using System;
using System.Collections;
using System.Reflection;
using System.Text;

/// <header>
/// <wox>
///     <version>1.0</version>
///     <author>Carlos R. Jaimez Gonzalez</author>
///     <author>Simon M. Lucas</author>
///     <site>http://woxserializer.sourceforge.net/</site>
/// </wox>
/// <wox>
///     <version>1.5</version>
///     <author>Steven M Lewis</author>
/// </wox>
/// <wox>
///     <version>2.0</version>
///     <author>George A Smith</author>
///     <svn>http://woxserializer.sourceforge.net/</svn>
///     <note>XML form for vs 2 is more compact and therefor incompatible with vs 1</note>
/// </wox>
/// </header>

namespace wox.serial
{
    public class ArrayHandler : AbstractHandler, WoxIsAHandler
    {
        public const String WOX_TYPE = "array";
        public static readonly ArrayHandler INSTANCE = new ArrayHandler();

        protected ArrayHandler()
        {
        }

        #region WoxIsAHandler Members

        public override string[] GetForReadObjectWoxTypeNames()
        {
            return new[] {WOX_TYPE}; // Because we only support one type
        }

        public override string GetWoxTypeFor( WoxHandlers pWoxHandlers, Type pType, FieldInfo pField, bool pJustType )
        {
            return WOX_TYPE; // Because we only support one type
        }

        public override bool WillReadObjectForWoxType( string pWoxType )
        {
            return Equals( WOX_TYPE, pWoxType );
        }

        public virtual bool IsFor( Type pType )
        {
            return typeof (Array).IsAssignableFrom( pType );
        }

        public override Type GetNativeTypeFor( WoxHandlers pWoxHandlers, string pWoxType )
        {
            throw new ApplicationException( "Array Handler does not support GetNativeTypeFor for any type, including: " + pWoxType );
        }

        public override object ReadObject( WoxHandlers pWoxHandlers, WoxReader pWoxReader, XMLreader pReader )
        {
            XMLreader zSubtree = pReader.CreateSubtreeReader();
            zSubtree.ReadStartElement(); //position the cursor to our element

            try
            {
                string zWoxArrayType = pReader.GetAttribute( Serial.ELEMENT_TYPE );

                WoxHandler zHandler = pWoxHandlers.GetWoxFieldHandler( zWoxArrayType );
                if ( zHandler != null && zHandler.WillFieldValueNeverHaveAnySpaces() )
                {
                    Type zFieldElementType = zHandler.GetNativeTypeFor( pWoxHandlers, zWoxArrayType );
                    // get element's value as string. e.g. "67 87 98 87"
                    String zValuesAsString = pReader.ReadElementText().Trim();
                    String[] zValues = (zValuesAsString.Length != 0) //
                                           ? SplitOnSpaces( zValuesAsString ) //
                                           : EMPTY_STRING_ARRAY;
                    return zHandler.CreateArrayFor( zFieldElementType, zValues );
                }
                Type zComponentType = CommonNativeType( pWoxHandlers, zWoxArrayType );
                if ( zComponentType == null )
                {
                    throw new ApplicationException( "No Native Type for Wox Type: " + zWoxArrayType );
                }
                ArrayList zList = ReadObjects( pWoxReader, zSubtree );
                Array zArray = Array.CreateInstance( zComponentType, zList.Count );
                for ( int i = 0; i < zList.Count; i++ )
                {
                    zArray.SetValue( zList[i], i );
                }
                return zArray;
            }
            catch ( Exception e )
            {
                throw new ApplicationException( "Array Exception is: " + e.Message, e );
            }
            finally
            {
                Consume( zSubtree );
            }
        }

        public override void WriteObject( WoxHandlers pWoxHandlers, WoxWriter pWoxWriter, object pObject, FieldInfo pField, XMLwriter pWriter, bool pJustType )
        {
            pWriter.WriteStartElement( Serial.OBJECT );
            pWriter.WriteAttributeString( Serial.TYPE, WOX_TYPE );

            Type zElementType = pObject.GetType().GetElementType();
            WoxHandler zHandler = pWoxHandlers.GetNativeHandler( zElementType );
            if ( zHandler.WillFieldValueNeverHaveAnySpaces() )
            {
                //These arrays can go easily to a string with spaces separating their elements.
                WriteInLineArray( pWoxHandlers, zHandler, zElementType, pObject, pWriter );
            }
            else
            {
                string zElementWoxType = CommonWoxType( pWoxHandlers, zElementType, pField, pJustType );

                pWriter.WriteAttributeString( Serial.ELEMENT_TYPE, zElementWoxType );

                var zArray = (Array) pObject;
                int zLength = zArray.GetLength( 0 ); // 0 == 1st Dimension!

                if ( zLength != 0 )
                {
                    pWriter.WriteAttributeString( Serial.ID, pWoxWriter.CreateIDfor( pObject ) );

                    foreach ( object zEntry in zArray )
                    {
                        pWoxWriter.Write( zEntry, pField, pWriter, pJustType );
                    }
                }
            }
            pWriter.WriteEndElement();
        }

        #endregion

        private static void WriteInLineArray( WoxHandlers pWoxHandlers, WoxHandler pHandler, Type pElementType, object pObject, XMLwriter pWriter )
        {
            pWriter.WriteAttributeString( Serial.ELEMENT_TYPE, pHandler.GetWoxTypeFor( pWoxHandlers, pElementType, null, false ) );

            var zArray = (Array) pObject;
            int zLength = zArray.GetLength( 0 ); // 0 == 1st Dimension!

            if ( zLength != 0 )
            {
                var sb = new StringBuilder();

                sb.Append( pHandler.CreateFieldValue( zArray.GetValue( 0 ) ) );

                for ( int i = 1; i < zLength; i++ )
                {
                    sb.Append( ' ' ).Append( pHandler.CreateFieldValue( zArray.GetValue( i ) ) );
                }

                pWriter.WriteElementText( sb.ToString() );
            }
        }

        private static string[] SplitOnSpaces( string pValuesAsString )
        {
            return pValuesAsString.Split( ' ' );
        }
    }
}