<?php

namespace App\Http\Controllers;

use App\Models\Inventory;
use App\Models\Product;
use App\Models\ProductionOrder;
use App\Models\ProductionOrderItem;
use App\Models\Unit;
use App\Models\Warehouse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Inertia\Inertia;
use Inertia\Response;

class ProductionOrderController extends Controller
{
    /**
     * 生產工單列表
     */
    public function index(Request $request): Response
    {
        $query = ProductionOrder::with(['product', 'warehouse', 'user']);

        // 搜尋
        if ($request->filled('search')) {
            $search = $request->search;
            $query->where(function ($q) use ($search) {
                $q->where('code', 'like', "%{$search}%")
                  ->orWhere('output_batch_number', 'like', "%{$search}%")
                  ->orWhereHas('product', fn($pq) => $pq->where('name', 'like', "%{$search}%"));
            });
        }

        // 狀態篩選
        if ($request->filled('status') && $request->status !== 'all') {
            $query->where('status', $request->status);
        }

        // 排序
        $sortField = $request->input('sort_field', 'created_at');
        $sortDirection = $request->input('sort_direction', 'desc');
        $allowedSorts = ['id', 'code', 'production_date', 'output_quantity', 'created_at'];
        if (!in_array($sortField, $allowedSorts)) {
            $sortField = 'created_at';
        }
        $query->orderBy($sortField, $sortDirection);

        // 分頁
        $perPage = $request->input('per_page', 10);
        $productionOrders = $query->paginate($perPage)->withQueryString();

        return Inertia::render('Production/Index', [
            'productionOrders' => $productionOrders,
            'filters' => $request->only(['search', 'status', 'per_page', 'sort_field', 'sort_direction']),
        ]);
    }

    /**
     * 新增生產單表單
     */
    public function create(): Response
    {
        return Inertia::render('Production/Create', [
            'products' => Product::with(['baseUnit'])->get(),
            'warehouses' => Warehouse::all(),
            'units' => Unit::all(),
        ]);
    }

    /**
     * 儲存生產單（含自動扣料與成品入庫）
     */
    public function store(Request $request)
    {
        $status = $request->input('status', 'draft'); // 預設為草稿

        // 共用驗證規則
        $baseRules = [
            'product_id' => 'required|exists:products,id',
            'output_batch_number' => 'required|string|max:50',
            'status' => 'nullable|in:draft,completed',
        ];

        // 完成模式需要完整驗證
        $completedRules = [
            'warehouse_id' => 'required|exists:warehouses,id',
            'output_quantity' => 'required|numeric|min:0.01',
            'output_box_count' => 'nullable|string|max:10',
            'production_date' => 'required|date',
            'expiry_date' => 'nullable|date|after_or_equal:production_date',
            'remark' => 'nullable|string',
            'items' => 'required|array|min:1',
            'items.*.inventory_id' => 'required|exists:inventories,id',
            'items.*.quantity_used' => 'required|numeric|min:0.0001',
            'items.*.unit_id' => 'nullable|exists:units,id',
        ];

        // 草稿模式的寬鬆規則
        $draftRules = [
            'warehouse_id' => 'nullable|exists:warehouses,id',
            'output_quantity' => 'nullable|numeric|min:0',
            'output_box_count' => 'nullable|string|max:10',
            'production_date' => 'nullable|date',
            'expiry_date' => 'nullable|date',
            'remark' => 'nullable|string',
            'items' => 'nullable|array',
            'items.*.inventory_id' => 'nullable|exists:inventories,id',
            'items.*.quantity_used' => 'nullable|numeric|min:0',
            'items.*.unit_id' => 'nullable|exists:units,id',
        ];

        $rules = $status === 'completed' 
            ? array_merge($baseRules, $completedRules)
            : array_merge($baseRules, $draftRules);

        $validated = $request->validate($rules, [
            'product_id.required' => '請選擇成品商品',
            'output_batch_number.required' => '請輸入成品批號',
            'warehouse_id.required' => '請選擇入庫倉庫',
            'output_quantity.required' => '請輸入生產數量',
            'production_date.required' => '請選擇生產日期',
            'items.required' => '請至少新增一項原物料',
            'items.min' => '請至少新增一項原物料',
        ]);

        DB::transaction(function () use ($validated, $request, $status) {
            // 1. 建立生產工單
            $productionOrder = ProductionOrder::create([
                'code' => ProductionOrder::generateCode(),
                'product_id' => $validated['product_id'],
                'warehouse_id' => $validated['warehouse_id'] ?? null,
                'output_quantity' => $validated['output_quantity'] ?? 0,
                'output_batch_number' => $validated['output_batch_number'],
                'output_box_count' => $validated['output_box_count'] ?? null,
                'production_date' => $validated['production_date'] ?? now()->toDateString(),
                'expiry_date' => $validated['expiry_date'] ?? null,
                'user_id' => auth()->id(),
                'status' => $status,
                'remark' => $validated['remark'] ?? null,
            ]);

