import { useCallback } from 'react';
import { useTranslation } from 'react-i18next';
import { SSE } from 'sse';
import { getUserIdFromLocalStorage } from '../helpers/index.js';
import {
  API_ENDPOINTS,
  MESSAGE_STATUS,
  DEBUG_TABS
} from '../utils/constants';
import {
  buildApiPayload,
  handleApiError
} from '../utils/apiUtils';
import {
  processThinkTags,
  processIncompleteThinkTags
} from '../utils/messageUtils';

export const useApiRequest = (
  setMessage,
  setDebugData,
  setActiveDebugTab,
  sseSourceRef,
  saveMessages
) => {
  const { t } = useTranslation();

  // 处理消息自动关闭逻辑的公共函数
  const applyAutoCollapseLogic = useCallback((message, isThinkingComplete = true) => {
    const shouldAutoCollapse = isThinkingComplete && !message.hasAutoCollapsed;
    return {
      isThinkingComplete,
      hasAutoCollapsed: shouldAutoCollapse || message.hasAutoCollapsed,
      isReasoningExpanded: shouldAutoCollapse ? false : message.isReasoningExpanded,
    };
  }, []);

  // 流式消息更新
  const streamMessageUpdate = useCallback((textChunk, type) => {
    setMessage(prevMessage => {
      const lastMessage = prevMessage[prevMessage.length - 1];
      if (!lastMessage) return prevMessage;
      if (lastMessage.role !== 'assistant') return prevMessage;
      if (lastMessage.status === MESSAGE_STATUS.ERROR) {
        return prevMessage;
      }

      if (lastMessage.status === MESSAGE_STATUS.LOADING ||
        lastMessage.status === MESSAGE_STATUS.INCOMPLETE) {

        let newMessage = { ...lastMessage };

        if (type === 'reasoning') {
          newMessage = {
            ...newMessage,
            reasoningContent: (lastMessage.reasoningContent || '') + textChunk,
            status: MESSAGE_STATUS.INCOMPLETE,
            isThinkingComplete: false,
          };
        } else if (type === 'content') {
          const shouldCollapseReasoning = !lastMessage.content && lastMessage.reasoningContent;
          const newContent = (lastMessage.content || '') + textChunk;

          let shouldCollapseFromThinkTag = false;
          let thinkingCompleteFromTags = lastMessage.isThinkingComplete;

          if (lastMessage.isReasoningExpanded && newContent.includes('</think>')) {
            const thinkMatches = newContent.match(/<think>/g);
            const thinkCloseMatches = newContent.match(/<\/think>/g);
            if (thinkMatches && thinkCloseMatches &&
              thinkCloseMatches.length >= thinkMatches.length) {
              shouldCollapseFromThinkTag = true;
              thinkingCompleteFromTags = true; // think标签闭合也标记思考完成
            }
          }

          // 如果开始接收content内容，且之前有reasoning内容，或者think标签已闭合，则标记思考完成
          const isThinkingComplete = (lastMessage.reasoningContent && !lastMessage.isThinkingComplete) ||
            thinkingCompleteFromTags;

          const autoCollapseState = applyAutoCollapseLogic(lastMessage, isThinkingComplete);

          newMessage = {
            ...newMessage,
            content: newContent,
            status: MESSAGE_STATUS.INCOMPLETE,
            ...autoCollapseState,
          };
        }

        return [...prevMessage.slice(0, -1), newMessage];
      }

      return prevMessage;
    });
  }, [setMessage, applyAutoCollapseLogic]);

  // 完成消息
  const completeMessage = useCallback((status = MESSAGE_STATUS.COMPLETE) => {
    setMessage(prevMessage => {
      const lastMessage = prevMessage[prevMessage.length - 1];
      if (lastMessage.status === MESSAGE_STATUS.COMPLETE ||
        lastMessage.status === MESSAGE_STATUS.ERROR) {
        return prevMessage;
      }

      const autoCollapseState = applyAutoCollapseLogic(lastMessage, true);

      const updatedMessages = [
        ...prevMessage.slice(0, -1),
        {
          ...lastMessage,
          status: status,
          ...autoCollapseState,
        }
      ];

      // 在消息完成时保存，传入更新后的消息列表
      if (status === MESSAGE_STATUS.COMPLETE || status === MESSAGE_STATUS.ERROR) {
        setTimeout(() => saveMessages(updatedMessages), 0);
      }

      return updatedMessages;
    });
  }, [setMessage, applyAutoCollapseLogic, saveMessages]);

