<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
    /**
     * Get the owning commentable model.
     */
    public function commentable()
    {
        return $this->morphTo();
    }
}

class Post extends Model
{
    /**
     * Get all of the post's comments.
     */
    public function comments()
    {
        return $this->morphMany('App\Comment', 'commentable');
    }
}

class Video extends Model
{
    /**
     * Get all of the video's comments.
     */
    public function comments()
    {
        return $this->morphMany('App\Comment', 'commentable');
    }
}

$post = App\Post::find(1);

foreach ($post->comments as $comment) {
    //
}

$comment = App\Comment::find(1);

$commentable = $comment->commentable;

public enum CommentType
{
    Article,
    Video,
    Event
}

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    public int? TypeId { get; set; }
    public CommentType CommentType { get; set; }
}

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }

    public virtual Article Article { get; set; }
    public int ArticleId { get; set; }
}

public class Article
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
    
    public virtual ICollection<Article> Articles { get; set; }
}

interface ICommentable
{
    int Id { get; set; }
}

public class Article : ICommentable
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
    
    [NotMapped]
    public ICollection<Comment> Comments { get; set; }
}

public class Video : ICommentable
{
    public int Id { get; set; }
    public string Url { get; set; }
    public string Description { get; set; }
    
    [NotMapped]
    public ICollection<Comment> Comments { get; set; }
}

public class Event : ICommentable
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTimeOffset? Start { get; set; }
    public DateTimeOffset? End { get; set; }
    
    [NotMapped]
    public ICollection<Comment> Comments { get; set; }
}

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    public int? TypeId { get; set; }
    public CommentType CommentType { get; set; }

    ICommentable _parent;

    [NotMapped]
    public ICommentable Parent
    {
        get => _parent;
        set
        {
            _parent = value;
            TypeId = value.Id;
            CommentType = (CommentType) Enum.Parse(typeof(CommentType), value.GetType().Name);
        }
    }
}

var article = dbContext.Articles.Find(1);
            
article.Comments = dbContext.Comments
    .Where(c => c.TypeId == article.Id
                && c.CommentType == CommentType.Article)
    .ToList();

foreach (var comment in article.Comments)
    comment.Parent = article;

foreach (var comment in article.Comments)
{
    Console.WriteLine($"{comment.User} - ${comment.CommentText} - {((Article) comment.Parent).Title}");
}

"ApplicationName": "Dependency Injection Demo",
"GreetingMessage": "Welcome to Dependency Injection Demo",
"AllowedHosts": "*",

"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},

namespace AspNetCoreDependencyInjection.Configs
{
    public class AppConfig
    {
        public string ApplicationName { get; set; }
        public string GreetingMessage { get; set; }
        public string AllowedHosts { get; set; }
    }
}

public IWebHostEnvironment Environment { get; }
public IConfiguration Configuration { get; }
public IServiceCollection Services { get; set; }

public Startup(IWebHostEnvironment environment)
{
var builder = new ConfigurationBuilder()
        .SetBasePath(environment.ContentRootPath)
        .AddJsonFile("appsettings.json", optional: true)
        .AddEnvironmentVariables();
        this.Environment = environment;
        this.Configuration = builder.Build();
}

var appSettingsFile = environment.IsProduction() ? "appsettings.json" : "appsettings_dev.json";
var builder = new ConfigurationBuilder()
.SetBasePath(environment.ContentRootPath)
                .AddJsonFile( appSettingsFile , optional: true)
                .AddEnvironmentVariables();

services.AddSingleton(services => new AppConfig { 
    ApplicationName = this.Configuration["ApplicationName"],
    GreetingMessage = this.Configuration["GreetingMessage"],
    AllowedHosts = this.Configuration["AllowedHosts"]
});

public class AppSettingsController : Controller
{
        private readonly AppConfig _appConfig;
        public AppSettingsController(AppConfig appConfig)
        {
            _appConfig = appConfig;
        } 
 // codes here …
}

"UserOptionConfig": {
    "UsersAvatarsFolder": "avatars",
    "UserDefaultPhoto": "icon-user-default.png",
    "UserAvatarImageOptions": {
         "MaxWidth": 150,
         "MaxHeight": 150
    }
},

"LiteDbConfig": {
   "ConnectionString": "Filename=\\Data\\DependencyInjectionDemo.db;Connection=direct;Password=@123456;"
}

services.AddSingleton(services => new LiteDbConfig
{
    ConnectionString = this.Configuration["LiteDbConfig:ConnectionString"],
});

namespace AspNetCoreDependencyInjection.Configs
{
    public class UserOptionConfig
    {
        public string UsersAvatarsFolder { get; set; }
        public string UserDefaultPhoto { get; set; }
        public UserAvatarImageOptions UserAvatarImageOptions { get; set; }
    }

    public class UserAvatarImageOptions
    {
        public int MaxHeight { get; set; }
        public int MaxWidth { get; set; }
    }
}

services.Configure<UserOptionConfig>(this.Configuration.GetSection("UserOptionConfig"));

private readonly LiteDbConfig _liteDbConfig;
private readonly AppConfig _appConfig;
private readonly UserOptionConfig _userOptionConfig; 

public AppSettingsController(AppConfig appConfig ,
    LiteDbConfig liteDbConfig ,
    IOptionsMonitor<UserOptionConfig> userOptionConfig)
{
    _appConfig = appConfig;
    _liteDbConfig = liteDbConfig;
    _userOptionConfig = userOptionConfig.CurrentValue;
}

 report.DataSources.Add(new ReportDataSource("Header", "از نوع لیست باشد"));