<?php

namespace App\Models;

use App\Services\Util;
use App\User;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

/**
 * Protokollzeile einer nachträglichen Korrektur an einem Einkauf/Wareneingang.
 * `field_changes` (Spaltenname bewusst nicht `changes` — kollidiert mit Model::$changes) = [feld => ['old' => …, 'new' => …]] mit Rohwerten (IDs, Y-m-d, Dezimal);
 * die lesbare Darstellung liefert describe().
 */
class StockEntryChange extends Model
{
    protected $fillable = [
        'stock_entry_id',
        'user_id',
        'status_before',
        'reason',
        'field_changes',
    ];

    /**
     * Felder, die im Protokoll verfolgt werden (Reihenfolge = Anzeige).
     *
     * @var array<int, string>
     */
    public const TRACKED = [
        'entry_type', 'ingredient_id', 'packaging_item_id', 'supplier_id', 'location_id',
        'ordered_at', 'ordered_quantity', 'purchase_unit', 'density_used',
        'price_per_kg', 'price_per_kg_gross', 'tax_rate_id', 'price_total',
        'received_at', 'received_quantity', 'batch_number', 'best_before', 'quality_id',
    ];

    /**
     * @return array<string, string>
     */
    protected function casts(): array
    {
        return ['field_changes' => 'array'];
    }

    /**
     * @return BelongsTo<StockEntry, $this>
     */
    public function stockEntry(): BelongsTo
    {
        return $this->belongsTo(StockEntry::class);
    }

    /**
     * @return BelongsTo<User, $this>
     */
    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class, 'user_id');
    }

    /**
     * Geänderte Felder als lesbare Zeilen [label, alt, neu].
     *
     * @return array<int, array{label: string, old: string, new: string}>
     */
    public function describe(): array
    {
        $rows = [];
        foreach (self::TRACKED as $field) {
            if (! isset($this->field_changes[$field])) {
                continue;
            }
            $rows[] = [
                'label' => self::label($field),
                'old' => $this->format($field, $this->field_changes[$field]['old'] ?? null),
                'new' => $this->format($field, $this->field_changes[$field]['new'] ?? null),
            ];
        }

        return $rows;
    }

    public static function label(string $field): string
    {
        return match ($field) {
            'entry_type' => __('Art'),
            'ingredient_id' => __('Inhaltsstoff'),
            'packaging_item_id' => __('Verpackungsartikel'),
            'supplier_id' => __('Lieferant'),
            'location_id' => __('Lagerort'),
            'ordered_at' => __('Bestelldatum'),
            'ordered_quantity' => __('Bestellte Menge'),
            'purchase_unit' => __('Einheit'),
            'density_used' => __('Dichte (g/ml)'),
            'price_per_kg' => __('Netto-Preis pro kg'),
            'price_per_kg_gross' => __('Brutto-Preis pro kg'),
            'tax_rate_id' => __('Umsatzsteuer'),
            'price_total' => __('Gesamtpreis netto'),
            'received_at' => __('Eingangsdatum'),
            'received_quantity' => __('Eingegangene Menge'),
            'batch_number' => __('Charge'),
            'best_before' => __('Mindesthaltbarkeit'),
            'quality_id' => __('Rohstoffqualität'),
            default => $field,
        };
    }

    protected function format(string $field, mixed $value): string
    {
        if ($value === null || $value === '') {
            return '—';
        }

        return match ($field) {
            'entry_type' => match ($value) {
                'ingredient' => __('Rohstoff'),
                'packaging' => __('Verpackung'),
                'shipping' => __('Versand'),
                default => (string) $value,
            },
            'ingredient_id' => Ingredient::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'packaging_item_id' => PackagingItem::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'supplier_id' => Supplier::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'location_id' => Location::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'quality_id' => MaterialQuality::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'tax_rate_id' => TaxRate::withTrashed()->whereKey($value)->value('name') ?? '#'.$value,
            'ordered_at', 'received_at', 'best_before' => Carbon::parse($value)->format('d.m.Y'),
            'ordered_quantity', 'received_quantity' => formatWawiQuantity((float) $value).' '.($this->stockEntry?->unit === 'piece' ? __('Stk.') : 'g'),
            'purchase_unit' => $value === 'ml' ? 'ml' : 'g',
            'density_used' => Util::formatNumber($value),
            'price_per_kg', 'price_per_kg_gross', 'price_total' => Util::formatNumber($value).' €',
            default => (string) $value,
        };
    }
}