const express = require('express');
const db = require('../db');
const asyncHandler = require('../middleware/asyncHandler');

const router = express.Router();

router.get('/', asyncHandler(async (req, res) => {
    const rows = await db.all('SELECT * FROM anbieter ORDER BY name');
    res.json(rows);
}));

router.post('/', asyncHandler(async (req, res) => {
    const { name } = req.body || {};
    if (!name || !name.trim()) {
        return res.status(400).json({ error: 'Name ist erforderlich' });
    }
    try {
        const result = await db.run('INSERT INTO anbieter (name) VALUES (?)', [name.trim()]);
        res.json({ id: result.lastID, name: name.trim() });
    } catch (err) {
        if (/UNIQUE/.test(err.message)) {
            return res.status(400).json({ error: 'Anbieter mit diesem Namen existiert bereits' });
        }
        throw err;
    }
}));

router.delete('/:id', asyncHandler(async (req, res) => {
    const { id } = req.params;

    const [tariffeRow, schaltungenRow] = await Promise.all([
        db.get('SELECT COUNT(*) AS n FROM tarife WHERE anbieter_id = ?', [id]),
        db.get('SELECT COUNT(*) AS n FROM schaltungen WHERE anbieter_id = ?', [id]),
    ]);

    if (tariffeRow.n + schaltungenRow.n > 0) {
        const reasons = [];
        if (tariffeRow.n > 0) reasons.push(`${tariffeRow.n} Tarif(e)`);
        if (schaltungenRow.n > 0) reasons.push(`${schaltungenRow.n} Schaltung(en)`);
        return res.status(400).json({
            error: `Anbieter kann nicht gelöscht werden: ${reasons.join(', ')} verwenden diesen Anbieter`,
        });
    }

    const deletedRules = await db.run('DELETE FROM anbieter_provisionsregeln WHERE anbieter_id = ?', [id]);
    const result = await db.run('DELETE FROM anbieter WHERE id = ?', [id]);
    if (result.changes === 0) {
        return res.status(404).json({ error: 'Anbieter nicht gefunden' });
    }
    let message = 'Anbieter erfolgreich gelöscht';
    if (deletedRules.changes > 0) {
        message += ` (${deletedRules.changes} Provisionsregel(n) wurden mit gelöscht)`;
    }
    res.json({ message });
}));

// Global commission rules for this provider
router.get('/:id/provisionsregeln', asyncHandler(async (req, res) => {
    const { id } = req.params;
    const rows = await db.all(
        `SELECT apr.*, a.name AS anbieter_name
         FROM anbieter_provisionsregeln apr
         JOIN anbieter a ON apr.anbieter_id = a.id
         WHERE apr.anbieter_id = ? AND apr.aktiv = 1
         ORDER BY apr.gueltig_ab DESC`,
        [id]
    );
    res.json(rows);
}));

// Mitarbeiter-Prozentsätze for this provider
router.get('/:id/mitarbeiter-prozentsaetze', asyncHandler(async (req, res) => {
    const { id } = req.params;
    const rows = await db.all(
        'SELECT * FROM mitarbeiter_prozentsaetze WHERE anbieter_id = ? ORDER BY gueltig_ab DESC',
        [id]
    );
    res.json(rows);
}));

module.exports = router;