/*
Copyright (C) 2003 Simon Mourier <simonm@microsoft.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:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. 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.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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;

namespace HtmlAgilityPack
{
	/// <summary>
	/// Represents an HTML attribute.
	/// </summary>
	public class HtmlAttribute: IComparable
	{
		internal int _line = 0;
		internal int _lineposition = 0;
		internal int _streamposition = 0;
		internal int _namestartindex = 0;
		internal int _namelength = 0;
		internal int _valuestartindex = 0;
		internal int _valuelength = 0;
		internal HtmlDocument _ownerdocument; // attribute can exists without a node
		internal HtmlNode _ownernode;
		internal string _name;
		internal string _value;

		internal HtmlAttribute(HtmlDocument ownerdocument)
		{
			_ownerdocument = ownerdocument;
		}

		/// <summary>
		/// Creates a duplicate of this attribute.
		/// </summary>
		/// <returns>The cloned attribute.</returns>
		public HtmlAttribute Clone()
		{
			HtmlAttribute att = new HtmlAttribute(_ownerdocument);
			att.Name = Name;
			att.Value = Value;
			return att;
		}

		/// <summary>
		/// Compares the current instance with another attribute. Comparison is based on attributes' name.
		/// </summary>
		/// <param name="obj">An attribute to compare with this instance.</param>
		/// <returns>A 32-bit signed integer that indicates the relative order of the names comparison.</returns>
		public int CompareTo(object obj)
		{
			HtmlAttribute att = obj as HtmlAttribute;
			if (att == null)
			{
				throw new ArgumentException("obj");
			}
			return Name.CompareTo(att.Name);
		}

		internal string XmlName
		{
			get
			{
				return GetXmlName(Name);
			}
		}

		/// <summary>
		/// Gets a valid XML name.
		/// </summary>
		/// <param name="name">Any text.</param>
		/// <returns>A string that is a valid XML name.</returns>
		internal static string GetXmlName(string name)
		{
			string xmlname = string.Empty;
			bool nameisok = true;
			for(int i=0;i<name.Length;i++)
			{
				// names are lcase
				// note: we are very limited here
				if (((name[i]>='a') && (name[i]<='z')) ||
					((name[i]>='0') && (name[i]<='9')) ||
					//					(name[i]==':') || (name[i]=='_') || (name[i]=='-') || (name[i]=='.')) // these are bads in fact
					(name[i]=='_') || (name[i]=='-') || (name[i]=='.'))
				{
					xmlname += name[i];
				}
				else
				{
					nameisok = false;
					byte[] bytes = System.Text.Encoding.UTF8.GetBytes(new char[]{name[i]});
					for(int j=0;j<bytes.Length;j++)
					{
						xmlname += bytes[j].ToString("x2");
					}
					xmlname += "_";
				}
															  
			}
			if (nameisok)
			{
				return xmlname;
			}
			return "_" + xmlname;
		}

		internal string XmlValue
		{
			get
			{
				return Value;
			}
		}

		/// <summary>
		/// Gets the qualified name of the attribute.
		/// </summary>
		public string Name
		{
			get
			{
				if (_name == null)
				{
					_name = _ownerdocument._text.Substring(_namestartindex, _namelength).ToLower();
				}
				return _name;
			}
			set
			{
				if (value == null)
				{
					throw new ArgumentNullException("value");
				}
				_name = value.ToLower();
				if (_ownernode != null)
				{
					_ownernode._innerchanged = true;
					_ownernode._outerchanged = true;
				}
			}
		}

		/// <summary>
		/// Gets or sets the value of the attribute.
		/// </summary>
		public string Value
		{
			get
			{
				if (_value == null)
				{
					_value = _ownerdocument._text.Substring(_valuestartindex, _valuelength);
				}
				return _value;
			}
			set
			{
				_value = value;
				if (_ownernode != null)
				{
					_ownernode._innerchanged = true;
					_ownernode._outerchanged = true;
				}
			}
		}

		/// <summary>
		/// Gets the line number of this attribute in the document.
		/// </summary>
		public int Line
		{
			get
			{
				return _line;
			}
		}

