<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Machine\Machine;
use App\Models\Machine\MachineSlot;
use App\Models\Product\Product;
use App\Models\Warehouse\ReplenishmentOrder;
use App\Models\Warehouse\ReplenishmentOrderItem;
use App\Models\Warehouse\StockInOrder;
use App\Models\Warehouse\StockInOrderItem;
use App\Models\Warehouse\StockMovement;
use App\Models\Warehouse\TransferOrder;
use App\Models\Warehouse\TransferOrderItem;
use App\Models\Warehouse\Warehouse;
use App\Models\Warehouse\WarehouseStock;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;

class WarehouseController extends Controller
{
    // ─── 模組 1：倉庫總覽 ───

    public function index(Request $request)
    {
        $query = Warehouse::query()
            ->withCount('stocks as products_count')
            ->withSum('stocks as total_stock', 'quantity');

        if ($search = $request->input('search')) {
            $query->where(function ($q) use ($search) {
                $q->where('name', 'like', "%{$search}%")
                    ->orWhere('address', 'like', "%{$search}%");
            });
        }

        if ($request->filled('type')) {
            $query->where('type', $request->input('type'));
        }

        $warehouses = $query->orderBy('type')->orderBy('name')
            ->paginate($request->input('per_page', 10))
            ->withQueryString();

        $stats = [
            'total' => Warehouse::count(),
            'main' => Warehouse::main()->count(),
            'branch' => Warehouse::branch()->count(),
            'low_stock' => WarehouseStock::lowStock()
                ->whereHas('warehouse', fn($q) => $q)->count(),
        ];

        return view('admin.warehouses.index', compact('warehouses', 'stats'));
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'name' => 'required|string|max:255',
            'type' => 'required|in:main,branch',
            'address' => 'nullable|string|max:500',
        ]);
        $validated['company_id'] = Auth::user()->company_id;
        Warehouse::create($validated);

        return redirect()->route('admin.warehouses.index')
            ->with('success', __('Warehouse created successfully'));
    }

    public function update(Request $request, Warehouse $warehouse)
    {
        $validated = $request->validate([
            'name' => 'required|string|max:255',
            'type' => 'required|in:main,branch',
            'address' => 'nullable|string|max:500',
            'is_active' => 'required|boolean',
        ]);
        $warehouse->update($validated);

        return redirect()->route('admin.warehouses.index')
            ->with('success', __('Warehouse updated successfully'));
    }

    public function destroy(Warehouse $warehouse)
    {
        if ($warehouse->stocks()->where('quantity', '>', 0)->exists()) {
            return redirect()->route('admin.warehouses.index')
                ->with('error', __('Cannot delete warehouse with existing stock'));
        }
        $warehouse->delete();

        return redirect()->route('admin.warehouses.index')
            ->with('success', __('Warehouse deleted successfully'));
    }

    public function toggleStatus(Warehouse $warehouse)
    {
        $warehouse->update(['is_active' => !$warehouse->is_active]);
        $status = $warehouse->is_active ? __('enabled') : __('disabled');

        return redirect()->route('admin.warehouses.index')
            ->with('success', __('Warehouse :status successfully', ['status' => $status]));
    }

    // ─── 模組 2：庫存管理 ───

    public function inventory(Request $request)
    {
        $tab = $request->input('tab', 'stock');
        $warehouses = Warehouse::active()->orderBy('name')->get();

        $data = compact('warehouses', 'tab');

        if ($tab === 'stock') {
            $query = WarehouseStock::with(['warehouse:id,name,type', 'product:id,name,image_url'])
                ->whereHas('warehouse', fn($q) => $q);

            if ($request->filled('warehouse_id')) {
                $query->where('warehouse_id', $request->input('warehouse_id'));
            }
            if ($search = $request->input('search')) {
                $query->whereHas('product', fn($q) => $q->where('name', 'like', "%{$search}%"));
            }

            $data['stocks'] = $query->orderBy('warehouse_id')
                ->paginate($request->input('per_page', 15))
                ->withQueryString();

        } elseif ($tab === 'stock-in') {
            $query = StockInOrder::with(['warehouse:id,name', 'creator:id,name'])
                ->latest();

            if ($request->filled('status')) {
                $query->where('status', $request->input('status'));
            }
            $data['orders'] = $query->paginate(10)->withQueryString();
            $data['products'] = Product::orderBy('name')->get(['id', 'name', 'image_url']);

