import { GoogleGenAI, Type } from "@google/genai";
import { Quiz, Question, AnswerOption } from "../types";
import { v4 as uuidv4 } from 'uuid';

const getClient = () => {
  const apiKey = process.env.API_KEY;
  if (!apiKey) {
    throw new Error("API_KEY environment variable is missing");
  }
  return new GoogleGenAI({ apiKey });
};

export const generateQuiz = async (topic: string): Promise<Quiz> => {
  const ai = getClient();
  
  const prompt = `Generate a trivia quiz about "${topic}". Create 10 engaging multiple-choice questions. Each question must have exactly 4 options, and exactly one correct answer. Vary the difficulty. For each option, provide a brief reason explaining why it is correct or incorrect - this helps players learn.`;

  const response = await ai.models.generateContent({
    model: "gemini-3-flash-preview",
    contents: prompt,
    config: {
      responseMimeType: "application/json",
      responseSchema: {
        type: Type.OBJECT,
        properties: {
          title: { type: Type.STRING, description: "A catchy title for the quiz" },
          questions: {
            type: Type.ARRAY,
            items: {
              type: Type.OBJECT,
              properties: {
                text: { type: Type.STRING, description: "The question text" },
                options: {
                  type: Type.ARRAY,
                  items: {
                    type: Type.OBJECT,
                    properties: {
                      text: { type: Type.STRING },
                      isCorrect: { type: Type.BOOLEAN },
                      reason: { type: Type.STRING, description: "Brief explanation of why this answer is correct or incorrect" }
                    },
                    required: ["text", "isCorrect", "reason"]
                  },
                }
              },
              required: ["text", "options"]
            }
          }
        },
        required: ["title", "questions"]
      }
    }
  });

  if (!response.text) {
    throw new Error("Failed to generate quiz content");
  }

  const data = JSON.parse(response.text);
  
  // Transform to our internal type with shapes/colors pre-assigned
  const questions: Question[] = data.questions.map((q: any) => {
    const shapes = ['triangle', 'diamond', 'circle', 'square'] as const;
    const colors = ['red', 'blue', 'yellow', 'green'] as const;
    
    // Shuffle options so the correct one isn't always first (though Gemini usually randomizes, safety first)
    // Actually, to map shapes consistently, let's keep array order but assign props
    const options: AnswerOption[] = q.options.map((opt: any, index: number) => ({
      text: opt.text,
      isCorrect: opt.isCorrect,
      shape: shapes[index % 4],
      color: colors[index % 4],
      reason: opt.reason
    }));

    return {
      id: uuidv4(),
      text: q.text,
      options: options,
      timeLimit: 20
    };
  });

  return {
    title: data.title,
    questions
  };
};