using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;
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>
    /// 文件持久化服务实现
    /// 将实例配置和内存数据保存到本地JSON文件
    /// </summary>
    public class FilePersistenceService : IPersistenceService
    {
        /// <summary>
        /// 数据目录路径
        /// </summary>
        private readonly string _dataPath;

        /// <summary>
        /// JSON序列化选项
        /// </summary>
        private readonly JsonSerializerOptions _jsonOptions;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="dataPath">数据目录路径</param>
        public FilePersistenceService(string dataPath = "Data")
        {
            _dataPath = dataPath;
            _jsonOptions = new JsonSerializerOptions
            {
                WriteIndented = true,
                PropertyNamingPolicy = JsonNamingPolicy.CamelCase
            };

            // 确保数据目录存在
            if (!Directory.Exists(_dataPath))
            {
                Directory.CreateDirectory(_dataPath);
            }
        }

        /// <summary>
        /// 保存实例配置
        /// </summary>
        public async Task SaveInstanceConfigAsync(InstanceConfig config)
        {
            if (config == null)
                throw new ArgumentNullException(nameof(config));

            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 File.WriteAllTextAsync(configPath, json);
        }

        /// <summary>
        /// 加载实例配置
        /// </summary>
        public async Task<InstanceConfig> LoadInstanceConfigAsync(string instanceId)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("实例ID不能为空", nameof(instanceId));

            var configPath = Path.Combine(GetInstanceDirectory(instanceId), "config.json");
            if (!File.Exists(configPath))
                throw new FileNotFoundException($"实例配置文件不存在: {configPath}");

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

            if (model == null)
                throw new InvalidOperationException("无法反序列化实例配置");

            return ToEntity(model);
        }

        /// <summary>
        /// 加载所有实例配置
        /// </summary>
        public async Task<List<InstanceConfig>> LoadAllInstanceConfigsAsync()
        {
            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)
                    {
                        // 跳过无法加载的配置文件
                        continue;
                    }
                }
            }

            return configs;
        }

        /// <summary>
        /// 删除实例配置
        /// </summary>
        public Task DeleteInstanceConfigAsync(string instanceId)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("实例ID不能为空", nameof(instanceId));

            var instanceDir = GetInstanceDirectory(instanceId);
            if (Directory.Exists(instanceDir))
            {
                Directory.Delete(instanceDir, recursive: true);
            }

            return Task.CompletedTask;
        }

        /// <summary>
        /// 保存内存数据
        /// </summary>
        public async Task SaveMemoryDataAsync(string instanceId, IMemoryStore memoryStore)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("实例ID不能为空", nameof(instanceId));

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

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

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

            // 将字节数组转换为Base64字符串以便JSON序列化
            var memoryDataModel = new MemoryDataModel
            {
                MemoryData = exportedData.ToDictionary(
                    kvp => kvp.Key,
                    kvp => Convert.ToBase64String(kvp.Value)
                )
            };

            var json = JsonSerializer.Serialize(memoryDataModel, _jsonOptions);
            await File.WriteAllTextAsync(memoryPath, json);
        }

        /// <summary>
        /// 加载内存数据
        /// </summary>
        public async Task LoadMemoryDataAsync(string instanceId, IMemoryStore memoryStore)
        {
            if (string.IsNullOrWhiteSpace(instanceId))
                throw new ArgumentException("实例ID不能为空", nameof(instanceId));

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

            var memoryPath = Path.Combine(GetInstanceDirectory(instanceId), "memory.json");
            if (!File.Exists(memoryPath))
                return; // 内存文件不存在，跳过加载

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

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

            // 将Base64字符串转换回字节数组
            var importedData = new Dictionary<string, byte[]>();
            foreach (var kvp in memoryDataModel.MemoryData)
            {
                try
                {
                    importedData[kvp.Key] = Convert.FromBase64String(kvp.Value);
                }
                catch (FormatException)
                {
                    // 跳过无效的Base64数据
                    continue;
                }
            }

            memoryStore.Import(importedData);
        }

        /// <summary>
        /// 获取实例目录路径
        /// </summary>
        private string GetInstanceDirectory(string instanceId)
        {
            return Path.Combine(_dataPath, $"instance-{instanceId}");
        }

        /// <summary>
        /// 将实体转换为数据模型
        /// </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,
                MemoryConfig = new MemoryRegionConfigModel
                {
                    MRegionSize = config.MemoryConfig.MRegionSize,
                    DBBlockCount = config.MemoryConfig.DBBlockCount,
                    DBBlockSize = config.MemoryConfig.DBBlockSize,
                    IRegionSize = config.MemoryConfig.IRegionSize,
                    QRegionSize = config.MemoryConfig.QRegionSize,
                    TRegionCount = config.MemoryConfig.TRegionCount,
                    CRegionCount = config.MemoryConfig.CRegionCount
                }
            };
        }

        /// <summary>
        /// 将数据模型转换为实体
        /// </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,
                MemoryConfig = new MemoryRegionConfig
                {
                    MRegionSize = model.MemoryConfig.MRegionSize,
                    DBBlockCount = model.MemoryConfig.DBBlockCount,
                    DBBlockSize = model.MemoryConfig.DBBlockSize,
                    IRegionSize = model.MemoryConfig.IRegionSize,
                    QRegionSize = model.MemoryConfig.QRegionSize,
                    TRegionCount = model.MemoryConfig.TRegionCount,
                    CRegionCount = model.MemoryConfig.CRegionCount
                }
            };
        }
    }
}