using System;
using System.IO;

namespace Housing.Services
{
    public class DatabaseSettings
    {
        public string Db_Server { get; set; } = string.Empty;
        public string Db_Name { get; set; } = string.Empty;
        public string Db_User { get; set; } = string.Empty;
        public string Db_Password { get; set; } = string.Empty;

        public static string GetDefaultFilePath()
        {
            string folder = AppDomain.CurrentDomain.BaseDirectory;
            if (!Directory.Exists(folder))
            {
                Directory.CreateDirectory(folder);
            }
            return Path.Combine(folder, "Database.ini");
        }

        private string _rawConnectionString = string.Empty;

        public string ConnectionString
        {
            get
            {
                // 개별 설정이 모두 지정되어 있는 경우 조합해서 사용
                if (!string.IsNullOrWhiteSpace(Db_Server) &&
                    !string.IsNullOrWhiteSpace(Db_Name) &&
                    !string.IsNullOrWhiteSpace(Db_User) &&
                    !string.IsNullOrWhiteSpace(Db_Password))
                {
                    return $"Server={Db_Server};Database={Db_Name};User Id={Db_User};Password={Db_Password};";
                }
                // 없으면 레거시 ConnectionString 필드를 그대로 사용
                return _rawConnectionString;
            }
            set
            {
                _rawConnectionString = value;
            }
        }

        private static readonly object _dbLock = new object();
        private static DatabaseSettings _cachedSettings;
        private static DateTime _lastWriteTime;
        private static string _cachedPath;

        public static DatabaseSettings Load(string path)
        {
            lock (_dbLock)
            {
                try
                {
                    if (File.Exists(path))
                    {
                        var currentWriteTime = File.GetLastWriteTime(path);
                        if (_cachedSettings != null && _cachedPath == path && _lastWriteTime == currentWriteTime)
                        {
                            return _cachedSettings;
                        }

                        var settings = new DatabaseSettings();
                        var lines = File.ReadAllLines(path);
                        foreach (var line in lines)
                        {
                            var trimmed = line.Trim();

                            // 주석 행 스킵
                            if (trimmed.StartsWith(";") || trimmed.StartsWith("#"))
                            {
                                continue;
                            }

                            if (trimmed.StartsWith("ConnectionString", StringComparison.OrdinalIgnoreCase))
                            {
                                var parts = trimmed.Split(new[] { '=' }, 2);
                                if (parts.Length == 2)
                                {
                                    settings.ConnectionString = parts[1].Trim();
                                }
                            }
                            else if (trimmed.StartsWith("Db_Server", StringComparison.OrdinalIgnoreCase))
                            {
                                var parts = trimmed.Split(new[] { '=' }, 2);
                                if (parts.Length == 2)
                                {
                                    settings.Db_Server = parts[1].Trim();
                                }
                            }
                            else if (trimmed.StartsWith("Db_Name", StringComparison.OrdinalIgnoreCase))
                            {
                                var parts = trimmed.Split(new[] { '=' }, 2);
                                if (parts.Length == 2)
                                {
                                    settings.Db_Name = parts[1].Trim();
                                }
                            }
                            else if (trimmed.StartsWith("Db_User", StringComparison.OrdinalIgnoreCase))
                            {
                                var parts = trimmed.Split(new[] { '=' }, 2);
                                if (parts.Length == 2)
                                {
                                    settings.Db_User = parts[1].Trim();
                                }
                            }
                            else if (trimmed.StartsWith("Db_Password", StringComparison.OrdinalIgnoreCase))
                            {
                                var parts = trimmed.Split(new[] { '=' }, 2);
                                if (parts.Length == 2)
                                {
                                    settings.Db_Password = parts[1].Trim();
                                }
                            }
                        }
                        _cachedSettings = settings;
                        _lastWriteTime = currentWriteTime;
                        _cachedPath = path;
                        return settings;
                    }
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine($"[DatabaseSettings Load Error] {ex.Message}");
                }
                return _cachedSettings ?? new DatabaseSettings();
            }
        }
    }
}