import { Question } from '../types';

export class ParsingService {
  static parseText(text: string): Question[] {
    const lines = text.split('\n').map(l => l.trim()).filter(l => l.length > 0);
    const questions: Question[] = [];
    let currentQuestion: Partial<Question> | null = null;

    lines.forEach((line) => {
      // Detect Question: 1. or 1) or Question 1
      const qMatch = line.match(/^(\d+)[\.\)]\s*(.*)$/i) || line.match(/^Question\s*(\d+)[:\.]?\s*(.*)$/i) || line.match(/^Q(\d+)[:\.]?\s*(.*)$/i);
      
      if (qMatch) {
         if (currentQuestion && currentQuestion.text) {
            questions.push(currentQuestion as Question);
         }
         currentQuestion = {
            id: qMatch[1],
            text: qMatch[2],
            options: [],
            correctOptionId: '',
            category: 'General',
            difficulty: 'medium'
         };
         return;
      }

      // Detect Option: A. or A) or (A)
      const oMatch = line.match(/^([A-D])[\.\)]\s*(.*)$/i) || line.match(/^\(([A-D])\)\s*(.*)$/i);
      if (oMatch && currentQuestion) {
         currentQuestion.options?.push({
           id: `opt-${oMatch[1].toLowerCase()}`,
           text: oMatch[2]
         });
         return;
      }

      // Detect Answer: Answer: A
      const aMatch = line.match(/^Answer:\s*([A-D])/i);
      if (aMatch && currentQuestion) {
         currentQuestion.correctOptionId = `opt-${aMatch[1].toLowerCase()}`;
         return;
      }

      // If it's just more text for the current question
      if (currentQuestion && !oMatch && !aMatch) {
         currentQuestion.text += ' ' + line;
      }
    });

    if (currentQuestion && currentQuestion.text) {
       questions.push(currentQuestion as Question);
    }

    return questions;
  }
}