using System;
using System.Collections.Generic;
using System.IO;
using System.Xml.Serialization;

namespace Housing.Services
{
    // XML 직렬화를 위한 데이터 컨테이너 클래스 정의
    [XmlRoot("LoginHistory")]
    public class LoginHistoryData
    {
        [XmlElement("Category")]
        public List<HistoryCategory> Categories { get; set; } = new List<HistoryCategory>();
    }

    public class HistoryCategory
    {
        [XmlAttribute("Name")]
        public string Name { get; set; }

        [XmlElement("Value")]
        public List<string> Values { get; set; } = new List<string>();
    }

    public class LoginHistoryStore
    {
        private readonly string _filePath;
        private readonly Dictionary<string, List<string>> _history = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);

        private LoginHistoryStore(string filePath)
        {
            _filePath = filePath;
        }

        public static LoginHistoryStore Load(string path)
        {
            var store = new LoginHistoryStore(path);
            store.LoadFromFile();
            return store;
        }

        public List<string> GetValues(string fieldName)
        {
            if (_history.TryGetValue(fieldName, out var list))
            {
                return new List<string>(list);
            }
            return new List<string>();
        }

        public void Remember(string fieldName, string value)
        {
            if (string.IsNullOrWhiteSpace(value)) return;
            value = value.Trim();

            if (!_history.TryGetValue(fieldName, out var list))
            {
                list = new List<string>();
                _history[fieldName] = list;
            }

            // 중복 제거 및 맨 앞으로 이동
            list.RemoveAll(x => string.Equals(x, value, StringComparison.OrdinalIgnoreCase));
            list.Insert(0, value);

            // 최대 5개 이력 유지
            if (list.Count > 5)
            {
                list.RemoveRange(5, list.Count - 5);
            }
        }

        public bool Forget(string fieldName, string value)
        {
            if (string.IsNullOrWhiteSpace(value)) return false;
            value = value.Trim();

            if (_history.TryGetValue(fieldName, out var list))
            {
                bool removed = list.RemoveAll(x => string.Equals(x, value, StringComparison.OrdinalIgnoreCase)) > 0;
                return removed;
            }
            return false;
        }

        public void Save()
        {
            try
            {
                var dir = Path.GetDirectoryName(_filePath);
                if (!string.IsNullOrEmpty(dir) && !Directory.Exists(dir))
                {
                    Directory.CreateDirectory(dir);
                }

                var data = new LoginHistoryData();
                foreach (var kvp in _history)
                {
                    data.Categories.Add(new HistoryCategory
                    {
                        Name = kvp.Key,
                        Values = kvp.Value
                    });
                }

                XmlSerializer serializer = new XmlSerializer(typeof(LoginHistoryData));
                using (var sw = new StreamWriter(_filePath))
                {
                    serializer.Serialize(sw, data);
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"[LoginHistoryStore Save Error] {ex.Message}");
            }
        }

        private void LoadFromFile()
        {
            try
            {
                if (!File.Exists(_filePath)) return;

                XmlSerializer serializer = new XmlSerializer(typeof(LoginHistoryData));
                using (var sr = new StreamReader(_filePath))
                {
                    var data = (LoginHistoryData)serializer.Deserialize(sr);
                    if (data?.Categories != null)
                    {
                        _history.Clear();
                        foreach (var cat in data.Categories)
                        {
                            if (!string.IsNullOrEmpty(cat.Name))
                            {
                                _history[cat.Name] = cat.Values ?? new List<string>();
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"[LoginHistoryStore Load Error] {ex.Message}");
            }
        }
    }
}