		/// <summary>
		/// Gets the column number of this attribute in the document.
		/// </summary>
		public int LinePosition
		{
			get
			{
				return _lineposition;
			}
		}

		/// <summary>
		/// Gets the stream position of this attribute in the document, relative to the start of the document.
		/// </summary>
		public int StreamPosition
		{
			get
			{
				return _streamposition;
			}
		}

		/// <summary>
		/// Gets the HTML node to which this attribute belongs.
		/// </summary>
		public HtmlNode OwnerNode
		{
			get
			{
				return _ownernode;
			}
		}

		/// <summary>
		/// Gets the HTML document to which this attribute belongs.
		/// </summary>
		public HtmlDocument OwnerDocument
		{
			get
			{
				return _ownerdocument;
			}
		}

	}

	/// <summary>
	/// Represents a combined list and collection of HTML nodes.
	/// </summary>
	public class HtmlAttributeCollection: IEnumerable
	{
		internal Hashtable _hashitems = new Hashtable();
		private ArrayList _items = new ArrayList();
		private HtmlNode _ownernode;

		internal HtmlAttributeCollection(HtmlNode ownernode)
		{
			_ownernode = ownernode;
		}

		/// <summary>
		/// Inserts the specified attribute as the last attribute in the collection.
		/// </summary>
		/// <param name="newAttribute">The attribute to insert. May not be null.</param>
		/// <returns>The appended attribute.</returns>
		public HtmlAttribute Append(HtmlAttribute newAttribute)
		{
			if (newAttribute == null)
			{
				throw new ArgumentNullException("newAttribute");
			}

			_hashitems[newAttribute.Name] = newAttribute;
			newAttribute._ownernode = _ownernode;
			_items.Add(newAttribute);

			_ownernode._innerchanged = true;
			_ownernode._outerchanged = true;
			return newAttribute;
		}

		/// <summary>
		/// Creates and inserts a new attribute as the last attribute in the collection.
		/// </summary>
		/// <param name="name">The name of the attribute to insert.</param>
		/// <returns>The appended attribute.</returns>
		public HtmlAttribute Append(string name)
		{
			HtmlAttribute att = _ownernode._ownerdocument.CreateAttribute(name);
			return Append(att);
		}

		/// <summary>
		/// Creates and inserts a new attribute as the last attribute in the collection.
		/// </summary>
		/// <param name="name">The name of the attribute to insert.</param>
		/// <param name="value">The value of the attribute to insert.</param>
		/// <returns>The appended attribute.</returns>
		public HtmlAttribute Append(string name, string value)
		{
			HtmlAttribute att = _ownernode._ownerdocument.CreateAttribute(name, value);
			return Append(att);
		}

		/// <summary>
		/// Inserts the specified attribute as the first node in the collection.
		/// </summary>
		/// <param name="newAttribute">The attribute to insert. May not be null.</param>
		/// <returns>The prepended attribute.</returns>
		public HtmlAttribute Prepend(HtmlAttribute newAttribute)
		{
			if (newAttribute == null)
			{
				throw new ArgumentNullException("newAttribute");
			}

			_hashitems[newAttribute.Name] = newAttribute;
			newAttribute._ownernode = _ownernode;
			_items.Insert(0, newAttribute);

			_ownernode._innerchanged = true;
			_ownernode._outerchanged = true;
			return newAttribute;
		}

		/// <summary>
		/// Removes the attribute at the specified index.
		/// </summary>
		/// <param name="index">The index of the attribute to remove.</param>
		public void RemoveAt(int index)
		{
			HtmlAttribute att = (HtmlAttribute)_items[index];
			_hashitems.Remove(att.Name);
			_items.RemoveAt(index);

			_ownernode._innerchanged = true;
			_ownernode._outerchanged = true;
		}

		/// <summary>
		/// Removes a given attribute from the list.
		/// </summary>
		/// <param name="attribute">The attribute to remove. May not be null.</param>
		public void Remove(HtmlAttribute attribute)
		{
			if (attribute == null)
			{
				throw new ArgumentNullException("attribute");
			}
			int index = GetAttributeIndex(attribute);
			if (index == -1)
			{
				throw new IndexOutOfRangeException();
			}
			RemoveAt(index);
		}

