<?php

namespace App\Http\Controllers\Admin\Inventory;

use App\Http\Controllers\Controller;
use App\Http\Requests\Inventory\StoreStockDisposalRequest;
use App\Models\DisposalReason;
use App\Models\Ingredient;
use App\Models\Location;
use App\Models\StockDisposal;
use App\Models\StockEntry;
use App\Services\InventoryService;
use App\Services\ProductionService;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;
use Illuminate\View\View;

class StockDisposalController extends Controller
{
    public function __construct(
        protected InventoryService $inventoryService,
    ) {}

    public function index(Request $request): View
    {
        $query = StockDisposal::query()
            ->with(['ingredient', 'packagingItem', 'location', 'stockEntry', 'user.account'])
            ->latest('disposed_at')
            ->latest('id');

        if (in_array($request->query('type'), ['ingredient', 'packaging'], true)) {
            $query->where('disposal_type', $request->query('type'));
        }

        // Audit N-5: Limit sichtbar machen statt still abzuschneiden (analog OPT-3).
        $limit = $request->boolean('all') ? null : 500;

        return view('admin.inventory.stock-disposals.index', [
            'values' => $limit !== null ? $query->limit($limit)->get() : $query->get(),
            'typeFilter' => $request->query('type'),
            'listLimit' => $limit,
        ]);
    }

    public function create(Request $request): View|RedirectResponse
    {
        if (! auth()->user()->isAdmin()) {
            return redirect()->route('home');
        }

        $prefill = [
            'disposal_type' => 'ingredient',
            'ingredient_id' => null,
            'ingredient_label' => null,
        ];

        $ingredientId = (int) $request->query('ingredient_id');
        if ($ingredientId > 0 && ($ingredient = Ingredient::query()->find($ingredientId))) {
            $prefill['ingredient_id'] = $ingredient->id;
            $prefill['ingredient_label'] = $ingredient->inci ? $ingredient->name.' ('.$ingredient->inci.')' : $ingredient->name;
        }

        return view('admin.inventory.stock-disposals.create', [
            'locations' => Location::query()->where('active', true)->orderBy('name')->get(),
            'reasons' => $this->reasons(),
            'prefill' => $prefill,
            // AP-50/F-17: Köln auch beim Ausschuss vorbelegen.
            'defaultLocationId' => Location::defaultId(),
        ]);
    }

    public function store(StoreStockDisposalRequest $request, ProductionService $productionService): RedirectResponse
    {
        $data = $request->validatedPayload();
        $data['user_id'] = (int) $request->user()->id;

        try {
            DB::transaction(function () use ($data, $productionService): void {
                $this->assertStillAvailable($data, $productionService);
                foreach ($this->splitAcrossBatches($data, $productionService) as $row) {
                    StockDisposal::query()->create($row);
                }
            });
        } catch (ValidationException $e) {
            return redirect()->back()->withInput()->withErrors($e->errors());
        }

        \Session::flash('alert-save', '1');

        return redirect()->route('admin.inventory.stock-disposals.index');
    }

    /**
     * Prüfung 08.09.2026 F-16: Bestandsprüfung innerhalb der Transaktion wiederholen,
     * nachdem die betroffenen Wareneingänge gesperrt wurden — die FormRequest-Prüfung
     * allein lässt zwei parallele Entnahmen denselben Rest bestehen.
     *
     * @param  array<string, mixed>  $data
     *
     * @throws ValidationException
     */
    private function assertStillAvailable(array $data, ProductionService $productionService): void
    {
        if (($data['disposal_type'] ?? null) !== 'ingredient') {
            return;
        }

        $ingredientId = (int) $data['ingredient_id'];
        $quantity = round((float) $data['quantity'], 2);

        if (! empty($data['stock_entry_id'])) {
            $entry = StockEntry::query()->lockForUpdate()->findOrFail((int) $data['stock_entry_id']);
            $available = $productionService->availableStockEntriesForIngredient($ingredientId, (int) $entry->location_id)->firstWhere('id', $entry->id);
            $remaining = $available !== null ? round((float) $available->getAttribute('remaining_quantity'), 2) : 0.0;
        } else {
            // Alle Eingänge des Rohstoffs am Standort sperren, dann Standortrest neu berechnen.
            StockEntry::query()->lockForUpdate()
                ->where('entry_type', 'ingredient')->where('ingredient_id', $ingredientId)
                ->where('location_id', (int) $data['location_id'])
                ->get();
            $remaining = round((float) ($this->inventoryService->remainingByLocationForIngredient($ingredientId)[(int) $data['location_id']] ?? 0.0), 2);
        }

        if ($quantity > $remaining) {
            throw ValidationException::withMessages([
                'quantity' => __('Die Menge (:qty g) übersteigt den Restbestand (:rest g) — Bestand hat sich zwischenzeitlich geändert.', [
                    'qty' => number_format($quantity, 2, ',', '.'),
                    'rest' => number_format(max(0, $remaining), 2, ',', '.'),
                ]),
            ]);
        }
    }

