// File: frontend/lib/api.ts (Update)
// Description: 添加运行工作流的 API 函数

import axios from "axios";
import type { Node, Edge } from "reactflow"; // Import React Flow types
import type {
  Assistant,
  Session,
  Message,
  AssistantCreateData,
  AssistantUpdateData,
  ChatApiResponse,
} from "./types"; // Assuming types are defined

// --- Types ---
// Workflow Run types (match backend pydantic models)
interface WorkflowNodeData {
  label?: string | null;
  text?: string | null;
  displayText?: string | null;
  model?: string | null;
  temperature?: number | null;
  systemPrompt?: string | null;
  // Add other node data fields as needed
  [key: string]: any; // Allow extra fields
}
interface WorkflowNode {
  id: string;
  type: string;
  position: { x: number; y: number };
  data: WorkflowNodeData;
}
interface WorkflowEdge {
  id: string;
  source: string;
  target: string;
  sourceHandle?: string | null;
  targetHandle?: string | null;
}
interface WorkflowRunPayload {
  nodes: WorkflowNode[];
  edges: WorkflowEdge[];
}
export interface WorkflowRunResult {
  success: boolean;
  message?: string | null;
  output?: string | null;
  output_node_id?: string | null;
}

// --- API Client Setup ---
const API_BASE_URL =
  process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000/api/v1";

const apiClient = axios.create({
  baseURL: API_BASE_URL,
  headers: {
    "Content-Type": "application/json",
  },
});

// --- Helper for Error Handling ---
const handleApiError = (error: unknown, context: string): string => {
  console.error(`API Error (${context}):`, error);
  if (axios.isAxiosError(error) && error.response) {
    // 尝试提取后端返回的详细错误信息
    return (
      error.response.data?.detail || `服务器错误 (${error.response.status})`
    );
  } else if (error instanceof Error) {
    return error.message;
  }
  return "发生未知网络错误";
};

// --- Chat API ---
/**
 * 发送聊天消息到后端 (更新)
 * @param message 用户消息
 * @param sessionId 当前会话 ID (可以是 'temp-new-chat')
 * @param assistantId 当前助手 ID
 * @returns 包含 AI 回复和可能的新会话信息的对象
 */
export const sendChatMessage = async (
  message: string,
  sessionId: string,
  assistantId: string
): Promise<ChatApiResponse> => {
  try {
    const response = await apiClient.post<ChatApiResponse>("/chat/", {
      message,
      session_id: sessionId,
      assistant_id: assistantId,
    });
    return response.data; // 返回整个响应体
  } catch (error) {
    throw new Error(handleApiError(error, "sendChatMessage"));
  }
};

// --- Assistant API ---
/** 获取所有助手列表 */
export const getAssistants = async (): Promise<Assistant[]> => {
  try {
    const response = await apiClient.get<Assistant[]>("/assistants/");
    return response.data;
  } catch (error) {
    throw new Error(handleApiError(error, "getAssistants"));
  }
};

/** 创建新助手 */
export const createAssistant = async (
  data: AssistantCreateData
): Promise<Assistant> => {
  try {
    const response = await apiClient.post<Assistant>("/assistants/", data);
    return response.data;
  } catch (error) {
    throw new Error(handleApiError(error, "createAssistant"));
  }
};

/** 更新助手 */
export const updateAssistant = async (
  id: string,
  data: AssistantUpdateData
): Promise<Assistant> => {
  try {
    const response = await apiClient.put<Assistant>(`/assistants/${id}`, data);
    return response.data;
  } catch (error) {
    throw new Error(handleApiError(error, "updateAssistant"));
  }
};

/** 删除助手 */
export const deleteAssistant = async (id: string): Promise<void> => {
  try {
    await apiClient.delete(`/assistants/${id}`);
  } catch (error) {
    throw new Error(handleApiError(error, "deleteAssistant"));
  }
};

// --- Session API ---
/** 获取指定助手的所有会话 */
export const getSessionsByAssistant = async (
  assistantId: string
): Promise<Session[]> => {
  try {
    const response = await apiClient.get<Session[]>(
      `/sessions/assistant/${assistantId}`
    );
    return response.data;
  } catch (error) {
    // 如果助手没有会话，后端可能返回 404 或空列表，这里统一处理为返回空列表
    if (axios.isAxiosError(error) && error.response?.status === 404) {
      return [];
    }
    throw new Error(handleApiError(error, "getSessionsByAssistant"));
  }
};

/** 删除会话 */
export const deleteSession = async (sessionId: string): Promise<void> => {
  try {
    await apiClient.delete(`/sessions/${sessionId}`);
  } catch (error) {
    throw new Error(handleApiError(error, "deleteSession"));
  }
};

// 注意：创建会话的 API (POST /sessions/) 在后端被整合到了 POST /chat/ 逻辑中，
//当前端发送 sessionId 为 'temp-new-chat' 的消息时，后端会自动创建。
//如果需要单独创建会话（例如，不发送消息就创建），则需要单独实现前端调用 POST /sessions/。

// --- Message API (New) ---
/** 获取指定会话的消息列表 */
export const getMessagesBySession = async (
  sessionId: string,
  limit: number = 100,
  skip: number = 0
): Promise<Message[]> => {
  try {
    const response = await apiClient.get<Message[]>(
      `/messages/session/${sessionId}`,
      {
        params: { limit, skip },
      }
    );
    return response.data;
  } catch (error) {
    // Handle 404 specifically if needed (session exists but no messages)
    if (axios.isAxiosError(error) && error.response?.status === 404) {
      return []; // Return empty list if session not found or no messages
    }
    throw new Error(handleApiError(error, "getMessagesBySession"));
  }
};

// --- Workflow API (New) ---
/**
 * 发送工作流定义到后端执行
 * @param nodes - React Flow 节点数组
 * @param edges - React Flow 边数组
 * @returns 工作流执行结果
 */
export const runWorkflow = async (nodes: Node[], edges: Edge[]): Promise<WorkflowRunResult> => {
    // Map React Flow nodes/edges to the structure expected by the backend API
    const payload: WorkflowRunPayload = {
        nodes: nodes.map(n => ({
            id: n.id,
            type: n.type || 'default', // Ensure type is present
            position: n.position,
            data: n.data as WorkflowNodeData, // Assume data matches for now
        })),
        edges: edges.map(e => ({
            id: e.id,
            source: e.source,
            target: e.target,
            sourceHandle: e.sourceHandle,
            targetHandle: e.targetHandle,
        })),
    };

    try {
        const response = await apiClient.post<WorkflowRunResult>('/workflow/run', payload);
        return response.data;
    } catch (error) {
        // Return a failed result structure on API error
        return {
            success: false,
            message: handleApiError(error, 'runWorkflow'),
        };
    }
};