  // 非流式请求
  const handleNonStreamRequest = useCallback(async (payload) => {
    setDebugData(prev => ({
      ...prev,
      request: payload,
      timestamp: new Date().toISOString(),
      response: null
    }));
    setActiveDebugTab(DEBUG_TABS.REQUEST);

    try {
      const response = await fetch(API_ENDPOINTS.CHAT_COMPLETIONS, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'New-Api-User': getUserIdFromLocalStorage(),
        },
        body: JSON.stringify(payload),
      });

      if (!response.ok) {
        let errorBody = '';
        try {
          errorBody = await response.text();
        } catch (e) {
          errorBody = '无法读取错误响应体';
        }

        const errorInfo = handleApiError(
          new Error(`HTTP error! status: ${response.status}, body: ${errorBody}`),
          response
        );

        setDebugData(prev => ({
          ...prev,
          response: JSON.stringify(errorInfo, null, 2)
        }));
        setActiveDebugTab(DEBUG_TABS.RESPONSE);

        throw new Error(`HTTP error! status: ${response.status}, body: ${errorBody}`);
      }

      const data = await response.json();

      setDebugData(prev => ({
        ...prev,
        response: JSON.stringify(data, null, 2)
      }));
      setActiveDebugTab(DEBUG_TABS.RESPONSE);

      if (data.choices?.[0]) {
        const choice = data.choices[0];
        let content = choice.message?.content || '';
        let reasoningContent = choice.message?.reasoning_content || '';

        const processed = processThinkTags(content, reasoningContent);

        setMessage(prevMessage => {
          const newMessages = [...prevMessage];
          const lastMessage = newMessages[newMessages.length - 1];
          if (lastMessage?.status === MESSAGE_STATUS.LOADING) {
            const autoCollapseState = applyAutoCollapseLogic(lastMessage, true);

            newMessages[newMessages.length - 1] = {
              ...lastMessage,
              content: processed.content,
              reasoningContent: processed.reasoningContent,
              status: MESSAGE_STATUS.COMPLETE,
              ...autoCollapseState,
            };
          }
          return newMessages;
        });
      }
    } catch (error) {
      console.error('Non-stream request error:', error);

      const errorInfo = handleApiError(error);
      setDebugData(prev => ({
        ...prev,
        response: JSON.stringify(errorInfo, null, 2)
      }));
      setActiveDebugTab(DEBUG_TABS.RESPONSE);

      setMessage(prevMessage => {
        const newMessages = [...prevMessage];
        const lastMessage = newMessages[newMessages.length - 1];
        if (lastMessage?.status === MESSAGE_STATUS.LOADING) {
          const autoCollapseState = applyAutoCollapseLogic(lastMessage, true);

          newMessages[newMessages.length - 1] = {
            ...lastMessage,
            content: t('请求发生错误: ') + error.message,
            status: MESSAGE_STATUS.ERROR,
            ...autoCollapseState,
          };
        }
        return newMessages;
      });
    }
  }, [setDebugData, setActiveDebugTab, setMessage, t, applyAutoCollapseLogic]);

  // SSE请求
  const handleSSE = useCallback((payload) => {
    setDebugData(prev => ({
      ...prev,
      request: payload,
      timestamp: new Date().toISOString(),
      response: null
    }));
    setActiveDebugTab(DEBUG_TABS.REQUEST);

    const source = new SSE(API_ENDPOINTS.CHAT_COMPLETIONS, {
      headers: {
        'Content-Type': 'application/json',
        'New-Api-User': getUserIdFromLocalStorage(),
      },
      method: 'POST',
      payload: JSON.stringify(payload),
    });

    sseSourceRef.current = source;

    let responseData = '';
    let hasReceivedFirstResponse = false;

    source.addEventListener('message', (e) => {
      if (e.data === '[DONE]') {
        source.close();
        sseSourceRef.current = null;
        setDebugData(prev => ({ ...prev, response: responseData }));
        completeMessage();
        return;
      }

      try {
        const payload = JSON.parse(e.data);
        responseData += e.data + '\n';

        if (!hasReceivedFirstResponse) {
          setActiveDebugTab(DEBUG_TABS.RESPONSE);
          hasReceivedFirstResponse = true;
        }

