<?php

namespace App\Modules\Procurement\Controllers;

use App\Http\Controllers\Controller;

use App\Modules\Procurement\Models\PurchaseOrder;
use App\Modules\Procurement\Models\Vendor;
// use App\Modules\Inventory\Models\Warehouse; // REFACTORED: 移除直接依賴
use App\Modules\Inventory\Contracts\InventoryServiceInterface; // NEW: 使用契約
use App\Modules\Core\Contracts\CoreServiceInterface; // NEW: 使用核心服務契約
use Illuminate\Http\Request;
use Inertia\Inertia;
use Illuminate\Support\Facades\DB;

class PurchaseOrderController extends Controller
{
    protected $inventoryService;
    protected $coreService;

    public function __construct(InventoryServiceInterface $inventoryService, CoreServiceInterface $coreService)
    {
        $this->inventoryService = $inventoryService;
        $this->coreService = $coreService;
    }

    public function index(Request $request)
    {
        // 1. 從關聯中移除 'warehouse' 與 'user'
        $query = PurchaseOrder::with(['vendor']);

        // 搜尋
        if ($request->search) {
            $query->where(function($q) use ($request) {
                $q->where('code', 'like', "%{$request->search}%")
                  ->orWhereHas('vendor', function($vq) use ($request) {
                      $vq->where('name', 'like', "%{$request->search}%");
                  });
            });
        }

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

        if ($request->warehouse_id && $request->warehouse_id !== 'all') {
            $query->where('warehouse_id', $request->warehouse_id);
        }

        // 日期範圍
        if ($request->date_start) {
            $query->whereDate('created_at', '>=', $request->date_start);
        }

        if ($request->date_end) {
            $query->whereDate('created_at', '<=', $request->date_end);
        }

        // 排序
        $sortField = $request->sort_field ?? 'id';
        $sortDirection = $request->sort_direction ?? 'desc';
        $allowedSortFields = ['id', 'code', 'status', 'total_amount', 'created_at', 'expected_delivery_date'];
        
        if (in_array($sortField, $allowedSortFields)) {
            $query->orderBy($sortField, $sortDirection);
        }

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

        // 2. 手動注入倉庫與使用者資料
        $warehouses = $this->inventoryService->getAllWarehouses();
        $userIds = $orders->getCollection()->pluck('user_id')->unique()->toArray();
        $users = $this->coreService->getUsersByIds($userIds)->keyBy('id');

        $orders->getCollection()->transform(function ($order) use ($warehouses, $users) {
            // 水和倉庫
            $warehouse = $warehouses->firstWhere('id', $order->warehouse_id);
            $order->setRelation('warehouse', $warehouse);

            // 水和使用者
            $user = $users->get($order->user_id);
            $order->setRelation('user', $user);

            // 轉換為前端期望的格式 (camelCase)
            return (object) [
                'id' => (string) $order->id,
                'poNumber' => $order->code,
                'supplierId' => (string) $order->vendor_id,
                'supplierName' => $order->vendor?->name ?? 'Unknown',
                'orderDate' => $order->order_date?->format('Y-m-d'), // 新增
                'expectedDate' => $order->expected_delivery_date?->toISOString(),
                'status' => $order->status,
                'totalAmount' => (float) $order->total_amount,
                'taxAmount' => (float) $order->tax_amount,
                'grandTotal' => (float) $order->grand_total,
                'createdAt' => $order->created_at->toISOString(),
                'createdBy' => $user?->name ?? 'System',
                'warehouse_id' => (int) $order->warehouse_id,
                'warehouse_name' => $warehouse?->name ?? 'Unknown',
                'remark' => $order->remark,
            ];
        });


        return Inertia::render('PurchaseOrder/Index', [
            'orders' => $orders,
            'filters' => $request->only(['search', 'status', 'warehouse_id', 'date_start', 'date_end', 'sort_field', 'sort_direction', 'per_page']),
            'warehouses' => $warehouses->map(fn($w)=>(object)['id'=>$w->id, 'name'=>$w->name]), 
        ]);
    }

    public function create()
    {
        // 1. 獲取廠商（無關聯）
        $vendors = Vendor::all();

