<?php

namespace App\Http\Controllers\Public;

use App\Http\Controllers\Controller;
use App\Models\Participant;
use App\Models\ProgramQrCode;
use App\Models\QuestionnaireResponse;
use App\Models\QuestionnaireAnswer;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Collection;
use Illuminate\View\View;

class QuestionnaireController extends Controller
{
    public function show(string $qr_token, string $participant_uuid): View|RedirectResponse
    {
        $qrCode = ProgramQrCode::where('token', $qr_token)->where('is_active', true)->firstOrFail();
        $program = $qrCode->program;

        $participant = Participant::where('uuid', $participant_uuid)->firstOrFail();

        $pp = $program->programParticipants()->where('participant_id', $participant->id)->first();
        abort_if(! $pp, 404);

        $pq = $program->questionnaire()->with('questionnaireSet')->first();

        if (! $pq || ! $pq->is_confirmed) {
            return redirect()->route('public.semak.show', $qr_token);
        }

        if (QuestionnaireResponse::where('program_id', $program->id)->where('participant_id', $participant->id)->exists()) {
            return view('public.questionnaire.already', compact('program', 'participant', 'qrCode'));
        }

        $questions = $this->loadHierarchical($pq);

        return view('public.questionnaire.show', compact('program', 'participant', 'qrCode', 'pq', 'questions'));
    }

    public function submit(Request $request, string $qr_token, string $participant_uuid): View|RedirectResponse
    {
        $qrCode = ProgramQrCode::where('token', $qr_token)->where('is_active', true)->firstOrFail();
        $program = $qrCode->program;

        $participant = Participant::where('uuid', $participant_uuid)->firstOrFail();

        $pp = $program->programParticipants()->where('participant_id', $participant->id)->first();
        abort_if(! $pp, 404);

        $pq = $program->questionnaire()->with('questionnaireSet')->first();
        abort_if(! $pq || ! $pq->is_confirmed, 404);

        if (QuestionnaireResponse::where('program_id', $program->id)->where('participant_id', $participant->id)->exists()) {
            return view('public.questionnaire.already', compact('program', 'participant', 'qrCode'));
        }

        $questions  = $this->loadHierarchical($pq);
        $answerable = $this->flatten($questions);

        $rules = [];
        foreach ($answerable as $q) {
            if ($q->question_type === 'multiple_choice') {
                $rules['q_' . $q->id] = ($q->is_required ? 'required|' : 'nullable|') . 'array';
            } else {
                $rules['q_' . $q->id] = $q->is_required ? 'required' : 'nullable';
            }
        }

        $request->validate($rules, ['q_*.required' => 'Soalan ini wajib dijawab.']);

        $response = QuestionnaireResponse::create([
            'program_id'           => $program->id,
            'participant_id'       => $participant->id,
            'questionnaire_set_id' => $pq->questionnaire_set_id,
            'submitted_at'         => now(),
            'ip_address'           => $request->ip(),
            'user_agent'           => substr($request->userAgent() ?? '', 0, 500),
        ]);

        foreach ($answerable as $q) {
            $raw = $request->input('q_' . $q->id);

            if ($raw === null && ! $q->is_required) {
                continue;
            }

            $value = match ($q->question_type) {
                'multiple_choice' => (array) $raw,
                'rating'          => (int) $raw,
                default           => $raw,
            };

            QuestionnaireAnswer::create([
                'questionnaire_response_id' => $response->id,
                'questionnaire_question_id' => $q->id,
                'answer_value'              => $value,
            ]);
        }

        return view('public.questionnaire.thankyou', compact('program', 'participant', 'qrCode'));
    }

    // ── Helpers ──────────────────────────────────────────────────────────────

    private function loadHierarchical($pq): Collection
    {
        return $pq->questionnaireSet->questions()
            ->whereNull('parent_id')
            ->with(['children' => fn($q) => $q->orderBy('sort_order')])
            ->orderBy('sort_order')
            ->get();
    }

    /** Return only answerable (non-tajuk) questions as a flat collection. */
    private function flatten(Collection $topLevel): Collection
    {
        $out = collect();
        foreach ($topLevel as $q) {
            if ($q->question_type === 'tajuk') {
                foreach ($q->children as $child) {
                    $out->push($child);
                }
            } else {
                $out->push($q);
            }
        }
        return $out;
    }
}