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

/// <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 ComparisonUtilities
    {
        public static bool Equivalent( Object o1, Object o2 )
        {
            if ( o1 == o2 )
            {
                return true;
            }
            if ( o1 == null || o2 == null )
            {
                return false; // both null covered in first test
            }
            Type type = o1.GetType();
            if ( type != o2.GetType() )
            {
                return false;
            }
            if ( (o1 is ValueType) || (type == typeof (DateTime)) || type.IsEnum )
            {
                return o1.Equals( o2 );
            }
            // Array special case
            if ( type.IsArray )
            {
                return EquivalentArrayValues( (Array) o1, (Array) o2 );
            }
            // List special case
            if ( type.GetInterface( "IList`1" ) != null )
            {
                return EquivalentListValues( (IList) o1, (IList) o2 );
            }
            // Dictionary special case
            if ( type.GetInterface( "IDictionary`2" ) != null )
            {
                return EquivalentMapValues( (IDictionary) o1, (IDictionary) o2 );
            }

            return EquivalentFieldValues( o1, o2 );
        }

        public static bool EquivalentFieldValues( Object o1, Object o2 )
        {
            Type type = o1.GetType();
            FieldInfo[] fields = type.GetFields();
            for ( int i = 0; i < fields.Length; i++ )
            {
                FieldInfo info = fields[i];
                if ( !EquivalentFieldValue( info, o1, o2 ) )
                {
                    return false;
                }
            }
            return true;
        }

        public static bool EquivalentArrayValues( Array o1, Array o2 )
        {
            if ( o1 == o2 )
            {
                return true;
            }
            if ( o1 == null || o2 == null )
            {
                return false; // both null covered in first test
            }
            if ( o1.Length != o2.Length )
            {
                return false;
            }
            for ( int i = 0; i < o1.Length; i++ )
            {
                if ( !Equivalent( o1.GetValue( i ), o2.GetValue( i ) ) )
                {
                    return false;
                }
            }
            return true;
        }

        public static bool EquivalentListValues( IList o1, IList o2 )
        {
            if ( o1 == o2 )
            {
                return true;
            }
            if ( o1 == null || o2 == null )
            {
                return false; // both null covered in first test
            }
            if ( o1.Count != o2.Count )
            {
                return false;
            }
            for ( int i = 0; i < o1.Count; i++ )
            {
                if ( !Equivalent( o1[i], o2[i] ) )
                {
                    return false;
                }
            }
            return true;
        }

        public static bool EquivalentMapValues( IDictionary o1, IDictionary o2 )
        {
            if ( o1 == o2 )
            {
                return true;
            }
            if ( o1 == null || o2 == null )
            {
                return false; // both null covered in first test
            }
            if ( o1.Count != o2.Count )
            {
                return false;
            }
            foreach ( Object key in o1.Keys )
            {
                if ( !o2.Contains( key ) )
                {
                    return false;
                }
                object item1 = o1[key];
                object item2 = o2[key];
                if ( !Equivalent( item1, item2 ) )
                {
                    return false;
                }
            }
            return true;
        }

        protected static bool EquivalentFieldValue( FieldInfo info, Object o1, Object o2 )
        {
            if ( info.IsNotSerialized || info.IsStatic )
            {
                return true;
            }
            Object f1 = info.GetValue( o1 );
            Object f2 = info.GetValue( o2 );
            return Equivalent( f1, f2 );
        }
    }
}