'use client';

import { useState } from 'react';
import { useLocale } from './LocaleProvider';
import { ts } from '@/lib/i18n';

interface QuizQuestion {
  question: Record<string, string>;
  options: Record<string, string[]>;
  correctIndex: number;
  explanation: Record<string, string>;
}

const QUESTIONS: QuizQuestion[] = [
  {
    question: {
      en: 'How long is one complete lunar cycle (synodic month)?',
      fr: 'Quelle est la durée d\'un cycle lunaire complet (mois synodique) ?',
    },
    options: {
      en: ['27.32 days', '28 days', '29.53 days', '30 days'],
      fr: ['27,32 jours', '28 jours', '29,53 jours', '30 jours'],
    },
    correctIndex: 2,
    explanation: {
      en: 'The synodic month lasts 29.53 days — the time between two identical phases (e.g., full moon to full moon).',
      fr: 'Le mois synodique dure 29,53 jours — le temps entre deux phases identiques.',
    },
  },
  {
    question: {
      en: 'What is the traditional name for the September full moon?',
      fr: 'Quel est le nom traditionnel de la pleine lune de septembre ?',
    },
    options: {
      en: ['Wolf Moon', 'Harvest Moon', 'Hunter\'s Moon', 'Blood Moon'],
      fr: ['Lune du Loup', 'Lune des Moissons', 'Lune du Chasseur', 'Lune de Sang'],
    },
    correctIndex: 1,
    explanation: {
      en: 'The Harvest Moon rises near sunset during harvest season, providing extra light for farmers.',
      fr: 'La Lune des Moissons se lève près du coucher du soleil, offrant de la lumière aux agriculteurs.',
    },
  },
  {
    question: {
      en: 'What causes the tides on Earth?',
      fr: 'Qu\'est-ce qui cause les marées sur Terre ?',
    },
    options: {
      en: ['Wind', 'Earth\'s rotation only', 'Gravitational pull of Moon and Sun', 'Ocean currents'],
      fr: ['Le vent', 'La rotation terrestre seule', 'L\'attraction gravitationnelle de la Lune et du Soleil', 'Les courants océaniques'],
    },
    correctIndex: 2,
    explanation: {
      en: 'Tides are primarily caused by the gravitational pull of the Moon and, to a lesser extent, the Sun.',
      fr: 'Les marées sont principalement causées par l\'attraction gravitationnelle de la Lune et du Soleil.',
    },
  },
  {
    question: {
      en: 'During which moon phase do we see the most light?',
      fr: 'Pendant quelle phase voit-on le plus de lumière ?',
    },
    options: {
      en: ['New Moon', 'First Quarter', 'Full Moon', 'Waning Crescent'],
      fr: ['Nouvelle Lune', 'Premier Quartier', 'Pleine Lune', 'Croissant Décroissant'],
    },
    correctIndex: 2,
    explanation: {
      en: 'The full moon is 100% illuminated, reflecting maximum sunlight toward Earth.',
      fr: 'La pleine lune est illuminée à 100%, reflétant le maximum de lumière solaire.',
    },
  },
  {
    question: {
      en: 'What is a "supermoon"?',
      fr: 'Qu\'est-ce qu\'une "super lune" ?',
    },
    options: {
      en: ['A moon larger than usual', 'A full moon at its closest point to Earth (perigee)', 'Two full moons in one month', 'A full moon during an eclipse'],
      fr: ['Une lune plus grande que d\'habitude', 'Une pleine lune au point le plus proche de la Terre (périgée)', 'Deux pleines lunes dans un mois', 'Une pleine lune pendant une éclipse'],
    },
    correctIndex: 1,
    explanation: {
      en: 'A supermoon occurs when the full moon coincides with perigee, appearing about 14% bigger and 30% brighter.',
      fr: 'Une super lune se produit quand la pleine lune coïncide avec le périgée, paraissant ~14% plus grande.',
    },
  },
  {
    question: {
      en: 'How much of the Moon\'s surface can we see from Earth?',
      fr: 'Quelle proportion de la surface lunaire peut-on voir depuis la Terre ?',
    },
    options: {
      en: ['50%', '41%', '59%', '100%'],
      fr: ['50%', '41%', '59%', '100%'],
    },
    correctIndex: 2,
    explanation: {
      en: 'Due to libration (slight wobble), we can see about 59% of the Moon\'s surface over time, though only 50% at any given moment.',
      fr: 'Grâce à la libration, on peut voir environ 59% de la surface lunaire au fil du temps.',
    },
  },
  {
    question: {
      en: 'What are "spring tides"?',
      fr: 'Que sont les "vives-eaux" ?',
    },
    options: {
      en: ['Tides in springtime', 'Extra high tides during full and new moons', 'Tides caused by storms', 'Low tides only'],
      fr: ['Les marées au printemps', 'Marées extra hautes pendant pleine et nouvelle lune', 'Marées causées par les tempêtes', 'Marées basses uniquement'],
    },
    correctIndex: 1,
    explanation: {
      en: 'Spring tides occur when Moon and Sun align (full and new moon), creating the highest and lowest tides.',
      fr: 'Les vives-eaux se produisent quand Lune et Soleil sont alignés, créant les marées les plus extrêmes.',
    },
  },
  {
    question: {
      en: 'Why does the Moon always show the same face to Earth?',
      fr: 'Pourquoi la Lune montre-t-elle toujours la même face à la Terre ?',
    },
    options: {
      en: ['It doesn\'t rotate', 'Tidal locking — rotation period equals orbital period', 'It\'s a coincidence', 'Earth\'s magnetic field keeps it locked'],
      fr: ['Elle ne tourne pas', 'Verrouillage gravitationnel — période de rotation = période orbitale', 'C\'est une coïncidence', 'Le champ magnétique terrestre la maintient'],
    },
    correctIndex: 1,
    explanation: {
      en: 'Tidal locking means the Moon rotates on its axis in the same time it takes to orbit Earth (~27.3 days).',
      fr: 'Le verrouillage gravitationnel fait que la Lune tourne sur elle-même en même temps qu\'elle orbite la Terre.',
    },
  },
  {
    question: {
      en: 'What is a "blue moon"?',
      fr: 'Qu\'est-ce qu\'une "lune bleue" ?',
    },
    options: {
      en: ['A moon that appears blue', 'The second full moon in a calendar month', 'A lunar eclipse', 'A new moon visible during daytime'],
      fr: ['Une lune de couleur bleue', 'La deuxième pleine lune dans un mois', 'Une éclipse lunaire', 'Une nouvelle lune visible le jour'],
    },
    correctIndex: 1,
    explanation: {
      en: 'A blue moon is the second full moon in a single calendar month, occurring roughly every 2.7 years.',
      fr: 'Une lune bleue est la deuxième pleine lune d\'un même mois, survenant environ tous les 2,7 ans.',
    },
  },
  {
    question: {
      en: 'What is the Moon\'s average distance from Earth?',
      fr: 'Quelle est la distance moyenne Terre-Lune ?',
    },
    options: {
      en: ['238,900 miles (384,400 km)', '150,000 miles (241,000 km)', '500,000 miles (800,000 km)', '93 million miles (150 million km)'],
      fr: ['384 400 km', '241 000 km', '800 000 km', '150 millions km'],
    },
    correctIndex: 0,
    explanation: {
      en: 'The Moon orbits at an average distance of 384,400 km (238,900 miles) from Earth.',
      fr: 'La Lune orbite à une distance moyenne de 384 400 km de la Terre.',
    },
  },
];