        } elseif ($tab === 'movements') {
            $query = StockMovement::with(['warehouse:id,name', 'product:id,name', 'creator:id,name'])
                ->orderBy('created_at', 'desc');

            if ($request->filled('warehouse_id')) {
                $query->where('warehouse_id', $request->input('warehouse_id'));
            }
            if ($request->filled('type')) {
                $query->where('type', $request->input('type'));
            }
            $data['movements'] = $query->paginate(15)->withQueryString();
        }

        return view('admin.warehouses.inventory', $data);
    }

    /**
     * 建立入庫單
     */
    public function storeStockIn(Request $request)
    {
        $validated = $request->validate([
            'warehouse_id' => 'required|exists:warehouses,id',
            'note' => 'nullable|string|max:500',
            'items' => 'required|array|min:1',
            'items.*.product_id' => 'required|exists:products,id',
            'items.*.quantity' => 'required|integer|min:1',
        ]);

        DB::transaction(function () use ($validated) {
            $order = StockInOrder::create([
                'company_id' => Auth::user()->company_id,
                'warehouse_id' => $validated['warehouse_id'],
                'order_no' => 'SI-' . now()->format('Ymd') . '-' . str_pad(StockInOrder::whereDate('created_at', today())->count() + 1, 4, '0', STR_PAD_LEFT),
                'status' => 'draft',
                'note' => $validated['note'] ?? null,
                'created_by' => Auth::id(),
            ]);

            foreach ($validated['items'] as $item) {
                $order->items()->create($item);
            }
        });

        return redirect()->route('admin.warehouses.inventory', ['tab' => 'stock-in'])
            ->with('success', __('Stock-in order created'));
    }

    /**
     * 確認入庫單（草稿 → 完成，同時增加庫存）
     */
    public function confirmStockIn(StockInOrder $stockInOrder)
    {
        if ($stockInOrder->status !== 'draft') {
            return back()->with('error', __('Order already processed'));
        }

        DB::transaction(function () use ($stockInOrder) {
            $stockInOrder->update([
                'status' => 'completed',
                'completed_at' => now(),
            ]);

            foreach ($stockInOrder->items as $item) {
                // 更新或建立倉庫庫存
                $stock = WarehouseStock::firstOrCreate(
                    ['warehouse_id' => $stockInOrder->warehouse_id, 'product_id' => $item->product_id],
                    ['quantity' => 0, 'safety_stock' => 0]
                );

                $before = $stock->quantity;
                $stock->increment('quantity', $item->quantity);

                // 記錄異動
                StockMovement::create([
                    'company_id' => $stockInOrder->company_id,
                    'warehouse_id' => $stockInOrder->warehouse_id,
                    'product_id' => $item->product_id,
                    'type' => 'in',
                    'quantity' => $item->quantity,
                    'before_qty' => $before,
                    'after_qty' => $before + $item->quantity,
                    'reference_type' => StockInOrder::class,
                    'reference_id' => $stockInOrder->id,
                    'note' => __('Stock-in order') . ' #' . $stockInOrder->order_no,
                    'created_by' => Auth::id(),
                    'created_at' => now(),
                ]);
            }
        });

        return back()->with('success', __('Stock-in order confirmed and inventory updated'));
    }

    // ─── 模組 3：調撥單 ───

    public function transfers(Request $request)
    {
        $query = TransferOrder::with(['fromWarehouse:id,name', 'toWarehouse:id,name', 'fromMachine:id,name,serial_no', 'creator:id,name', 'items'])
            ->latest();

        if ($request->filled('type')) {
            $query->where('type', $request->input('type'));
        }
        if ($request->filled('status')) {
            $query->where('status', $request->input('status'));
        }

        $orders = $query->paginate(10)->withQueryString();
        $warehouses = Warehouse::active()->orderBy('name')->get(['id', 'name', 'type']);
        $machines = Machine::orderBy('name')->get(['id', 'name', 'serial_no']);
        $products = Product::orderBy('name')->get(['id', 'name', 'image_url']);

        return view('admin.warehouses.transfers', compact('orders', 'warehouses', 'machines', 'products'));
    }

    /**
     * 建立調撥單（W2W 或 M2W）
     */
    public function storeTransfer(Request $request)
    {
        $validated = $request->validate([
            'type' => 'required|in:warehouse_to_warehouse,machine_to_warehouse',
            'from_warehouse_id' => 'required_if:type,warehouse_to_warehouse|nullable|exists:warehouses,id',
            'from_machine_id' => 'required_if:type,machine_to_warehouse|nullable|exists:machines,id',
            'to_warehouse_id' => 'required|exists:warehouses,id',
            'note' => 'nullable|string|max:500',
            'items' => 'required|array|min:1',
            'items.*.product_id' => 'required|exists:products,id',
            'items.*.quantity' => 'required|integer|min:1',
        ]);

