json(
      { error: error.message || 'Failed to get recommendations' },
      { status: 500 }
    );
  }
}