POP3 (RFC 1939) & MIME (RFC 2045) Compliant Client

/*
Copyright (c) 2007, Robert Wallstr�m, smithimage.com
All rights reserved.
 
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
	
	* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 
	* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 
	* Neither the name of the SMITHIMAGE nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH  DAMAGE.
*/
using System;
using System.Collections.Generic;
using System.Text;

using System.Text.RegularExpressions;

namespace MIMER.RFC2045
{
    public class ContentTypeFieldParser:RFC822.FieldParser, IFieldParser
    {        
        protected readonly string m_ValuePattern;
        protected readonly string m_ParameterPattern;
        protected readonly string m_XTokenPattern;
        protected readonly string m_ExtensionTokenPattern;
        protected readonly string m_BoundaryStartDelimiterPattern;
        protected readonly string m_BoundaryEndDelimiterPattern;
        protected readonly string m_MIMEVersionPattern;

        private Regex m_Content;
        private Regex m_Type;
        private Regex m_SubType;
        private Regex m_Parameters;
        private Regex m_CompositeType;
        private Regex m_DescriteType;
        private Regex m_StartBoundary;
        private Regex m_EndBoundary;
        private Regex m_MIMEVersion;

        public Regex MIMEVersion
        {
            get { return m_MIMEVersion; }
            set { m_MIMEVersion = value; }
        }
        public Regex StartBoundary
        {
            get { return m_StartBoundary; }
            set { m_StartBoundary = value; }
        }        
        public Regex EndBoundary
        {
            get { return m_EndBoundary; }
            set { m_EndBoundary = value; }
        }
        public Regex DescriteType
        {
            get { return m_DescriteType; }
            set { m_DescriteType = value; }
        }
        public Regex CompositeType
        {
            get { return m_CompositeType; }
            set { m_CompositeType = value; }
        }
        
        private StringBuilder m_DiscreteBuilder;
        private StringBuilder m_CompositeBuilder;
        private StringBuilder m_MultipartSubtypesBuilder;
        private StringBuilder m_TextSubtypesBuilder;
        private StringBuilder m_ImageSubtypesBuilder;
        private StringBuilder m_ApplicationSubtypesBuilder;
        private StringBuilder m_MessageSubtypesBuilder;
        private StringBuilder m_AudioSubtypesBuilder;

        protected IList<string> m_DiscreteTypes;
        protected IList<string> m_CompositeTypes;
        protected IList<string> m_MultipartSubTypes;
        protected IList<string> m_TextSubtypes;
        protected IList<string> m_ImageSubTypes;
        protected IList<string> m_ApplicationSubtypes;
        protected IList<string> m_MessageSubtypes;
        protected IList<string> m_AudioSubtypes;

        private bool m_StrictMatch = false;

        public bool StrictMatch
        {
            get { return m_StrictMatch; }
            set { m_StrictMatch = value; }
        }

        public ContentTypeFieldParser() 
        {
            m_BoundaryStartDelimiterPattern = "--.{1,70}\x0D\x0A";
            m_BoundaryEndDelimiterPattern = "--.{1,68}--\x0D\x0A"; 
            m_XTokenPattern = "(X-|x-)" + m_TokenPattern;
            m_ExtensionTokenPattern = m_XTokenPattern; // or ietf-token
            m_ValuePattern = "(" + m_TokenPattern + "|" + m_QuotedStringPattern + ")";
            m_ParameterPattern = m_TokenPattern + "=" + m_ValuePattern;

            m_MIMEVersionPattern = "MIME-Version:([0-9]{1,1}|\\x2E{1,1}|" + m_CommentPattern + ")*";

            m_DiscreteTypes = new List<string>();
            m_CompositeTypes = new List<string>();
            m_MultipartSubTypes = new List<string>();
            m_TextSubtypes = new List<string>();
            m_ImageSubTypes = new List<string>();
            m_ApplicationSubtypes = new List<string>();
            m_MessageSubtypes = new List<string>();
            m_AudioSubtypes = new List<string>();
        }

        public override void CompilePattern()
        {
            m_DiscreteTypes.Add("text");
            m_DiscreteTypes.Add("image");
            m_DiscreteTypes.Add("audio");
            m_DiscreteTypes.Add("video");
            m_DiscreteTypes.Add("application");

            m_CompositeTypes.Add("message");
            m_CompositeTypes.Add("multipart");