        // 2. 手動注入：獲取 Pivot 資料
        $vendorIds = $vendors->pluck('id')->toArray();
        $pivots = DB::table('product_vendor')->whereIn('vendor_id', $vendorIds)->get();
        $productIds = $pivots->pluck('product_id')->unique()->toArray();
        
        // 3. 從服務獲取商品
        $products = $this->inventoryService->getProductsByIds($productIds)->keyBy('id');

        // 4. 重建前端結構
        $vendors = $vendors->map(function ($vendor) use ($pivots, $products) {
            $vendorProductPivots = $pivots->where('vendor_id', $vendor->id);
            
            $commonProducts = $vendorProductPivots->map(function($pivot) use ($products) {
                $product = $products[$pivot->product_id] ?? null;
                if (!$product) return null;
                
                return [
                    'productId' => (string) $product->id,
                    'productName' => $product->name,
                    'base_unit_id' => $product->base_unit_id,
                    'base_unit_name' => $product->baseUnit?->name,
                    'large_unit_id' => $product->large_unit_id,
                    'large_unit_name' => $product->largeUnit?->name,
                    'purchase_unit_id' => $product->purchase_unit_id,
                    'conversion_rate' => (float) $product->conversion_rate,
                    'lastPrice' => (float) $pivot->last_price,
                ];
            })->filter()->values();

            return [
                'id' => (string) $vendor->id,
                'name' => $vendor->name,
                'commonProducts' => $commonProducts
            ];
        });

        $warehouses = $this->inventoryService->getAllWarehouses()->map(function ($w) {
            return [
                'id' => (string) $w->id,
                'name' => $w->name,
            ];
        });

        return Inertia::render('PurchaseOrder/Create', [
            'suppliers' => $vendors,
            'warehouses' => $warehouses,
        ]);
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'vendor_id' => 'required|exists:vendors,id',
            'warehouse_id' => 'required|exists:warehouses,id',
            'order_date' => 'required|date', // 新增驗證
            'expected_delivery_date' => 'nullable|date',
            'remark' => 'nullable|string',
            'invoice_number' => ['nullable', 'string', 'max:11', 'regex:/^[A-Z]{2}-\d{8}$/'],
            'invoice_date' => 'nullable|date',
            'invoice_amount' => 'nullable|numeric|min:0',
            'items' => 'required|array|min:1',
            'items.*.productId' => 'required|exists:products,id',
            'items.*.quantity' => 'required|numeric|min:0.01',
            'items.*.subtotal' => 'required|numeric|min:0', // 總金額
            'items.*.unitId' => 'nullable|exists:units,id',
            'tax_amount' => 'nullable|numeric|min:0',
        ]);

        try {
            DB::beginTransaction();

            // 生成單號：YYYYMMDD001
            $today = now()->format('Ymd');
            $lastOrder = PurchaseOrder::where('code', 'like', $today . '%')
                ->lockForUpdate() // 鎖定以避免並發衝突
                ->orderBy('code', 'desc')
                ->first();

            if ($lastOrder) {
                // 取得最後 3 碼序號並加 1
                $lastSequence = intval(substr($lastOrder->code, -3));
                $sequence = str_pad($lastSequence + 1, 3, '0', STR_PAD_LEFT);
            } else {
                $sequence = '001';
            }
            $code = $today . $sequence;

            $totalAmount = 0;
            foreach ($validated['items'] as $item) {
                $totalAmount += $item['subtotal'];
            }

            // 稅額計算
            $taxAmount = isset($validated['tax_amount']) ? $validated['tax_amount'] : round($totalAmount * 0.05, 2);
            $grandTotal = $totalAmount + $taxAmount;

            // 確保有一個有效的使用者 ID
            $userId = auth()->id();
            if (!$userId) {
                $user = $this->coreService->ensureSystemUserExists();                $userId = $user->id;
            }

