import {
  _notifyInitialized,
  _setUserInfo,
  getUserId as getCommonUserId,
  getUserInfo as getCommonUserInfo,
  initConfigFromRemote,
  isInitialized,
  type XuqmInitOptions,
  type XuqmLoginOptions,
  type XuqmUserInfo,
} from './config'
import { DEFAULT_TENANT_PLATFORM_URL } from './constants'
import { _clearAccessToken, _saveAccessToken, configureHttp } from './http'
import { decryptConfigFile } from './crypto'

let _initPromise: Promise<void> | null = null
let _configFileInitPromise: Promise<void> | null = null
let _initializationKey: string | null = null
let _sessionTransition: Promise<void> = Promise.resolve()
let _activeSessionKey: string | null = null

function initializationKey(options: XuqmInitOptions): string {
  return `${options.appKey.trim()}\n${(options.platformUrl ?? DEFAULT_TENANT_PLATFORM_URL).replace(/\/$/, '')}`
}

function startInitialization(options: XuqmInitOptions, signingKey?: string): Promise<void> {
  const nextKey = initializationKey(options)
  if (isInitialized()) {
    if (_initializationKey !== nextKey) {
      return Promise.reject(new Error('[XuqmSDK] Already initialized with a different config.'))
    }
    return Promise.resolve()
  }
  if (_initPromise) {
    if (_initializationKey !== nextKey) {
      return Promise.reject(
        new Error('[XuqmSDK] Initialization is already running with a different config.'),
      )
    }
    return _initPromise
  }

  _initializationKey = nextKey
  _initPromise = (async () => {
    const baseUrl = options.platformUrl ?? DEFAULT_TENANT_PLATFORM_URL
    const configUrl = `${baseUrl.replace(/\/$/, '')}/api/sdk/config?appKey=${encodeURIComponent(options.appKey)}`
    const res = await fetch(configUrl)
    if (!res.ok) {
      throw new Error(`[XuqmSDK] Platform config request failed: ${res.status}`)
    }
    const json = (await res.json()) as Record<string, unknown>
    const remote = (json.data ?? json) as Record<string, unknown>
    initConfigFromRemote(
      options,
      {
        apiUrl: remote.apiUrl as string | undefined,
        imWsUrl: remote.imWsUrl as string | undefined,
        fileServiceUrl: remote.fileServiceUrl as string | undefined,
        imEnabled: remote.imEnabled as boolean | undefined,
        pushEnabled: remote.pushEnabled as boolean | undefined,
        bugCollectApiUrl: remote.bugCollectApiUrl as string | undefined,
        bugCollectEnabled: remote.bugCollectEnabled as boolean | undefined,
      },
      signingKey,
    )
    configureHttp({
      baseUrl: (remote.apiUrl as string | undefined) ?? baseUrl,
      debug: options.debug,
    })
    await _notifyInitialized()
  })().catch(error => {
    _initPromise = null
    _initializationKey = null
    throw error
  })
  return _initPromise
}

function enqueueSessionTransition(action: () => Promise<void>): Promise<void> {
  const next = _sessionTransition.catch(() => undefined).then(action)
  _sessionTransition = next
  return next
}

export const XuqmSDK = {
  /**
   * 方式 B：手动初始化。
   *
   * 请求平台获取该 appKey 的完整服务配置（IM、Push、文件服务等 URL 及开通状态）。
   * 失败时直接抛出，不降级。
   *
   * @param options.appKey      应用标识
   * @param options.platformUrl 平台地址；不传则使用内置默认公有平台地址
   * @param options.debug       是否开启调试日志
   */
  async initialize(options: XuqmInitOptions): Promise<void> {
    if (!options.appKey.trim()) {
      throw new Error('[XuqmSDK] appKey is required.')
    }
    await startInitialization(options)
  },

  /**
   * 等待初始化完成。在任意子 SDK 内部调用以确保 XuqmSDK 已就绪。
   */
  async awaitInitialization(): Promise<void> {
    await awaitInitialization()
  },

  getUserId(): string | null {
    return getCommonUserId()
  },

  /**
   * 用户认证核心枢纽。登录成功后调用一次，所有已安装的扩展 SDK 自动同步状态。
   * 登出时传 null，触发所有子 SDK 登出。
   */
  async login(options: XuqmLoginOptions): Promise<void> {
    const userId = options.userId.trim()
    if (!userId) throw new Error('[XuqmSDK] userId is required.')
    const accessToken = options.accessToken?.trim() || undefined
    const normalized = { ...options, accessToken, userId }
    const nextSessionKey = JSON.stringify(normalized)
    await enqueueSessionTransition(async () => {
      await awaitInitialization()
      if (_activeSessionKey === nextSessionKey && getCommonUserInfo()) return
      if (accessToken) await _saveAccessToken(accessToken)
      else await _clearAccessToken()
      const { accessToken: _accessToken, ...userInfo } = normalized
      await _setUserInfo(userInfo)
      _activeSessionKey = nextSessionKey
    })
  },

  async logout(): Promise<void> {
    await enqueueSessionTransition(async () => {
      await _clearAccessToken()
      if (getCommonUserInfo()) await _setUserInfo(null)
      _activeSessionKey = null
    })
  },

  getUserInfo(): XuqmUserInfo | null {
    return getCommonUserInfo()
  },
}

export async function awaitInitialization(): Promise<void> {
  if (isInitialized()) return
  const pendingInitialization = _configFileInitPromise ?? _initPromise
  if (!pendingInitialization) {
    throw new Error(
      '[XuqmSDK] Automatic initialization did not start. Place config.xuqmconfig in src/assets/config and wrap Metro with withXuqmConfig(), or call XuqmSDK.initialize().',
    )
  }
  await pendingInitialization
}

/** Internal entry used only by the Metro auto-init module. */
export function _initializeFromConfigFile(
  encryptedContent: string,
  options?: { debug?: boolean },
): Promise<void> {
  if (_configFileInitPromise) return _configFileInitPromise

  _configFileInitPromise = (async () => {
    const file = await decryptConfigFile(encryptedContent)
    const platformUrl = file.serverUrl ?? file.baseUrl ?? undefined
    await startInitialization(
      { appKey: file.appKey, platformUrl, debug: options?.debug },
      file.signingKey,
    )
  })().catch(error => {
    _configFileInitPromise = null
    throw error
  })

  return _configFileInitPromise
}