frontend/src/utils/sseClient.ts

export interface SSEMessage {
  type: 'progress' | 'chunk' | 'result' | 'error' | 'done';
  message?: string;
  progress?: number;
  status?: 'processing' | 'success' | 'error' | 'warning';
  content?: string;
  data?: any;
  error?: string;
  code?: number;
}

export interface SSEClientOptions {
  onProgress?: (message: string, progress: number, status: string) => void;
  onChunk?: (content: string) => void;
  onResult?: (data: any) => void;
  onError?: (error: string, code?: number) => void;
  onComplete?: () => void;
  onConnectionError?: (error: Event) => void;
}

export class SSEClient {
  private eventSource: EventSource | null = null;
  private url: string;
  private options: SSEClientOptions;
  private accumulatedContent: string = '';

  constructor(url: string, options: SSEClientOptions = {}) {
    this.url = url;
    this.options = options;
  }

  connect(): Promise<any> {
    return new Promise((resolve, reject) => {
      try {
        this.eventSource = new EventSource(this.url);
        
        this.eventSource.onmessage = (event) => {
          try {
            const message: SSEMessage = JSON.parse(event.data);
            this.handleMessage(message, resolve, reject);
          } catch (error) {
            console.error('解析SSE消息失败:', error);
          }
        };

        this.eventSource.onerror = (error) => {
          console.error('SSE连接错误:', error);
          if (this.options.onConnectionError) {
            this.options.onConnectionError(error);
          }
          this.close();
          reject(new Error('SSE连接失败'));
        };

      } catch (error) {
        reject(error);
      }
    });
  }

  private handleMessage(message: SSEMessage, resolve: Function, reject: Function) {
    switch (message.type) {
      case 'progress':
        if (this.options.onProgress && message.message && message.progress !== undefined) {
          this.options.onProgress(message.message, message.progress, message.status || 'processing');
        }
        break;

      case 'chunk':
        if (message.content) {
          this.accumulatedContent += message.content;
          if (this.options.onChunk) {
            this.options.onChunk(message.content);
          }
        }
        break;

      case 'result':
        if (this.options.onResult && message.data) {
          this.options.onResult(message.data);
        }
        break;

      case 'error':
        if (this.options.onError) {
          this.options.onError(message.error || '未知错误', message.code);
        }
        this.close();
        reject(new Error(message.error || '未知错误'));
        break;

      case 'done':
        if (this.options.onComplete) {
          this.options.onComplete();
        }
        this.close();
        if (!this.options.onResult && this.accumulatedContent) {
          resolve({ content: this.accumulatedContent });
        } else {
          resolve(true);
        }
        break;
    }
  }

  close() {
    if (this.eventSource) {
      this.eventSource.close();
      this.eventSource = null;
    }
  }

  getAccumulatedContent(): string {
    return this.accumulatedContent;
  }
}

export class SSEPostClient {
  private url: string;
  private data: any;
  private options: SSEClientOptions;
  private abortController: AbortController | null = null;
  private accumulatedContent: string = '';

  constructor(url: string, data: any, options: SSEClientOptions = {}) {
    this.url = url;
    this.data = data;
    this.options = options;
  }

  async connect(): Promise<any> {
    return new Promise(async (resolve, reject) => {
      try {
        this.abortController = new AbortController();

        const response = await fetch(this.url, {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify(this.data),
          signal: this.abortController.signal,
        });

        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status}`);
        }

        const reader = response.body?.getReader();
        const decoder = new TextDecoder();

        if (!reader) {
          throw new Error('无法获取响应流');
        }

        let buffer = '';

        while (true) {
          const { done, value } = await reader.read();

          if (done) {
            break;
          }

          buffer += decoder.decode(value, { stream: true });
          
          const lines = buffer.split('\n\n');
          buffer = lines.pop() || '';

          for (const line of lines) {
            if (line.trim() === '' || line.startsWith(':')) {
              continue;
            }

            try {
              const dataMatch = line.match(/^data: (.+)$/m);
              if (dataMatch) {
                const message: SSEMessage = JSON.parse(dataMatch[1]);
                await this.handleMessage(message, resolve, reject);
              }
            } catch (error) {
              console.error('解析SSE消息失败:', error, line);
            }
          }
        }

      } catch (error: any) {
        if (error.name === 'AbortError') {
          console.log('请求已取消');
        } else {
          console.error('SSE POST请求失败:', error);
          if (this.options.onError) {
            this.options.onError(error.message || '请求失败');
          }
          reject(error);
        }
      }
    });
  }

  private async handleMessage(message: SSEMessage, resolve: Function, reject: Function) {
    switch (message.type) {
      case 'progress':
        if (this.options.onProgress && message.message && message.progress !== undefined) {
          this.options.onProgress(message.message, message.progress, message.status || 'processing');
        }
        break;

      case 'chunk':
        if (message.content) {
          this.accumulatedContent += message.content;
          if (this.options.onChunk) {
            this.options.onChunk(message.content);
          }
        }
        break;

      case 'result':
        if (this.options.onResult && message.data) {
          this.options.onResult(message.data);
        }
        (this as any).resultData = message.data;
        break;

      case 'error':
        if (this.options.onError) {
          this.options.onError(message.error || '未知错误', message.code);
        }
        reject(new Error(message.error || '未知错误'));
        break;

      case 'done':
        if (this.options.onComplete) {
          this.options.onComplete();
        }
        if ((this as any).resultData) {
          resolve((this as any).resultData);
        } else if (this.accumulatedContent) {
          resolve({ content: this.accumulatedContent });
        } else {
          resolve(true);
        }
        break;
    }
  }

  abort() {
    if (this.abortController) {
      this.abortController.abort();
    }
  }

  getAccumulatedContent(): string {
    return this.accumulatedContent;
  }
}

export async function ssePost<T = any>(
  url: string,
  data: any,
  options: SSEClientOptions = {}
): Promise<T> {
  const client = new SSEPostClient(url, data, options);
  try {
    return await client.connect();
  } finally {
    client.abort();
  }
}