<?php

namespace App\Http\Controllers;

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

class HandoverController extends Controller
{
    public function index()
    {
        return view('handovers.index', [
            'employees' => Employee::where('status', 'active')->whereHas('issues', fn ($q) => $q->where('status', 'issued'))->orderBy('name')->get(),
            'handovers' => Handover::with(['employee', 'items.issue.variant.item'])->latest('handover_date')->get(),
        ]);
    }

    public function create(Employee $employee)
    {
        $employee->load(['issues' => fn ($q) => $q->where('status', 'issued')->with('variant.item')]);
        abort_if($employee->status !== 'active', 422, 'This employee has already left.');

        return view('handovers.create', compact('employee'));
    }

    public function store(Request $request, Employee $employee)
    {
        $data = $request->validate([
            'handover_date' => ['required', 'date'],
            'notes' => ['nullable', 'string', 'max:1000'],
            'items' => ['required', 'array'],
            'items.*.issue_id' => ['required', 'integer', 'distinct', 'exists:uniform_issues,id'],
            'items.*.condition' => ['required', Rule::in(['reusable', 'damaged', 'not_returned'])],
        ]);

        DB::transaction(function () use ($data, $employee) {
            $lockedEmployee = Employee::lockForUpdate()->findOrFail($employee->id);
            if ($lockedEmployee->status !== 'active') {
                throw ValidationException::withMessages(['employee' => 'This employee has already completed handover.']);
            }

            $openIssues = UniformIssue::where('employee_id', $employee->id)->where('status', 'issued')->lockForUpdate()->get()->keyBy('id');
            if ($openIssues->count() !== count($data['items'])) {
                throw ValidationException::withMessages(['items' => 'Every outstanding uniform must be accounted for before handover is completed.']);
            }

            $handover = Handover::create(['employee_id' => $employee->id, 'handover_date' => $data['handover_date'], 'notes' => $data['notes'] ?? null]);

            foreach ($data['items'] as $itemData) {
                $issue = $openIssues->get($itemData['issue_id']);
                if (! $issue) {
                    throw ValidationException::withMessages(['items' => 'An invalid issue was submitted.']);
                }
                $quantity = $issue->outstanding_quantity;
                $handover->items()->create(['uniform_issue_id' => $issue->id, 'quantity' => $quantity, 'condition' => $itemData['condition']]);

                if ($itemData['condition'] === 'reusable') {
                    $variant = $issue->variant()->lockForUpdate()->first();
                    $variant->increment('quantity', $quantity);
                    $variant->increment('returned_quantity', $quantity);
                    StockMovement::create([
                        'stock_variant_id' => $issue->stock_variant_id,
                        'employee_id' => $employee->id,
                        'uniform_issue_id' => $issue->id,
                        'type' => 'return',
                        'quantity_change' => $quantity,
                        'stock_category' => 'returned',
                        'unit_value' => $variant->unit_value,
                        'notes' => 'Reusable return during employee exit handover',
                    ]);
                }

                $issue->update(['returned_quantity' => $issue->quantity, 'status' => $itemData['condition'] === 'not_returned' ? 'not_returned' : 'returned']);
            }

            $lockedEmployee->update(['status' => 'left', 'left_at' => $data['handover_date']]);
        });

        return redirect()->route('handovers.index')->with('success', 'Handover completed and employee marked as left.');
    }
}