/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

using System;
using System.Text;

namespace uno
{

/** This class can be used as a base class for UNO objects.
    It implements the capability to be kept weakly
    (unoidl.com.sun.star.uno.XWeak) and it implements
    unoidl.com.sun.star.lang.XTypeProvider which is necessary for
    using the object from StarBasic.
*/
public struct Any
{
    private object _value;
    private Type _type;

    public static Any VOID = new Any(typeof(void), null);
    
    private static void checkArgs(Type type, Object value)
    {
        //value can only be null if type == void
        if (type == null 
			|| (value == null 
                && type != typeof(void) 
                && type != typeof(object) 
                && type.IsInterface == false))
            throw new System.Exception(
                "uno.Any: Constructor called with illegal arguments!");
        //If value is a polymorphic struct then type must be
        //uno.Polymorphic
        if (value != null)
        {
            TypeParametersAttribute t = (TypeParametersAttribute) Attribute.GetCustomAttribute(
                value.GetType(), typeof(TypeParametersAttribute));
            if (t != null && !(type is PolymorphicType))
                throw new System.Exception(
                    "uno.Any: The value has a polymorphic type but the type argument is not " +
                    "uno.PolymorphicType. Please use the constructor Any(Type, object) and " +
                    "supply a uno.PolymorphicType as type argument!");
        }
    }

    /** constructs an instance.

       <p>If the arguments are invalid then an exception is thrown.</p>
       @exception System.Exception
     */
    public Any(Type type, object value)
    {
        checkArgs(type, value);
        _type = type;
        _value = value;
    }

    /** sets the type and value.
       <p>If the arguments ar invalid then an exception is thrown.</p>
       @exception System.Exception
     */
    public void setValue(Type type, object value)
    {
        checkArgs(type, value);
        _type = type;
        _value = value;
    }
    
    public Type Type
    {
        get
        {
            if (_type == null)
                _type = typeof(void);
            return _type;
        }
    }

    public Object Value
    {
        get
        {
            return _value;
        }
    }
    
    public Any(char value): this(typeof(char), value)
    {
    }

    public Any(bool value): this(typeof(bool), value)
    {
    }

    public Any(byte value): this(typeof(byte), value)
    {
    }
    
    public Any(short value): this(typeof(short), value)
    {
    }

    public Any(ushort value): this(typeof(ushort), value)
    {
    }

    public Any(int value): this(typeof(int), value)
    {
    }

    public Any(uint value): this(typeof(uint), value)
    {
    }

    public Any(long value): this(typeof(long), value)
    {
    }

    public Any(ulong value): this(typeof(ulong), value)
    {
    }

    public Any(float value): this(typeof(float), value)
    {
    }

    public Any(double value): this(typeof(double), value)
    {
    }

    public Any(Type value): this(typeof(Type), value)
    {
    }

    public Any(string value): this(typeof(string), value)
    {
    }

    public override string ToString()
    {
        StringBuilder msg = new StringBuilder("uno.Any { Type= ");
        msg.Append(Type.ToString());
        msg.Append(", Value=");
        msg.Append(Value.ToString());
        msg.Append("}");
        return msg.ToString();
    }
    
    public bool hasValue()
    {
        if (Type == null || Type == typeof(void))
            return false;
        return true;
    }

    public override bool Equals(object obj)
    {
        if (obj != null)
        {
            try
            {
                return Equals((Any) obj);
            }
            catch (InvalidCastException)
            {
            }
        }
        return false;
    }

    public bool Equals(Any obj)
    {
        return Type.Equals(obj.Type)
            && (Value == null ?
            obj.Value == null  :
            Value.Equals(obj.Value));
    }

    public override int GetHashCode()
    {
        return Type.GetHashCode() ^ (Value != null ? Value.GetHashCode() : 0);
    }   
}

}