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

// POST - Execute a query on a table
export async function POST(request: NextRequest) {
  try {
    // Get the access token from cookie or header
    const accessToken =
      request.cookies.get('sb-access-token')?.value ||
      request.headers.get('authorization')?.replace('Bearer ', '');

    if (!accessToken) {
      return NextResponse.json(
        { success: false, error: 'Not authenticated' },
        { status: 401 }
      );
    }

    // Verify user
    const { data: userData, error: userError } = await supabase.auth.getUser(accessToken);
    if (userError || !userData.user) {
      return NextResponse.json(
        { success: false, error: 'Invalid authentication' },
        { status: 401 }
      );
    }

    const userId = userData.user.id;
    const { table, operation, data: queryData, filters } = await request.json();

    if (!table) {
      return NextResponse.json(
        { success: false, error: 'Table name is required' },
        { status: 400 }
      );
    }

    let result;

    switch (operation) {
      case 'select': {
        let query = supabase.from(table).select('*');

        // Apply filters if provided
        if (filters) {
          for (const [key, value] of Object.entries(filters)) {
            query = query.eq(key, value);
          }
        }

        // Only allow user to query their own data
        const { data: columns } = await supabase
          .from(table)
          .select('*')
          .limit(1);

        if (columns && columns.length > 0 && 'user_id' in columns[0]) {
          query = query.eq('user_id', userId);
        }

        const { data, error } = await query;
        if (error) throw error;
        result = data;
        break;
      }

      case 'insert': {
        const insertData = {
          ...queryData,
          user_id: userId,
        };

        const { data, error } = await supabase
          .from(table)
          .insert(insertData)
          .select()
          .single();

        if (error) throw error;
        result = data;
        break;
      }

      case 'update': {
        if (!filters || Object.keys(filters).length === 0) {
          return NextResponse.json(
            { success: false, error: 'Filters required for update' },
            { status: 400 }
          );
        }

        let query = supabase.from(table).update(queryData);

        // Apply filters
        for (const [key, value] of Object.entries(filters)) {
          query = query.eq(key, value);
        }

        // Ensure user can only update their own data
        const { data: columns } = await supabase
          .from(table)
          .select('*')
          .limit(1);

        if (columns && columns.length > 0 && 'user_id' in columns[0]) {
          query = query.eq('user_id', userId);
        }

        const { data, error } = await query.select().single();
        if (error) throw error;
        result = data;
        break;
      }

      case 'delete': {
        if (!filters || Object.keys(filters).length === 0) {
          return NextResponse.json(
            { success: false, error: 'Filters required for delete' },
            { status: 400 }
          );
        }

        let query = supabase.from(table).delete();

        // Apply filters
        for (const [key, value] of Object.entries(filters)) {
          query = query.eq(key, value);
        }

        // Ensure user can only delete their own data
        const { data: columns } = await supabase
          .from(table)
          .select('*')
          .limit(1);

        if (columns && columns.length > 0 && 'user_id' in columns[0]) {
          query = query.eq('user_id', userId);
        }

        const { error } = await query;
        if (error) throw error;
        result = { deleted: true };
        break;
      }

      default:
        return NextResponse.json(
          { success: false, error: 'Invalid operation' },
          { status: 400 }
        );
    }

    return NextResponse.json({
      success: true,
      data: result,
    });
  } catch (error) {
    console.error('Database query error:', error);
    return NextResponse.json(
      { success: false, error: 'Query failed' },
      { status: 500 }
    );
  }
}