            $order = PurchaseOrder::create([
                'code' => $code,
                'vendor_id' => $validated['vendor_id'],
                'warehouse_id' => $validated['warehouse_id'],
                'user_id' => $userId,
                'status' => 'draft',
                'order_date' => $validated['order_date'], // 新增
                'expected_delivery_date' => $validated['expected_delivery_date'],
                'total_amount' => $totalAmount,
                'tax_amount' => $taxAmount,
                'grand_total' => $grandTotal,
                'remark' => $validated['remark'],
                'invoice_number' => $validated['invoice_number'] ?? null,
                'invoice_date' => $validated['invoice_date'] ?? null,
                'invoice_amount' => $validated['invoice_amount'] ?? null,
            ]);

            foreach ($validated['items'] as $item) {
                // 反算單價
                $unitPrice = $item['quantity'] > 0 ? $item['subtotal'] / $item['quantity'] : 0;

                $order->items()->create([
                    'product_id' => $item['productId'],
                    'quantity' => $item['quantity'],
                    'unit_id' => $item['unitId'] ?? null, 
                    'unit_price' => $unitPrice,
                    'subtotal' => $item['subtotal'],
                ]);
            }

            DB::commit();

            return redirect()->route('purchase-orders.index')->with('success', '採購單已成功建立');

        } catch (\Exception $e) {
            DB::rollBack();
            return back()->withErrors(['error' => '建立失敗：' . $e->getMessage()]);
        }
    }

    public function show($id)
    {
        $order = PurchaseOrder::with(['vendor', 'items'])->findOrFail($id);
        
        // 手動注入
        $order->setRelation('warehouse', $this->inventoryService->getWarehouse($order->warehouse_id));
        $order->setRelation('user', $this->coreService->getUser($order->user_id));

        $productIds = $order->items->pluck('product_id')->unique()->toArray();
        $products = $this->inventoryService->getProductsByIds($productIds)->keyBy('id');

        $formattedItems = $order->items->map(function ($item) use ($order, $products) {
            $product = $products[$item->product_id] ?? null;
            return (object) [
                'productId' => (string) $item->product_id,
                'productName' => $product?->name ?? 'Unknown',
                'quantity' => (float) $item->quantity,
                'unitId' => $item->unit_id,
                'base_unit_id' => $product?->base_unit_id,
                'base_unit_name' => $product?->baseUnit?->name,
                'large_unit_id' => $product?->large_unit_id,
                'large_unit_name' => $product?->largeUnit?->name,
                'purchase_unit_id' => $product?->purchase_unit_id,
                'conversion_rate' => (float) ($product?->conversion_rate ?? 1),
                'selectedUnit' => ($item->unit_id && $product?->large_unit_id && $item->unit_id == $product->large_unit_id) ? 'large' : 'base',
                'unitPrice' => (float) $item->unit_price,
                'previousPrice' => (float) (DB::table('product_vendor')->where('vendor_id', $order->vendor_id)->where('product_id', $item->product_id)->value('last_price') ?? 0),
                'subtotal' => (float) $item->subtotal,
            ];
        });

        $formattedOrder = (object) [
            'id' => (string) $order->id,
            'poNumber' => $order->code,
            'supplierId' => (string) $order->vendor_id,
            'supplierName' => $order->vendor?->name ?? 'Unknown',
            'orderDate' => $order->order_date?->format('Y-m-d'), // 新增
            'expectedDate' => $order->expected_delivery_date?->toISOString(),
            'status' => $order->status,
            'items' => $formattedItems,
            'totalAmount' => (float) $order->total_amount,
            'taxAmount' => (float) $order->tax_amount,
            'grandTotal' => (float) $order->grand_total,
            'createdAt' => $order->created_at->toISOString(),
            'createdBy' => $order->user?->name ?? 'System',
            'warehouse_id' => (int) $order->warehouse_id,
            'warehouse_name' => $order->warehouse?->name ?? 'Unknown',
            'remark' => $order->remark,
            'invoiceNumber' => $order->invoice_number,
            'invoiceDate' => $order->invoice_date,
            'invoiceAmount' => (float) $order->invoice_amount,
        ];

        return Inertia::render('PurchaseOrder/Show', [
            'order' => $formattedOrder
        ]);
    }

    public function edit($id)
    {
        // 1. 獲取訂單
        $order = PurchaseOrder::with(['items'])->findOrFail($id);

