import { AIMessage } from '@langchain/core/messages';
import { RunnableConfig } from '@langchain/core/runnables';
import { EvaluationState } from '../state';

/**
 * Node responsible for presenting the current question or follow-up to the user.
 */
export const interviewerNode = async (
  state: EvaluationState,
  config?: RunnableConfig,
): Promise<Partial<EvaluationState>> => {
  const { questions, currentQuestionIndex, shouldFollowUp, messages } = state;

  console.log('[InterviewerNode] Entering node...', {
    numQuestions: questions?.length,
    currentIndex: currentQuestionIndex,
    shouldFollowUp,
    numMessages: messages?.length,
  });

  if (!questions || questions.length === 0) {
    const isZh = state.language === 'zh';
    const isJa = state.language === 'ja';
    const msg = isZh
      ? '很抱歉，我无法为此会话生成任何问题。'
      : isJa
        ? '申し訳ありませんが、このセッションの問題を生成できませんでした。'
        : "I'm sorry, I couldn't generate any questions for this session.";
    return {
      messages: [new AIMessage(msg)],
    };
  }

  const currentQuestion = questions[currentQuestionIndex];

  if (currentQuestionIndex >= questions.length) {
    return { shouldFollowUp: false };
  }

  const isZh = state.language === 'zh';
  const isJa = state.language === 'ja';

  let prompt = '';

  if (
    shouldFollowUp &&
    state.feedbackHistory &&
    state.feedbackHistory.length > 0
  ) {
    const lastFeedbackMsg =
      state.feedbackHistory[state.feedbackHistory.length - 1];
    prompt = lastFeedbackMsg.content.toString();
  } else if (currentQuestion.questionType === 'MULTIPLE_CHOICE' && currentQuestion.options?.length > 0) {
    const label = isZh
      ? `问题 ${currentQuestionIndex + 1}`
      : isJa
        ? `質問 ${currentQuestionIndex + 1}`
        : `Question ${currentQuestionIndex + 1}`;

    const instruction = isZh
      ? '请选择一个选项'
      : isJa
        ? '選択肢から1つ選んでください'
        : 'Please select one option';

    prompt = `${label}: ${currentQuestion.questionText}\n\n${instruction}`;
  } else {
    const label = isZh
      ? `问题 ${currentQuestionIndex + 1}`
      : isJa
        ? `質問 ${currentQuestionIndex + 1}`
        : `Question ${currentQuestionIndex + 1}`;

    const instruction = isZh
      ? '请提供您的回答。'
      : isJa
        ? '回答を入力してください。'
        : 'Please provide your answer.';

    prompt = `${label}: ${currentQuestion.questionText}\n\n${instruction}`;
  }

  console.log('[InterviewerNode] Returning question:', { currentQuestionIndex, questionText: currentQuestion?.questionText });
  return {
    messages: [new AIMessage(prompt)],
    shouldFollowUp: false,
  };
};