package model;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;


/**
 * 读取用户文件夹下已有题目的所有题目文本（用于查重）
 */
public class LoadFile {

  public static List<String> loadExistingQuestions(String username) {
    List<String> all = new ArrayList<>();
    Path userDir = Paths.get("data", username);
    if (!Files.exists(userDir)) {
      return all;
    }
    try (DirectoryStream<Path> ds = Files.newDirectoryStream(userDir, "*.txt")) {
      for (Path p : ds) {
        List<String> lines = Files.readAllLines(p, StandardCharsets.UTF_8);
        StringBuilder cur = new StringBuilder();
        for (String line : lines) {
          if (line.matches("^\\s*\\d+\\..*")) {
            if (!cur.isEmpty()) {
              all.add(cur.toString().trim());
            }
            cur.setLength(0);
            cur.append(line.replaceFirst("^\\s*\\d+\\.", "").trim());
          } else {
            if (line.trim().isEmpty()) {
              if (!cur.isEmpty()) {
                all.add(cur.toString().trim());
                cur.setLength(0);
              }
            } else {
              if (!cur.isEmpty()) {
                cur.append(" ");
              }
              cur.append(line.trim());
            }
          }
        }
        if (!cur.isEmpty()) {
          all.add(cur.toString().trim());
        }
      }
    } catch (IOException e) {
      throw new RuntimeException("读取题目文件失败：" + e.getMessage(), e);
    }
    return all.stream().map(String::trim).filter(s -> !s.isEmpty()).distinct()
        .collect(Collectors.toList());
  }
}