<?php

declare(strict_types=1);

namespace Steuerkram\Models;

use Steuerkram\Database;

class Booking
{
    public static function forBeleg(int $belegId): array
    {
        return Database::fetchAll(
            'SELECT bk.*,
                    s.kontonummer as soll_nr, s.bezeichnung as soll_name,
                    h.kontonummer as haben_nr, h.bezeichnung as haben_name
             FROM bookings bk
             JOIN accounts s ON bk.soll_konto_id = s.id
             JOIN accounts h ON bk.haben_konto_id = h.id
             WHERE bk.beleg_id = ?
             ORDER BY bk.buchungs_datum, bk.id',
            [$belegId]
        );
    }

    public static function journal(array $filter = [], int $page = 1, int $perPage = 50): array
    {
        $where  = ['1=1'];
        $params = [];

        if (!empty($filter['year'])) {
            $where[] = 'fy.year = ?';
            $params[] = (int)$filter['year'];
        }
        if (!empty($filter['month'])) {
            $where[] = 'MONTH(bk.buchungs_datum) = ?';
            $params[] = (int)$filter['month'];
        }
        if (!empty($filter['konto'])) {
            $where[] = '(bk.soll_konto_id = ? OR bk.haben_konto_id = ?)';
            $params[] = (int)$filter['konto'];
            $params[] = (int)$filter['konto'];
        }
        if (!empty($filter['search'])) {
            $where[] = 'bk.buchungstext LIKE ?';
            $params[] = '%' . $filter['search'] . '%';
        }

        $offset = ($page - 1) * $perPage;
        $sql = 'SELECT bk.*,
                       s.kontonummer as soll_nr, s.bezeichnung as soll_name,
                       h.kontonummer as haben_nr, h.bezeichnung as haben_name,
                       bl.beleg_nr, fy.year as fiscal_year_nr
                FROM bookings bk
                JOIN accounts s ON bk.soll_konto_id = s.id
                JOIN accounts h ON bk.haben_konto_id = h.id
                JOIN belege bl ON bk.beleg_id = bl.id
                JOIN fiscal_years fy ON bk.fiscal_year_id = fy.id
                WHERE ' . implode(' AND ', $where) . '
                ORDER BY bk.buchungs_datum DESC, bk.id DESC
                LIMIT ? OFFSET ?';

        $params[] = $perPage;
        $params[] = $offset;

        $rows = Database::fetchAll($sql, $params);

        $countSql    = 'SELECT COUNT(*) as cnt FROM bookings bk
                        JOIN fiscal_years fy ON bk.fiscal_year_id = fy.id
                        WHERE ' . implode(' AND ', $where);
        $countParams = array_slice($params, 0, -2);
        $total       = (int)(Database::fetchOne($countSql, $countParams)['cnt'] ?? 0);

        return ['rows' => $rows, 'total' => $total, 'pages' => (int)ceil($total / $perPage)];
    }

    public static function find(int $id): array|false
    {
        return Database::fetchOne('SELECT * FROM bookings WHERE id = ?', [$id]);
    }

    public static function create(array $data): int
    {
        // Determine fiscal year
        $year  = (int)date('Y', strtotime($data['buchungs_datum']));
        $fy    = FiscalYear::findOrCreateByYear($year);

        if ($fy['locked']) {
            throw new \RuntimeException("Geschäftsjahr {$year} ist gesperrt. Neue Buchungen nicht möglich.");
        }

        // Calculate amounts
        $netto  = round((float)$data['betrag_netto'], 2);
        $ust    = round((float)($data['ust_satz'] ?? 0) / 100 * $netto, 2);
        $brutto = round($netto + $ust, 2);

        $nr = self::generateBuchungsNr();

        Database::execute(
            'INSERT INTO bookings (buchungs_nr, beleg_id, buchungs_datum, soll_konto_id, haben_konto_id,
             betrag_netto, ust_satz, betrag_ust, betrag_brutto, buchungstext, fiscal_year_id)
             VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)',
            [
                $nr,
                (int)$data['beleg_id'],
                $data['buchungs_datum'],
                (int)$data['soll_konto_id'],
                (int)$data['haben_konto_id'],
                $netto,
                (float)($data['ust_satz'] ?? 0),
                $ust,
                $brutto,
                $data['buchungstext'],
                $fy['id'],
            ]
        );

        $id = (int)Database::lastInsertId();

        // Mark Beleg as booked
        Database::execute('UPDATE belege SET booked=1, updated_at=NOW() WHERE id=?', [(int)$data['beleg_id']]);

        return $id;
    }

    public static function reverse(int $id, string $reason): int
    {
        $orig = self::find($id);
        if (!$orig) throw new \RuntimeException('Buchung nicht gefunden.');
        if ($orig['is_reversal']) throw new \RuntimeException('Stornobuchungen können nicht storniert werden.');

        // Create reversal: swap Soll/Haben, same amounts
        $reversalData = [
            'beleg_id'       => $orig['beleg_id'],
            'buchungs_datum' => date('Y-m-d'),
            'soll_konto_id'  => $orig['haben_konto_id'],
            'haben_konto_id' => $orig['soll_konto_id'],
            'betrag_netto'   => $orig['betrag_netto'],
            'ust_satz'       => $orig['ust_satz'],
            'buchungstext'   => 'STORNO zu ' . $orig['buchungs_nr'] . ': ' . $reason,
        ];

        $year = (int)date('Y', strtotime($reversalData['buchungs_datum']));
        $fy   = FiscalYear::findOrCreateByYear($year);

        $nr = self::generateBuchungsNr();

        Database::execute(
            'INSERT INTO bookings (buchungs_nr, beleg_id, buchungs_datum, soll_konto_id, haben_konto_id,
             betrag_netto, ust_satz, betrag_ust, betrag_brutto, buchungstext, is_reversal, fiscal_year_id)
             VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1, ?)',
            [
                $nr,
                $reversalData['beleg_id'],
                $reversalData['buchungs_datum'],
                $reversalData['soll_konto_id'],
                $reversalData['haben_konto_id'],
                $orig['betrag_netto'],
                $orig['ust_satz'],
                $orig['betrag_ust'],
                $orig['betrag_brutto'],
                $reversalData['buchungstext'],
                $fy['id'],
            ]
        );

        $reversalId = (int)Database::lastInsertId();

        // Link original to reversal
        Database::execute('UPDATE bookings SET reversed_by=? WHERE id=?', [$reversalId, $id]);

        return $reversalId;
    }

    public static function generateBuchungsNr(): string
    {
        $year   = date('Y');
        $result = Database::fetchOne(
            'SELECT COUNT(*) as cnt FROM bookings WHERE YEAR(buchungs_datum) = ?',
            [$year]
        );
        $next = (int)($result['cnt'] ?? 0) + 1;
        return sprintf('BU-%s-%06d', $year, $next);
    }

    public static function sumByYear(int $year): array
    {
        return Database::fetchAll(
            'SELECT bk.soll_konto_id, bk.haben_konto_id,
                    SUM(bk.betrag_netto) as sum_netto,
                    SUM(bk.betrag_ust) as sum_ust,
                    SUM(bk.betrag_brutto) as sum_brutto
             FROM bookings bk
             JOIN fiscal_years fy ON bk.fiscal_year_id = fy.id
             WHERE fy.year = ?
             GROUP BY bk.soll_konto_id, bk.haben_konto_id',
            [$year]
        );
    }
}