package xitongshezhi;

import java.io.*;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.concurrent.locks.ReentrantLock;

public class Charulog {
    private static final String LOG_FILE = "log.properties";
    private static final int MAX_RECORDS = 500;
    private static final ReentrantLock lock = new ReentrantLock();
    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    /**
     * 静态方法：记录操作日志
     * @param operation 操作内容
     */
    public static void logOperation(String operation) {
        lock.lock();
        try {
            // 添加时间戳
            String timestamp = dateFormat.format(new Date());
            String logEntry = "[" + timestamp + "] " + operation;
            
            // 读取现有日志
            Properties logProps = readLogFile();
            
            // 添加新记录
            addNewLogEntry(logProps, logEntry);
            
            // 如果超过最大记录数，删除最早的记录
            if (logProps.size() > MAX_RECORDS) {
                removeOldestEntries(logProps);
            }
            
            // 写回文件
            writeLogFile(logProps);
            
        } catch (Exception e) {
            System.err.println("记录日志时发生错误: " + e.getMessage());
        } finally {
            lock.unlock();
        }
    }
    
    /**
     * 读取日志文件
     */
    private static Properties readLogFile() {
        Properties props = new Properties();
        File file = new File(LOG_FILE);
        
        if (file.exists()) {
            try (FileInputStream fis = new FileInputStream(file)) {
                props.load(fis);
            } catch (IOException e) {
                System.err.println("读取日志文件失败: " + e.getMessage());
            }
        }
        
        return props;
    }
    
    /**
     * 添加新的日志条目
     */
    private static void addNewLogEntry(Properties props, String logEntry) {
        // 使用时间戳作为key，确保唯一性
        String key = "log_" + System.currentTimeMillis() + "_" + UUID.randomUUID().toString().substring(0, 8);
        props.setProperty(key, logEntry);
    }
    
    /**
     * 移除最早的记录
     */
    private static void removeOldestEntries(Properties props) {
        // 将属性转换为列表以便排序
        List<Map.Entry<Object, Object>> entries = new ArrayList<>(props.entrySet());
        
        // 按键排序（假设键包含时间信息）
        entries.sort((e1, e2) -> {
            String key1 = (String) e1.getKey();
            String key2 = (String) e2.getKey();
            return key1.compareTo(key2);
        });
        
        // 删除超出限制的最早记录
        while (entries.size() > MAX_RECORDS) {
            Map.Entry<Object, Object> oldest = entries.remove(0);
            props.remove(oldest.getKey());
        }
    }
    
    /**
     * 写入日志文件
     */
    private static void writeLogFile(Properties props) {
        try (FileOutputStream fos = new FileOutputStream(LOG_FILE)) {
            // 添加文件头注释
            props.store(fos, "操作日志记录 - 最后更新: " + new Date());
        } catch (IOException e) {
            System.err.println("写入日志文件失败: " + e.getMessage());
        }
    }
    
    /**
     * 获取当前日志记录数量（用于测试）
     */
    public static int getLogCount() {
        Properties props = readLogFile();
        return props.size();
    }
    
    /**
     * 清空日志文件（用于测试）
     */
    public static void clearLogs() {
        lock.lock();
        try {
            Properties props = new Properties();
            writeLogFile(props);
        } finally {
            lock.unlock();
        }
    }
    
    /**
     * 读取并打印所有日志（用于测试）
     */
    public static void printAllLogs() {
        Properties props = readLogFile();
        List<Map.Entry<Object, Object>> entries = new ArrayList<>(props.entrySet());
        
        // 按键排序
        entries.sort((e1, e2) -> {
            String key1 = (String) e1.getKey();
            String key2 = (String) e2.getKey();
            return key1.compareTo(key2);
        });
        
        System.out.println("=== 操作日志记录 (共 " + entries.size() + " 条) ===");
        for (Map.Entry<Object, Object> entry : entries) {
            System.out.println(entry.getValue());
        }
        System.out.println("=== 日志结束 ===");
    }
    
}