        // 2. 獲取廠商與商品（與 create 邏輯一致）
        $vendors = Vendor::all();
        $vendorIds = $vendors->pluck('id')->toArray();
        $pivots = DB::table('product_vendor')->whereIn('vendor_id', $vendorIds)->get();
        $productIds = $pivots->pluck('product_id')->unique()->toArray();
        $products = $this->inventoryService->getProductsByIds($productIds)->keyBy('id');

        $vendors = $vendors->map(function ($vendor) use ($pivots, $products) {
            $vendorProductPivots = $pivots->where('vendor_id', $vendor->id);
            $commonProducts = $vendorProductPivots->map(function($pivot) use ($products) {
                $product = $products[$pivot->product_id] ?? null;
                if (!$product) return null;
                return [
                    'productId' => (string) $product->id,
                    'productName' => $product->name,
                    'base_unit_id' => $product->base_unit_id,
                    'base_unit_name' => $product->baseUnit?->name,
                    'large_unit_id' => $product->large_unit_id,
                    'large_unit_name' => $product->largeUnit?->name,
                    'purchase_unit_id' => $product->purchase_unit_id,
                    'conversion_rate' => (float) $product->conversion_rate,
                    'lastPrice' => (float) $pivot->last_price,
                ];
            })->filter()->values();

            return [
                'id' => (string) $vendor->id,
                'name' => $vendor->name,
                'commonProducts' => $commonProducts
            ];
        });

        // 3. 獲取倉庫
        $warehouses = $this->inventoryService->getAllWarehouses()->map(function ($w) {
            return [
                'id' => (string) $w->id,
                'name' => $w->name,
            ];
        });

        // 4. 注入訂單項目特定資料
        // 2. 注入訂單項目
        $itemProductIds = $order->items->pluck('product_id')->toArray();
        $itemProducts = $this->inventoryService->getProductsByIds($itemProductIds)->keyBy('id');
        
        $vendorId = $order->vendor_id;
        $formattedItems = $order->items->map(function ($item) use ($vendorId, $itemProducts) {
             $product = $itemProducts[$item->product_id] ?? null;
             return (object) [
                'productId' => (string) $item->product_id,
                'productName' => $product?->name ?? 'Unknown',
                'quantity' => (float) $item->quantity,
                'unitId' => $item->unit_id,
                'base_unit_id' => $product?->base_unit_id,
                'base_unit_name' => $product?->baseUnit?->name,
                'large_unit_id' => $product?->large_unit_id,
                'large_unit_name' => $product?->largeUnit?->name,
                'conversion_rate' => (float) ($product?->conversion_rate ?? 1),
                'selectedUnit' => ($item->unit_id && $product?->large_unit_id && $item->unit_id == $product->large_unit_id) ? 'large' : 'base',
                'unitPrice' => (float) $item->unit_price,
                'previousPrice' => (float) (DB::table('product_vendor')->where('vendor_id', $vendorId)->where('product_id', $item->product_id)->value('last_price') ?? 0),
                'subtotal' => (float) $item->subtotal,
            ];
        });

        $formattedOrder = (object) [
            'id' => (string) $order->id,
            'poNumber' => $order->code,
            'supplierId' => (string) $order->vendor_id,
            'warehouse_id' => (int) $order->warehouse_id,
            'orderDate' => $order->order_date?->format('Y-m-d'), // 新增
            'expectedDate' => $order->expected_delivery_date?->format('Y-m-d'),
            'status' => $order->status,
            'items' => $formattedItems,
            'remark' => $order->remark,
            'invoiceNumber' => $order->invoice_number,
            'invoiceDate' => $order->invoice_date,
            'invoiceAmount' => (float) $order->invoice_amount,
            'taxAmount' => (float) $order->tax_amount,
        ];

        return Inertia::render('PurchaseOrder/Create', [
            'order' => $formattedOrder,
            'suppliers' => $vendors,
            'warehouses' => $warehouses,
        ]);
    }

    public function update(Request $request, $id)
    {
        $order = PurchaseOrder::findOrFail($id);

