<?php

namespace App\Http\Controllers;

use App\Models\Employee;
use App\Models\StockMovement;
use App\Models\StockVariant;
use App\Models\UniformIssue;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class IssueController extends Controller
{
    public function index()
    {
        return view('issues.index', [
            'selectedEmployee' => old('employee_id') ? Employee::find(old('employee_id')) : null,
            'selectedVariant' => old('stock_variant_id') ? StockVariant::with('item')->find(old('stock_variant_id')) : null,
            'issues' => UniformIssue::with(['employee', 'variant.item'])->latest('issued_at')->paginate(15),
        ]);
    }

    public function employeeLookup(Request $request)
    {
        $term = trim((string) $request->query('q', ''));

        return response()->json(Employee::query()
            ->where('status', 'active')
            ->when($term, fn ($query) => $query->where(fn ($query) => $query
                ->where('name', 'like', "%{$term}%")
                ->orWhere('employee_no', 'like', "%{$term}%")
                ->orWhere('department', 'like', "%{$term}%")))
            ->orderBy('name')->limit(20)->get()
            ->map(fn ($employee) => [
                'id' => $employee->id,
                'title' => $employee->name,
                'subtitle' => "{$employee->employee_no} / {$employee->department}",
            ]));
    }

    public function variantLookup(Request $request)
    {
        $term = trim((string) $request->query('q', ''));

        return response()->json(StockVariant::query()->with('item')
            ->where('quantity', '>', 0)
            ->when($term, fn ($query) => $query->where(fn ($query) => $query
                ->where('size', 'like', "%{$term}%")
                ->orWhereHas('item', fn ($item) => $item->where('name', 'like', "%{$term}%")->orWhere('code', 'like', "%{$term}%"))))
            ->join('uniform_items', 'uniform_items.id', '=', 'stock_variants.uniform_item_id')
            ->orderBy('uniform_items.name')->orderBy('stock_variants.size')
            ->select('stock_variants.*')->limit(20)->get()
            ->map(fn ($variant) => [
                'id' => $variant->id,
                'title' => "{$variant->item->name} / Size {$variant->size}",
                'subtitle' => "{$variant->item->code} / {$variant->quantity} available",
            ]));
    }

    public function store(Request $request)
    {
        $data = $request->validate([
            'employee_id' => ['required', 'exists:employees,id'],
            'stock_variant_id' => ['required', 'exists:stock_variants,id'],
            'quantity' => ['required', 'integer', 'min:1'],
            'issued_at' => ['required', 'date'],
            'notes' => ['nullable', 'string', 'max:500'],
        ]);

        DB::transaction(function () use ($data) {
            $employee = Employee::lockForUpdate()->findOrFail($data['employee_id']);
            if ($employee->status !== 'active') {
                throw ValidationException::withMessages(['employee_id' => 'Uniforms can only be issued to active employees.']);
            }

            $variant = StockVariant::lockForUpdate()->findOrFail($data['stock_variant_id']);
            if ($variant->quantity < $data['quantity']) {
                throw ValidationException::withMessages(['quantity' => "Only {$variant->quantity} item(s) are available in this size."]);
            }

            $issue = UniformIssue::create($data);
            $returnedUsed = min($variant->returned_quantity, $data['quantity']);
            $newUsed = $data['quantity'] - $returnedUsed;
            $variant->decrement('quantity', $data['quantity']);
            if ($returnedUsed) {
                $variant->decrement('returned_quantity', $returnedUsed);
            }
            if ($newUsed) {
                $variant->decrement('new_quantity', $newUsed);
            }
            StockMovement::create([
                'stock_variant_id' => $variant->id,
                'employee_id' => $employee->id,
                'uniform_issue_id' => $issue->id,
                'type' => 'issue',
                'quantity_change' => -$data['quantity'],
                'stock_category' => $returnedUsed && $newUsed ? 'mixed' : ($returnedUsed ? 'returned' : 'new'),
                'unit_value' => $variant->unit_value,
                'notes' => "Issued to {$employee->name}",
            ]);
        });

        return back()->with('success', 'Uniform issued and stock adjusted.');
    }
}