export default function Quiz() {
  const { locale } = useLocale();
  const lang = (locale === 'fr') ? 'fr' : 'en';

  const [started, setStarted] = useState(false);
  const [currentQ, setCurrentQ] = useState(0);
  const [selected, setSelected] = useState<number | null>(null);
  const [score, setScore] = useState(0);
  const [finished, setFinished] = useState(false);
  const [answered, setAnswered] = useState(false);

  const question = QUESTIONS[currentQ];

  const handleSelect = (index: number) => {
    if (answered) return;
    setSelected(index);
    setAnswered(true);
    if (index === question.correctIndex) {
      setScore(s => s + 1);
    }
  };

  const handleNext = () => {
    if (currentQ + 1 >= QUESTIONS.length) {
      setFinished(true);
    } else {
      setCurrentQ(q => q + 1);
      setSelected(null);
      setAnswered(false);
    }
  };

  const restart = () => {
    setStarted(true);
    setCurrentQ(0);
    setSelected(null);
    setScore(0);
    setFinished(false);
    setAnswered(false);
  };

  const scorePercentage = Math.round((score / QUESTIONS.length) * 100);
  const getScoreMessage = () => {
    if (scorePercentage >= 90) return locale === 'fr' ? '🏆 Expert lunaire !' : '🏆 Lunar Expert!';
    if (scorePercentage >= 70) return locale === 'fr' ? '🌟 Très bien !' : '🌟 Great job!';
    if (scorePercentage >= 50) return locale === 'fr' ? '👍 Pas mal !' : '👍 Not bad!';
    return locale === 'fr' ? '📚 À réviser !' : '📚 Keep learning!';
  };

  return (
    <section id="quiz" aria-label="Moon Knowledge Quiz" className="section-container">
      <div className="text-center mb-10">
        <h2 className="section-title">{ts('quiz_title', locale)}</h2>
        <p className="section-subtitle mx-auto">{ts('quiz_subtitle', locale)}</p>
      </div>

