Function sendMessage

frontend/src/api/chat.ts:110–167

* 发送消息并消费 SSE 响应流

(
    payload: SendChatMessageRequest,
    handlers: {
      onEvent: (event: ChatStreamEvent) => void
      onError?: (error: Error) => void
    }
  )

   * 发送消息并消费 SSE 响应流
   */
  async sendMessage(
    payload: SendChatMessageRequest,
    handlers: {
      onEvent: (event: ChatStreamEvent) => void
      onError?: (error: Error) => void
    }
  ) {
    const token = localStorage.getItem('token') || ''
    const response = await fetch('/api/user/chat/send', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: token
      },
      body: JSON.stringify(payload)
    })

    const contentType = response.headers.get('content-type') || ''
    if (!response.ok || !response.body || !contentType.includes('text/event-stream')) {
      const error = new Error(await resolveErrorMessage(response))
      handlers.onError?.(error)
      throw error
    }

    const reader = response.body.getReader()
    const decoder = new TextDecoder('utf-8')
    let buffer = ''

    try {
      while (true) {
        const { done, value } = await reader.read()
        if (done) {
          break
        }
        buffer += decoder.decode(value, { stream: true })
        const blocks = buffer.split('\n\n')
        buffer = blocks.pop() || ''
        for (const block of blocks) {
          const event = parseSseBlock(block)
          if (event) {
            handlers.onEvent(event)
          }
        }
      }
      if (buffer.trim()) {
        const event = parseSseBlock(buffer)
        if (event) {
          handlers.onEvent(event)
        }
      }
    } catch (error) {
      const streamError = error instanceof Error ? error : new Error('SSE 流解析失败')
      handlers.onError?.(streamError)
      throw streamError
    } finally {
      reader.releaseLock()
    }
  }