'use server'
import {API_BASE_URL, ApiResponse, CLIENT_ID, CLIENT_SECRET} from '@/lib/api'
import {add, isBefore} from 'date-fns'
import {cookies, headers} from 'next/headers'
import {cache} from 'react'

export type TokenResp = {
  access_token: string
  refresh_token: string
  expires_in: number
  token_type: string
  scope?: string
}

export async function getApiUrl() {
  return {
    success: true,
    data: API_BASE_URL,
  } satisfies ApiResponse<string>
}

// ======================
// public
// ======================

async function callPublic<R = undefined>(
  endpoint: string,
  data?: unknown,
): Promise<ApiResponse<R>> {
  return _callPublic(endpoint, data ? JSON.stringify(data) : undefined)
}

const _callPublic = cache(async <R = undefined>(
  endpoint: string,
  data?: string,
): Promise<ApiResponse<R>> => {
  return call(`${API_BASE_URL}${endpoint}`, data)
})

// ======================
// device
// ======================

let token: string | null = null
let token_expire: Date | null = null

async function callByDevice<R = undefined>(
  endpoint: string,
  data: unknown,
): Promise<ApiResponse<R>> {
  return _callByDevice(endpoint, data ? JSON.stringify(data) : undefined)
}

const _callByDevice = cache(async <R = undefined>(
  endpoint: string,
  data?: string,
): Promise<ApiResponse<R>> => {
  if (!token || !token_expire || isBefore(token_expire, new Date())) {
    const basic = Buffer.from(`${CLIENT_ID}:${CLIENT_SECRET}`).toString('base64url')
    const resp = await call<TokenResp>(`${API_BASE_URL}/api/auth/token`, JSON.stringify({
      grant_type: 'client_credentials',
    }), `Basic ${basic}`)
    if (!resp.success) {
      return resp
    }
    token = resp.data.access_token
    token_expire = add(new Date(), {seconds: resp.data.expires_in})
  }

  // 发起请求
  return call(`${API_BASE_URL}${endpoint}`, data, `Bearer ${token}`)
})

// ======================
// user
// ======================

async function callByUser<R = undefined>(
  endpoint: string,
  data?: unknown,
): Promise<ApiResponse<R>> {
  return _callByUser(endpoint, data ? JSON.stringify(data) : undefined)
}

const _callByUser = cache(async <R = undefined>(
  endpoint: string,
  data?: string,
): Promise<ApiResponse<R>> => {
  // 获取用户令牌
  const cookie = await cookies()
  const token = cookie.get('auth_token')?.value
  if (!token) {
    return {
      success: false,
      status: 401,
      message: '会话已失效',
    }
  }

  // 发起请求
  return await call<R>(`${API_BASE_URL}${endpoint}`, data, `Bearer ${token}`)
})

// ======================
// call
// ======================

async function call<R = undefined>(url: string, body: RequestInit['body'], auth?: string): Promise<ApiResponse<R>> {
  let response: Response
  try {
    const reqHeaders = await headers()
    const reqIP = reqHeaders.get('x-forwarded-for')
    const reqUA = reqHeaders.get('user-agent')
    const callHeaders: RequestInit['headers'] = {
      'Content-Type': 'application/json',
    }
    if (auth) callHeaders['Authorization'] = auth
    if (reqIP) callHeaders['X-Forwarded-For'] = reqIP
    if (reqUA) callHeaders['User-Agent'] = reqUA

    response = await fetch(url, {
      method: 'POST',
      headers: callHeaders,
      body,
    })
  }
  catch (e) {
    console.error('后端请求失败', url, (e as Error).message)
    throw new Error(`请求失败，网络错误`)
  }

  const type = response.headers.get('Content-Type') ?? 'text/plain'
  if (type.indexOf('text/plain') !== -1) {
    const text = await response.text()
    if (!response.ok) {
      console.log('后端请求失败', url, `status=${response.status}`, text)
      return {
        success: false,
        status: response.status,
        message: text || '请求失败',
      }
    }

    if (!!text?.trim()?.length) {
      console.log('未处理的响应成功', `type=text`, `text=${text}`)
    }
    return {
      success: true,
      data: undefined as R, // 强转类型，考虑优化
    }
  }
  else if (type.indexOf('application/json') !== -1) {
    const json = await response.json()
    if (!response.ok) {
      console.log('后端请求失败', url, `status=${response.status}`, json)

      return {
        success: false,
        status: response.status,
        message: json.message || json.error_description || '请求失败', // 业务错误（message）或者 oauth 错误（error_description）
      }
    }
    return {
      success: true,
      data: json,
    }
  }

  throw new Error(`无法解析响应数据，未处理的 Content-Type: ${type}`)
}

// 导出
export {
  callPublic,
  callByDevice,
  callByUser,
}