// Mobile menu toggle
document.addEventListener('DOMContentLoaded', function() {
  const toggle = document.querySelector('.menu-toggle');
  const navList = document.querySelector('.nav-list');

  if (toggle) {
    toggle.addEventListener('click', function() {
      navList.classList.toggle('open');
    });
  }

  // Close menu on link click
  const navLinks = document.querySelectorAll('.nav-list a');
  navLinks.forEach(function(link) {
    link.addEventListener('click', function() {
      if (navList) navList.classList.remove('open');
    });
  });

  // Highlight active page in nav
  const currentPage = window.location.pathname.split('/').pop() || 'index.html';
  navLinks.forEach(function(link) {
    const href = link.getAttribute('href');
    if (href === currentPage) {
      link.classList.add('active');
    }
  });
});

// --- Exercises ---
function checkExercise(btn) {
  const exercise = btn.closest('.exercise');
  const selected = exercise.querySelector('input[type="radio"]:checked');
  const feedback = exercise.querySelector('.feedback');

  if (!selected) {
    feedback.textContent = 'Please select an answer!';
    feedback.className = 'feedback wrong';
    feedback.style.display = 'block';
    return;
  }

  const options = exercise.querySelectorAll('.option');
  options.forEach(function(opt) {
    opt.classList.remove('correct', 'wrong');
  });

  const parent = selected.closest('.option');
  const isCorrect = selected.value === 'true';

  if (isCorrect) {
    parent.classList.add('correct');
    feedback.textContent = 'Correct!  +10 XP';
    feedback.className = 'feedback correct';
    var exId = exercise.getAttribute('data-ex-id') || exercise.querySelector('h3').textContent.trim();
    markExerciseDone(exId);
  } else {
    parent.classList.add('wrong');
    feedback.textContent = 'Try again!';
    feedback.className = 'feedback wrong';
    options.forEach(function(opt) {
      const radio = opt.querySelector('input[type="radio"]');
      if (radio && radio.value === 'true') {
        opt.classList.add('correct');
      }
    });
  }
  feedback.style.display = 'block';
}

function checkFill(input) {
  const exercise = input.closest('.exercise');
  const answer = input.getAttribute('data-answer');
  const feedback = exercise.querySelector('.feedback');

  input.classList.remove('correct', 'wrong');

  if (input.value.trim().toLowerCase() === answer.toLowerCase()) {
    input.classList.add('correct');
    feedback.textContent = 'Correct!  +10 XP';
    feedback.className = 'feedback correct';
    var exId = input.closest('.exercise').getAttribute('data-ex-id') || input.closest('.exercise').querySelector('h3').textContent.trim();
    markExerciseDone(exId);
  } else {
    input.classList.add('wrong');
    feedback.textContent = 'Try again! Correct answer: ' + answer;
    feedback.className = 'feedback wrong';
  }
  feedback.style.display = 'block';
}

function checkTranslate(btn) {
  const exercise = btn.closest('.exercise');
  const input = exercise.querySelector('input[type="text"]');
  const feedback = exercise.querySelector('.feedback');
  const answer = input.getAttribute('data-answer');

  input.classList.remove('correct', 'wrong');

  if (input.value.trim().toLowerCase() === answer.toLowerCase()) {
    input.classList.add('correct');
    feedback.textContent = 'Correct!  +10 XP';
    feedback.className = 'feedback correct';
    var exId = exercise.getAttribute('data-ex-id') || exercise.querySelector('h3').textContent.trim();
    markExerciseDone(exId);
  } else {
    input.classList.add('wrong');
    feedback.textContent = 'Try again! Correct answer: ' + answer;
    feedback.className = 'feedback wrong';
  }
  feedback.style.display = 'block';
}

function checkMatch(btn) {
  const exercise = btn.closest('.exercise');
  const inputs = exercise.querySelectorAll('input[type="text"]');
  const feedback = exercise.querySelector('.feedback');
  let allCorrect = true;

  inputs.forEach(function(input) {
    const answer = input.getAttribute('data-answer');
    input.classList.remove('correct', 'wrong');
    if (input.value.trim().toLowerCase() === answer.toLowerCase()) {
      input.classList.add('correct');
    } else {
      input.classList.add('wrong');
      allCorrect = false;
    }
  });

  if (allCorrect) {
    feedback.textContent = 'All correct! Great job!  +10 XP';
    feedback.className = 'feedback correct';
    var exId = exercise.getAttribute('data-ex-id') || exercise.querySelector('h3').textContent.trim();
    markExerciseDone(exId);
  } else {
    feedback.textContent = 'Some answers are wrong. Try again!';
    feedback.className = 'feedback wrong';
  }
  feedback.style.display = 'block';
}