        $validated = $request->validate([
            'vendor_id' => 'required|exists:vendors,id',
            'warehouse_id' => 'required|exists:warehouses,id',
            'order_date' => 'required|date', // 新增驗證
            'expected_delivery_date' => 'nullable|date',
            'remark' => 'nullable|string',
            'status' => 'required|string|in:draft,pending,processing,shipping,confirming,completed,cancelled',
            'invoice_number' => ['nullable', 'string', 'max:11', 'regex:/^[A-Z]{2}-\d{8}$/'],
            'invoice_date' => 'nullable|date',
            'invoice_amount' => 'nullable|numeric|min:0',
            'items' => 'required|array|min:1',
            'items.*.productId' => 'required|exists:products,id',
            'items.*.quantity' => 'required|numeric|min:0.01',
            'items.*.subtotal' => 'required|numeric|min:0', // 總金額
            'items.*.unitId' => 'nullable|exists:units,id',
            // 允許 tax_amount 和 taxAmount 以保持相容性
            'tax_amount' => 'nullable|numeric|min:0', 
            'taxAmount' => 'nullable|numeric|min:0',
        ]);

        try {
            DB::beginTransaction();

            $totalAmount = 0;
            foreach ($validated['items'] as $item) {
                $totalAmount += $item['subtotal'];
            }

            // 稅額計算（處理兩個鍵）
            $inputTax = $validated['tax_amount'] ?? $validated['taxAmount'] ?? null;
            $taxAmount = !is_null($inputTax) ? $inputTax : round($totalAmount * 0.05, 2);
            $grandTotal = $totalAmount + $taxAmount;

            // 1. 填充屬性但暫不儲存以捕捉變更
            $order->fill([
                'vendor_id' => $validated['vendor_id'],
                'warehouse_id' => $validated['warehouse_id'],
                'order_date' => $validated['order_date'], // 新增
                'expected_delivery_date' => $validated['expected_delivery_date'],
                'total_amount' => $totalAmount,
                'tax_amount' => $taxAmount,
                'grand_total' => $grandTotal,
                'remark' => $validated['remark'],
                'status' => $validated['status'],
                'invoice_number' => $validated['invoice_number'] ?? null,
                'invoice_date' => $validated['invoice_date'] ?? null,
                'invoice_amount' => $validated['invoice_amount'] ?? null,
            ]);

            // 捕捉變更屬性以進行手動記錄
            $dirty = $order->getDirty();
            $oldAttributes = [];
            $newAttributes = [];

            foreach ($dirty as $key => $value) {
                $oldAttributes[$key] = $order->getOriginal($key);
                $newAttributes[$key] = $value;
            }

            // 儲存但不觸發事件（防止重複記錄）
            $order->saveQuietly();

            // 2. 捕捉包含商品名稱的舊項目以進行比對
            $oldItems = $order->items()->with('product', 'unit')->get()->map(function($item) {
                return [
                    'id' => $item->id,
                    'product_id' => $item->product_id,
                    'product_name' => $item->product?->name,
                    'quantity' => (float) $item->quantity,
                    'unit_id' => $item->unit_id,
                    'unit_name' => $item->unit?->name,
                    'subtotal' => (float) $item->subtotal,
                ];
            })->keyBy('product_id');

            // 同步項目（原始邏輯）
            $order->items()->delete();
            
            $newItemsData = [];
            foreach ($validated['items'] as $item) {
                // 反算單價
                $unitPrice = $item['quantity'] > 0 ? $item['subtotal'] / $item['quantity'] : 0;

                $newItem = $order->items()->create([
                    'product_id' => $item['productId'],
                    'quantity' => $item['quantity'],
                    'unit_id' => $item['unitId'] ?? null, 
                    'unit_price' => $unitPrice,
                    'subtotal' => $item['subtotal'],
                ]);
                $newItemsData[] = $newItem;
            }

            // 3. 計算項目差異
            $itemDiffs = [
                'added' => [],
                'removed' => [],
                'updated' => [],
            ];

            // 重新獲取新項目以確保擁有最新的關聯
            $newItemsFormatted = $order->items()->with('product', 'unit')->get()->map(function($item) {
                return [
                    'product_id' => $item->product_id,
                    'product_name' => $item->product?->name,
                    'quantity' => (float) $item->quantity,
                    'unit_id' => $item->unit_id,
                    'unit_name' => $item->unit?->name,
                    'subtotal' => (float) $item->subtotal,
                ];
            })->keyBy('product_id');

