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

// GET - Ambil semua data user
export async function GET() {
  try {
    const { data, error } = await supabase
      .from('user_app')
      .select('id_user, username, nip, role_user, created_at, updated_at')
      .order('id_user', { ascending: true });
    
    if (error) {
      console.error('Error fetching users:', error);
      return NextResponse.json(
        { error: 'Failed to fetch users' },
        { status: 500 }
      );
    }
    
    return NextResponse.json(data);
  } catch (error) {
    console.error('Error fetching users:', error);
    return NextResponse.json(
      { error: 'Failed to fetch users' },
      { status: 500 }
    );
  }
}

// POST - Buat user baru
export async function POST(request: NextRequest) {
  try {
    const { username, nip, password, role_user } = await request.json();
    
    // Validasi input
    if (!username || username.trim() === '') {
      return NextResponse.json(
        { error: 'Username is required' },
        { status: 400 }
      );
    }

    if (!password || password.trim() === '') {
      return NextResponse.json(
        { error: 'Password is required' },
        { status: 400 }
      );
    }

    if (!role_user || !['admin', 'ketuajurusan', 'ketuaprodi'].includes(role_user)) {
      return NextResponse.json(
        { error: 'Role user must be either admin, ketuajurusan, or ketuaprodi' },
        { status: 400 }
      );
    }

    // Cek apakah username sudah ada
    const { data: existingUsername, error: existingUsernameError } = await supabase
      .from('user_app')
      .select('id_user')
      .ilike('username', username.trim());
    
    if (existingUsernameError) {
      console.error('Error checking existing username:', existingUsernameError);
      return NextResponse.json(
        { error: 'Failed to check existing username' },
        { status: 500 }
      );
    }
    
    if (existingUsername && existingUsername.length > 0) {
      return NextResponse.json(
        { error: 'Username sudah digunakan' },
        { status: 409 }
      );
    }

    // Cek apakah NIP sudah ada (jika NIP diisi)
    if (nip && nip.trim() !== '') {
      const { data: existingNip, error: existingNipError } = await supabase
        .from('user_app')
        .select('id_user')
        .eq('nip', nip.trim());
      
      if (existingNipError) {
        console.error('Error checking existing NIP:', existingNipError);
        return NextResponse.json(
          { error: 'Failed to check existing NIP' },
          { status: 500 }
        );
      }
      
      if (existingNip && existingNip.length > 0) {
        return NextResponse.json(
          { error: 'NIP sudah digunakan' },
          { status: 409 }
        );
      }
    }

    // Hash password
    const hashedPassword = await bcrypt.hash(password, 10);

    // Insert user baru
    const { data, error } = await supabase
      .from('user_app')
      .insert([{
        username: username.trim(),
        nip: nip && nip.trim() !== '' ? nip.trim() : null,
        password: hashedPassword,
        role_user: role_user
      }])
      .select('id_user, username, nip, role_user, created_at, updated_at')
      .single();
    
    if (error) {
      console.error('Error creating user:', error);
      return NextResponse.json(
        { error: 'Failed to create user' },
        { status: 500 }
      );
    }
    
    return NextResponse.json(data, { status: 201 });
  } catch (error) {
    console.error('Error creating user:', error);
    return NextResponse.json(
      { error: 'Failed to create user' },
      { status: 500 }
    );
  }
}

// PUT - Update data user (termasuk reset password)
export async function PUT(request: NextRequest) {
  try {
    const { id_user, username, nip, password, role_user } = await request.json();
    
    // Validasi input
    if (!id_user) {
      return NextResponse.json(
        { error: 'ID user is required' },
        { status: 400 }
      );
    }

    if (!username || username.trim() === '') {
      return NextResponse.json(
        { error: 'Username is required' },
        { status: 400 }
      );
    }

    if (!role_user || !['admin', 'ketuajurusan', 'ketuaprodi'].includes(role_user)) {
      return NextResponse.json(
        { error: 'Role user must be either admin, ketuajurusan, or ketuaprodi' },
        { status: 400 }
      );
    }

