using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using WIDESEAWCS_S7Simulator.Core.Entities;
using WIDESEAWCS_S7Simulator.Core.Enums;
using WIDESEAWCS_S7Simulator.Core.Interfaces;
using WIDESEAWCS_S7Simulator.Core.Persistence.Models;

namespace WIDESEAWCS_S7Simulator.Core.Persistence
{
    /// <summary>
    /// 鏂囦欢鎸佷箙鍖栨湇鍔″疄鐜?
    /// 灏嗗疄渚嬮厤缃拰鍐呭瓨鏁版嵁淇濆瓨鍒版湰鍦癑SON鏂囦欢
    /// </summary>
    public class FilePersistenceService : IPersistenceService
    {
        /// <summary>
        /// 鏁版嵁鐩綍璺緞
        /// </summary>
        private readonly string _dataPath;

        /// <summary>
        /// JSON搴忓垪鍖栭€夐」锛堢嚎绋嬪畨鍏級
        /// </summary>
        private static readonly JsonSerializerOptions _jsonOptions = new JsonSerializerOptions
        {
            WriteIndented = true,
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
        };

        /// <summary>
        /// 鏂囦欢鎿嶄綔閿侊紙绾跨▼瀹夊叏锛?
        /// </summary>
        private readonly SemaphoreSlim _fileLock = new SemaphoreSlim(1, 1);

        /// <summary>
        /// 鏋勯€犲嚱鏁?
        /// </summary>
        /// <param name="dataPath">鏁版嵁鐩綍璺緞</param>
        public FilePersistenceService(string dataPath = "Data")
        {
            // 杞崲涓虹粷瀵硅矾寰勶紙鍩轰簬褰撳墠宸ヤ綔鐩綍锛?
            _dataPath = Path.GetFullPath(dataPath);

            try
            {
                // 纭繚鏁版嵁鐩綍瀛樺湪
                if (!Directory.Exists(_dataPath))
                {
                    Directory.CreateDirectory(_dataPath);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error creating data directory '{_dataPath}': {ex.Message}");
                throw;
            }
        }

        /// <summary>
        /// 淇濆瓨瀹炰緥閰嶇疆
        /// </summary>
        public async Task SaveInstanceConfigAsync(InstanceConfig config)
        {
            if (config == null)
                throw new ArgumentNullException(nameof(config));

            await _fileLock.WaitAsync();
            try
            {
                var instanceDir = GetInstanceDirectory(config.Id);
                if (!Directory.Exists(instanceDir))
                {
                    Directory.CreateDirectory(instanceDir);
                }

                var configPath = Path.Combine(instanceDir, "config.json");
                var model = ToDataModel(config);

                var json = JsonSerializer.Serialize(model, _jsonOptions);
                await WriteFileAtomicAsync(configPath, json);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error saving instance config for '{config.Id}': {ex.Message}");
                throw;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 鍔犺浇瀹炰緥閰嶇疆
        /// </summary>
        public async Task<InstanceConfig> LoadInstanceConfigAsync(string instanceId)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("瀹炰緥ID涓嶈兘涓虹┖", nameof(instanceId));

            ValidateInstanceId(instanceId);

            await _fileLock.WaitAsync();
            try
            {
                var configPath = Path.Combine(GetInstanceDirectory(instanceId), "config.json");
                if (!File.Exists(configPath))
                    throw new FileNotFoundException($"瀹炰緥閰嶇疆鏂囦欢涓嶅瓨鍦? {configPath}");

                var json = await File.ReadAllTextAsync(configPath);
                var model = JsonSerializer.Deserialize<InstanceDataModel>(json, _jsonOptions);

                if (model == null)
                    throw new InvalidOperationException("鏃犳硶鍙嶅簭鍒楀寲瀹炰緥閰嶇疆");

                return ToEntity(model);
            }
            catch (Exception ex) when (!(ex is FileNotFoundException || ex is InvalidOperationException || ex is ArgumentException))
            {
                Console.WriteLine($"Error loading instance config for '{instanceId}': {ex.Message}");
                throw;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 鍔犺浇鎵€鏈夊疄渚嬮厤缃?
        /// </summary>
        public async Task<List<InstanceConfig>> LoadAllInstanceConfigsAsync()
        {
            await _fileLock.WaitAsync();
            try
            {
                var configs = new List<InstanceConfig>();

                if (!Directory.Exists(_dataPath))
                    return configs;

