/**
 * 本地存储工具
 * storage key 设计：
 *   draw_learning_progress  - 学习进度
 *   draw_recent_history     - 最近学习记录
 *   draw_favorite_courses   - 收藏课程
 *   draw_works_records      - 作品上传记录
 *   draw_user_settings      - 用户设置
 */

const KEYS = {
  PROGRESS: 'draw_learning_progress',
  HISTORY: 'draw_recent_history',
  FAVORITE: 'draw_favorite_courses',
  WORKS: 'draw_works_records',
  SETTINGS: 'draw_user_settings',
}

// --------- 学习进度 ---------
// 格式：{ [courseId]: { currentStep: 0, completed: false, updatedAt: timestamp } }
function getProgress() {
  return wx.getStorageSync(KEYS.PROGRESS) || {}
}

function saveProgress(courseId, stepIndex, completed = false) {
  const progress = getProgress()
  progress[courseId] = {
    currentStep: stepIndex,
    completed,
    updatedAt: Date.now()
  }
  wx.setStorageSync(KEYS.PROGRESS, progress)
}

function getCourseProgress(courseId) {
  const progress = getProgress()
  return progress[courseId] || { currentStep: 0, completed: false }
}

function getCompletedCount() {
  const progress = getProgress()
  return Object.values(progress).filter(p => p.completed).length
}

// --------- 最近学习记录 ---------
// 格式：[{ courseId, courseTitle, coverEmoji, coverColor, stepIndex, timestamp }]
function getRecentHistory() {
  return wx.getStorageSync(KEYS.HISTORY) || []
}

function addRecentHistory(courseInfo) {
  let history = getRecentHistory()
  // 去重
  history = history.filter(h => h.courseId !== courseInfo.courseId)
  history.unshift({ ...courseInfo, timestamp: Date.now() })
  // 最多保留10条
  history = history.slice(0, 10)
  wx.setStorageSync(KEYS.HISTORY, history)
}

// --------- 收藏课程 ---------
// 格式：[courseId]
function getFavorites() {
  return wx.getStorageSync(KEYS.FAVORITE) || []
}

function toggleFavorite(courseId) {
  let favorites = getFavorites()
  const idx = favorites.indexOf(courseId)
  if (idx >= 0) {
    favorites.splice(idx, 1)
  } else {
    favorites.unshift(courseId)
  }
  wx.setStorageSync(KEYS.FAVORITE, favorites)
  return idx < 0 // true=已收藏
}

function isFavorite(courseId) {
  return getFavorites().includes(courseId)
}

// --------- 作品记录 ---------
// 格式：[{ id, courseId, courseTitle, imagePath, savedAt }]
function getWorksRecords() {
  return wx.getStorageSync(KEYS.WORKS) || []
}

function addWorkRecord(record) {
  let records = getWorksRecords()
  records.unshift({ ...record, savedAt: Date.now(), id: Date.now().toString() })
  wx.setStorageSync(KEYS.WORKS, records)
}

function getCompletedPracticeCount() {
  return getWorksRecords().length
}

// --------- 用户设置 ---------
function getSettings() {
  return wx.getStorageSync(KEYS.SETTINGS) || {
    reminderEnabled: false,
    reminderTime: '08:00',
    nickname: '学画的你',
    avatar: '',
    joinDays: 0,
    joinDate: null
  }
}

function saveSettings(settings) {
  const current = getSettings()
  const merged = { ...current, ...settings }
  // 计算学习天数
  if (!merged.joinDate) {
    merged.joinDate = Date.now()
    merged.joinDays = 1
  } else {
    merged.joinDays = Math.max(1, Math.ceil((Date.now() - merged.joinDate) / 86400000))
  }
  wx.setStorageSync(KEYS.SETTINGS, merged)
  return merged
}

function initSettings() {
  const settings = getSettings()
  if (!settings.joinDate) {
    saveSettings({})
  }
  return getSettings()
}

module.exports = {
  saveProgress,
  getCourseProgress,
  getCompletedCount,
  getRecentHistory,
  addRecentHistory,
  getFavorites,
  toggleFavorite,
  isFavorite,
  getWorksRecords,
  addWorkRecord,
  getCompletedPracticeCount,
  getSettings,
  saveSettings,
  initSettings
}