        const delta = payload.choices?.[0]?.delta;
        if (delta) {
          if (delta.reasoning_content) {
            streamMessageUpdate(delta.reasoning_content, 'reasoning');
          }
          if (delta.content) {
            streamMessageUpdate(delta.content, 'content');
          }
        }
      } catch (error) {
        console.error('Failed to parse SSE message:', error);
        const errorInfo = `解析错误: ${error.message}`;

        setDebugData(prev => ({
          ...prev,
          response: responseData + `\n\nError: ${errorInfo}`
        }));
        setActiveDebugTab(DEBUG_TABS.RESPONSE);

        streamMessageUpdate(t('解析响应数据时发生错误'), 'content');
        completeMessage(MESSAGE_STATUS.ERROR);
      }
    });

    source.addEventListener('error', (e) => {
      console.error('SSE Error:', e);
      const errorMessage = e.data || t('请求发生错误');

      const errorInfo = handleApiError(new Error(errorMessage));
      errorInfo.readyState = source.readyState;

      setDebugData(prev => ({
        ...prev,
        response: responseData + '\n\nSSE Error:\n' + JSON.stringify(errorInfo, null, 2)
      }));
      setActiveDebugTab(DEBUG_TABS.RESPONSE);

      streamMessageUpdate(errorMessage, 'content');
      completeMessage(MESSAGE_STATUS.ERROR);
      sseSourceRef.current = null;
      source.close();
    });

    source.addEventListener('readystatechange', (e) => {
      if (e.readyState >= 2 && source.status !== undefined && source.status !== 200) {
        const errorInfo = handleApiError(new Error('HTTP状态错误'));
        errorInfo.status = source.status;
        errorInfo.readyState = source.readyState;

        setDebugData(prev => ({
          ...prev,
          response: responseData + '\n\nHTTP Error:\n' + JSON.stringify(errorInfo, null, 2)
        }));
        setActiveDebugTab(DEBUG_TABS.RESPONSE);

        source.close();
        streamMessageUpdate(t('连接已断开'), 'content');
        completeMessage(MESSAGE_STATUS.ERROR);
      }
    });

    try {
      source.stream();
    } catch (error) {
      console.error('Failed to start SSE stream:', error);
      const errorInfo = handleApiError(error);

      setDebugData(prev => ({
        ...prev,
        response: 'Stream启动失败:\n' + JSON.stringify(errorInfo, null, 2)
      }));
      setActiveDebugTab(DEBUG_TABS.RESPONSE);

      streamMessageUpdate(t('建立连接时发生错误'), 'content');
      completeMessage(MESSAGE_STATUS.ERROR);
    }
  }, [setDebugData, setActiveDebugTab, streamMessageUpdate, completeMessage, t, applyAutoCollapseLogic]);

  // 停止生成
  const onStopGenerator = useCallback(() => {
    // 如果仍有活动的 SSE 连接，首先关闭
    if (sseSourceRef.current) {
      sseSourceRef.current.close();
      sseSourceRef.current = null;
    }

    // 无论是否存在 SSE 连接，都尝试处理最后一条正在生成的消息
    setMessage(prevMessage => {
      if (prevMessage.length === 0) return prevMessage;
      const lastMessage = prevMessage[prevMessage.length - 1];

      if (lastMessage.status === MESSAGE_STATUS.LOADING ||
        lastMessage.status === MESSAGE_STATUS.INCOMPLETE) {

        const processed = processIncompleteThinkTags(
          lastMessage.content || '',
          lastMessage.reasoningContent || ''
        );

        const autoCollapseState = applyAutoCollapseLogic(lastMessage, true);

        const updatedMessages = [
          ...prevMessage.slice(0, -1),
          {
            ...lastMessage,
            status: MESSAGE_STATUS.COMPLETE,
            reasoningContent: processed.reasoningContent || null,
            content: processed.content,
            ...autoCollapseState,
          }
        ];

        // 停止生成时也保存，传入更新后的消息列表
        setTimeout(() => saveMessages(updatedMessages), 0);

        return updatedMessages;
      }
      return prevMessage;
    });
  }, [setMessage, applyAutoCollapseLogic, saveMessages]);

  // 发送请求
  const sendRequest = useCallback((payload, isStream) => {
    if (isStream) {
      handleSSE(payload);
    } else {
      handleNonStreamRequest(payload);
    }
  }, [handleSSE, handleNonStreamRequest]);

  return {
    sendRequest,
    onStopGenerator,
    streamMessageUpdate,
    completeMessage,
  };
}; 