                var instanceDirs = Directory.GetDirectories(_dataPath)
                    .Where(d => Path.GetFileName(d).StartsWith("instance-"))
                    .ToList();

                foreach (var dir in instanceDirs)
                {
                    var configPath = Path.Combine(dir, "config.json");
                    if (File.Exists(configPath))
                    {
                        try
                        {
                            var json = await File.ReadAllTextAsync(configPath);
                            var model = JsonSerializer.Deserialize<InstanceDataModel>(json, _jsonOptions);
                            if (model != null)
                            {
                                configs.Add(ToEntity(model));
                            }
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine($"Error loading instance config from '{configPath}': {ex.Message}");
                            // 璺宠繃鏃犳硶鍔犺浇鐨勯厤缃枃浠?
                            continue;
                        }
                    }
                }

                return configs;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 鍒犻櫎瀹炰緥閰嶇疆
        /// </summary>
        public async Task DeleteInstanceConfigAsync(string instanceId)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("瀹炰緥ID涓嶈兘涓虹┖", nameof(instanceId));

            ValidateInstanceId(instanceId);

            await _fileLock.WaitAsync();
            try
            {
                var instanceDir = GetInstanceDirectory(instanceId);
                if (Directory.Exists(instanceDir))
                {
                    Directory.Delete(instanceDir, recursive: true);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error deleting instance '{instanceId}': {ex.Message}");
                throw;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 淇濆瓨鍐呭瓨鏁版嵁
        /// </summary>
        public async Task SaveMemoryDataAsync(string instanceId, IMemoryStore memoryStore)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("瀹炰緥ID涓嶈兘涓虹┖", nameof(instanceId));

            ValidateInstanceId(instanceId);

            if (memoryStore == null)
                throw new ArgumentNullException(nameof(memoryStore));

            await _fileLock.WaitAsync();
            try
            {
                var instanceDir = GetInstanceDirectory(instanceId);
                if (!Directory.Exists(instanceDir))
                {
                    Directory.CreateDirectory(instanceDir);
                }

                var memoryPath = Path.Combine(instanceDir, "memory.json");
                var exportedData = memoryStore.Export();

                // 灏嗗瓧鑺傛暟缁勮浆鎹负Base64瀛楃涓蹭互渚縅SON搴忓垪鍖?
                var memoryDataModel = new MemoryDataModel
                {
                    MemoryData = exportedData.ToDictionary(
                        kvp => kvp.Key,
                        kvp => Convert.ToBase64String(kvp.Value)
                    )
                };

                var json = JsonSerializer.Serialize(memoryDataModel, _jsonOptions);
                await WriteFileAtomicAsync(memoryPath, json);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error saving memory data for instance '{instanceId}': {ex.Message}");
                throw;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 鍔犺浇鍐呭瓨鏁版嵁
        /// </summary>
        public async Task LoadMemoryDataAsync(string instanceId, IMemoryStore memoryStore)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("瀹炰緥ID涓嶈兘涓虹┖", nameof(instanceId));

            ValidateInstanceId(instanceId);

            if (memoryStore == null)
                throw new ArgumentNullException(nameof(memoryStore));

            await _fileLock.WaitAsync();
            try
            {
                var memoryPath = Path.Combine(GetInstanceDirectory(instanceId), "memory.json");
                if (!File.Exists(memoryPath))
                    return; // 鍐呭瓨鏂囦欢涓嶅瓨鍦紝璺宠繃鍔犺浇

                var json = await File.ReadAllTextAsync(memoryPath);
                var memoryDataModel = JsonSerializer.Deserialize<MemoryDataModel>(json, _jsonOptions);

                if (memoryDataModel?.MemoryData == null)
                    return;

                // 灏咮ase64瀛楃涓茶浆鎹㈠洖瀛楄妭鏁扮粍
                var importedData = new Dictionary<string, byte[]>();
                foreach (var kvp in memoryDataModel.MemoryData)
                {
                    try
                    {
                        importedData[kvp.Key] = Convert.FromBase64String(kvp.Value);
                    }
                    catch (FormatException ex)
                    {
                        Console.WriteLine($"Warning: Invalid Base64 data for memory region '{kvp.Key}' in instance '{instanceId}': {ex.Message}");
                        // 璺宠繃鏃犳晥鐨凚ase64鏁版嵁
                        continue;
                    }
                }

                memoryStore.Import(importedData);
            }
            catch (Exception ex) when (!(ex is FileNotFoundException))
            {
                Console.WriteLine($"Error loading memory data for instance '{instanceId}': {ex.Message}");
                throw;
            }
            finally
            {
                _fileLock.Release();
            }
        }

