<?php

namespace App\Models;

use Carbon\Carbon;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

/**
 * Position einer Angebotsversion (Modul 6).
 *
 * `travel_program_id` und `fewo_lodging_id` bleiben FK-frei, solange
 * Modul 12 (v2-Reiseverwaltung) noch nicht nach Laravel migriert ist.
 * `metadata` enthält einen Snapshot der Referenzdaten (Titel, Preis,
 * Leistungen) — so bleiben Positionen lesbar, auch wenn das Original
 * später gelöscht / migriert / umbenannt wird.
 *
 * @property int $id
 * @property int $offer_version_id
 * @property int $position
 * @property string $type
 * @property string $title
 * @property string|null $description
 * @property int $quantity
 * @property float $price_per_unit
 * @property float $total_price
 * @property int|null $travel_program_id
 * @property int|null $fewo_lodging_id
 * @property array|null $metadata
 * @property Carbon $created_at
 * @property Carbon $updated_at
 * @property-read OfferVersion $version
 */
class OfferItem extends Model
{
    use HasFactory;

    public const TYPE_TRAVEL    = 'travel';
    public const TYPE_SERVICE   = 'service';
    public const TYPE_OPTION    = 'option';
    public const TYPE_DISCOUNT  = 'discount';
    public const TYPE_INSURANCE = 'insurance';
    public const TYPE_CUSTOM    = 'custom';

    protected $table = 'offer_items';

    protected $fillable = [
        'offer_version_id',
        'position',
        'type',
        'title',
        'description',
        'quantity',
        'price_per_unit',
        'total_price',
        'travel_program_id',
        'fewo_lodging_id',
        'metadata',
    ];

    protected $casts = [
        'offer_version_id'  => 'int',
        'position'          => 'int',
        'quantity'          => 'int',
        'price_per_unit'    => 'decimal:2',
        'total_price'       => 'decimal:2',
        'travel_program_id' => 'int',
        'fewo_lodging_id'   => 'int',
        'metadata'          => 'array',
    ];

    public function version(): BelongsTo
    {
        return $this->belongsTo(OfferVersion::class, 'offer_version_id');
    }

    /**
     * Aus Menge × Einzelpreis den Positions-Gesamtpreis berechnen
     * (Rabatte negativ — gehört in den Service-Layer zur Summierung).
     */
    public function calculateTotal(): float
    {
        return round($this->quantity * (float) $this->price_per_unit, 2);
    }
}