            // 2. 建立明細 (草稿與完成模式皆需儲存)
            if (!empty($validated['items'])) {
                foreach ($validated['items'] as $item) {
                    if (empty($item['inventory_id'])) continue;

                    // 建立明細
                    ProductionOrderItem::create([
                        'production_order_id' => $productionOrder->id,
                        'inventory_id' => $item['inventory_id'],
                        'quantity_used' => $item['quantity_used'] ?? 0,
                        'unit_id' => $item['unit_id'] ?? null,
                    ]);

                    // 若為完成模式，則扣減原物料庫存
                    if ($status === 'completed') {
                        $inventory = Inventory::findOrFail($item['inventory_id']);
                        $inventory->decrement('quantity', $item['quantity_used']);
                    }
                }
            }

            // 3. 若為完成模式，執行成品入庫
            if ($status === 'completed') {
                $product = Product::findOrFail($validated['product_id']);
                Inventory::create([
                    'warehouse_id' => $validated['warehouse_id'],
                    'product_id' => $validated['product_id'],
                    'quantity' => $validated['output_quantity'],
                    'batch_number' => $validated['output_batch_number'],
                    'box_number' => $validated['output_box_count'],
                    'origin_country' => 'TW', // 生產預設為本地
                    'arrival_date' => $validated['production_date'],
                    'expiry_date' => $validated['expiry_date'] ?? null,
                    'quality_status' => 'normal',
                ]);
            }
        });

        $message = $status === 'completed' 
            ? '生產單已建立，原物料已扣減，成品已入庫'
            : '生產單草稿已儲存';

        return redirect()->route('production-orders.index')
            ->with('success', $message);
    }

    /**
     * 檢視生產單詳情（含追溯資訊）
     */
    public function show(ProductionOrder $productionOrder): Response
    {
        $productionOrder->load([
            'product.baseUnit',
            'warehouse',
            'user',
            'items.inventory.product',
            'items.inventory.sourcePurchaseOrder.vendor',
            'items.unit',
        ]);

        return Inertia::render('Production/Show', [
            'productionOrder' => $productionOrder,
        ]);
    }

    /**
     * 取得倉庫內可用庫存（供 BOM 選擇）
     */
    public function getWarehouseInventories(Warehouse $warehouse)
    {
        $inventories = Inventory::with(['product.baseUnit', 'product.largeUnit'])
            ->where('warehouse_id', $warehouse->id)
            ->where('quantity', '>', 0)
            ->where('quality_status', 'normal')
            ->orderBy('arrival_date', 'asc') // FIFO：舊的排前面
            ->get()
            ->map(function ($inv) {
                return [
                    'id' => $inv->id,
                    'product_id' => $inv->product_id,
                    'product_name' => $inv->product->name,
                    'product_code' => $inv->product->code,
                    'batch_number' => $inv->batch_number,
                    'box_number' => $inv->box_number,
                    'quantity' => $inv->quantity,
                    'arrival_date' => $inv->arrival_date?->format('Y-m-d'),
                    'expiry_date' => $inv->expiry_date?->format('Y-m-d'),
                    'unit_name' => $inv->product->baseUnit?->name,
                    'base_unit_id' => $inv->product->base_unit_id,
                    'base_unit_name' => $inv->product->baseUnit?->name,
                    'large_unit_id' => $inv->product->large_unit_id,
                    'large_unit_name' => $inv->product->largeUnit?->name,
                    'conversion_rate' => $inv->product->conversion_rate,
                ];
            });

        return response()->json($inventories);
    }

    /**
     * 編輯生產單（僅限草稿狀態）
     */
    public function edit(ProductionOrder $productionOrder): Response
    {
        // 只有草稿可以編輯
        if ($productionOrder->status !== 'draft') {
            return redirect()->route('production-orders.show', $productionOrder->id)
                ->with('error', '只有草稿狀態的生產單可以編輯');
        }

        $productionOrder->load(['product', 'warehouse', 'items.inventory.product', 'items.unit']);

        return Inertia::render('Production/Edit', [
            'productionOrder' => $productionOrder,
            'products' => Product::with(['baseUnit'])->get(),
            'warehouses' => Warehouse::all(),
            'units' => Unit::all(),
        ]);
    }

