import { ElNotification } from 'element-plus'

export const chatMessage = (params, funcs) => {
  fetch(
    `${(import.meta as any).env.VITE_WORKFLOW_API_PROXY}/app/chat-messages`,
    {
      method: 'POST',
      body: JSON.stringify(params),
      headers: {
        Authorization: localStorage.getItem(
          (import.meta as any).env.VITE_TOKEN,
        ),
        'Content-Type': 'application/json',
      } as any,
    },
  ).then((res) => {
    handleStream({ response: res, ...funcs })
  })
}

const handleStream = ({
  response,
  onData,
  onMessageEnd,
  onStart,
  onEnd,
  onError,
}) => {
  if (!response.ok) {
    onError?.(`${response.status}：${response.statusText}`, response)
    throw new Error('Network response was not ok')
  }

  const reader = response.body?.getReader()
  const decoder = new TextDecoder('utf-8')
  let buffer = ''
  let bufferObj: any = {}
  const dataFlag = 'data:'
  const read = () => {
    let hasError = false
    reader?.read().then((result: any) => {
      if (result.done) {
        onEnd?.()
        return
      }
      buffer += decoder.decode(result.value, { stream: true })
      const lines = buffer.split('\n')
      try {
        lines.forEach((message) => {
          if (message.startsWith(dataFlag)) {
            try {
              bufferObj = JSON.parse(message.substring(dataFlag.length))
            } catch (e) {
              return
            }
            const { event } = bufferObj
            if (event === 'chat_start') {
              onStart?.(bufferObj)
            } else if (event === 'message') {
              onData(unicodeToChar(bufferObj.answer), bufferObj)
            } else if (event === 'message_end') {
              onMessageEnd(bufferObj)
            } else if (event === 'error') {
              ElNotification({
                title: bufferObj.error_type,
                message: bufferObj.error_message,
                type: 'error',
                duration: 0,
              })
              onError?.(bufferObj.message, bufferObj)
            } else {
              console.error(bufferObj)
            }
          }
        })
        buffer = lines[lines.length - 1]
      } catch (e) {
        hasError = true
        return
      }
      if (!hasError) read()
    })
  }
  read()
}

const unicodeToChar = (text: string) => {
  if (!text) return ''

  return text.replace(/\\u[0-9a-f]{4}/g, (_match, p1) => {
    return String.fromCharCode(parseInt(p1, 16))
  })
}

// //判断当前浏览器是否支持SSE
// let source = ''
// if (!!window.EventSource) {
//   source = new EventSource('http://localhost:8088/sse/')
// } else {
//   thrownewError('当前浏览器不支持SSE')
// }
//
// //对于建立链接的监听
// source.onopen = function (event) {
//   console.log(source.readyState)
//   console.log('长连接打开')
// }
//
// //对服务端消息的监听
// source.onmessage = function (event) {
//   console.log(JSON.parse(event.data))
//   console.log('收到长连接信息')
//   let li = createLi(JSON.parse(event.data))
//   document.getElementById('ul').appendChild(li)
// }
//
// //对断开链接的监听
// source.onerror = function (event) {
//   console.log(source.readyState)
//   console.log('长连接中断')
// }