const fs = require('fs')
const path = require('path')
const passwords = require('./passwords')

const file = process.env.DB_FILE
  ? path.resolve(process.env.DB_FILE)
  : path.join(__dirname, '../data/db.json')

const SEED = {
  users: [],
  admins: [{ username: 'admin', password: '123456', token: '' }],
  adminAllowlist: [],
  activities: [
    {
      id: '93',
      title: '2026年卓米第93期卓米会',
      brandName: '卓米会 ZHUOMI',
      brandDesc: '专注于品牌增长与企业服务的共创平台，连接资源、方法与同行者。',
      cover: '',
      video: '',
      startAt: '2026-06-18 14:00',
      address: '上海市浦东新区世纪大道 100 号 卓米中心 3F',
      latitude: 31.235929,
      longitude: 121.506321,
      status: 'current',
      isCurrent: true,
      pinned: false,
      pinnedAt: '',
      theme: 0,
      createdAt: '2026-06-01T00:00:00.000Z',
      updatedAt: '2026-06-01T00:00:00.000Z'
    }
  ],
  posters: [],
  signups: [],
  checkinCodes: [],
  settings: {
    // 微信公众平台 → 订阅消息 → 选用「活动提醒」类模板后填入模板 ID
    subscribeTmplId: process.env.WX_SUBSCRIBE_TMPL_ID || ''
  }
}

const COLLECTIONS = ['users', 'admins', 'adminAllowlist', 'activities', 'posters', 'signups', 'checkinCodes']

let cache = null

// Returns true when the stored shape changed and must be persisted.
function normalize(data) {
  let dirty = false
  COLLECTIONS.forEach((key) => {
    if (!Array.isArray(data[key])) {
      data[key] = []
      dirty = true
    }
  })
  if (!data.settings || typeof data.settings !== 'object') {
    data.settings = { subscribeTmplId: process.env.WX_SUBSCRIBE_TMPL_ID || '' }
    dirty = true
  } else if (typeof data.settings.subscribeTmplId !== 'string') {
    data.settings.subscribeTmplId = process.env.WX_SUBSCRIBE_TMPL_ID || ''
    dirty = true
  } else if (!data.settings.subscribeTmplId && process.env.WX_SUBSCRIBE_TMPL_ID) {
    data.settings.subscribeTmplId = process.env.WX_SUBSCRIBE_TMPL_ID
    dirty = true
  }

  // The allowlist is the only source of truth for mini-program admins.
  data.users.forEach((user) => {
    // Client temp paths (http://tmp/..., wxfile://...) were saved by older builds and never resolve.
    if (user.avatarUrl && !user.avatarUrl.startsWith('/static/uploads/')) {
      user.avatarUrl = ''
      dirty = true
    }
    if (!('role' in user)) return
    if (user.role === 'admin' && !data.adminAllowlist.includes(user.openid)) {
      data.adminAllowlist.push(user.openid)
    }
    delete user.role
    dirty = true
  })

  data.admins.forEach((admin) => {
    if (!passwords.isHashed(admin.password)) {
      admin.password = passwords.hash(admin.password || '')
      dirty = true
    }
  })
  return dirty
}

function persist(data) {
  fs.mkdirSync(path.dirname(file), { recursive: true })
  const tmp = `${file}.${process.pid}.tmp`
  fs.writeFileSync(tmp, JSON.stringify(data, null, 2))
  fs.renameSync(tmp, file)
}

function load() {
  if (cache) return cache
  const data = fs.existsSync(file)
    ? JSON.parse(fs.readFileSync(file, 'utf8'))
    : JSON.parse(JSON.stringify(SEED))
  if (normalize(data) || !fs.existsSync(file)) persist(data)
  cache = data
  return cache
}

function read() {
  return load()
}

function update(mutator) {
  const data = load()
  const result = mutator(data)
  persist(data)
  return result
}

function reset() {
  cache = null
}

module.exports = { read, update, reset, file, SEED }