		/// <summary>
		/// Removes an attribute from the list, using its name. If there are more than one attributes with this name, they will all be removed.
		/// </summary>
		/// <param name="name">The attribute's name. May not be null.</param>
		public void Remove(string name)
		{
			if (name == null)
			{
				throw new ArgumentNullException("name");
			}

			string lname = name.ToLower();
			for(int i=0;i<_items.Count;i++)
			{
				HtmlAttribute att = (HtmlAttribute)_items[i];
				if (att.Name == lname)
				{
					RemoveAt(i);
				}
			}
		}

		/// <summary>
		/// Remove all attributes in the list.
		/// </summary>
		public void RemoveAll()
		{
			_hashitems.Clear();
			_items.Clear();

			_ownernode._innerchanged = true;
			_ownernode._outerchanged = true;
		}

		/// <summary>
		/// Gets the number of elements actually contained in the list.
		/// </summary>
		public int Count
		{
			get
			{
				return _items.Count;
			}
		}

		internal int GetAttributeIndex(HtmlAttribute attribute)
		{
			if (attribute == null)
			{
				throw new ArgumentNullException("attribute");
			}
			for(int i=0;i<_items.Count;i++)
			{
				if (((HtmlAttribute)_items[i])==attribute)
					return i;
			}
			return -1;
		}

		internal int GetAttributeIndex(string name)
		{
			if (name == null)
			{
				throw new ArgumentNullException("name");
			}
			string lname = name.ToLower();
			for(int i=0;i<_items.Count;i++)
			{
				if (((HtmlAttribute)_items[i]).Name==lname)
					return i;
			}
			return -1;
		}

		/// <summary>
		/// Gets a given attribute from the list using its name.
		/// </summary>
		public HtmlAttribute this[string name]
		{
			get
			{
				if (name == null)
				{
					throw new ArgumentNullException("name");
				}
				return _hashitems[name.ToLower()] as HtmlAttribute;
			}
		}

		/// <summary>
		/// Gets the attribute at the specified index.
		/// </summary>
		public HtmlAttribute this[int index]
		{
			get
			{
				return _items[index] as HtmlAttribute;
			}
		}

		internal void Clear()
		{
			_hashitems.Clear();
			_items.Clear();
		}

		/// <summary>
		/// Returns an enumerator that can iterate through the list.
		/// </summary>
		/// <returns>An IEnumerator for the entire list.</returns>
		public HtmlAttributeEnumerator GetEnumerator() 
		{
			return new HtmlAttributeEnumerator(_items);
		}

		IEnumerator IEnumerable.GetEnumerator() 
		{
			return GetEnumerator();
		}

		/// <summary>
		/// Represents an enumerator that can iterate through the list.
		/// </summary>
		public class HtmlAttributeEnumerator: IEnumerator 
		{
			int _index;
			ArrayList _items;

			internal HtmlAttributeEnumerator(ArrayList items) 
			{
				_items = items;
				_index = -1;
			}

			/// <summary>
			/// Sets the enumerator to its initial position, which is before the first element in the collection.
			/// </summary>
			public void Reset() 
			{
				_index = -1;
			}

			/// <summary>
			/// Advances the enumerator to the next element of the collection.
			/// </summary>
			/// <returns>true if the enumerator was successfully advanced to the next element, false if the enumerator has passed the end of the collection.</returns>
			public bool MoveNext() 
			{
				_index++;
				return (_index<_items.Count);
			}

			/// <summary>
			/// Gets the current element in the collection.
			/// </summary>
			public HtmlAttribute Current 
			{
				get 
				{
					return (HtmlAttribute)(_items[_index]);
				}
			}

			/// <summary>
			/// Gets the current element in the collection.
			/// </summary>
			object IEnumerator.Current 
			{
				get 
				{
					return (Current);
				}
			}
		}
	}

}