    // Check if user exists
    const { data: existingData, error: existingError } = await supabase
      .from('user_app')
      .select('id_user')
      .eq('id_user', id_user)
      .single();
    
    if (existingError || !existingData) {
      return NextResponse.json(
        { error: 'User tidak ditemukan' },
        { status: 404 }
      );
    }

    // Cek apakah username sudah ada untuk user lain
    const { data: duplicateUsername, error: duplicateUsernameError } = await supabase
      .from('user_app')
      .select('id_user')
      .ilike('username', username.trim())
      .neq('id_user', id_user);
    
    if (duplicateUsernameError) {
      console.error('Error checking duplicate username:', duplicateUsernameError);
      return NextResponse.json(
        { error: 'Failed to check duplicate username' },
        { status: 500 }
      );
    }
    
    if (duplicateUsername && duplicateUsername.length > 0) {
      return NextResponse.json(
        { error: 'Username sudah digunakan oleh user lain' },
        { status: 409 }
      );
    }

    // Cek apakah NIP sudah ada untuk user lain (jika NIP diisi)
    if (nip && nip.trim() !== '') {
      const { data: duplicateNip, error: duplicateNipError } = await supabase
        .from('user_app')
        .select('id_user')
        .eq('nip', nip.trim())
        .neq('id_user', id_user);
      
      if (duplicateNipError) {
        console.error('Error checking duplicate NIP:', duplicateNipError);
        return NextResponse.json(
          { error: 'Failed to check duplicate NIP' },
          { status: 500 }
        );
      }
      
      if (duplicateNip && duplicateNip.length > 0) {
        return NextResponse.json(
          { error: 'NIP sudah digunakan oleh user lain' },
          { status: 409 }
        );
      }
    }

    // Siapkan data update
    const updateData: any = {
      username: username.trim(),
      nip: nip && nip.trim() !== '' ? nip.trim() : null,
      role_user: role_user,
      updated_at: new Date().toISOString()
    };

    // Jika password diisi, hash dan update password
    if (password && password.trim() !== '') {
      const hashedPassword = await bcrypt.hash(password, 10);
      updateData.password = hashedPassword;
    }

    const { data, error } = await supabase
      .from('user_app')
      .update(updateData)
      .eq('id_user', id_user)
      .select('id_user, username, nip, role_user, created_at, updated_at')
      .single();
    
    if (error) {
      console.error('Error updating user:', error);
      return NextResponse.json(
        { error: 'Failed to update user' },
        { status: 500 }
      );
    }
    
    return NextResponse.json(data);
  } catch (error) {
    console.error('Error updating user:', error);
    return NextResponse.json(
      { error: 'Failed to update user' },
      { status: 500 }
    );
  }
}

// DELETE - Hapus user
export async function DELETE(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url);
    const id_user = searchParams.get('id_user');
    
    if (!id_user) {
      return NextResponse.json(
        { error: 'ID user is required' },
        { status: 400 }
      );
    }

    // Check if user exists
    const { data: existingData, error: existingError } = await supabase
      .from('user_app')
      .select('id_user, username')
      .eq('id_user', id_user)
      .single();
    
    if (existingError || !existingData) {
      return NextResponse.json(
        { error: 'User tidak ditemukan' },
        { status: 404 }
      );
    }

    // Prevent deleting admin account (optional safety check)
    // Uncomment jika ingin mencegah penghapusan admin
    // const { data: userData } = await supabase
    //   .from('user_app')
    //   .select('role_user')
    //   .eq('id_user', id_user)
    //   .single();
    // 
    // if (userData && userData.role_user === 'admin') {
    //   return NextResponse.json(
    //     { error: 'Tidak dapat menghapus akun admin' },
    //     { status: 403 }
    //   );
    // }
    
    const { error } = await supabase
      .from('user_app')
      .delete()
      .eq('id_user', id_user);
    
    if (error) {
      console.error('Error deleting user:', error);
      return NextResponse.json(
        { error: 'Failed to delete user' },
        { status: 500 }
      );
    }
    
    return NextResponse.json(
      { message: 'User berhasil dihapus' },
      { status: 200 }
    );
  } catch (error) {
    console.error('Error deleting user:', error);
    return NextResponse.json(
      { error: 'Failed to delete user' },
      { status: 500 }
    );
  }
}