<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Attribute;
use App\Models\AttributeValue;
use App\Models\Category;
use App\Models\Product;
use App\Models\ProductImage;
use App\Models\ProductVariant;
use Illuminate\Http\Request;
use Illuminate\Support\Str;

class ProductController extends Controller
{
    public function index(Request $request)
    {
        $query = Product::with('category')->latest();
        if ($request->filled('q')) {
            $query->where('name', 'like', '%'.$request->q.'%');
        }
        $products = $query->paginate(25);
        return view('admin.products.index', compact('products'));
    }

    public function create()
    {
        $categories    = Category::orderBy('name')->get();
        $attributes    = Attribute::with('values')->get();
        $variantsJson  = '[]';
        return view('admin.products.form', compact('categories', 'attributes', 'variantsJson'));
    }

    public function store(Request $request)
    {
        $data = $request->validate([
            'name'        => 'required|string|max:255',
            'category_id' => 'nullable|exists:categories,id',
            'description' => 'nullable|string',
            'base_price'  => 'required|numeric|min:0',
            'tax_rate'    => 'required|numeric|in:7,19',
            'weight'      => 'nullable|numeric|min:0',
            'active'       => 'boolean',
            'featured'     => 'boolean',
            'track_stock'  => 'boolean',
            'sort_order'   => 'integer',
        ]);
        $data['slug']        = Str::slug($data['name']);
        $data['active']      = $request->boolean('active');
        $data['featured']    = $request->boolean('featured');
        $data['track_stock'] = $request->boolean('track_stock');

        $product = Product::create($data);

        $this->syncImages($request, $product);
        $this->syncVariants($request, $product);

        return redirect()->route('admin.products.index')->with('success', 'Artikel erstellt.');
    }

    public function edit(Product $product)
    {
        $product->load('images', 'variants.attributeValues.attribute');
        $categories   = Category::orderBy('name')->get();
        $attributes   = Attribute::with('values')->get();
        $variantsJson = json_encode($product->variants->map(fn($v) => [
            'id'                  => $v->id,
            'sku'                 => $v->sku,
            'price_override'      => $v->price_override,
            'stock'               => $v->stock,
            'stock_warning'       => $v->stock_warning,
            'active'              => (bool) $v->active,
            'attribute_value_ids' => $v->attributeValues->pluck('id')->values()->all(),
        ]));
        return view('admin.products.form', compact('product', 'categories', 'attributes', 'variantsJson'));
    }

    public function update(Request $request, Product $product)
    {
        $data = $request->validate([
            'name'        => 'required|string|max:255',
            'category_id' => 'nullable|exists:categories,id',
            'description' => 'nullable|string',
            'base_price'  => 'required|numeric|min:0',
            'tax_rate'    => 'required|numeric|in:7,19',
            'weight'      => 'nullable|numeric|min:0',
            'active'       => 'boolean',
            'featured'     => 'boolean',
            'track_stock'  => 'boolean',
            'sort_order'   => 'integer',
        ]);
        $data['slug']        = Str::slug($data['name']);
        $data['active']      = $request->boolean('active');
        $data['featured']    = $request->boolean('featured');
        $data['track_stock'] = $request->boolean('track_stock');

        $product->update($data);

        $this->syncImages($request, $product);
        $this->syncVariants($request, $product);

        return redirect()->route('admin.products.index')->with('success', 'Artikel aktualisiert.');
    }

    public function destroy(Product $product)
    {
        $product->delete();
        return redirect()->route('admin.products.index')->with('success', 'Artikel gelöscht.');
    }

    private function syncImages(Request $request, Product $product): void
    {
        if ($request->hasFile('images')) {
            foreach ($request->file('images') as $i => $file) {
                $path = $file->store('products', 'public');
                ProductImage::create(['product_id' => $product->id, 'path' => $path, 'sort_order' => $i]);
            }
        }
        // Bild löschen
        if ($request->filled('delete_images')) {
            ProductImage::whereIn('id', $request->delete_images)
                ->where('product_id', $product->id)
                ->delete();
        }
    }

    private function syncVariants(Request $request, Product $product): void
    {
        $variants = $request->input('variants', []);
        $existingIds = [];

        foreach ($variants as $v) {
            if (empty($v['sku'])) continue;

            $variant = isset($v['id'])
                ? ProductVariant::find($v['id'])
                : null;

            $variantData = [
                'product_id'     => $product->id,
                'sku'            => $v['sku'],
                'price_override' => filled($v['price_override']) ? $v['price_override'] : null,
                'stock'          => (int) ($v['stock'] ?? 0),
                'stock_warning'  => (int) ($v['stock_warning'] ?? 5),
                'active'         => isset($v['active']),
            ];

            if ($variant) {
                $variant->update($variantData);
            } else {
                $variant = ProductVariant::create($variantData);
            }

            // Attributwerte synchronisieren
            $valueIds = array_filter((array) ($v['attribute_value_ids'] ?? []));
            $variant->attributeValues()->sync($valueIds);

            $existingIds[] = $variant->id;
        }

        // Nicht mehr vorhandene Varianten löschen
        $product->variants()->whereNotIn('id', $existingIds)->delete();

        // Sicherstellen dass jedes Produkt mindestens eine Standard-Variante hat
        if ($product->variants()->count() === 0) {
            ProductVariant::create([
                'product_id'    => $product->id,
                'sku'           => 'DEFAULT-' . $product->id,
                'price_override'=> null,
                'stock'         => 0,
                'stock_warning' => 5,
                'active'        => true,
            ]);
        }
    }
}