        DB::transaction(function () use ($validated) {
            $order = TransferOrder::create([
                'company_id' => Auth::user()->company_id,
                'order_no' => 'TR-' . now()->format('Ymd') . '-' . str_pad(TransferOrder::whereDate('created_at', today())->count() + 1, 4, '0', STR_PAD_LEFT),
                'type' => $validated['type'],
                'from_warehouse_id' => $validated['from_warehouse_id'] ?? null,
                'from_machine_id' => $validated['from_machine_id'] ?? null,
                'to_warehouse_id' => $validated['to_warehouse_id'],
                'status' => TransferOrder::STATUS_DRAFT,
                'note' => $validated['note'] ?? null,
                'created_by' => Auth::id(),
            ]);

            foreach ($validated['items'] as $item) {
                $order->items()->create($item);
            }
        });

        return redirect()->route('admin.warehouses.transfers')
            ->with('success', __('Transfer order created'));
    }

    /**
     * 確認調撥（扣除來源庫存 + 增加目標庫存）
     */
    public function confirmTransfer(TransferOrder $transferOrder)
    {
        if ($transferOrder->status !== TransferOrder::STATUS_DRAFT) {
            return back()->with('error', __('Order already processed'));
        }

        DB::transaction(function () use ($transferOrder) {
            $transferOrder->loadMissing('items');

            foreach ($transferOrder->items as $item) {
                // 扣除來源庫存（僅 W2W）
                if ($transferOrder->type === TransferOrder::TYPE_W2W && $transferOrder->from_warehouse_id) {
                    $fromStock = WarehouseStock::where('warehouse_id', $transferOrder->from_warehouse_id)
                        ->where('product_id', $item->product_id)->first();

                    if (!$fromStock || $fromStock->quantity < $item->quantity) {
                        throw new \Exception(__('Insufficient stock for transfer'));
                    }

                    $beforeFrom = $fromStock->quantity;
                    $fromStock->decrement('quantity', $item->quantity);

                    StockMovement::create([
                        'company_id' => $transferOrder->company_id,
                        'warehouse_id' => $transferOrder->from_warehouse_id,
                        'product_id' => $item->product_id,
                        'type' => 'transfer_out',
                        'quantity' => $item->quantity,
                        'before_qty' => $beforeFrom,
                        'after_qty' => $beforeFrom - $item->quantity,
                        'reference_type' => TransferOrder::class,
                        'reference_id' => $transferOrder->id,
                        'note' => __('Transfer out') . ' #' . $transferOrder->order_no,
                        'created_by' => Auth::id(),
                        'created_at' => now(),
                    ]);
                }

                // 增加目標倉庫庫存
                $toStock = WarehouseStock::firstOrCreate(
                    ['warehouse_id' => $transferOrder->to_warehouse_id, 'product_id' => $item->product_id],
                    ['quantity' => 0, 'safety_stock' => 0]
                );
                $beforeTo = $toStock->quantity;
                $toStock->increment('quantity', $item->quantity);

                StockMovement::create([
                    'company_id' => $transferOrder->company_id,
                    'warehouse_id' => $transferOrder->to_warehouse_id,
                    'product_id' => $item->product_id,
                    'type' => 'transfer_in',
                    'quantity' => $item->quantity,
                    'before_qty' => $beforeTo,
                    'after_qty' => $beforeTo + $item->quantity,
                    'reference_type' => TransferOrder::class,
                    'reference_id' => $transferOrder->id,
                    'note' => __('Transfer in') . ' #' . $transferOrder->order_no,
                    'created_by' => Auth::id(),
                    'created_at' => now(),
                ]);
            }

            $transferOrder->update([
                'status' => TransferOrder::STATUS_COMPLETED,
                'completed_at' => now(),
            ]);
        });

        return back()->with('success', __('Transfer completed'));
    }

    // ─── 模組 4：機台庫存總覽 ───

    public function machineInventory(Request $request)
    {
        $query = Machine::with(['slots' => fn($q) => $q->with('product:id,name,image_url')->orderByRaw('CAST(slot_no AS UNSIGNED) ASC')])
            ->withCount('slots as total_slots')
            ->withSum('slots as total_stock', 'stock');

        if ($search = $request->input('search')) {
            $query->where(function ($q) use ($search) {
                $q->where('name', 'like', "%{$search}%")
                    ->orWhere('serial_no', 'like', "%{$search}%");
            });
        }

