import axios from 'axios'
import { fetchEventSource } from '@microsoft/fetch-event-source'

const service = axios.create({
  baseURL: process.env.VITE_APP_BASE_API,
  timeout: 30000
})

// 请求拦截器
service.interceptors.request.use(
  config => {
    // 如果配置中已经包含了 Authorization header，则使用配置中的值
    if (!config.headers['Authorization']) {
      const token = localStorage.getItem('token')
      if (token) {
        config.headers['Authorization'] = `Bearer ${token}`
      }
    }
    config.headers['Content-Type'] = 'application/json'
    return config
  },
  error => {
    return Promise.reject(error)
  }
)

// 响应拦截器
service.interceptors.response.use(
  response => {
    return response.data
  },
  error => {
    return Promise.reject(error)
  }
)

// SSE 请求方法
export const sseRequest = (config) => {
  return new Promise((resolve) => {
    try {
      const url = new URL(`${config.url}`, window.location.origin)
      const ctrl = new AbortController()
      let messageQueue = []
      let resolveQueue = null
      
      const messageGenerator = async function* () {
        const source = new fetchEventSource(url.toString(), {
          method: 'POST',
          headers: {
            'Authorization': config.headers?.Authorization || `Bearer ${localStorage.getItem('token')}`,
            'Content-Type': 'application/json',
            'Accept': 'text/event-stream'
          },
          body: JSON.stringify(config.params),
          signal: ctrl.signal,
          openWhenHidden: true,
          onmessage: (event) => {
            try {
              const data = JSON.parse(event.data)
              if (resolveQueue) {
                resolveQueue(data)
                resolveQueue = null
              } else {
                messageQueue.push(data)
              }
            } catch (error) {
              console.error('Error parsing SSE message:', error)
            }
          },
          onerror: (error) => {
            console.error('EventSource failed:', error)
            ctrl.abort()
            if (resolveQueue) {
              resolveQueue(null)
              resolveQueue = null
            }
          },
          onclose: () => {
            console.log('Connection closed')
            if (resolveQueue) {
              resolveQueue(null)
              resolveQueue = null
            }
          }
        })

        try {
          while (true) {
            if (messageQueue.length > 0) {
              yield messageQueue.shift()
            } else {
              const message = await new Promise(resolve => {
                resolveQueue = resolve
              })
              if (message === null) {
                break
              }
              yield message
            }
          }
        } finally {
          ctrl.abort()
        }
      }
      
      resolve(messageGenerator())
    } catch (error) {
      console.error('SSE request setup failed:', error)
      resolve((async function* () {})())
    }
  })
}

export default service