import AsyncStorage from '@react-native-async-storage/async-storage'
import { DEFAULT_TENANT_PLATFORM_URL } from './constants'
import { getOptionalConfig, getUserId } from './config'
import { hmacSha256Base64Url } from './crypto'
import { safeRequestPath } from './api/diagnostics'

const TOKEN_KEY = '@xuqm:token'
let _baseUrl = DEFAULT_TENANT_PLATFORM_URL
let _debugHttp = false

export function configureHttp(options: { baseUrl?: string; debug?: boolean } = {}) {
  if (options.baseUrl) {
    _baseUrl = options.baseUrl.replace(/\/$/, '')
  }
  if (typeof options.debug === 'boolean') {
    _debugHttp = options.debug
  }
}

export async function _getAccessToken(): Promise<string | null> {
  return AsyncStorage.getItem(TOKEN_KEY)
}

export async function _saveAccessToken(token: string): Promise<void> {
  return AsyncStorage.setItem(TOKEN_KEY, token)
}

export async function _clearAccessToken(): Promise<void> {
  return AsyncStorage.removeItem(TOKEN_KEY)
}

let nonceSequence = 0

function generateRequestNonce(secret: string, appKey: string): string {
  nonceSequence = (nonceSequence + 1) % Number.MAX_SAFE_INTEGER
  const seed = `${Date.now()}\n${nonceSequence}\n${appKey}`
  const value = hmacSha256Base64Url(secret, seed)
  return `${value.slice(0, 8)}-${value.slice(8, 12)}-4${value.slice(13, 16)}-a${value.slice(17, 20)}-${value.slice(20, 32)}`
}

export async function apiRequest<T>(
  path: string,
  options: {
    method?: string
    body?: unknown
    params?: Record<string, string>
    skipAuth?: boolean
    /** 调用方取消信号；版本检查等可在页面退出时立即停止。 */
    signal?: AbortSignal
    /** 默认 30 秒，必须为正数；防止网络异常永久阻塞扩展入口。 */
    timeoutMs?: number
  } = {},
): Promise<T> {
  let url = path.startsWith('http://') || path.startsWith('https://') ? path : `${_baseUrl}${path}`
  if (options.params) {
    const qs = new URLSearchParams(options.params).toString()
    url += (url.includes('?') ? '&' : '?') + qs
  }

  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    Accept: 'application/json',
  }

  if (!options.skipAuth) {
    const token = await _getAccessToken()
    if (token) headers['Authorization'] = `Bearer ${token}`
  }

  const config = getOptionalConfig()
  const signingKey = config?.signingKey
  if (config && signingKey) {
    const timestamp = Math.floor(Date.now() / 1000).toString()
    const nonce = generateRequestNonce(signingKey, config.appKey)
    const userId = getUserId() ?? ''
    const payload = `${config.appKey}\n${userId}\n${timestamp}\n${nonce}`
    headers['X-App-Key'] = config.appKey
    headers['X-Timestamp'] = timestamp
    headers['X-Nonce'] = nonce
    headers['X-Signature'] = hmacSha256Base64Url(signingKey, payload)
    if (userId) headers['X-User-Id'] = userId
  }

  if (_debugHttp) {
    console.debug('[XuqmSDK][HTTP] request', {
      method: options.method ?? 'GET',
      path: safeRequestPath(url),
      hasBody: Boolean(options.body),
    })
  }

  const timeoutMs = options.timeoutMs ?? 30_000
  if (!Number.isFinite(timeoutMs) || timeoutMs <= 0) {
    throw new Error('[XuqmSDK][HTTP] timeoutMs must be a positive number')
  }

  const controller = new AbortController()
  const abortFromCaller = () => controller.abort(options.signal?.reason)
  if (options.signal?.aborted) abortFromCaller()
  else options.signal?.addEventListener('abort', abortFromCaller, { once: true })
  const timeout = setTimeout(() => {
    controller.abort(new Error(`[XuqmSDK][HTTP] Request timed out after ${timeoutMs}ms`))
  }, timeoutMs)

  let res: Response
  try {
    res = await fetch(url, {
      method: options.method ?? 'GET',
      headers,
      body: options.body ? JSON.stringify(options.body) : undefined,
      signal: controller.signal,
    })
  } finally {
    clearTimeout(timeout)
    options.signal?.removeEventListener('abort', abortFromCaller)
  }

  if (!res.ok) {
    const err = await res.json().catch(() => ({ message: res.statusText }))
    if (_debugHttp) {
      console.debug('[XuqmSDK][HTTP] response', {
        path: safeRequestPath(url),
        status: res.status,
        ok: false,
      })
    }
    throw new Error((err as { message?: string }).message ?? `HTTP ${res.status}`)
  }

  const json = await res.json()
  if (_debugHttp) {
    console.debug('[XuqmSDK][HTTP] response', {
      path: safeRequestPath(url),
      status: res.status,
      ok: true,
    })
  }
  return (json.data ?? json) as T
}