<?php

namespace App\Services\Ppm;

use App\Models\Application;
use App\Models\Position;
use App\Models\PusatMengundi;
use App\Models\StaffAssignment;
use App\Models\User;
use App\Services\Public\KtmVacancyService;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class PpmApplicationReviewService
{
    /**
     * @param  array{approved_position_code: string, saluran_mengundi_id?: int|null, ktm_assignment_id?: int|null, note?: string|null}  $data
     */
    public function approve(Application $application, User $actor, array $data): StaffAssignment
    {
        return DB::transaction(function () use ($application, $actor, $data): StaffAssignment {
            $application->loadMissing(['documents', 'pusatMengundi', 'requestedPosition']);

            if (! $this->hasRequiredDocuments($application)) {
                throw ValidationException::withMessages([
                    'documents' => 'Permohonan hanya boleh diluluskan jika dokumen IC dan penyata bank telah dimuat naik.',
                ]);
            }

            if (! in_array($application->status, ['submitted', 'under_ppm_review', 'approved'], true)) {
                throw ValidationException::withMessages([
                    'status' => 'Status permohonan tidak membenarkan kelulusan.',
                ]);
            }

            $position = Position::query()
                ->where('code', $data['approved_position_code'])
                ->whereIn('code', ['KTM', 'KP', 'KPDP', 'PAPM'])
                ->firstOrFail();

            $assignmentContext = $this->assignmentContext($application, $position, $data);
            $previousStatus = $application->status;
            $previousPositionId = $application->approved_position_id ?: $application->requested_position_id;

            $application->forceFill([
                'status' => 'assigned',
                'approved_position_id' => $position->id,
                'approved_by_user_id' => $actor->id,
                'approved_at' => now(),
                'selected_ktm_assignment_id' => $assignmentContext['reports_to_assignment_id'],
            ])->save();

            $assignment = StaffAssignment::query()->updateOrCreate(
                ['application_id' => $application->id],
                [
                    'election_id' => $application->election_id,
                    'user_id' => $application->user_id,
                    'position_id' => $position->id,
                    'pusat_mengundi_id' => $application->pusat_mengundi_id,
                    'saluran_mengundi_id' => $assignmentContext['saluran_mengundi_id'],
                    'reports_to_assignment_id' => $assignmentContext['reports_to_assignment_id'],
                    'status' => 'active',
                    'assigned_by_user_id' => $actor->id,
                    'assigned_at' => now(),
                    'source' => 'ppm_approval',
                ],
            );

            $application->statusHistories()->create([
                'from_status' => $previousStatus,
                'to_status' => 'assigned',
                'changed_by_user_id' => $actor->id,
                'note' => $data['note'] ?? null,
                'metadata' => [
                    'approved_position_code' => $position->code,
                    'previous_position_id' => $previousPositionId,
                    'saluran_mengundi_id' => $assignmentContext['saluran_mengundi_id'],
                    'reports_to_assignment_id' => $assignmentContext['reports_to_assignment_id'],
                ],
            ]);

            $assignment->histories()->create([
                'from_position_id' => $previousPositionId,
                'to_position_id' => $position->id,
                'to_pusat_mengundi_id' => $application->pusat_mengundi_id,
                'to_saluran_mengundi_id' => $assignmentContext['saluran_mengundi_id'],
                'to_reports_to_assignment_id' => $assignmentContext['reports_to_assignment_id'],
                'changed_by_user_id' => $actor->id,
                'note' => $data['note'] ?? 'Application approved by PPM.',
            ]);

            if ($previousPositionId !== $position->id) {
                activity('ppm_review')
                    ->performedOn($application)
                    ->causedBy($actor)
                    ->withProperties([
                        'from_position_id' => $previousPositionId,
                        'to_position_id' => $position->id,
                    ])
                    ->log('application_role_changed_by_ppm');
            }

            activity('ppm_review')
                ->performedOn($application)
                ->causedBy($actor)
                ->withProperties([
                    'assignment_id' => $assignment->id,
                    'approved_position_code' => $position->code,
                    'saluran_mengundi_id' => $assignmentContext['saluran_mengundi_id'],
                    'reports_to_assignment_id' => $assignmentContext['reports_to_assignment_id'],
                ])
                ->log('application_approved_assigned_by_ppm');

            return $assignment;
        });
    }

    public function reject(Application $application, User $actor, string $reason): Application
    {
        return DB::transaction(function () use ($application, $actor, $reason): Application {
            if (! in_array($application->status, ['submitted', 'under_ppm_review', 'approved'], true)) {
                throw ValidationException::withMessages([
                    'status' => 'Status permohonan tidak membenarkan penolakan.',
                ]);
            }

