using System;
using System.IO;
using System.Text;
using UnityEngine;
namespace IchniOnline.Online.Util
{
    public class PersistentFileLogger : MonoBehaviour
    {
        private static StreamWriter _writer;
        private static readonly object LockObj = new object();

        private string _logFilePath;

        [Header("日志文件夹名称")]
        public string logFolderName = "Logs";

        [Header("启动时打印日志路径")]
        public bool printLogPath = true;

        private void Awake()
        {
            DontDestroyOnLoad(gameObject);

            InitializeLogger();
        }

        private void InitializeLogger()
        {
            if (_writer != null)
                return;

            string logDir = Path.Combine(
                Application.persistentDataPath,
                logFolderName);

            Directory.CreateDirectory(logDir);

            string fileName =
                $"log_{DateTime.Now:yyyyMMdd_HHmmss}.txt";

            _logFilePath = Path.Combine(logDir, fileName);

            _writer = new StreamWriter(
                new FileStream(
                    _logFilePath,
                    FileMode.Create,
                    FileAccess.Write,
                    FileShare.ReadWrite,
                    4096,
                    FileOptions.WriteThrough),
                Encoding.UTF8);

            _writer.AutoFlush = true;

            Application.logMessageReceivedThreaded += OnLogReceived;

            WriteRaw("==================================================");
            WriteRaw($"Unity Version : {Application.unityVersion}");
            WriteRaw($"Platform      : {Application.platform}");
            WriteRaw($"Start Time    : {DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}");
            WriteRaw($"Log File      : {_logFilePath}");
            WriteRaw("==================================================");

            if (printLogPath)
            {
                Debug.Log($"Log file: {_logFilePath}");
            }
        }

        private void OnDestroy()
        {
            ShutdownLogger();
        }

        private void OnApplicationQuit()
        {
            ShutdownLogger();
        }

        private void ShutdownLogger()
        {
            Application.logMessageReceivedThreaded -= OnLogReceived;

            lock (LockObj)
            {
                if (_writer != null)
                {
                    WriteRaw("Application Exit");

                    _writer.Flush();
                    _writer.Close();
                    _writer.Dispose();

                    _writer = null;
                }
            }
        }

        private static void OnLogReceived(
            string condition,
            string stackTrace,
            LogType type)
        {
            lock (LockObj)
            {
                if (_writer == null)
                    return;

                string timestamp =
                    DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");

                _writer.WriteLine(
                    $"[{timestamp}] [{type}] {condition}");

                if (type == LogType.Error ||
                    type == LogType.Exception ||
                    type == LogType.Assert)
                {
                    if (!string.IsNullOrWhiteSpace(stackTrace))
                    {
                        _writer.WriteLine(stackTrace);
                    }
                }

                _writer.Flush();
            }
        }

        private static void WriteRaw(string message)
        {
            lock (LockObj)
            {
                if (_writer == null)
                    return;

                _writer.WriteLine(message);
                _writer.Flush();
            }
        }
    }
}