const DB_COLLECTION = 'plank_data'

let _db = null
let _pushTimer = null
let _enabled = false

const getDb = () => {
  if (!_enabled) return null
  if (!_db) {
    try { _db = wx.cloud.database() } catch (e) { _enabled = false }
  }
  return _db
}

const init = () => {
  try {
    wx.cloud.init({ env: 'cloudbase-d1g56kl2q8f4f7d8a', traceUser: true })
    _enabled = true
  } catch (e) {
    _enabled = false
  }
}

const pullAll = async () => {
  const db = getDb()
  if (!db) return null
  try {
    const res = await db.collection(DB_COLLECTION)
      .where({ _openid: '{openid}' })
      .get()
    return (res && res.data && res.data.length > 0) ? res.data[0] : null
  } catch (e) {
    return null
  }
}

const pushAll = () => {
  if (!_enabled) return
  if (_pushTimer) clearTimeout(_pushTimer)
  _pushTimer = setTimeout(() => _doPush(), 2000)
}

const _doPush = async () => {
  const db = getDb()
  if (!db) return
  try {
    const storage = require('./storage')
    const themeMod = require('./theme')

    const data = {
      records: storage.getRecords(),
      settings: storage.getSettings(),
      streak: storage.getStreak(),
      themeId: themeMod.getCurrentTheme().id,
      updatedAt: db.serverDate()
    }

    // Query then upsert: one doc per user
    const existing = await db.collection(DB_COLLECTION)
      .where({ _openid: '{openid}' })
      .get()
    if (existing && existing.data && existing.data.length > 0) {
      await db.collection(DB_COLLECTION)
        .doc(existing.data[0]._id)
        .update({ data })
    } else {
      await db.collection(DB_COLLECTION).add({ data })
    }
  } catch (e) {
    // Silently retry on next write
  }
}

const clearAll = async () => {
  const db = getDb()
  if (!db) return
  try {
    const existing = await db.collection(DB_COLLECTION)
      .where({ _openid: '{openid}' })
      .get()
    if (existing && existing.data && existing.data.length > 0) {
      await db.collection(DB_COLLECTION)
        .doc(existing.data[0]._id)
        .remove()
    }
  } catch (e) {
    // Nothing to clear
  }
}

module.exports = { init, pullAll, pushAll, clearAll, get enabled() { return _enabled } }