//-----------------------------------------------------------------------------
// <copyright file="MailAddressCollection.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//-----------------------------------------------------------------------------
 
namespace System.Net.Mail
{
    using System;
    using System.Collections;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Text;
    using System.Net.Mime;
 
    public class MailAddressCollection: Collection<MailAddress> {
        public MailAddressCollection(){
        }
 
        public void Add(string addresses) {
            if (addresses == null) {
                throw new ArgumentNullException("addresses");
            }
            if (addresses == string.Empty) {
                throw new ArgumentException(SR.GetString(SR.net_emptystringcall, "addresses"), "addresses");
            }
 
            ParseValue(addresses);
        }
 
        protected override void SetItem(int index, MailAddress item){
              if(item==null) {
                  throw new ArgumentNullException("item");
              }
    
              base.SetItem(index,item);
        }
        
        protected override void InsertItem(int index, MailAddress item){
              if(item==null){
                   throw new ArgumentNullException("item");
              }
    
              base.InsertItem(index,item);
        }
 
        internal void ParseValue(string addresses){
            IList<MailAddress> result = MailAddressParser.ParseMultipleAddresses(addresses);
 
            for (int i = 0; i < result.Count; i++) {
                this.Add(result[i]);
            }
        }
 
        public override string ToString(){
            bool first = true;
            StringBuilder builder = new StringBuilder();
 
            foreach (MailAddress address in this) {
                if (!first) {
                    builder.Append(", ");
                }
 
                builder.Append(address.ToString());
                first = false;
            }
 
            return builder.ToString();;
        }
 
        internal string Encode(int charsConsumed, bool allowUnicode) {
            string encodedAddresses = string.Empty;
 
            //encode each address individually (except the first), fold and separate with a comma
            foreach (MailAddress address in this) {
                if (String.IsNullOrEmpty(encodedAddresses)) {
                    //no need to append a comma to the first one because it may be the only one.
                    encodedAddresses = address.Encode(charsConsumed, allowUnicode);
                } 
                else {
                    //appending another one, append a comma to separate and then fold and add the encoded address
                    //the charsConsumed will be 1 because only the first line needs to account for the header itself for 
                    //line length; subsequent lines have a single whitespace character because they are folded here
                    encodedAddresses += ", " + address.Encode(1, allowUnicode);
                }
            }
            return encodedAddresses;
        }
    }
}