import { NextResponse } from 'next/server';
import { executeQuery } from '@/lib/clickhouse';
import { NextRequest } from 'next/server';

export async function GET(request: NextRequest) {
  try {
    // Get pagination and filter parameters from the URL
    const searchParams = request.nextUrl.searchParams;
    const page = parseInt(searchParams.get('page') || '1', 10);
    const pageSize = parseInt(searchParams.get('page_size') || '10', 10);
    const search = searchParams.get('search');
    const team = searchParams.get('team');

    // Calculate OFFSET
    const offset = (page - 1) * pageSize;

    // Build WHERE conditions
    const whereConditions = ['deleted_at IS NULL'];
    
    if (search) {
      // Expand search to include more fields: slug, shortUrl in attributes, team name, tag name, original_url
      whereConditions.push(`(
        slug ILIKE '%${search}%' OR 
        original_url ILIKE '%${search}%' OR 
        title ILIKE '%${search}%' OR
        JSONHas(attributes, 'shortUrl') AND JSONExtractString(attributes, 'shortUrl') ILIKE '%${search}%' OR
        arrayExists(x -> JSONExtractString(x, 'team_name') ILIKE '%${search}%', JSONExtractArrayRaw(teams)) OR
        arrayExists(x -> JSONExtractString(x, 'tag_name') ILIKE '%${search}%', JSONExtractArrayRaw(tags))
      )`);
    }
    
    if (team) {
      whereConditions.push(`hasToken(teams, 'team_id', '${team}')`);
    }
    
    const whereClause = whereConditions.join(' AND ');

    // First query to get total count
    const countQuery = `
      SELECT count(*) as total
      FROM shorturl_analytics.shorturl
      WHERE ${whereClause}
    `;

    const countResult = await executeQuery(countQuery);
    // Handle the result safely by using an explicit type check
    const total = Array.isArray(countResult) && countResult.length > 0 && typeof countResult[0] === 'object' && countResult[0] !== null && 'total' in countResult[0]
      ? Number(countResult[0].total)
      : 0;
    const totalPages = Math.ceil(total / pageSize);

    // Main query with pagination
    const query = `
      SELECT 
        id,
        external_id,
        type,
        slug,
        original_url,
        title,
        description,
        attributes,
        schema_version,
        creator_id,
        creator_email,
        creator_name,
        created_at,
        updated_at,
        deleted_at,
        projects,
        teams,
        tags,
        qr_codes AS qr_codes,
        channels,
        favorites,
        expires_at,
        click_count,
        unique_visitors
      FROM shorturl_analytics.shorturl
      WHERE ${whereClause}
      ORDER BY created_at DESC
      LIMIT ${pageSize} OFFSET ${offset}
    `;

    // Execute the query using the shared client
    const rows = await executeQuery(query);

    // Return the data with pagination metadata
    return NextResponse.json({ 
      links: rows,
      total: total,
      total_pages: totalPages,
      page: page,
      page_size: pageSize
    });
  } catch (error) {
    console.error('Error fetching shortlinks from ClickHouse:', error);
    return NextResponse.json(
      { error: 'Failed to fetch shortlinks' },
      { status: 500 }
    );
  }
}