            $previousStatus = $application->status;

            $application->forceFill([
                'status' => 'rejected',
                'rejected_by_user_id' => $actor->id,
                'rejected_at' => now(),
                'rejection_reason' => $reason,
            ])->save();

            $application->statusHistories()->create([
                'from_status' => $previousStatus,
                'to_status' => 'rejected',
                'changed_by_user_id' => $actor->id,
                'note' => $reason,
            ]);

            activity('ppm_review')
                ->performedOn($application)
                ->causedBy($actor)
                ->withProperties([
                    'reason' => $reason,
                ])
                ->log('application_rejected_by_ppm');

            return $application;
        });
    }

    private function hasRequiredDocuments(Application $application): bool
    {
        $types = $application->documents()
            ->whereIn('document_type', ['ic_document', 'bank_statement'])
            ->pluck('document_type')
            ->unique();

        return $types->contains('ic_document') && $types->contains('bank_statement');
    }

    /**
     * @param  array{approved_position_code: string, saluran_mengundi_id?: int|null, ktm_assignment_id?: int|null, note?: string|null}  $data
     * @return array{saluran_mengundi_id: int|null, reports_to_assignment_id: int|null}
     */
    private function assignmentContext(Application $application, Position $position, array $data): array
    {
        $pusatMengundi = $application->pusatMengundi;

        if (! $pusatMengundi instanceof PusatMengundi) {
            throw ValidationException::withMessages([
                'pusat_mengundi_id' => 'Pusat Mengundi permohonan tidak sah.',
            ]);
        }

        if ($position->code === 'PAPM') {
            if (! app(AssignmentVacancyService::class)->hasPusatVacancy($pusatMengundi, 'PAPM')) {
                throw ValidationException::withMessages([
                    'approved_position_code' => 'Kekosongan PAPM untuk Pusat Mengundi ini telah penuh.',
                ]);
            }

            return [
                'saluran_mengundi_id' => null,
                'reports_to_assignment_id' => null,
            ];
        }

        if ($position->code === 'KTM') {
            $saluranId = (int) ($data['saluran_mengundi_id'] ?? 0);

            if (! app(AssignmentVacancyService::class)->hasSaluranVacancy($pusatMengundi, $saluranId, 'KTM')) {
                throw ValidationException::withMessages([
                    'saluran_mengundi_id' => 'Saluran Mengundi yang dipilih tidak sah atau kekosongan KTM telah penuh.',
                ]);
            }

            return [
                'saluran_mengundi_id' => $saluranId,
                'reports_to_assignment_id' => null,
            ];
        }

        if (in_array($position->code, ['KP', 'KPDP'], true)) {
            $ktmAssignmentId = (int) ($data['ktm_assignment_id'] ?? 0);

            if (! app(KtmVacancyService::class)->hasVacancyForAssignment($ktmAssignmentId, $pusatMengundi, $position->code, $application->id)) {
                throw ValidationException::withMessages([
                    'ktm_assignment_id' => 'KTM yang dipilih tidak sah atau kekosongan jawatan ini telah penuh.',
                ]);
            }

            $ktmAssignment = StaffAssignment::query()->findOrFail($ktmAssignmentId);

            return [
                'saluran_mengundi_id' => $ktmAssignment->saluran_mengundi_id,
                'reports_to_assignment_id' => $ktmAssignment->id,
            ];
        }

        throw ValidationException::withMessages([
            'approved_position_code' => 'Jawatan yang dipilih tidak sah untuk kelulusan PPM.',
        ]);
    }
}