using System;
using System.IO;

namespace PulseDock.App.Services.Implementations
{
    public class LoggerService : Interfaces.ILoggerService
    {
        private readonly string _logDir;
        private readonly string _logFilePath;
        private readonly object _lock = new();
        private const long MaxLogFileSizeBytes = 2 * 1024 * 1024; // 2 MB

        public LoggerService()
        {
            var appData = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
            _logDir = Path.Combine(appData, "PulseDock", "logs");
            Directory.CreateDirectory(_logDir);
            _logFilePath = Path.Combine(_logDir, "pulse_dock.log");
        }

        public void LogInfo(string message) => WriteLog("INFO", message);
        public void LogWarning(string message) => WriteLog("WARN", message);
        public void LogError(string message, Exception? exception = null)
        {
            var fullMessage = exception != null ? $"{message} | Exception: {exception}" : message;
            WriteLog("ERROR", fullMessage);
        }

        private void WriteLog(string level, string message)
        {
            lock (_lock)
            {
                try
                {
                    RotateLogsIfNeeded();
                    var line = $"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] [{level}] {message}{Environment.NewLine}";
                    File.AppendAllText(_logFilePath, line);
                }
                catch
                {
                    // Fail silently to avoid crash from logger
                }
            }
        }

        private void RotateLogsIfNeeded()
        {
            if (!File.Exists(_logFilePath)) return;

            var fileInfo = new FileInfo(_logFilePath);
            if (fileInfo.Length >= MaxLogFileSizeBytes)
            {
                var backupPath = Path.Combine(_logDir, $"pulse_dock_{DateTime.Now:yyyyMMdd_HHmmss}.log");
                File.Move(_logFilePath, backupPath);

                // Keep only top 3 oldest logs
                var oldLogs = Directory.GetFiles(_logDir, "pulse_dock_*.log");
                if (oldLogs.Length > 3)
                {
                    Array.Sort(oldLogs);
                    for (int i = 0; i < oldLogs.Length - 3; i++)
                    {
                        try { File.Delete(oldLogs[i]); } catch { }
                    }
                }
            }
        }
    }
}