      <div className="glass-card max-w-2xl mx-auto p-4 sm:p-6 md:p-8">
        {!started ? (
          <div className="text-center">
            <p className="text-6xl mb-6">🌙</p>
            <p className="text-lg text-white/60 mb-8">
              {QUESTIONS.length} {locale === 'fr' ? 'questions sur la lune et ses mystères' : 'questions about the moon and its mysteries'}
            </p>
            <button onClick={() => setStarted(true)} className="glow-btn text-lg px-8 py-3">
              {ts('quiz_start', locale)}
            </button>
          </div>
        ) : finished ? (
          <div className="text-center">
            <p className="text-6xl mb-4">{scorePercentage >= 70 ? '🎉' : '🌙'}</p>
            <h3 className="text-2xl font-bold mb-2">{ts('quiz_results', locale)}</h3>
            <p className="text-4xl font-bold text-indigo-300 mb-2">{score}/{QUESTIONS.length}</p>
            <p className="text-lg text-white/60 mb-2">{scorePercentage}%</p>
            <p className="text-xl mb-8">{getScoreMessage()}</p>

            {/* Score bar */}
            <div className="w-full h-3 bg-white/10 rounded-full mb-8 max-w-xs mx-auto">
              <div
                className={`h-full rounded-full transition-all duration-1000 ${
                  scorePercentage >= 70 ? 'bg-green-400' : scorePercentage >= 50 ? 'bg-yellow-400' : 'bg-red-400'
                }`}
                style={{ width: `${scorePercentage}%` }}
              />
            </div>

            <button onClick={restart} className="glow-btn">
              {ts('quiz_restart', locale)}
            </button>
          </div>
        ) : (
          <>
            {/* Progress */}
            <div className="flex items-center justify-between mb-6">
              <span className="text-sm text-white/40">
                {currentQ + 1}/{QUESTIONS.length}
              </span>
              <div className="flex-1 mx-4 h-1.5 bg-white/10 rounded-full">
                <div
                  className="h-full bg-indigo-400 rounded-full transition-all duration-300"
                  style={{ width: `${((currentQ + 1) / QUESTIONS.length) * 100}%` }}
                />
              </div>
              <span className="text-sm text-indigo-300">{ts('quiz_score', locale)}: {score}</span>
            </div>

            {/* Question */}
            <h3 className="text-xl font-semibold mb-6">
              {question.question[lang] || question.question.en}
            </h3>

            {/* Options */}
            <div className="space-y-3 mb-6">
              {(question.options[lang] || question.options.en).map((option, i) => (
                <button
                  key={i}
                  onClick={() => handleSelect(i)}
                  className={`quiz-option w-full text-left ${
                    answered
                      ? i === question.correctIndex
                        ? 'correct'
                        : i === selected
                        ? 'wrong'
                        : ''
                      : ''
                  }`}
                >
                  <span className="flex items-center gap-3">
                    <span className={`w-8 h-8 rounded-full flex items-center justify-center text-sm font-bold border ${
                      answered && i === question.correctIndex
                        ? 'bg-green-500/20 border-green-400 text-green-300'
                        : answered && i === selected
                        ? 'bg-red-500/20 border-red-400 text-red-300'
                        : 'border-white/20 text-white/50'
                    }`}>
                      {String.fromCharCode(65 + i)}
                    </span>
                    {option}
                  </span>
                </button>
              ))}
            </div>

            {/* Explanation */}
            {answered && (
              <div className={`p-4 rounded-xl mb-6 ${
                selected === question.correctIndex
                  ? 'bg-green-500/10 border border-green-500/20'
                  : 'bg-red-500/10 border border-red-500/20'
              }`}>
                <p className="font-semibold mb-1">
                  {selected === question.correctIndex ? ts('quiz_correct', locale) : ts('quiz_wrong', locale)}
                </p>
                <p className="text-sm text-white/70">
                  {question.explanation[lang] || question.explanation.en}
                </p>
              </div>
            )}

            {answered && (
              <button onClick={handleNext} className="glow-btn w-full">
                {currentQ + 1 >= QUESTIONS.length ? ts('quiz_results', locale) : ts('quiz_next', locale)}
              </button>
            )}
          </>
        )}
      </div>
    </section>
  );
}