/**
 * 请求拦截器封装
 * 统一处理HTTP请求和响应
 */

import { getBaseUrl, getTimeout, getStorageKey, statusCode } from '../config/index.js'

// 请求队列（用于取消重复请求）
const pendingRequests = new Map()

// 是否正在刷新token
let isRefreshing = false
// 等待刷新token的请求队列
let refreshSubscribers = []

/**
 * 生成请求唯一标识
 */
const generateRequestKey = (config) => {
  const { url, method, data } = config
  return `${method}_${url}_${JSON.stringify(data || {})}`
}

/**
 * 添加请求到队列
 */
const addPendingRequest = (config) => {
  const key = generateRequestKey(config)
  if (!pendingRequests.has(key)) {
    pendingRequests.set(key, config)
  }
}

/**
 * 从队列移除请求
 */
const removePendingRequest = (config) => {
  const key = generateRequestKey(config)
  pendingRequests.delete(key)
}

/**
 * 取消重复请求
 */
const cancelPendingRequest = (config) => {
  const key = generateRequestKey(config)
  if (pendingRequests.has(key)) {
    return true
  }
  return false
}

/**
 * 获取请求头
 */
const getHeaders = (needAuth = true) => {
  const headers = {
    'Content-Type': 'application/json'
  }

  if (needAuth) {
    const token = uni.getStorageSync(getStorageKey('token'))
    if (token) {
      headers['Authorization'] = `Bearer ${token}`
    }
  }

  return headers
}

/**
 * 处理响应错误
 * 优先使用后端返回的 message
 */
const handleResponseError = (response) => {
  const { statusCode: code, data } = response

  // 优先使用后端返回的 message
  const message = data?.message

  switch (code) {
    case 400:
      uni.showToast({
        title: message || '请求参数错误',
        icon: 'none'
      })
      break

    case 401:
      // Token过期，清除登录状态并跳转登录页
      uni.removeStorageSync(getStorageKey('token'))
      uni.removeStorageSync(getStorageKey('userInfo'))
      uni.showToast({
        title: message || '登录已过期，请重新登录',
        icon: 'none'
      })
      setTimeout(() => {
        uni.reLaunch({
          url: '/pages/login/login'
        })
      }, 1500)
      break

    case 403:
      uni.showToast({
        title: message || '没有权限执行此操作',
        icon: 'none'
      })
      break

    case 404:
      uni.showToast({
        title: message || '请求的资源不存在',
        icon: 'none'
      })
      break

    case 500:
      uni.showToast({
        title: message || '服务器错误，请稍后重试',
        icon: 'none'
      })
      break

    default:
      uni.showToast({
        title: message || '请求失败',
        icon: 'none'
      })
  }
}

/**
 * 统一请求方法
 * @param {Object} options - 请求配置
 * @param {boolean} needAuth - 是否需要认证
 * @returns {Promise}
 */
const request = (options = {}, needAuth = true) => {
  const baseUrl = getBaseUrl()
  const timeout = getTimeout()

  const config = {
    url: options.url.startsWith('http') ? options.url : `${baseUrl}${options.url}`,
    method: options.method || 'GET',
    data: options.data || {},
    header: { ...getHeaders(needAuth), ...options.header },
    timeout: options.timeout || timeout
  }

  // 检查重复请求
  if (cancelPendingRequest(config)) {
    return Promise.reject(new Error('重复请求'))
  }

  // 添加请求到队列
  addPendingRequest(config)

  return new Promise((resolve, reject) => {
    uni.request({
      ...config,
      success: (response) => {
        const { statusCode: code, data } = response

        // 请求成功
        if (code >= 200 && code < 300) {
          // 如果后端返回的数据没有 code 字段，直接视为成功
          if (!data.code || data.code === 200) {
            resolve(data)
          } else {
            // 业务逻辑失败
            uni.showToast({
              title: data.message || '操作失败',
              icon: 'none'
            })
            reject(data)
          }
        } else {
          // HTTP错误
          handleResponseError(response)
          reject(response)
        }
      },
      fail: (error) => {
        uni.showToast({
          title: '网络错误，请检查网络连接',
          icon: 'none'
        })
        reject(error)
      },
      complete: () => {
        // 从队列移除请求
        removePendingRequest(config)
      }
    })
  })
}

/**
 * GET请求
 */
export const get = (url, params = {}, needAuth = true) => {
  // 构建查询字符串
  const queryString = Object.keys(params)
    .map(key => `${encodeURIComponent(key)}=${encodeURIComponent(params[key])}`)
    .join('&')

  const fullUrl = queryString ? `${url}?${queryString}` : url

  return request({
    url: fullUrl,
    method: 'GET'
  }, needAuth)
}

/**
 * POST请求
 */
export const post = (url, data = {}, needAuth = true) => {
  return request({
    url,
    method: 'POST',
    data
  }, needAuth)
}

/**
 * PUT请求
 */
export const put = (url, data = {}, needAuth = true) => {
  return request({
    url,
    method: 'PUT',
    data
  }, needAuth)
}

/**
 * DELETE请求
 */
export const del = (url, data = {}, needAuth = true) => {
  return request({
    url,
    method: 'DELETE',
    data
  }, needAuth)
}

/**
 * 上传文件
 */
export const upload = (url, filePath, formData = {}, needAuth = true) => {
  const baseUrl = getBaseUrl()
  const token = uni.getStorageSync(getStorageKey('token'))

  return new Promise((resolve, reject) => {
    uni.uploadFile({
      url: `${baseUrl}${url}`,
      filePath,
      name: 'file',
      formData,
      header: needAuth && token ? { 'Authorization': `Bearer ${token}` } : {},
      success: (response) => {
        const data = JSON.parse(response.data)
        if (data.code === 200) {
          resolve(data)
        } else {
          uni.showToast({
            title: data.message || '上传失败',
            icon: 'none'
          })
          reject(data)
        }
      },
      fail: (error) => {
        uni.showToast({
          title: '上传失败',
          icon: 'none'
        })
        reject(error)
      }
    })
  })
}

/**
 * 下载文件
 */
export const download = (url, needAuth = true) => {
  const baseUrl = getBaseUrl()
  const token = uni.getStorageSync(getStorageKey('token'))

  return new Promise((resolve, reject) => {
    uni.downloadFile({
      url: `${baseUrl}${url}`,
      header: needAuth && token ? { 'Authorization': `Bearer ${token}` } : {},
      success: (response) => {
        if (response.statusCode === 200) {
          resolve(response)
        } else {
          reject(response)
        }
      },
      fail: (error) => {
        reject(error)
      }
    })
  })
}

export default {
  request,
  get,
  post,
  put,
  delete: del,
  upload,
  download
}