using Microsoft.AspNetCore.Hosting;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Options;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System;

using System.Collections.Generic;

using System.IO;

using System.Text;

namespace Blog.Common

{

/// <summary>

/// 修改json文件节点的实现类

/// </summary>

/// <typeparam name="T"></typeparam>

public class WritableOptions<T> : IWritableOptions<T> where T : class, new()

{

private readonly IHostingEnvironment _environment;

private readonly IOptionsMonitor<T> _options;

private readonly string _section;

private readonly string _file;

public WritableOptions(

IHostingEnvironment environment,

IOptionsMonitor<T> options,

string section,

string file)

{

_environment = environment;

_options = options;

_section = section;

_file = file;

}

public T Value => this._options.CurrentValue;

//public T CurrentValue => this._options.CurrentValue;

public T Get(string name) => _options.Get(name);

//public IDisposable OnChange(Action<T, string> listener)

//{

// throw new NotImplementedException();

//}

public void Update(Action<T> applyChanges)

{

var fileProvider = _environment.ContentRootFileProvider;

var fileInfo = fileProvider.GetFileInfo(_file);

var physicalPath = fileInfo.PhysicalPath;

var jObject = JsonConvert.DeserializeObject<JObject>(File.ReadAllText(physicalPath));

var sectionObject = jObject.TryGetValue(_section, out JToken section) ?

JsonConvert.DeserializeObject<T>(section.ToString()) : (Value ?? new T());

applyChanges(sectionObject);

jObject[_section] = JObject.Parse(JsonConvert.SerializeObject(sectionObject));

File.WriteAllText(physicalPath, JsonConvert.SerializeObject(jObject, Formatting.Indented));

}

}

/// <summary>

/// 把json文件节点绑定到类的扩展方法，具有修改功能

/// </summary>

public static class ServiceCollectionExtensions

{

public static void ConfigureWritable<T>(

this IServiceCollection services,

IConfigurationSection section,

string file = "appsettings.json") where T : class, new()

{

services.Configure<T>(section);

services.AddTransient<IWritableOptions<T>>(provider =>

{

var environment = provider.GetService<IHostingEnvironment>();

var options = provider.GetService<IOptionsMonitor<T>>();

return new WritableOptions<T>(environment, options, section.Key, file);

});

}

}

}