DeliveryStatusDecoder.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Dsn
{
    public class DeliveryStatusDecoder : IContentDecoder
    {
        public const string ContentType = "message/delivery-status";
 
        public DeliveryStatusDecoder()
        {
        }
 
        public string[] ContentTypes => new string[] { ContentType };
 
        public string[] FileExtensions => new string[] { "dsn" };
 
        public bool Decodes(string ContentType, out Grade Grade)
        {
            if (ContentType == DeliveryStatusDecoder.ContentType)
            {
                Grade = Grade.Excellent;
                return true;
            }
            else
            {
                Grade = Grade.NotAtAll;
                return false;
            }
        }
 
        public bool TryGetContentType(string FileExtension, out string ContentType)
        {
            if (string.Compare(FileExtension, "dsn", true) == 0)
            {
                ContentType = DeliveryStatusDecoder.ContentType;
                return true;
            }
            else
            {
                ContentType = string.Empty;
                return false;
            }
        }
 
        public bool TryGetFileExtension(string ContentType, out string FileExtension)
        {
            switch (ContentType.ToLower())
            {
                case DeliveryStatusDecoder.ContentType:
                    FileExtension = "dsn";
                    return true;
 
                default:
                    FileExtension = string.Empty;
                    return false;
            }
        }
 
        public Task<object> DecodeAsync(string ContentType, byte[] Data, Encoding Encoding, KeyValuePair<string, string>[] Fields, Uri BaseUri)
        {
            string Dsn = CommonTypes.GetString(Data, Encoding ?? Encoding.ASCII);
            List<string[]> Sections = new List<string[]>();
            List<string> Section = new List<string>();
 
            foreach (string Row in Dsn.Replace("\r\n", "\n").Replace("\r", "\n").Split('\n'))
            {
                if (string.IsNullOrEmpty(Row))
                {
                    if (Section.Count > 0)
                    {
                        Sections.Add(Section.ToArray());
                        Section.Clear();
                    }
                }
                else
                {
                    if (Row[0] <= ' ' && Section.Count > 0)
                        Section[Section.Count - 1] += Row;
                    else
                        Section.Add(Row);
                }
            }
 
            if (Section.Count > 0)
            {
                Sections.Add(Section.ToArray());
                Section.Clear();
            }
 
            PerMessageFields PerMessage;
            PerRecipientFields[] PerRecipients;
            int i, c = Sections.Count;
 
            if (c == 0)
            {
                PerMessage = new PerMessageFields(new string[0]);
                PerRecipients = new PerRecipientFields[0];
            }
            else
            {
                PerMessage = new PerMessageFields(Sections[0]);
                PerRecipients = new PerRecipientFields[c - 1];
 
                for (i = 1; i < c; i++)
                    PerRecipients[i - 1] = new PerRecipientFields(Sections[i]);
            }
 
            return Task.FromResult<object>(new DeliveryStatus(Dsn, PerMessage, PerRecipients));
        }
    }
}