using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Net.Mail;
using System.Net.Mime;
using System.Text;

namespace Roblox.Common.Mime;

public class MimeEntity
{
	private StringBuilder _encodedMessage;

	private List<MimeEntity> _children;

	private ContentType _contentType;

	private string _mediaSubType;

	private string _mediaMainType;

	private NameValueCollection _headers;

	private string _mimeVersion;

	private string _contentId;

	private string _contentDescription;

	private ContentDisposition _contentDisposition;

	private string _transferEncoding;

	private TransferEncoding _contentTransferEncoding;

	private string _startBoundry;

	private MimeEntity _parent;

	private MemoryStream _content;

	public StringBuilder EncodedMessage => _encodedMessage;

	public List<MimeEntity> Children => _children;

	public ContentType ContentType => _contentType;

	public string MediaSubType => _mediaSubType;

	public string MediaMainType => _mediaMainType;

	public NameValueCollection Headers => _headers;

	public string MimeVersion
	{
		get
		{
			return _mimeVersion;
		}
		set
		{
			_mimeVersion = value;
		}
	}

	public string ContentId
	{
		get
		{
			return _contentId;
		}
		set
		{
			_contentId = value;
		}
	}

	public string ContentDescription
	{
		get
		{
			return _contentDescription;
		}
		set
		{
			_contentDescription = value;
		}
	}

	public ContentDisposition ContentDisposition
	{
		get
		{
			return _contentDisposition;
		}
		set
		{
			_contentDisposition = value;
		}
	}

	public string TransferEncoding
	{
		get
		{
			return _transferEncoding;
		}
		set
		{
			_transferEncoding = value;
		}
	}

	public TransferEncoding ContentTransferEncoding
	{
		get
		{
			return _contentTransferEncoding;
		}
		set
		{
			_contentTransferEncoding = value;
		}
	}

	public bool HasBoundry
	{
		get
		{
			if (string.IsNullOrEmpty(_contentType.Boundary))
			{
				return !string.IsNullOrEmpty(_startBoundry);
			}
			return true;
		}
	}

	public string StartBoundry
	{
		get
		{
			if (string.IsNullOrEmpty(_startBoundry) || !string.IsNullOrEmpty(_contentType.Boundary))
			{
				return "--" + _contentType.Boundary;
			}
			return _startBoundry;
		}
	}

	public string EndBoundry => StartBoundry + "--";

	public MimeEntity Parent
	{
		get
		{
			return _parent;
		}
		set
		{
			_parent = value;
		}
	}

	public MemoryStream Content
	{
		get
		{
			return _content;
		}
		set
		{
			_content = value;
		}
	}

	public MimeEntity()
	{
		_children = new List<MimeEntity>();
		_headers = new NameValueCollection();
		_contentType = MimeReader.GetContentType(string.Empty);
		_parent = null;
		_encodedMessage = new StringBuilder();
	}

	public MimeEntity(MimeEntity parent)
		: this()
	{
		if (parent == null)
		{
			throw new ArgumentNullException("parent");
		}
		_parent = parent;
		_startBoundry = parent.StartBoundry;
	}

	internal void SetContentType(ContentType contentType)
	{
		_contentType = contentType;
		_contentType.MediaType = MimeReader.GetMediaType(contentType.MediaType);
		_mediaMainType = MimeReader.GetMediaMainType(contentType.MediaType);
		_mediaSubType = MimeReader.GetMediaSubType(contentType.MediaType);
	}

	public MailMessageEx ToMailMessageEx()
	{
		return ToMailMessageEx(this);
	}

	public MailMessageEx ToMailMessageEx(MimeEntity entity)
	{
		if (entity == null)
		{
			throw new ArgumentNullException("entity");
		}
		MailMessageEx mailMessage = MailMessageEx.CreateMailMessageFromEntity(entity);
		if (!string.IsNullOrEmpty(entity.ContentType.Boundary))
		{
			mailMessage = MailMessageEx.CreateMailMessageFromEntity(entity);
			BuildMultiPartMessage(entity, mailMessage);
		}
		else if (string.Equals(entity.ContentType.MediaType, MediaTypes.MessageRfc822, StringComparison.InvariantCultureIgnoreCase))
		{
			if (entity.Children.Count < 0)
			{
				throw new ApplicationException("Invalid child count on message/rfc822 entity.");
			}
			mailMessage = MailMessageEx.CreateMailMessageFromEntity(entity.Children[0]);
			BuildMultiPartMessage(entity, mailMessage);
		}
		else
		{
			mailMessage = MailMessageEx.CreateMailMessageFromEntity(entity);
			BuildSinglePartMessage(entity, mailMessage);
		}
		return mailMessage;
	}

