<?php

namespace App\Repositories;

use App\Models\Offer;
use App\Models\OfferVersion;
use Carbon\Carbon;
use Illuminate\Database\QueryException;
use Illuminate\Support\Facades\DB;

/**
 * Repository für das Angebot (Kopf-Datensatz).
 *
 * Konventionen:
 *  - Nur DB-Operationen, keine Business-Rules (die liegen im OfferService / A4).
 *  - Alle Multi-Statement-Operationen laufen in einer Transaktion.
 *  - `offer_number` ist UNIQUE auf DB-Ebene → wir akzeptieren Race-Kollisionen
 *    und versuchen bis zu 3×, eine freie Nummer zu ziehen.
 */
class OfferRepository extends BaseRepository
{
    /** Max. Retries beim Generieren einer freien Angebotsnummer. */
    public const MAX_NUMBER_RETRIES = 3;

    public function __construct(Offer $model)
    {
        $this->model = $model;
    }

    /**
     * Legt ein neues Angebot + initiale Version 1 (status=draft) an.
     * Rollback erfolgt, falls irgendein Teilschritt fehlschlägt.
     *
     * Erwartete Keys in `$data`:
     *  - `status` (optional, default 'draft')
     *  - `current_version`: array mit Daten für die erste OfferVersion
     *      (mindestens `created_by`, optional `headline`, `valid_until`, `template_id`)
     *
     * @param  array<string,mixed>  $data
     */
    public function create(array $data, int $contactId, ?int $inquiryId = null, ?int $bookingId = null): Offer
    {
        return DB::transaction(function () use ($data, $contactId, $inquiryId, $bookingId) {
            $versionData = $data['current_version'] ?? [];
            $createdBy   = $versionData['created_by'] ?? $data['created_by'] ?? null;
            if (! $createdBy) {
                throw new \InvalidArgumentException('OfferRepository::create benötigt created_by');
            }

            $offer = new Offer([
                'offer_number' => $this->generateOfferNumber(),
                'contact_id'   => $contactId,
                'inquiry_id'   => $inquiryId,
                'booking_id'   => $bookingId,
                'status'       => $data['status'] ?? Offer::STATUS_DRAFT,
                'created_by'   => $createdBy,
            ]);
            $offer->save();

            $version = new OfferVersion(array_merge([
                'status'      => OfferVersion::STATUS_DRAFT,
                'total_price' => 0,
                'created_by'  => $createdBy,
            ], $versionData, [
                'offer_id'   => $offer->id,
                'version_no' => 1,
            ]));
            $version->save();

            $offer->current_version_id = $version->id;
            $offer->save();

            return $offer->fresh(['currentVersion']);
        });
    }

    /**
     * Erzeugt die nächste freie Angebotsnummer im Format `YYYY-NNNNN`.
     * Race-Safety: `lockForUpdate()` serialisiert konkurrierende Generierungen
     * pro Jahr. Zusätzlicher Schutz über den UNIQUE-Index auf `offer_number`.
     */
    public function generateOfferNumber(): string
    {
        $year = Carbon::now()->format('Y');

        $attempt = 0;
        while (true) {
            $attempt++;
            try {
                return DB::transaction(function () use ($year) {
                    $last = Offer::withTrashed()
                        ->where('offer_number', 'LIKE', $year . '-%')
                        ->orderByDesc('offer_number')
                        ->lockForUpdate()
                        ->value('offer_number');

                    $nextSeq = $last ? ((int) substr($last, 5)) + 1 : 1;

                    return sprintf('%s-%05d', $year, $nextSeq);
                });
            } catch (QueryException $e) {
                if ($attempt >= self::MAX_NUMBER_RETRIES) {
                    throw $e;
                }
                usleep(50_000 * $attempt);
            }
        }
    }

    public function findByNumber(string $offerNumber): ?Offer
    {
        return Offer::where('offer_number', $offerNumber)->first();
    }

    /** Convenience für Controller: Offer inkl. Version/Items/Files eager-loaden. */
    public function getByIdFull(int $id): Offer
    {
        return Offer::with([
            'contact',
            'inquiry',
            'booking',
            'currentVersion.items',
            'currentVersion.files',
            'currentVersion.tokens',
            'versions' => fn ($q) => $q->orderBy('version_no'),
            'createdBy',
        ])->findOrFail($id);
    }
}