import { NextRequest, NextResponse } from 'next/server';

export async function GET(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url);
    const page = parseInt(searchParams.get('page') || '1');
    const limit = parseInt(searchParams.get('limit') || '12');
    const framework = searchParams.get('framework');
    const learningArea = searchParams.get('learningArea');
    const subLearningArea = searchParams.get('subLearningArea');
    
    const { MongoClient } = require('mongodb');
    const uri = process.env.MONGODB_URI || 'mongodb://localhost/beanstalk';
    const client = new MongoClient(uri);
    await client.connect();
    const db = client.db('beanstalk');
    const collection = db.collection('observations');
    
    // Build filter query
    let filter: any = {};
    
    if (framework) {
      filter['indicators.developmentAreas.framework'] = framework.trim();
    }
    
    if (learningArea) {
      filter['indicators.developmentAreas.learningArea'] = learningArea.trim();
    }
    
    if (subLearningArea) {
      filter['indicators.developmentAreas.subLearningArea'] = subLearningArea.trim();
    }
    
    // Get total count for pagination
    const totalCount = await collection.countDocuments(filter);
    
    // Calculate skip value for pagination
    const skip = (page - 1) * limit;
    
    // Fetch observations with pagination and sort by createdAt (newest first)
    const documents = await collection
      .find(filter)
      .sort({ createdAt: -1 })
      .skip(skip)
      .limit(limit)
      .toArray();
    
    await client.close();
    
    return NextResponse.json({
      success: true,
      data: documents,
      pagination: {
        currentPage: page,
        totalPages: Math.ceil(totalCount / limit),
        totalCount: totalCount,
        limit: limit,
        hasNextPage: page < Math.ceil(totalCount / limit),
        hasPrevPage: page > 1
      }
    });
    
  } catch (error: any) {
    console.error('Error fetching observations:', error);
    return NextResponse.json(
      {
        error: 'Failed to fetch observations',
        message: error.message
      },
      { status: 500 }
    );
  }
}