            m_MultipartSubTypes.Add("mixed");
            m_MultipartSubTypes.Add("alternative");
            m_MultipartSubTypes.Add("parallel");
            m_MultipartSubTypes.Add("digest");
            m_MultipartSubTypes.Add("related");

            m_TextSubtypes.Add("plain");
            m_TextSubtypes.Add("enriched");
            m_TextSubtypes.Add("html");

            m_ImageSubTypes.Add("jpeg");
            m_ImageSubTypes.Add("gif");

            m_ApplicationSubtypes.Add("octet-stream");
            m_ApplicationSubtypes.Add("PostScript");//TODO: add the rest se rfc 2046
            m_ApplicationSubtypes.Add("pdf");

            m_MessageSubtypes.Add("rfc822");
            m_MessageSubtypes.Add("partial");
            m_MessageSubtypes.Add("external-body");

            m_AudioSubtypes.Add("mpeg");
            
            CompileDescreteTypes();
            CompileCompositeTypes();
            CompileMultipartSubtypes();
            CompileTextSubtypes();
            CompileImageSubtypes();
            CompileApplicationSubtypes();
            CompileMessageSubtypes();
            CompileAudioSubtypes();

            m_StartBoundary = new Regex(m_BoundaryStartDelimiterPattern, RegexOptions.Compiled);

            m_EndBoundary = new Regex(m_BoundaryEndDelimiterPattern, RegexOptions.Compiled);

            m_Parameters = new Regex(m_ParameterPattern, RegexOptions.Compiled);

            m_CompositeType = new Regex("(" + m_CompositeBuilder.ToString() + ")", RegexOptions.Compiled);

            m_DescriteType = new Regex("(" + m_DiscreteBuilder.ToString() + ")", RegexOptions.Compiled);

            m_Type = new Regex("(" + m_DescriteType.ToString() + "|" + m_CompositeType.ToString() + ")", 
                RegexOptions.Compiled);

            m_MIMEVersion = new Regex(m_MIMEVersionPattern, RegexOptions.Compiled);

            m_SubType = new Regex("((?<=multipart/)" + m_MultipartSubtypesBuilder.ToString() + "|" +
            "(?<=text/)" + m_TextSubtypesBuilder.ToString() + "|" + "(?<=image/)" + m_ImageSubtypesBuilder.ToString() + "|" +
            "(?<=application/)" + m_ApplicationSubtypesBuilder.ToString() + "|" + "(?<=message/)" + 
            m_MessageSubtypesBuilder.ToString() + "|" + "(?<=audio/)" + m_AudioSubtypesBuilder.ToString() + ")", 
            RegexOptions.Compiled); //TODO: continue with the rest of subtypes

            string content = "(?i)Content-Type(?i):[\x5C\x73]{1,1}" + m_Type.ToString() + "/";

            if (m_StrictMatch)
            {
                content += m_SubType.ToString();
            }
            else
            {
                content += "(" + m_ExtensionTokenPattern + "|" + m_TokenPattern + ")"; // |IanaToken??
            }
            content += "(;[\x5Cs]+" + m_Parameters.ToString() + ")*";

            m_Content = new Regex(content, RegexOptions.Compiled);                  

            // This should be called if we want to add functionality in this method
            // but let base build/compile it
            base.CompilePattern();
        }

        public override void Parse(ref IList<RFC822.Field> fields, ref string fieldString)
        {
            if (!IsPatternCompiled())
                CompilePattern();

            if (fields.Count == 0)
                base.Parse(ref fields, ref fieldString);

            MatchCollection matches = m_Content.Matches(fieldString);

            foreach (Match match in matches)
            {
                ContentTypeField tmpContent = new ContentTypeField();
                tmpContent.Name = "Content-Type";
                MatchCollection parameters;
                string key, val;