        $machines = $query->orderBy('name')
            ->paginate($request->input('per_page', 10))
            ->withQueryString();

        return view('admin.warehouses.machine-inventory', compact('machines'));
    }

    /**
     * AJAX：取得單台機台貨道詳情
     */
    public function machineSlots(Machine $machine)
    {
        $slots = $machine->slots()
            ->with('product:id,name,image_url')
            ->orderByRaw('CAST(slot_no AS UNSIGNED) ASC')
            ->get();

        return response()->json(['success' => true, 'slots' => $slots]);
    }

    // ─── 模組 5：機台補貨 ───

    public function replenishments(Request $request)
    {
        $query = ReplenishmentOrder::with(['warehouse:id,name', 'machine:id,name,serial_no', 'assignee:id,name', 'creator:id,name'])
            ->withCount('items')
            ->latest();

        if ($request->filled('status')) {
            $query->where('status', $request->input('status'));
        }

        $orders = $query->paginate(10)->withQueryString();
        $warehouses = Warehouse::active()->orderBy('name')->get(['id', 'name']);
        $machines = Machine::orderBy('name')->get(['id', 'name', 'serial_no']);

        return view('admin.warehouses.replenishments', compact('orders', 'warehouses', 'machines'));
    }

    /**
     * 建立補貨單
     */
    public function storeReplenishment(Request $request)
    {
        $validated = $request->validate([
            'warehouse_id' => 'required|exists:warehouses,id',
            'machine_id' => 'required|exists:machines,id',
            'note' => 'nullable|string|max:500',
            'items' => 'required|array|min:1',
            'items.*.product_id' => 'required|exists:products,id',
            'items.*.slot_no' => 'required|integer',
            'items.*.quantity' => 'required|integer|min:1',
        ]);

        DB::transaction(function () use ($validated) {
            $order = ReplenishmentOrder::create([
                'company_id' => Auth::user()->company_id,
                'order_no' => 'RP-' . now()->format('Ymd') . '-' . str_pad(ReplenishmentOrder::whereDate('created_at', today())->count() + 1, 4, '0', STR_PAD_LEFT),
                'warehouse_id' => $validated['warehouse_id'],
                'machine_id' => $validated['machine_id'],
                'status' => ReplenishmentOrder::STATUS_PENDING,
                'note' => $validated['note'] ?? null,
                'created_by' => Auth::id(),
            ]);

            foreach ($validated['items'] as $item) {
                $order->items()->create($item);
            }
        });

        return redirect()->route('admin.warehouses.replenishments')
            ->with('success', __('Replenishment order created'));
    }

    /**
     * 確認補貨完成（扣倉庫庫存 + 增加機台貨道庫存）
     */
    public function confirmReplenishment(ReplenishmentOrder $replenishmentOrder)
    {
        if ($replenishmentOrder->status === ReplenishmentOrder::STATUS_COMPLETED) {
            return back()->with('error', __('Order already completed'));
        }

        DB::transaction(function () use ($replenishmentOrder) {
            $replenishmentOrder->loadMissing('items');

            foreach ($replenishmentOrder->items as $item) {
                // 扣除倉庫庫存
                $stock = WarehouseStock::where('warehouse_id', $replenishmentOrder->warehouse_id)
                    ->where('product_id', $item->product_id)->first();

                if ($stock && $stock->quantity >= $item->quantity) {
                    $before = $stock->quantity;
                    $stock->decrement('quantity', $item->quantity);

                    StockMovement::create([
                        'company_id' => $replenishmentOrder->company_id,
                        'warehouse_id' => $replenishmentOrder->warehouse_id,
                        'product_id' => $item->product_id,
                        'type' => 'out',
                        'quantity' => $item->quantity,
                        'before_qty' => $before,
                        'after_qty' => $before - $item->quantity,
                        'reference_type' => ReplenishmentOrder::class,
                        'reference_id' => $replenishmentOrder->id,
                        'note' => __('Replenishment') . ' #' . $replenishmentOrder->order_no,
                        'created_by' => Auth::id(),
                        'created_at' => now(),
                    ]);
                }

                // 增加機台貨道庫存
                MachineSlot::where('machine_id', $replenishmentOrder->machine_id)
                    ->where('slot_no', $item->slot_no)
                    ->increment('stock', $item->quantity);
            }

            $replenishmentOrder->update([
                'status' => ReplenishmentOrder::STATUS_COMPLETED,
                'completed_at' => now(),
            ]);
        });

        return back()->with('success', __('Replenishment completed'));
    }
}