package src;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;

public class FileManager {

  private String baseDir;

  public FileManager() {
    this.baseDir = System.getProperty("user.dir") + File.separator + "papers";
    createBaseDirectory();
  }

  // 创建基础目录
  private void createBaseDirectory() {
    File dir = new File(baseDir);
    if (!dir.exists()) {
      dir.mkdirs();
    }
  }

  // 为用户创建目录
  private String createUserDirectory(String username) {
    String userDir = baseDir + File.separator + username;
    File dir = new File(userDir);
    if (!dir.exists()) {
      dir.mkdirs();
    }
    return userDir;
  }

  // 生成文件名
  private String generateFileName() {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
    return sdf.format(new Date()) + ".txt";
  }

  // 保存题目到文件
  public void saveQuestions(String username, String[] questions) throws IOException {
    String userDir = createUserDirectory(username);
    String fileName = generateFileName();
    String filePath = userDir + File.separator + fileName;

    try (PrintWriter writer = new PrintWriter(new FileWriter(filePath))) {
      for (int i = 0; i < questions.length; i++) {
        writer.println((i + 1) + ". " + questions[i]);
        if (i < questions.length - 1) {
          writer.println(); // 题目之间空一行
        }
      }
    }

    System.out.println("题目已保存到: " + filePath);
  }

  // 检查题目是否重复（读取用户目录下所有文件）
  public Set<String> loadExistingQuestions(String username) {
    Set<String> existingQuestions = new HashSet<>();
    String userDir = baseDir + File.separator + username;
    File dir = new File(userDir);

    if (dir.exists() && dir.isDirectory()) {
      File[] files = dir.listFiles((d, name) -> name.endsWith(".txt"));
      if (files != null) {
        for (File file : files) {
          try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
            String line;
            StringBuilder questionBuilder = new StringBuilder();
            while ((line = reader.readLine()) != null) {
              if (line.trim().isEmpty()) {
                if (!questionBuilder.isEmpty()) {
                  // 移除题号
                  String question = questionBuilder.toString().replaceAll("^\\d+\\.\\s*", "");
                  existingQuestions.add(question.trim());
                  questionBuilder.setLength(0);
                }
              } else {
                questionBuilder.append(line).append(" ");
              }
            }
            // 处理最后一个题目
            if (!questionBuilder.isEmpty()) {
              String question = questionBuilder.toString().replaceAll("^\\d+\\.\\s*", "");
              existingQuestions.add(question.trim());
            }
          } catch (IOException e) {
            System.out.println("读取文件失败: " + file.getName());
          }
        }
      }
    }

    return existingQuestions;
  }
}