//
// System.Data.SqlTypes.SqlChars
//
// Author:
//   Tim Coleman <tim@timcoleman.com>
//
// Copyright (C) Tim Coleman, 2003
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#if NET_2_0

using System;
using System.Globalization;
using System.Xml;
using System.Text;
using System.Xml.Schema;
using System.Xml.Serialization;
using System.Runtime.Serialization;

namespace System.Data.SqlTypes
{
	[SerializableAttribute]
	[XmlSchemaProvider ("GetXsdType")]
	public sealed class SqlChars : INullable, IXmlSerializable, ISerializable
	{
		#region Fields

		bool notNull;
		char [] buffer;
		StorageState storage = StorageState.UnmanagedBuffer;

		#endregion

		#region Constructors

		public SqlChars ()
		{
			notNull = false;
			buffer = null;
		}

		public SqlChars (char[] buffer)
		{
			if (buffer == null) {
				notNull = false;
				this.buffer = null;
			} else {
				notNull = true;
				this.buffer = buffer;
				storage = StorageState.Buffer;
			}
		}

		public SqlChars (SqlString value)
		{
			if (value.IsNull) {
				notNull = false;
				buffer = null;
			} else {
				notNull = true;
				buffer = value.Value.ToCharArray ();
				storage = StorageState.Buffer;
			}
		}

		#endregion

		#region Properties

		public char [] Buffer {
			get { return buffer; }
		}

		public bool IsNull {
			get { return !notNull; }
		}

		public char this [long offset] {
			set {
				if (notNull && offset >= 0 && offset < buffer.Length)
					buffer [offset] = value;
			}
			get {
				if (buffer == null)
					throw new SqlNullValueException ("Data is Null");
				if (offset < 0 || offset >= buffer.Length)
					throw new ArgumentOutOfRangeException ("Parameter name: offset");
				return buffer [offset];
			}
		}

		public long Length {
			get {
				if (!notNull || buffer == null)
					throw new SqlNullValueException ("Data is Null");
				if (buffer.Length < 0)
					return -1;
				return buffer.Length;
			}
		}

		public long MaxLength {
			get {
				if (!notNull || buffer == null || storage == StorageState.Stream)
					return -1;
				return buffer.Length;
			}
		}

		public static SqlChars Null {
			get {
				return new SqlChars ();
			}
		}

		public StorageState Storage {
			get {
				if (storage == StorageState.UnmanagedBuffer)
					throw new SqlNullValueException ("Data is Null");
				return storage;
			}
		}

		public char [] Value {
			get {
				if (buffer == null)
					return buffer;
				return (char []) buffer.Clone ();
			}
		}

		#endregion

		#region Methods

		public void SetLength (long value)
		{
			if (buffer == null)
				throw new SqlTypeException ("There is no buffer");
			if (value < 0 || value > buffer.Length)
				throw new ArgumentOutOfRangeException ("Specified argument was out of the range of valid values.");
			Array.Resize (ref buffer, (int) value);
		}

		public void SetNull ()
		{
			buffer = null;
			notNull = false;
		}

		public static explicit operator SqlString (SqlChars value)
		{
			if (value.IsNull)
				return SqlString.Null;
			else {
				return new SqlString (new String (value.Value));
			}
		}

		public static explicit operator SqlChars (SqlString value)
		{
			if (value.IsNull)
				return Null;
			else
				return new SqlChars (value.Value);
		}

		public SqlString ToSqlString ()
		{
			if (buffer == null) {
				return SqlString.Null;
			} else {
				return new SqlString (buffer.ToString ());
			}
		}

		public long Read (long offset, char [] buffer, int offsetInBuffer, int count)
		{
			if (buffer == null)
				throw new ArgumentNullException ("buffer");

			if (IsNull)
				throw new SqlNullValueException ("There is no buffer. Read or write operation failed");
			
			if (count > MaxLength || count > buffer.Length || 
			    count < 0 || ((offsetInBuffer + count) > buffer.Length))
				throw new ArgumentOutOfRangeException ("count");
			
			if (offset < 0 || offset > MaxLength)
				throw new ArgumentOutOfRangeException ("offset");
			
			if (offsetInBuffer < 0 || offsetInBuffer > buffer.Length)
				throw new ArgumentOutOfRangeException ("offsetInBuffer");
			
			/*	LAMESPEC: If count specifies more characters than what is available from 
				offset to the Length of the SqlChars instance, only the available 
				characters are copied 
			 */
			
			/* Final count of what will be copied */
			long actualCount = count;
			if (count + offset > Length)
				actualCount = Length - offset;
			
			Array.Copy (this.buffer, offset, buffer, offsetInBuffer, actualCount);
			
			return actualCount;
		}

		public void Write (long offset, char [] buffer, int offsetInBuffer, int count)
		{
			if (buffer == null)
				throw new ArgumentNullException ("buffer");

			if (IsNull)
				throw new SqlTypeException ("There is no buffer. Read or write operation failed.");
							
			if (offset < 0) 
				throw new ArgumentOutOfRangeException ("offset");
			
			if (offsetInBuffer < 0 || offsetInBuffer > buffer.Length 
			    || offsetInBuffer > Length 
			    || offsetInBuffer + count > Length
			    || offsetInBuffer + count > buffer.Length)
				throw new ArgumentOutOfRangeException ("offsetInBuffer");
			
			if (count < 0 || count > MaxLength)
				throw new ArgumentOutOfRangeException ("count");
			
			if (offset > MaxLength || offset+count > MaxLength)
				throw new SqlTypeException ("The buffer is insufficient. Read or write operation failed.");
			
			if (count + offset > Length && 
			    count + offset <= MaxLength)
				SetLength (count);
			
			Array.Copy (buffer, offsetInBuffer, this.buffer, offset, count);
		}

		public static XmlQualifiedName GetXsdType (XmlSchemaSet schemaSet)
		{
			if (schemaSet != null && schemaSet.Count == 0) {
				XmlSchema xs = new XmlSchema ();
				XmlSchemaComplexType ct = new XmlSchemaComplexType ();
				ct.Name = "string";
				xs.Items.Add (ct);
				schemaSet.Add (xs);
			}
			return new XmlQualifiedName ("string", "http://www.w3.org/2001/XMLSchema");
		}
		
		XmlSchema IXmlSerializable.GetSchema ()
		{
			return null;
		}
		
		void IXmlSerializable.ReadXml (XmlReader reader)
		{
			if (reader == null)
				return;

			switch (reader.ReadState) {
			case ReadState.EndOfFile:
			case ReadState.Error:
			case ReadState.Closed:
				return;
			}
			// Skip XML declaration and prolog
			// or do I need to validate for the <string> tag?
			reader.MoveToContent ();
			if (reader.EOF)
				return;
			
			reader.Read ();
			if (reader.NodeType == XmlNodeType.EndElement)
				return;

			if (reader.Value.Length > 0) {
				if (String.Compare ("Null", reader.Value) == 0) {
					// means a null reference/invalid value
					notNull = false;
					return; 
				}
				// FIXME: Validate the value for expected format
				this.buffer = reader.Value.ToCharArray ();
				this.notNull = true;
				this.storage = StorageState.Buffer;
			}
		}
		
		void IXmlSerializable.WriteXml (XmlWriter writer) 
		{
			writer.WriteString (this.buffer.ToString ());
		}

		[MonoTODO]
		void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
		{
			throw new NotImplementedException ();
		}

		#endregion
	}
}

#endif