	private void BuildSinglePartMessage(MimeEntity entity, MailMessageEx message)
	{
		SetMessageBody(message, entity);
	}

	public Encoding GetEncoding()
	{
		if (string.IsNullOrEmpty(ContentType.CharSet))
		{
			return Encoding.ASCII;
		}
		try
		{
			return Encoding.GetEncoding(ContentType.CharSet);
		}
		catch (ArgumentException)
		{
			return Encoding.ASCII;
		}
	}

	private void BuildMultiPartMessage(MimeEntity entity, MailMessageEx message)
	{
		foreach (MimeEntity mimeEntity in entity.Children)
		{
			if (string.Equals(mimeEntity.ContentType.MediaType, MediaTypes.MultipartAlternative, StringComparison.InvariantCultureIgnoreCase) || string.Equals(mimeEntity.ContentType.MediaType, MediaTypes.MultipartMixed, StringComparison.InvariantCultureIgnoreCase))
			{
				BuildMultiPartMessage(mimeEntity, message);
			}
			else if (IsAttachment(mimeEntity) && (string.Equals(mimeEntity.ContentType.MediaType, MediaTypes.TextPlain) || string.Equals(mimeEntity.ContentType.MediaType, MediaTypes.TextHtml)))
			{
				message.AlternateViews.Add(CreateAlternateView(mimeEntity));
				SetMessageBody(message, mimeEntity);
			}
			else if (string.Equals(mimeEntity.ContentType.MediaType, MediaTypes.MessageRfc822, StringComparison.InvariantCultureIgnoreCase) && string.Equals(mimeEntity.ContentDisposition.DispositionType, "attachment", StringComparison.InvariantCultureIgnoreCase))
			{
				message.Children.Add(ToMailMessageEx(mimeEntity));
			}
			else if (IsAttachment(mimeEntity))
			{
				message.Attachments.Add(CreateAttachment(mimeEntity));
			}
		}
	}

	private static bool IsAttachment(MimeEntity child)
	{
		if (child.ContentDisposition != null)
		{
			return string.Equals(child.ContentDisposition.DispositionType, "attachment", StringComparison.InvariantCultureIgnoreCase);
		}
		return false;
	}

	private void SetMessageBody(MailMessageEx message, MimeEntity child)
	{
		Encoding encoding = child.GetEncoding();
		message.Body = DecodeBytes(child.Content.ToArray(), encoding);
		message.BodyEncoding = encoding;
		message.IsBodyHtml = string.Equals(MediaTypes.TextHtml, child.ContentType.MediaType, StringComparison.InvariantCultureIgnoreCase);
	}

	private string DecodeBytes(byte[] buffer, Encoding encoding)
	{
		if (buffer == null)
		{
			return null;
		}
		if (encoding == null)
		{
			encoding = Encoding.UTF7;
		}
		return encoding.GetString(buffer);
	}

	private AlternateView CreateAlternateView(MimeEntity view)
	{
		return new AlternateView(view.Content, view.ContentType)
		{
			TransferEncoding = view.ContentTransferEncoding,
			ContentId = TrimBrackets(view.ContentId)
		};
	}

	public static string TrimBrackets(string value)
	{
		if (value == null)
		{
			return value;
		}
		if (value.StartsWith("<") && value.EndsWith(">"))
		{
			return value.Trim('<', '>');
		}
		return value;
	}

	private Attachment CreateAttachment(MimeEntity entity)
	{
		Attachment attachment = new Attachment(entity.Content, entity.ContentType);
		if (entity.ContentDisposition != null)
		{
			attachment.ContentDisposition.Parameters.Clear();
			foreach (object i in entity.ContentDisposition.Parameters.Keys)
			{
				string key = (string)i;
				attachment.ContentDisposition.Parameters.Add(key, entity.ContentDisposition.Parameters[key]);
			}
			attachment.ContentDisposition.CreationDate = entity.ContentDisposition.CreationDate;
			attachment.ContentDisposition.DispositionType = entity.ContentDisposition.DispositionType;
			attachment.ContentDisposition.FileName = entity.ContentDisposition.FileName;
			attachment.ContentDisposition.Inline = entity.ContentDisposition.Inline;
			attachment.ContentDisposition.ModificationDate = entity.ContentDisposition.ModificationDate;
			attachment.ContentDisposition.ReadDate = entity.ContentDisposition.ReadDate;
			attachment.ContentDisposition.Size = entity.ContentDisposition.Size;
		}
		if (!string.IsNullOrEmpty(entity.ContentId))
		{
			attachment.ContentId = TrimBrackets(entity.ContentId);
		}
		attachment.TransferEncoding = entity.ContentTransferEncoding;
		return attachment;
	}
}