    /**
     * Prüfung 08.09.2026 F-09: Rohstoff-Ausschuss ohne bestimmte Charge wird — wie der
     * Produktionsverbrauch (AP-27, FEFO) — auf die am Lagerort verfügbaren Chargen
     * verteilt und je Charge gebucht. Sonst sinkt nur der Gesamtbestand, während die
     * Chargen in Produktion/Ausschuss weiter als voll verfügbar angeboten würden.
     * Ohne verfügbare Charge (Altbestand ohne Chargenbezug) bleibt die Buchung ungebunden.
     *
     * @param  array<string, mixed>  $data
     * @return array<int, array<string, mixed>>
     */
    private function splitAcrossBatches(array $data, ProductionService $productionService): array
    {
        if (($data['disposal_type'] ?? null) !== 'ingredient' || ! empty($data['stock_entry_id'])) {
            return [$data];
        }

        $entries = $productionService->availableStockEntriesForIngredient((int) $data['ingredient_id'], (int) $data['location_id']);
        if ($entries->isEmpty()) {
            return [$data];
        }

        $rows = [];
        $needed = round((float) $data['quantity'], 2);
        $lastIndex = $entries->count() - 1;
        foreach ($entries as $index => $entry) {
            $capacity = (float) $entry->getAttribute('remaining_quantity');
            $take = $index === $lastIndex ? $needed : round(min($needed, $capacity), 2);
            if ($take > 0) {
                $rows[] = array_merge($data, ['stock_entry_id' => (int) $entry->id, 'quantity' => $take]);
            }
            $needed = round($needed - $take, 2);
            if ($needed <= 0) {
                break;
            }
        }

        return $rows;
    }

    /**
     * Anforderung 15.07.2026: Ausschuss-Buchungen löschbar (Soft-Delete).
     * Die Bestandsaggregationen schließen gelöschte Buchungen automatisch
     * aus — der Bestand steht danach wieder zur Verfügung.
     */
    public function destroy(StockDisposal $stockDisposal): RedirectResponse
    {
        if (! auth()->user()->isAdmin()) {
            return redirect()->route('home');
        }

        $stockDisposal->delete();

        \Session::flash('alert-success', __('Ausschuss-Buchung gelöscht — die Menge steht dem Bestand wieder zur Verfügung.'));

        return redirect()->route('admin.inventory.stock-disposals.index');
    }

    public function ingredientCharges(Ingredient $ingredient): JsonResponse
    {
        $remainingByLocation = $this->inventoryService->remainingByLocationForIngredient($ingredient->id);

        $charges = StockEntry::query()
            ->where('status', 'received')
            ->where('entry_type', 'ingredient')
            ->where('ingredient_id', $ingredient->id)
            ->with('location')
            ->orderBy('best_before')
            ->get(['id', 'location_id', 'batch_number', 'best_before', 'received_quantity']);

        $results = $charges->map(function (StockEntry $charge) {
            $label = $charge->batch_number ? __('Charge').' '.$charge->batch_number : __('Charge #:id', ['id' => $charge->id]);
            if ($charge->location) {
                $label .= ' · '.$charge->location->name;
            }
            if ($charge->best_before) {
                $label .= ' · MHD '.$charge->best_before->format('d.m.Y');
            }

            return [
                'id' => $charge->id,
                'location_id' => $charge->location_id,
                'text' => $label,
            ];
        })->values()->all();

        return response()->json([
            'charges' => $results,
            'remaining_by_location' => $remainingByLocation,
        ]);
    }

    /**
     * Aktive Ausschuss-Gründe aus den Einstellungen (Warenwirtschaft → Allgemein).
     *
     * @return array<int, string>
     */
    protected function reasons(): array
    {
        return DisposalReason::query()
            ->active()
            ->orderBy('pos')
            ->orderBy('label')
            ->pluck('label')
            ->all();
    }
}