                Match tmpMatch = Regex.Match(match.Value, ":.+");

                tmpContent.Body = tmpMatch.Value.TrimStart(new char[] { ':' });
                tmpMatch = m_Type.Match(match.Value);
                tmpContent.Type = tmpMatch.Value;
                tmpMatch = m_SubType.Match(match.Value);
                tmpContent.SubType = tmpMatch.Value;
                parameters = m_Parameters.Matches(match.Value);
                foreach (Match m in parameters)
                {
                    tmpMatch = Regex.Match(m.Value, m_TokenPattern + "=");
                    key = tmpMatch.Value.TrimEnd(new char[] { '=' });
                    tmpMatch = Regex.Match(m.Value, "(?<==)" + m_ValuePattern);                    
                    val = tmpMatch.Value.Trim(new char[] { '\\', '"' });
                    tmpContent.Parameters.Add(key, val);
                }

                fields.Add(tmpContent);
            }
        }

        private bool IsPatternCompiled()
        {
            return (m_Content != null && m_Type != null && m_SubType != null &&
                m_Parameters != null);
        }
        private void CompileDescreteTypes()
        {
            m_DiscreteBuilder = new StringBuilder("(");
            for (int i = 0; i < m_DiscreteTypes.Count; i++)
            {
                m_DiscreteBuilder.Append(m_DiscreteTypes[i]);
                if (i < (m_DiscreteTypes.Count - 1))
                    m_DiscreteBuilder.Append("|");
            }
            m_DiscreteBuilder.Append(")");
        }
        private void CompileCompositeTypes()
        {
            m_CompositeBuilder = new StringBuilder("(");
            for (int i = 0; i < m_CompositeTypes.Count; i++)
            {
                m_CompositeBuilder.Append(m_CompositeTypes[i]);
                if (i < (m_CompositeTypes.Count - 1))
                    m_CompositeBuilder.Append("|");
            }
            m_CompositeBuilder.Append(")");
        }
        private void CompileMultipartSubtypes()
        {
            m_MultipartSubtypesBuilder = new StringBuilder("(");
            for (int i = 0; i < m_MultipartSubTypes.Count; i++)
            {
                m_MultipartSubtypesBuilder.Append(m_MultipartSubTypes[i]);
                if (i < (m_MultipartSubTypes.Count - 1))
                    m_MultipartSubtypesBuilder.Append("|");
            }
            m_MultipartSubtypesBuilder.Append(")");
        }
        private void CompileTextSubtypes()
        {
            m_TextSubtypesBuilder = new StringBuilder("(");
            for (int i = 0; i < m_TextSubtypes.Count; i++)
            {
                m_TextSubtypesBuilder.Append(m_TextSubtypes[i]);
                if (i < (m_TextSubtypes.Count - 1))
                    m_TextSubtypesBuilder.Append("|");
            }
            m_TextSubtypesBuilder.Append(")");
        }
        private void CompileImageSubtypes()
        {            
            m_ImageSubtypesBuilder = new StringBuilder("(?i)(");
            for (int i = 0; i < m_ImageSubTypes.Count; i++)
            {
                m_ImageSubtypesBuilder.Append(m_ImageSubTypes[i]);
                if (i < (m_ImageSubTypes.Count - 1))
                    m_ImageSubtypesBuilder.Append("|");
            }
            m_ImageSubtypesBuilder.Append(")(?i)");
            
        }
        private void CompileApplicationSubtypes()
        {
            m_ApplicationSubtypesBuilder = new StringBuilder("(");
            for (int i = 0; i < m_ApplicationSubtypes.Count; i++)
            {
                m_ApplicationSubtypesBuilder.Append(m_ApplicationSubtypes[i]);
                if (i < (m_ApplicationSubtypes.Count - 1))
                    m_ApplicationSubtypesBuilder.Append("|");
            }
            m_ApplicationSubtypesBuilder.Append(")");

        }
        private void CompileMessageSubtypes()
        {
            m_MessageSubtypesBuilder = new StringBuilder("(");
            for (int i = 0; i < m_MessageSubtypes.Count; i++)
            {
                m_MessageSubtypesBuilder.Append(m_MessageSubtypes[i]);
                if (i < (m_MessageSubtypes.Count - 1))
                    m_MessageSubtypesBuilder.Append("|");
            }
            m_MessageSubtypesBuilder.Append(")");

        }
        private void CompileAudioSubtypes()
        {
            m_AudioSubtypesBuilder = new StringBuilder("(");
            for (int i = 0; i < m_AudioSubtypes.Count; i++)
            {
                m_AudioSubtypesBuilder.Append(m_AudioSubtypes[i]);
                if (i < (m_AudioSubtypes.Count - 1))
                    m_AudioSubtypesBuilder.Append("|");
            }
            m_AudioSubtypesBuilder.Append(")");
        }
        
    }
}