// ==++==
// 
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
// SiteString
// 
// <OWNER>Microsoft</OWNER>
// 
 
namespace System.Security.Util {
    using System;
    using System.Collections;
    using System.Globalization;
    using System.Diagnostics.Contracts;
 
    [Serializable]
    internal class SiteString
    {
        protected String m_site;
        protected ArrayList m_separatedSite;
 
        protected static char[] m_separators = { '.' };
        
        protected internal SiteString()
        {
            // Only call this in derived classes when you know what you're doing.
        }
        
        public SiteString( String site )
        {
            m_separatedSite = CreateSeparatedSite( site );
            m_site = site;
        }
 
        private SiteString(String site, ArrayList separatedSite)
        {
            m_separatedSite = separatedSite;
            m_site = site;
        }
 
        private static ArrayList CreateSeparatedSite(String site)
        {
            if (site == null || site.Length == 0)
            {
                throw new ArgumentException( Environment.GetResourceString("Argument_InvalidSite" ));
            }
            Contract.EndContractBlock();
 
            ArrayList list = new ArrayList();
            int braIndex = -1;
            int ketIndex = -1;
            braIndex = site.IndexOf('[');
            if (braIndex == 0)
                ketIndex = site.IndexOf(']', braIndex+1);
 
            if (ketIndex != -1)
            {
                // Found an IPv6 address. Special case that
                String ipv6Addr = site.Substring(braIndex+1, ketIndex-braIndex-1);
                list.Add(ipv6Addr);
                return list;
            }
 
            // Regular hostnames or IPv4 addresses
            // We dont need to do this for IPv4 addresses, but it's easier to do it anyway
            String[] separatedArray = site.Split( m_separators );
            
            for (int index = separatedArray.Length-1; index > -1; --index)
            {
                if (separatedArray[index] == null)
                {
                    throw new ArgumentException( Environment.GetResourceString("Argument_InvalidSite" ));
                }
                else if (separatedArray[index].Equals( "" )) 
                {
                    if (index != separatedArray.Length-1) 
                    {
                        throw new ArgumentException( Environment.GetResourceString("Argument_InvalidSite" ));
                    }
                }
                else if (separatedArray[index].Equals( "*" ))
                {
                    if (index != 0)
                    {
                        throw new ArgumentException( Environment.GetResourceString("Argument_InvalidSite" ));
                    }
                    list.Add( separatedArray[index] );
                }
                else if (!AllLegalCharacters( separatedArray[index] ))
                {
                    throw new ArgumentException( Environment.GetResourceString("Argument_InvalidSite" ));
                }
                else
                {
                    list.Add( separatedArray[index] );
                }
            }
            
            return list;
        }
 
        // KB# Q188997 - http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q188997& gives the list of allowed characters in
        // a NETBIOS name. DNS names are a subset of that (alphanumeric or '-').
        private static bool AllLegalCharacters( String str )
        {
            for (int i = 0; i < str.Length; ++i)
            {
                char c = str[i];
 
                if (IsLegalDNSChar(c) ||
                    IsNetbiosSplChar(c))
                {
                    continue;
                }
                else
                {
                    return false;
                }
            }
 
            return true;
        }
 
        private static bool IsLegalDNSChar(char c)
        {
            if ((c >= 'a' && c <= 'z') ||
                (c >= 'A' && c <= 'Z') ||
                (c >= '0' && c <= '9') ||
                (c == '-'))
                return true;
            else
                return false;
        }
        private static bool IsNetbiosSplChar(char c)
        {
            //  ! @ # $ % ^ & ( ) - _ ' { } . ~ are OK
            switch (c) {
                case '-':
                case '_':
                case '@':
                case '!':
                case '#':
                case '$':
                case '%':
                case '^':
                case '&':
                case '(':
                case ')':
                case '\'':
                case '{':
                case '}':
                case '.':
                case '~':
                    return true;
                default:
                    return false;
            }
        }
 
        public override String ToString()
        {
            return m_site;
        }
        
        public override bool Equals(Object o)
        {
            if (o == null || !(o is SiteString))
                return false;
            else
                return this.Equals( (SiteString)o, true );
        }
 
        public override int GetHashCode()
        {
            TextInfo info = CultureInfo.InvariantCulture.TextInfo;
 
            return info.GetCaseInsensitiveHashCode( this.m_site );
        }
 
        internal bool Equals( SiteString ss, bool ignoreCase )
        {
            if (this.m_site == null)
                return ss.m_site == null;
            if (ss.m_site == null)
                return false;
            return this.IsSubsetOf(ss, ignoreCase) && ss.IsSubsetOf(this, ignoreCase);
        }
            
        
        public virtual SiteString Copy()
        {
            return new SiteString( m_site, m_separatedSite );
        }
 
        public virtual bool IsSubsetOf( SiteString operand )
        {
            return this.IsSubsetOf( operand, true );
        }
 
        public virtual bool IsSubsetOf( SiteString operand, bool ignoreCase )
        {
            StringComparison strComp = (ignoreCase? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal);
            if (operand == null)
            {
                return false;
            }
            else if (this.m_separatedSite.Count == operand.m_separatedSite.Count &&
                     this.m_separatedSite.Count == 0)
            {
                return true;
            }
            else if (this.m_separatedSite.Count < operand.m_separatedSite.Count - 1)
            {
                return false;
            }
            else if (this.m_separatedSite.Count > operand.m_separatedSite.Count &&
                     operand.m_separatedSite.Count > 0 &&
                     !operand.m_separatedSite[operand.m_separatedSite.Count - 1].Equals("*"))
            {
                return false;
            }
            else if (String.Compare( this.m_site, operand.m_site, strComp) == 0)
            {
                return true;
            }
 
            for (int index = 0; index < operand.m_separatedSite.Count - 1; ++index)
            {
                if (String.Compare((String)this.m_separatedSite[index], (String)operand.m_separatedSite[index], strComp) != 0)
                {
                    return false;
                }
            }
 
            if (this.m_separatedSite.Count < operand.m_separatedSite.Count)
            {
                return operand.m_separatedSite[operand.m_separatedSite.Count - 1].Equals("*");
            }
            else if (this.m_separatedSite.Count == operand.m_separatedSite.Count)
            {
                // last item must be the same or operand must have a * in its last item
                return (String.Compare((String)this.m_separatedSite[this.m_separatedSite.Count - 1],
                                                    (String)operand.m_separatedSite[this.m_separatedSite.Count - 1], 
                                                    strComp ) == 0 ||
                           operand.m_separatedSite[operand.m_separatedSite.Count - 1].Equals("*"));
                    
            }
            else 
                return true;
        }
                
        
    
        public virtual SiteString Intersect( SiteString operand )
        {
            if (operand == null)
            {
                return null;
            }
            else if (this.IsSubsetOf( operand ))
            {
                return this.Copy();
            }
            else if (operand.IsSubsetOf( this ))
            {
                return operand.Copy();
            }
            else
            {
                return null;
            }
        }
        
        public virtual SiteString Union( SiteString operand )
        {
            if (operand == null)
            {
                return this;
            }
            else if (this.IsSubsetOf( operand ))
            {
                return operand.Copy();
            }
            else if (operand.IsSubsetOf( this ))
            {
                return this.Copy();
            }
            else
            {
                return null;
            }
        }
    }
}