// --- Tests ---
function checkTest() {
  let score = 0;
  const total = document.querySelectorAll('.test-question').length;
  const questions = document.querySelectorAll('.test-question');

  questions.forEach(function(q) {
    const selected = q.querySelector('input[type="radio"]:checked');
    if (selected && selected.value === 'true') {
      score++;
    }
  });

  markTestDone(score, total);

  var data = getProgress();
  var info = getLevelProgress(data.xp);

  const resultBox = document.getElementById('test-result');
  const scoreDisplay = document.getElementById('score');
  scoreDisplay.textContent = score + '/' + total;
  resultBox.classList.add('show');

  var detail = document.getElementById('test-detail');
  if (detail) {
    detail.innerHTML = 'Level: <strong>' + info.current.label + '</strong> &nbsp;|&nbsp; XP: <strong>' + data.xp + '</strong> &nbsp;|&nbsp; Best: <strong>' + data.bestTestScore + '/' + total + '</strong>';
  }

  resultBox.scrollIntoView({ behavior: 'smooth' });
}

// --- Contact form ---
function submitForm(event) {
  event.preventDefault();
  const message = document.getElementById('form-message');
  message.classList.add('show');
  document.getElementById('contact-form').reset();
  setTimeout(function() {
    message.classList.remove('show');
  }, 5000);
}

// --- Pronunciation ---
function speakWord(word, rate) {
  if (!window.speechSynthesis) {
    alert('Speech synthesis is not supported in your browser.');
    return;
  }
  window.speechSynthesis.cancel();
  var utterance = new SpeechSynthesisUtterance(word);
  utterance.lang = 'en-US';
  utterance.rate = rate || 0.9;
  utterance.pitch = 1;
  window.speechSynthesis.speak(utterance);
}

function repeatWord(btn) {
  var word = btn.getAttribute('data-word');
  speakWord(word, 0.8);
  btn.textContent = '🔊 Playing...';
  markWordListened();
  setTimeout(function() { btn.textContent = '🔊 Listen'; }, 1500);
}

function speakSlow(btn) {
  var word = btn.getAttribute('data-word');
  speakWord(word, 0.4);
  btn.textContent = '🐢 Slow...';
  setTimeout(function() { btn.innerHTML = '🐢 Slow'; }, 2000);
}

function checkDictation(input) {
  var exercise = input.closest('.exercise');
  var answer = input.getAttribute('data-answer');
  var feedback = exercise.querySelector('.feedback');

  input.classList.remove('correct', 'wrong');

  if (input.value.trim().toLowerCase() === answer.toLowerCase()) {
    input.classList.add('correct');
    feedback.textContent = 'Correct! Great listening!';
    feedback.className = 'feedback correct';
  } else {
    input.classList.add('wrong');
    feedback.textContent = 'Not quite. The correct word is: ' + answer;
    feedback.className = 'feedback wrong';
  }
  feedback.style.display = 'block';
}

function speakPhrase(btn) {
  var phrase = btn.getAttribute('data-phrase');
  speakWord(phrase, 0.8);
  btn.textContent = '🔊 Playing...';
  setTimeout(function() { btn.innerHTML = '🔊 Hear Phrase'; }, 1500);
}

// --- Progress Tracking ---
var PROGRESS_KEY = 'english_easy_progress';

var LEVELS = [
  { min: 0, label: 'A0 Beginner', desc: 'You are just starting your English journey!' },
  { min: 50, label: 'A1 Starter', desc: 'You know basic words and phrases.' },
  { min: 150, label: 'A2 Elementary', desc: 'You can understand simple sentences.' },
  { min: 300, label: 'B1 Intermediate', desc: 'You can talk about familiar topics.' },
  { min: 500, label: 'B2 Upper Intermediate', desc: 'You can communicate fluently.' },
  { min: 800, label: 'C1 Advanced', desc: 'You understand complex texts and ideas.' }
];

function getProgress() {
  var data = JSON.parse(localStorage.getItem(PROGRESS_KEY));
  if (!data) {
    data = {
      xp: 0,
      exercisesDone: [],
      testsDone: 0,
      bestTestScore: 0,
      lastTestScore: 0,
      wordsListened: 0,
      readingDone: [],
      joined: new Date().toISOString().split('T')[0]
    };
    localStorage.setItem(PROGRESS_KEY, JSON.stringify(data));
  }
  return data;
}

function saveProgress(data) {
  localStorage.setItem(PROGRESS_KEY, JSON.stringify(data));
}

function addXP(amount, reason) {
  var data = getProgress();
  data.xp += amount;
  saveProgress(data);
  updateLevelBadge();
  return data;
}

function getLevel(xp) {
  for (var i = LEVELS.length - 1; i >= 0; i--) {
    if (xp >= LEVELS[i].min) return LEVELS[i];
  }
  return LEVELS[0];
}

function getLevelProgress(xp) {
  var current = getLevel(xp);
  var nextMin = 9999;
  for (var i = 0; i < LEVELS.length; i++) {
    if (LEVELS[i].min > current.min) {
      nextMin = LEVELS[i].min;
      break;
    }
  }
  var range = nextMin - current.min;
  var progress = xp - current.min;
  return { current: current, nextMin: nextMin, progress: progress, range: range, percent: range > 0 ? Math.min(100, Math.round(progress / range * 100)) : 100 };
}

