<?php

declare(strict_types=1);

namespace App\Http\Controllers\Api\V1;

use App\Enums\PersonStatus;
use App\Enums\ShiftAssignmentStatus;
use App\Http\Controllers\Controller;
use App\Http\Requests\Api\V1\BulkApproveShiftAssignmentRequest;
use App\Http\Requests\Api\V1\RejectShiftAssignmentRequest;
use App\Http\Resources\Api\V1\ShiftAssignmentResource;
use App\Models\Event;
use App\Models\Person;
use App\Models\Shift;
use App\Models\ShiftAssignment;
use App\Services\ShiftAssignmentService;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Http\Resources\Json\AnonymousResourceCollection;
use Illuminate\Support\Facades\Gate;

final class ShiftAssignmentController extends Controller
{
    public function __construct(
        private readonly ShiftAssignmentService $service,
    ) {}

    public function index(Request $request, Event $event): AnonymousResourceCollection
    {
        Gate::authorize('viewAny', [ShiftAssignment::class, $event]);

        $query = ShiftAssignment::query()
            ->whereHas('shift.festivalSection', fn ($q) => $q->where('event_id', $event->id))
            ->with(['person', 'shift.festivalSection', 'shift.timeSlot']);

        if ($request->filled('status')) {
            $status = ShiftAssignmentStatus::tryFrom($request->string('status')->toString());
            if ($status !== null) {
                $query->where('status', $status);
            }
        }

        if ($request->filled('shift_id')) {
            $query->where('shift_id', $request->string('shift_id')->toString());
        }

        if ($request->filled('person_id')) {
            $query->where('person_id', $request->string('person_id')->toString());
        }

        if ($request->filled('section_id')) {
            $query->whereHas('shift', fn ($q) => $q->where('festival_section_id', $request->string('section_id')->toString()));
        }

        $assignments = $query->orderByDesc('created_at')->paginate(50);

        return ShiftAssignmentResource::collection($assignments);
    }

    public function approve(Event $event, ShiftAssignment $shiftAssignment): JsonResponse
    {
        Gate::authorize('approve', [$shiftAssignment, $event]);

        $shiftAssignment = $this->service->approve($shiftAssignment, request()->user());

        return $this->success(new ShiftAssignmentResource($shiftAssignment->load(['person', 'shift.festivalSection', 'shift.timeSlot'])));
    }

    public function reject(RejectShiftAssignmentRequest $request, Event $event, ShiftAssignment $shiftAssignment): JsonResponse
    {
        Gate::authorize('reject', [$shiftAssignment, $event]);

        $shiftAssignment = $this->service->reject(
            $shiftAssignment,
            $request->user(),
            $request->validated('reason'),
        );

        return $this->success(new ShiftAssignmentResource($shiftAssignment->load(['person', 'shift.festivalSection', 'shift.timeSlot'])));
    }

    public function cancel(Event $event, ShiftAssignment $shiftAssignment): JsonResponse
    {
        Gate::authorize('cancel', [$shiftAssignment, $event]);

        $shiftAssignment = $this->service->cancel($shiftAssignment, request()->user());

        return $this->success(new ShiftAssignmentResource($shiftAssignment->load(['person', 'shift.festivalSection', 'shift.timeSlot'])));
    }

    public function bulkApprove(BulkApproveShiftAssignmentRequest $request, Event $event): JsonResponse
    {
        Gate::authorize('bulkApprove', [ShiftAssignment::class, $event]);

        $assignments = ShiftAssignment::whereIn('id', $request->validated('assignment_ids'))
            ->with('shift')
            ->get();

        $results = $this->service->bulkApprove($assignments, $request->user());

        return $this->success($results);
    }

    public function assignablePersons(Event $event, Shift $shift): JsonResponse
    {
        Gate::authorize('viewAny', [ShiftAssignment::class, $event]);

        $festivalEventId = $event->parent_event_id ?? $event->id;
        $timeSlotId = $shift->time_slot_id;
        $shiftId = $shift->id;

        // Get all conflict assignments for this time slot in one query
        $conflicts = ShiftAssignment::where('time_slot_id', $timeSlotId)
            ->whereIn('status', [
                ShiftAssignmentStatus::PENDING_APPROVAL,
                ShiftAssignmentStatus::APPROVED,
            ])
            ->with(['shift.festivalSection', 'shift.timeSlot'])
            ->get()
            ->keyBy('person_id');

        // Get all assignments for THIS shift in one query
        $alreadyAssigned = ShiftAssignment::where('shift_id', $shiftId)
            ->whereNotIn('status', [
                ShiftAssignmentStatus::REJECTED,
                ShiftAssignmentStatus::CANCELLED,
            ])
            ->pluck('person_id')
            ->flip();

        $persons = Person::where('event_id', $festivalEventId)
            ->where('status', PersonStatus::APPROVED)
            ->with('crowdType')
            ->orderBy('name')
            ->get()
            ->map(function (Person $person) use ($conflicts, $alreadyAssigned, $shiftId) {
                $isAlreadyAssigned = $alreadyAssigned->has($person->id);
                $conflict = $conflicts->get($person->id);
                $hasConflict = $conflict && $conflict->shift_id !== $shiftId;

                return [
                    'id' => $person->id,
                    'name' => $person->name,
                    'email' => $person->email,
                    'status' => $person->status,
                    'crowd_type' => $person->crowdType ? [
                        'id' => $person->crowdType->id,
                        'name' => $person->crowdType->name,
                        'system_type' => $person->crowdType->system_type,
                    ] : null,
                    'is_available' => ! $hasConflict && ! $isAlreadyAssigned,
                    'already_assigned' => $isAlreadyAssigned,
                    'conflict' => $hasConflict ? [
                        'section_name' => $conflict->shift->festivalSection->name,
                        'shift_title' => $conflict->shift->title ?? $conflict->shift->festivalSection->name,
                        'time_slot_name' => $conflict->shift->timeSlot->name,
                        'time' => $conflict->shift->timeSlot->start_time
                            . '–' . $conflict->shift->timeSlot->end_time,
                    ] : null,
                ];
            })
            ->sortBy([
                ['already_assigned', 'asc'],
                ['is_available', 'desc'],
                ['name', 'asc'],
            ])
            ->values();

        return response()->json(['data' => $persons]);
    }
}