// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Xaml.Schema;
using System.Reflection;
 
namespace System.Windows.Baml2006
{
    internal class WpfKnownMemberInvoker : XamlMemberInvoker
    {
        private WpfKnownMember _member;
        private bool _hasShouldSerializeMethodBeenLookedup = false;
        private MethodInfo _shouldSerializeMethod = null;
 
        public WpfKnownMemberInvoker(WpfKnownMember member) : base(member)
        {
            _member = member;
        }
 
        public override object GetValue(object instance)
        {
            if (_member.DependencyProperty != null)
            {
                return ((DependencyObject)instance).GetValue(_member.DependencyProperty);
            }
            else
            {
                return _member.GetDelegate(instance);
            }
        }
 
        public override void SetValue(object instance, object value)
        {
            if (_member.DependencyProperty != null)
            {
                ((DependencyObject)instance).SetValue(_member.DependencyProperty, value);
            }
            else
            {
                _member.SetDelegate(instance, value);
            }
        }
 
        public override ShouldSerializeResult ShouldSerializeValue(object instance)
        {
            // Look up the ShouldSerializeMethod
            if (!_hasShouldSerializeMethodBeenLookedup)
            {
                Type declaringType = _member.UnderlyingMember.DeclaringType;
                string methodName = $"ShouldSerialize{_member.Name}";
                BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static;
                Type[] args = new Type[] { typeof(DependencyObject) };
                if (_member.IsAttachable)
                {
                    _shouldSerializeMethod = declaringType.GetMethod(methodName, flags, null, args, null);
                }
                else
                {
                    flags |= BindingFlags.Instance;
                    _shouldSerializeMethod = declaringType.GetMethod(methodName, flags, null, args, null);
                }
 
                _hasShouldSerializeMethodBeenLookedup = true;
            }
 
            // Invoke the method if we found one
            if (_shouldSerializeMethod != null)
            {
                bool result;
                var args = new object[] { instance as DependencyObject };
                if (_member.IsAttachable)
                {
                    result = (bool)_shouldSerializeMethod.Invoke(null, args);
                }
                else
                {
                    result = (bool)_shouldSerializeMethod.Invoke(instance, args);
                }
 
                return result ? ShouldSerializeResult.True : ShouldSerializeResult.False;
            }
 
            DependencyObject dObject = instance as DependencyObject;
            if (dObject != null && _member.DependencyProperty != null)
            {
                // Call DO's ShouldSerializeProperty to see if the property is set.
                // If the property is unset, the property should not be serialized
                bool isPropertySet = dObject.ShouldSerializeProperty(_member.DependencyProperty);
 
                if (!isPropertySet)
                {
                    return ShouldSerializeResult.False;
                }
            }
 
            return base.ShouldSerializeValue(instance);
        }
    }
}