function updateLevelBadge() {
  var data = getProgress();
  var info = getLevelProgress(data.xp);
  var badge = document.querySelector('.level-badge');
  if (badge) {
    badge.innerHTML = '<span class="level-label">' + info.current.label + '</span><span class="level-xp">' + data.xp + ' XP</span>';
  }
  var bar = document.querySelector('.level-bar-fill');
  if (bar) bar.style.width = info.percent + '%';
}

function markExerciseDone(id) {
  var data = getProgress();
  if (data.exercisesDone.indexOf(id) === -1) {
    data.exercisesDone.push(id);
    data.xp += 10;
    saveProgress(data);
  }
}

function markTestDone(score, total) {
  var data = getProgress();
  data.testsDone++;
  data.lastTestScore = score;
  if (score > data.bestTestScore) data.bestTestScore = score;
  data.xp += 15 + score * 2;
  saveProgress(data);
}

function markWordListened() {
  var data = getProgress();
  data.wordsListened++;
  if (data.wordsListened % 5 === 0) {
    data.xp += 5;
    saveProgress(data);
  }
}

// --- Daily Reminder at 20:00 ---
(function() {
  var LS_KEY = 'english_easy_daily';
  var TOAST_SHOWN = false;

  function getToday() {
    return new Date().toDateString();
  }

  function getStreak() {
    var data = JSON.parse(localStorage.getItem(LS_KEY) || '{"streak":0,"lastDate":""}');
    var yesterday = new Date();
    yesterday.setDate(yesterday.getDate() - 1);
    var yesterdayStr = yesterday.toDateString();
    var today = getToday();
    if (data.lastDate === today) {
      // already done today
    } else if (data.lastDate === yesterdayStr) {
      // consecutive day
    } else if (data.lastDate && data.lastDate !== today) {
      data.streak = 0;
    }
    return data;
  }

  function saveStreak(data) {
    data.lastDate = getToday();
    localStorage.setItem(LS_KEY, JSON.stringify(data));
  }

  function showDailyToast() {
    if (TOAST_SHOWN) return;
    TOAST_SHOWN = true;

    var data = getStreak();
    var existing = document.querySelector('.daily-toast');
    if (existing) existing.remove();

    var toast = document.createElement('div');
    toast.className = 'daily-toast';

    var streakHTML = '';
    if (data.streak > 0) {
      streakHTML = '<div class="streak">🔥 Day ' + data.streak + ' streak!</div>';
    }

    toast.innerHTML =
      '<div class="toast-header">' +
        '<div class="toast-title">⏰ Daily Practice</div>' +
        '<button class="toast-close" onclick="this.closest(\'.daily-toast\').remove()">✕</button>' +
      '</div>' +
      streakHTML +
      '<p>It\'s time for your daily English practice! Spend 5 minutes on an exercise or test.</p>' +
      '<div class="toast-actions">' +
        '<a href="exercises.html" class="btn" onclick="saveStreakFunc()">Practice Now</a>' +
        '<button class="btn btn-outline" onclick="this.closest(\'.daily-toast\').remove()">Later</button>' +
      '</div>';

    document.body.appendChild(toast);

    // trigger animation
    setTimeout(function() { toast.classList.add('show'); }, 100);

    // also try browser notification
    if ('Notification' in window && Notification.permission === 'granted') {
      new Notification('English Easy — Daily Practice', {
        body: 'Time for your daily English practice! 5 minutes is all you need.',
        icon: '/images/icon.png'
      });
    }
  }

  // Expose saveStreak for the toast button
  window.saveStreakFunc = function() {
    var data = getStreak();
    data.streak = (data.streak || 0) + 1;
    saveStreak(data);
  };

  // Request notification permission
  function requestNotifPermission() {
    if ('Notification' in window && Notification.permission === 'default') {
      Notification.requestPermission();
    }
  }

  function checkDailyReminder() {
    var now = new Date();
    var hours = now.getHours();
    var minutes = now.getMinutes();
    var data = getStreak();

    // Show if it's >= 20:00 and we haven't shown today
    if (hours >= 20 && data.lastDate !== getToday()) {
      showDailyToast();
      return true;
    }
    return false;
  }

  // Check on page load
  document.addEventListener('DOMContentLoaded', function() {
    requestNotifPermission();
    checkDailyReminder();

    // Check every 30 seconds if it's 20:00
    setInterval(function() {
      var now = new Date();
      if (now.getHours() === 20 && now.getMinutes() === 0) {
        checkDailyReminder();
      }
    }, 30000);
  });
})();

// --- Vocabulary filter ---
function filterVocab(category, btn) {
  const rows = document.querySelectorAll('.vocab-row');
  const buttons = document.querySelectorAll('.category-btn');

  buttons.forEach(function(b) { b.classList.remove('active'); });
  if (btn) btn.classList.add('active');

  rows.forEach(function(row) {
    if (category === 'all' || row.getAttribute('data-category') === category) {
      row.style.display = '';
    } else {
      row.style.display = 'none';
    }
  });
}