            // 找出已移除的項目
            foreach ($oldItems as $productId => $oldItem) {
                if (!$newItemsFormatted->has($productId)) {
                    $itemDiffs['removed'][] = $oldItem;
                }
            }

            // 找出新增和更新的項目
            foreach ($newItemsFormatted as $productId => $newItem) {
                if (!$oldItems->has($productId)) {
                    $itemDiffs['added'][] = $newItem;
                } else {
                    $oldItem = $oldItems[$productId];
                    // 比對欄位
                    if (
                        $oldItem['quantity'] != $newItem['quantity'] || 
                        $oldItem['unit_id'] != $newItem['unit_id'] ||
                        $oldItem['subtotal'] != $newItem['subtotal']
                    ) {
                        $itemDiffs['updated'][] = [
                            'product_name' => $newItem['product_name'],
                            'old' => [
                                'quantity' => $oldItem['quantity'],
                                'unit_name' => $oldItem['unit_name'],
                                'subtotal' => $oldItem['subtotal'],
                            ],
                            'new' => [
                                'quantity' => $newItem['quantity'],
                                'unit_name' => $newItem['unit_name'],
                                'subtotal' => $newItem['subtotal'],
                            ]
                        ];
                    }
                }
            }

            // 4. 手動記錄活動（單一整合記錄）
            // 如果有屬性變更或項目變更則記錄
            if (!empty($newAttributes) || !empty($itemDiffs['added']) || !empty($itemDiffs['removed']) || !empty($itemDiffs['updated'])) {
                activity()
                    ->performedOn($order)
                    ->causedBy(auth()->user())
                    ->event('updated')
                    ->withProperties([
                        'attributes' => $newAttributes,
                        'old' => $oldAttributes,
                        'items_diff' => $itemDiffs,
                        'snapshot' => [
                            'po_number' => $order->code,
                            'vendor_name' => $order->vendor?->name,
                            'warehouse_name' => $order->warehouse?->name,
                            'user_name' => $order->user?->name,
                        ]
                    ])
                    ->log('updated');
            }

            DB::commit();

            return redirect()->route('purchase-orders.index')->with('success', '採購單已更新');

        } catch (\Exception $e) {
            DB::rollBack();
            return back()->withErrors(['error' => '更新失敗：' . $e->getMessage()]);
        }
    }

    public function destroy($id)
    {
        try {
            DB::beginTransaction();
            
            $order = PurchaseOrder::with(['items'])->findOrFail($id);
            
            // 為記錄注入資料
            $productIds = $order->items->pluck('product_id')->unique()->toArray();
            $products = $this->inventoryService->getProductsByIds($productIds)->keyBy('id');

            // 捕捉項目以進行記錄
            $items = $order->items->map(function ($item) use ($products) {
                $product = $products[$item->product_id] ?? null;
                return [
                    'product_name' => $product?->name ?? 'Unknown',
                    'quantity' => floatval($item->quantity),
                    'unit_name' => 'N/A', 
                    'subtotal' => floatval($item->subtotal),
                ];
            })->toArray();

            // 手動記錄包含項目的刪除操作
            activity()
                ->performedOn($order)
                ->causedBy(auth()->user())
                ->event('deleted')
                ->withProperties([
                    'attributes' => $order->getAttributes(),
                    'items_diff' => [
                        'added' => [],
                        'removed' => $items,
                        'updated' => [],
                    ],
                    'snapshot' => [
                        'po_number' => $order->code,
                        'vendor_name' => $order->vendor?->name,
                        'warehouse_name' => $order->warehouse?->name,
                        'user_name' => $order->user?->name,
                    ]
                ])
                ->log('deleted');

            // 對此操作停用自動記錄
            $order->disableLogging();
            
            // 先刪除關聯項目
            $order->items()->delete();
            $order->delete();
            
            DB::commit();
            
            return redirect()->route('purchase-orders.index')->with('success', '採購單已刪除');
        } catch (\Exception $e) {
            DB::rollBack();
            return back()->withErrors(['error' => '刪除失敗：' . $e->getMessage()]);
        }
    }
}