        /// <summary>
        /// 鑾峰彇瀹炰緥鐩綍璺緞
        /// </summary>
        private string GetInstanceDirectory(string instanceId)
        {
            return Path.Combine(_dataPath, $"instance-{instanceId}");
        }

        /// <summary>
        /// 楠岃瘉瀹炰緥ID锛堥槻姝㈣矾寰勯亶鍘嗘敾鍑伙級
        /// </summary>
        private void ValidateInstanceId(string instanceId)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("瀹炰緥ID涓嶈兘涓虹┖", nameof(instanceId));

            // 妫€鏌ヨ矾寰勯亶鍘嗗瓧绗?
            if (instanceId.Contains("..") || instanceId.Contains("/") || instanceId.Contains("\\"))
                throw new ArgumentException("瀹炰緥ID鍖呭惈闈炴硶瀛楃", nameof(instanceId));

            // 妫€鏌ユ棤鏁堣矾寰勫瓧绗?
            var invalidChars = Path.GetInvalidFileNameChars();
            if (instanceId.IndexOfAny(invalidChars) >= 0)
                throw new ArgumentException("瀹炰緥ID鍖呭惈闈炴硶瀛楃", nameof(instanceId));
        }

        /// <summary>
        /// 鍐欏叆鏂囦欢锛堢洿鎺ュ啓鍏ワ紝绠€鍖栫増鏈級
        /// </summary>
        private async Task WriteFileAtomicAsync(string filePath, string content)
        {
            // 纭繚鐩爣鏂囦欢鐨勭埗鐩綍瀛樺湪
            var directory = Path.GetDirectoryName(filePath);
            if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
            {
                Directory.CreateDirectory(directory);
            }

            // 鐩存帴鍐欏叆鏂囦欢
            await File.WriteAllTextAsync(filePath, content, Encoding.UTF8);
        }

        /// <summary>
        /// 灏嗗疄浣撹浆鎹负鏁版嵁妯″瀷
        /// </summary>
        private InstanceDataModel ToDataModel(InstanceConfig config)
        {
            return new InstanceDataModel
            {
                Id = config.Id,
                Name = config.Name,
                PlcType = config.PLCType.ToString(),
                Port = config.Port,
                ActivationKey = config.ActivationKey,
                AutoStart = config.AutoStart,
                ProtocolTemplateId = config.ProtocolTemplateId,
                MemoryConfig = new MemoryRegionConfigModel
                {
                    MRegionSize = config.MemoryConfig.MRegionSize,
                    DBBlockCount = config.MemoryConfig.DBBlockCount,
                    DBBlockNumbers = config.MemoryConfig.DBBlockNumbers.ToList(),
                    DBBlockSize = config.MemoryConfig.DBBlockSize,
                    IRegionSize = config.MemoryConfig.IRegionSize,
                    QRegionSize = config.MemoryConfig.QRegionSize,
                    TRegionCount = config.MemoryConfig.TRegionCount,
                    CRegionCount = config.MemoryConfig.CRegionCount
                }
            };
        }

        /// <summary>
        /// 灏嗘暟鎹ā鍨嬭浆鎹负瀹炰綋
        /// </summary>
        private InstanceConfig ToEntity(InstanceDataModel model)
        {
            return new InstanceConfig
            {
                Id = model.Id,
                Name = model.Name,
                PLCType = Enum.Parse<SiemensPLCType>(model.PlcType),
                Port = model.Port,
                ActivationKey = model.ActivationKey,
                AutoStart = model.AutoStart,
                ProtocolTemplateId = model.ProtocolTemplateId,
                MemoryConfig = new MemoryRegionConfig
                {
                    MRegionSize = model.MemoryConfig.MRegionSize,
                    DBBlockCount = model.MemoryConfig.DBBlockCount,
                    DBBlockNumbers = model.MemoryConfig.DBBlockNumbers?.ToList() ?? new List<int>(),
                    DBBlockSize = model.MemoryConfig.DBBlockSize,
                    IRegionSize = model.MemoryConfig.IRegionSize,
                    QRegionSize = model.MemoryConfig.QRegionSize,
                    TRegionCount = model.MemoryConfig.TRegionCount,
                    CRegionCount = model.MemoryConfig.CRegionCount
                }
            };
        }
    }
}