import { ref } from "vue";

// 火山方舟 Chat Completions API 配置
const LLM_API_URL =
  "https://ai.yantootech.com/polyhedron/api/ark/chat/completions";
const DEFAULT_MODEL = "bot-20260605135355-68pth";

// ChatBase API 配置
const CHATBASE_API_URL = "https://www.chatbase.co/api/v1/chat";
const CHATBASE_API_KEY = "ca4616db-417c-4dce-8c65-b9909621f53e";
const CHATBASE_CHATBOT_ID = "TRIe58TuVExBm6K0HKTfz";

interface LLMMessage {
  role: "system" | "user" | "assistant";
  content: string;
}

interface ChatBaseMessage {
  content: string;
  role: "user";
}

interface LLMChoice {
  index: number;
  message: {
    role: string;
    content: string;
  };
  finish_reason: string;
}

interface LLMResponse {
  id?: string;
  object?: string;
  created?: number;
  model?: string;
  choices?: LLMChoice[];
  usage?: {
    prompt_tokens: number;
    completion_tokens: number;
    total_tokens: number;
  };
  error?: string;
  details?: string;
}

export function useLLM() {
  const isLoading = ref(false);
  const error = ref("");
  const conversationHistory = ref<LLMMessage[]>([]);

  const SYSTEM_PROMPT: LLMMessage = {
    role: "system",
    content: "你是一个友好的数字人助手，请用简洁自然的语言回答用户的问题。",
  };

  const sendToLLM = async (userMessage: string): Promise<string> => {
    if (!userMessage.trim()) return "";

    isLoading.value = true;
    error.value = "";

    conversationHistory.value.push({
      role: "user",
      content: userMessage,
    });

    try {
      const messages: LLMMessage[] = [
        SYSTEM_PROMPT,
        ...conversationHistory.value,
      ];

      const response = await fetch(LLM_API_URL, {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          model: DEFAULT_MODEL,
          stream: false,
          messages,
        }),
      });

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

      const data: LLMResponse = await response.json();

      if (data.error) {
        throw new Error(`API错误: ${data.error}`);
      }

      const aiReply = data.choices?.[0]?.message?.content || "";

      conversationHistory.value.push({
        role: "assistant",
        content: aiReply,
      });

      return aiReply;
    } catch (err: any) {
      const errorMsg = err.message || "请求失败";
      error.value = errorMsg;
      console.error("LLM请求错误:", err);
      throw err;
    } finally {
      isLoading.value = false;
    }
  };

  const clearHistory = () => {
    conversationHistory.value = [];
  };

  const sendToChatBase = async (userMessage: string): Promise<string> => {
    if (!userMessage.trim()) return "";

    isLoading.value = true;
    error.value = "";

    try {
      const messages: ChatBaseMessage[] = [
        { content: userMessage, role: "user" },
      ];

      const response = await fetch(CHATBASE_API_URL, {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
          Authorization: `Bearer ${CHATBASE_API_KEY}`,
        },
        body: JSON.stringify({
          messages,
          chatbotId: CHATBASE_CHATBOT_ID,
        }),
      });

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

      const data = await response.json();
      const aiReply = data.text || "";

      conversationHistory.value.push({
        role: "user",
        content: userMessage,
      });

      conversationHistory.value.push({
        role: "assistant",
        content: aiReply,
      });

      return aiReply;
    } catch (err: any) {
      const errorMsg = err.message || "请求失败";
      error.value = errorMsg;
      console.error("ChatBase请求错误:", err);
      throw err;
    } finally {
      isLoading.value = false;
    }
  };

  return {
    isLoading,
    error,
    conversationHistory,
    sendToLLM,
    sendToChatBase,
    clearHistory,
  };
}