    /**
     * 更新生產單
     */
    public function update(Request $request, ProductionOrder $productionOrder)
    {
        // 只有草稿可以編輯
        if ($productionOrder->status !== 'draft') {
            return redirect()->route('production-orders.show', $productionOrder->id)
                ->with('error', '只有草稿狀態的生產單可以編輯');
        }

        $status = $request->input('status', 'draft');

        // 共用驗證規則
        $baseRules = [
            'product_id' => 'required|exists:products,id',
            'output_batch_number' => 'required|string|max:50',
            'status' => 'nullable|in:draft,completed',
        ];

        // 完成模式需要完整驗證
        $completedRules = [
            'warehouse_id' => 'required|exists:warehouses,id',
            'output_quantity' => 'required|numeric|min:0.01',
            'output_box_count' => 'nullable|string|max:10',
            'production_date' => 'required|date',
            'expiry_date' => 'nullable|date|after_or_equal:production_date',
            'remark' => 'nullable|string',
            'items' => 'required|array|min:1',
            'items.*.inventory_id' => 'required|exists:inventories,id',
            'items.*.quantity_used' => 'required|numeric|min:0.0001',
            'items.*.unit_id' => 'nullable|exists:units,id',
        ];

        // 草稿模式的寬鬆規則
        $draftRules = [
            'warehouse_id' => 'nullable|exists:warehouses,id',
            'output_quantity' => 'nullable|numeric|min:0',
            'output_box_count' => 'nullable|string|max:10',
            'production_date' => 'nullable|date',
            'expiry_date' => 'nullable|date',
            'remark' => 'nullable|string',
            'items' => 'nullable|array',
            'items.*.inventory_id' => 'nullable|exists:inventories,id',
            'items.*.quantity_used' => 'nullable|numeric|min:0',
            'items.*.unit_id' => 'nullable|exists:units,id',
        ];

        $rules = $status === 'completed' 
            ? array_merge($baseRules, $completedRules)
            : array_merge($baseRules, $draftRules);

        $validated = $request->validate($rules, [
            'product_id.required' => '請選擇成品商品',
            'output_batch_number.required' => '請輸入成品批號',
            'warehouse_id.required' => '請選擇入庫倉庫',
            'output_quantity.required' => '請輸入生產數量',
            'production_date.required' => '請選擇生產日期',
            'items.required' => '請至少新增一項原物料',
            'items.min' => '請至少新增一項原物料',
        ]);

        DB::transaction(function () use ($validated, $status, $productionOrder) {
            // 更新生產工單基本資料
            $productionOrder->update([
                'product_id' => $validated['product_id'],
                'warehouse_id' => $validated['warehouse_id'] ?? null,
                'output_quantity' => $validated['output_quantity'] ?? 0,
                'output_batch_number' => $validated['output_batch_number'],
                'output_box_count' => $validated['output_box_count'] ?? null,
                'production_date' => $validated['production_date'] ?? now()->toDateString(),
                'expiry_date' => $validated['expiry_date'] ?? null,
                'status' => $status,
                'remark' => $validated['remark'] ?? null,
            ]);

            // 刪除舊的明細
            $productionOrder->items()->delete();

            // 重新建立明細 (草稿與完成模式皆需儲存)
            if (!empty($validated['items'])) {
                foreach ($validated['items'] as $item) {
                    if (empty($item['inventory_id'])) continue;

                    ProductionOrderItem::create([
                        'production_order_id' => $productionOrder->id,
                        'inventory_id' => $item['inventory_id'],
                        'quantity_used' => $item['quantity_used'] ?? 0,
                        'unit_id' => $item['unit_id'] ?? null,
                    ]);

                    // 若為完成模式，則扣減原物料庫存
                    if ($status === 'completed') {
                        $inventory = Inventory::findOrFail($item['inventory_id']);
                        $inventory->decrement('quantity', $item['quantity_used']);
                    }
                }
            }

            // 若為完成模式，執行成品入庫
            if ($status === 'completed') {
                Inventory::create([
                    'warehouse_id' => $validated['warehouse_id'],
                    'product_id' => $validated['product_id'],
                    'quantity' => $validated['output_quantity'],
                    'batch_number' => $validated['output_batch_number'],
                    'box_number' => $validated['output_box_count'],
                    'origin_country' => 'TW',
                    'arrival_date' => $validated['production_date'],
                    'expiry_date' => $validated['expiry_date'] ?? null,
                    'quality_status' => 'normal',
                ]);
            }
        });

        $message = $status === 'completed' 
            ? '生產單已完成，原物料已扣減，成品已入庫'
            : '生產單草稿已更新';

        return redirect()->route('production-orders.index')
            ->with('success', $message);
    }
}