import java.util.HashSet;
import java.util.Random;
import java.util.Set;


public class PaperGenerator {
    private IQuestionGenerator questionGenerator;
    private User currentUser;
    private Random random;
    
    public PaperGenerator(User user) {
        this.currentUser = user;
        this.questionGenerator = QuestionGeneratorFactory.createGenerator(user.getUserType());
        this.random = new Random();
    }
    
    public void setUserType(UserType userType) {
        this.questionGenerator = QuestionGeneratorFactory.createGenerator(userType);
    }
    
    public String[] generatePaper(int questionCount, Filemanager fileManager) {
        if (questionCount < 10 || questionCount > 30) {
            throw new IllegalArgumentException("题目数量必须在10-30之间");
        }
        
        Set<String> allHistoryQuestions = fileManager.loadAllQuestions(currentUser.getUsername());
        System.out.println("历史题目数量: " + allHistoryQuestions.size());
        
        String[] questions = new String[questionCount];
        Set<String> usedQuestions = new HashSet<>();
        
        for (int i = 0; i < questionCount; i++) {
            String question;
            int attempt = 0;
            int maxAttempts = 500; 
            
            do {
                question = questionGenerator.generateQuestion();
                attempt++;
                
                if (attempt > 100) {
                    question = generateSimpleQuestion();
                }
                
                if (attempt >= maxAttempts) {
                    System.out.println("警告：第 " + (i+1) + " 题尝试次数过多，使用备用题目");
                    question = generateFallbackQuestion();
                    break;
                }
                
            } while (allHistoryQuestions.contains(question) || 
                     usedQuestions.contains(question) || 
                     !questionGenerator.isValidQuestion(question));
            
            usedQuestions.add(question);
            questions[i] = (i + 1) + ". " + question;
            System.out.println("成功生成第 " + (i+1) + " 题");
        }
        
        return questions;
    }
    

    private String generateSimpleQuestion() {
        switch (currentUser.getUserType()) {
            case PRIMARY:
                return generateSimplePrimaryQuestion();
            case JUNIOR:
                return generateSimpleJuniorQuestion();
            case SENIOR:
                return generateSimpleSeniorQuestion();
            default:
                return generateSimplePrimaryQuestion();
        }
    }
    
    private String generateSimplePrimaryQuestion() {
        int a = random.nextInt(100) + 1;
        int b = random.nextInt(100) + 1;
        String[] ops = {"+", "-", "*", "/"};
        String op = ops[random.nextInt(ops.length)];
        return a + " " + op + " " + b + " = ";
    }
    
    private String generateSimpleJuniorQuestion() {
        int a = random.nextInt(100) + 1;
        int b = random.nextInt(100) + 1;
        String[] ops = {"+", "-", "*", "/"};
        String op = ops[random.nextInt(ops.length)];
        
        if (random.nextBoolean()) {
            return "√" + a + " " + op + " " + b + " = ";
        } else {
            return a + "² " + op + " " + b + " = ";
        }
    }
    
    private String generateSimpleSeniorQuestion() {
        int a = random.nextInt(100) + 1;
        int angle = random.nextInt(360) + 1;
        String[] ops = {"+", "-", "*", "/"};
        String op = ops[random.nextInt(ops.length)];
        String[] trig = {"sin", "cos", "tan"};
        String trigFunc = trig[random.nextInt(trig.length)];
        
        return trigFunc + "(" + angle + "°) " + op + " " + a + " = ";
    }
    
    private String generateFallbackQuestion() {
        switch (currentUser.getUserType()) {
            case PRIMARY:
                return (random.nextInt(100) + 1) + " + " + (random.nextInt(100) + 1) + " = ";
            case JUNIOR:
                return "√" + (random.nextInt(100) + 1) + " + " + (random.nextInt(100) + 1) + " = ";
            case SENIOR:
                return "sin(" + (random.nextInt(360) + 1) + "°) + " + (random.nextInt(100) + 1) + " = ";
            default:
                return (random.nextInt(100) + 1) + " + " + (random.nextInt(100) + 1) + " = ";
        }
    }
}