<?php

namespace App\Http\Controllers;

use App\Models\Course;
use App\Models\Lesson;
use App\Models\UserProgress;
use Illuminate\Http\Request;
use Inertia\Inertia;
use Inertia\Response;

class ExamController extends Controller
{
    /**
     * Show the exam interface.
     */
    public function show(Request $request, string $courseSlug, string $lessonSlug): Response
    {
        $user = $request->user();
        
        $course = Course::where('slug', $courseSlug)->firstOrFail();
        $lesson = Lesson::where('slug', $lessonSlug)->where('type', 'quiz')->firstOrFail();

        // Check if already completed
        $progress = UserProgress::where('user_id', $user->id)
            ->where('lesson_id', $lesson->id)
            ->first();

        $previousResut = null;
        if ($progress && $progress->completed_at) {
            $previousResut = $progress->metadata['score'] ?? 0;
        }

        // Parse questions from metadata
        // Assuming structure: metadata->questions = [{ id, question, options[], correct_answer }]
        // We do NOT send 'correct_answer' to frontend
        $questions = collect($lesson->metadata['questions'] ?? [])->map(function ($q) {
            return [
                'id' => $q['id'],
                'question' => $q['question'],
                'options' => $q['options'],
            ];
        });

        // Use same layout data as CoursePlayer (simplified modules list)
        // Ideally refactor this shared logic or use a Service
        $modules = $course->modules()->with('lessons')->get()->map(function ($module) use ($user) {
            return [
                'id' => $module->id,
                'title' => $module->title,
                'lessons' => $module->lessons->map(function ($l) {
                     return [
                        'id' => $l->id,
                        'title' => $l->title,
                        'slug' => $l->slug,
                        'type' => $l->type,
                        'is_completed' => false // Simplified for now
                     ];
                })
            ];
        });

        return Inertia::render('Courses/Exam', [
            'course' => [
                'title' => $course->title,
                'slug' => $course->slug,
            ],
            'modules' => $modules,
            'lesson' => [
                'id' => $lesson->id,
                'title' => $lesson->title,
                'slug' => $lesson->slug,
                'questions' => $questions,
            ],
            'previousResult' => $previousResut,
        ]);
    }

    /**
     * Handle exam submission.
     */
    public function store(Request $request, string $courseSlug, string $lessonSlug)
    {
        $lesson = Lesson::where('slug', $lessonSlug)->firstOrFail();
        $user = $request->user();

        $answers = $request->input('answers', []); // [question_id => selected_option]
        $questions = $lesson->metadata['questions'] ?? [];

        $score = 0;
        $total = count($questions);
        $correctAnswers = 0;

        foreach ($questions as $q) {
            $userAnswer = $answers[$q['id']] ?? null;
            if ($userAnswer === $q['correct_answer']) {
                $correctAnswers++;
            }
        }

        $minPassPercentage = 70; // Hardcoded requirement for certificate
        $accuracy = ($total > 0) ? round(($correctAnswers / $total) * 100) : 0;
        
        $passed = $accuracy >= $minPassPercentage;

        // Save progress with score
        UserProgress::updateOrCreate(
            ['user_id' => $user->id, 'lesson_id' => $lesson->id],
            [
                'completed_at' => $passed ? now() : null, // Only mark complete if passed? Or mark complete but with failing score? Let's say only if passed.
                'metadata' => [
                    'score' => $accuracy,
                    'answers' => $answers, // Store user answers if needed for review
                    'passed' => $passed
                ]
            ]
        );

        if ($passed) {
             $user->increment('xp_points', 100);
        }

        return back()->with('flash', [
            'score' => $accuracy,
            'passed' => $passed,
            'message' => $passed ? 'Selamat! Anda lulus ujian.' : 'Maaf, nilai anda belum mencukupi. Silahkan coba lagi.'
        ]);
    }
}