import { NextResponse } from 'next/server';
import { query } from '@/lib/db';
import { getSession } from '@/lib/session';

export interface FahrkostenRow {
  ID: number;
  Kuerzel: string;
  Name: string;
  Anzahl: number;
}

const EXCLUDED = "'PrF','Beob','BEOS','TD','ToT'";

export async function GET(req: Request) {
  const session = await getSession();
  if (!session) return NextResponse.json({ error: 'Nicht angemeldet' }, { status: 401 });

  const { searchParams } = new URL(req.url);
  const ab = searchParams.get('ab');
  if (!ab || !/^\d{4}-\d{2}-\d{2}$/.test(ab)) {
    return NextResponse.json({ error: 'Parameter ab (YYYY-MM-DD) fehlt' }, { status: 400 });
  }

  try {
    const rows = await query(
      'SELECT b.id AS ID, b.`kürzel` AS Kuerzel,' +
      ' CONCAT(IFNULL(b.vorname, \'\'), IF(b.vorname IS NOT NULL, \' \', \'\'), b.name) AS Name,' +
      ' COUNT(DISTINCT l.ID) AS Anzahl' +
      ' FROM beos b' +
      ' JOIN logbuch_beos lb ON lb.BeoID = b.id' +
      ' JOIN logbuch l ON l.ID = lb.LogbuchID' +
      ' WHERE l.Beginn >= ? AND l.ArtFuehrung NOT IN (' + EXCLUDED + ')' +
      ' GROUP BY b.id, b.`kürzel`, b.name, b.vorname' +
      ' ORDER BY b.name ASC',
      [ab + ' 00:00:00']
    ) as FahrkostenRow[];
    return NextResponse.json(rows);
  } catch (error) {
    console.error('GET /api/fahrkosten:', error);
    return NextResponse.json({ error: 'Datenbankfehler' }, { status: 500 });
  }
}