<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Program;
use App\Models\Attendance;
use App\Models\Certificate;
use App\Models\QuestionnaireAnswer;
use App\Models\QuestionnaireQuestion;
use App\Models\QuestionnaireResponse;
use Illuminate\Http\Request;
use Illuminate\Http\Response;
use Illuminate\View\View;

class StatisticsController extends Controller
{
    public function show(Program $program): View
    {
        $program->load(['questionnaire.questionnaireSet.questions']);

        // Attendance by session
        $bySession = $program->attendances()
            ->selectRaw('attendance_session, COUNT(*) as total')
            ->groupBy('attendance_session')
            ->pluck('total', 'attendance_session')
            ->toArray();

        // Attendance by source
        $bySource = $program->attendances()
            ->selectRaw('attendance_source, COUNT(*) as total')
            ->groupBy('attendance_source')
            ->pluck('total', 'attendance_source')
            ->toArray();

        // Certificate status breakdown
        $certStats = $program->certificates()
            ->selectRaw('status, COUNT(*) as total')
            ->groupBy('status')
            ->pluck('total', 'status')
            ->toArray();

        // Response rate + question stats
        $pq = $program->questionnaire;
        $responseRate = null;
        $questionStats = [];
        $totalResponses = 0;

        if ($pq && $pq->is_confirmed) {
            $totalAttended = array_sum($bySession);  // reuse already-fetched data
            $totalResponses = QuestionnaireResponse::where('program_id', $program->id)->count();
            $responseRate = $totalAttended > 0 ? round($totalResponses / $totalAttended * 100) : 0;

            $questions = $pq->questionnaireSet->questions ?? collect();

            // Load ALL answers in one query, group by question — avoids N+1
            $allAnswers = QuestionnaireAnswer::whereIn('questionnaire_question_id', $questions->pluck('id'))
                ->get()
                ->groupBy('questionnaire_question_id');

            foreach ($questions as $q) {
                $answers = $allAnswers->get($q->id, collect());

                if ($q->question_type === 'rating') {
                    $values = $answers->map(fn($a) => is_array($a->answer_value) ? (int) ($a->answer_value[0] ?? 0) : (int) $a->answer_value);
                    $questionStats[] = [
                        'id'      => $q->id,
                        'text'    => $q->question_text,
                        'type'    => 'rating',
                        'average' => $values->count() > 0 ? round($values->avg(), 2) : null,
                        'count'   => $values->count(),
                    ];
                } elseif (in_array($q->question_type, ['single_choice', 'multiple_choice'])) {
                    $counts = [];
                    foreach ($answers as $row) {
                        $items = is_array($row->answer_value) ? $row->answer_value : [$row->answer_value];
                        foreach ($items as $item) {
                            $counts[$item] = ($counts[$item] ?? 0) + 1;
                        }
                    }
                    $questionStats[] = [
                        'id'      => $q->id,
                        'text'    => $q->question_text,
                        'type'    => $q->question_type,
                        'options' => $q->options_json ?? [],
                        'counts'  => $counts,
                        'total'   => $answers->count(),
                    ];
                }
            }
        }

        // Reuse data already computed above — no extra queries
        $summary = [
            'total_attendances'  => array_sum($bySession),
            'pre_registered'     => $bySource['pre_registered_staff'] ?? 0,
            'walk_in'            => $bySource['walk_in_external']     ?? 0,
            'total_certificates' => array_sum($certStats),
            'generated_certs'    => ($certStats['generated'] ?? 0) + ($certStats['emailed'] ?? 0) + ($certStats['downloaded'] ?? 0),
            'downloaded_certs'   => $certStats['downloaded'] ?? 0,
            'total_responses'    => $totalResponses,
        ];

        return view('admin.programs.statistics.show', compact(
            'program', 'summary', 'bySession', 'bySource',
            'certStats', 'responseRate', 'questionStats'
        ));
    }

    public function export(Program $program): Response
    {
        $rows = $program->attendances()
            ->with('participant')
            ->get()
            ->map(fn($a) => [
                $a->participant->name,
                $a->participant->agency ?: '',
                $a->attendance_session,
                $a->attendance_source,
                $a->checked_in_at->format('d/m/Y H:i'),
            ]);

        $csv = "\xEF\xBB\xBF";
        $csv .= implode(',', ['Nama', 'Agensi', 'Sesi', 'Sumber', 'Masa Check-In']) . "\n";
        foreach ($rows as $row) {
            $csv .= implode(',', array_map(fn($v) => '"' . str_replace('"', '""', $v) . '"', $row)) . "\n";
        }

        $filename = 'statistik-' . str($program->title)->slug() . '-' . now()->format('Ymd') . '.csv';

        return response($csv, 200, [
            'Content-Type'        => 'text/csv; charset=UTF-8',
            'Content-Disposition' => 'attachment; filename="' . $filename . '"',
        ]);
    }
}