// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
//
//
// Description: Defines DataTrigger object, akin to Trigger except it
//              gets values from data.
//
 
using System;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
using System.Windows.Data;
using System.Windows.Markup;
 
namespace System.Windows
{
    /// <summary>
    ///     A single Style data conditional dependency driver
    /// </summary>
    [ContentProperty("Setters")]
    [XamlSetMarkupExtensionAttribute("ReceiveMarkupExtension")] 
    public class DataTrigger : TriggerBase, IAddChild
    {
        /// <summary>
        ///     Binding declaration of the conditional
        /// </summary>
        [Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // Not localizable by-default
        public BindingBase Binding
        {
            get
            {
                // Verify Context Access
                VerifyAccess();
 
                return _binding;
            }
            set
            {
                // Verify Context Access
                VerifyAccess();
 
                if (IsSealed)
                {
                    throw new InvalidOperationException(SR.Format(SR.CannotChangeAfterSealed, "DataTrigger"));
                }
 
                _binding = value;
            }
        }
 
        /// <summary>
        ///     Value of the condition (equality check)
        /// </summary>
        [DependsOn("Binding")]
        [Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // Not localizable by-default
        public object Value
        {
            get
            {
                // Verify Context Access
                VerifyAccess();
 
                return _value;
            }
            set
            {
                // Verify Context Access
                VerifyAccess();
 
                if (IsSealed)
                {
                    throw new InvalidOperationException(SR.Format(SR.CannotChangeAfterSealed, "DataTrigger"));
                }
 
                if (value is MarkupExtension)
                {
                    throw new ArgumentException(SR.Format(SR.ConditionValueOfMarkupExtensionNotSupported,
                                                       value.GetType().Name));
                }
 
                if( value is Expression )
                {
                    throw new ArgumentException(SR.ConditionValueOfExpressionNotSupported);
                }
 
                _value = value;
            }
        }
 
        /// <summary>
        ///     Collection of Setter objects, which describes what to apply
        /// when this trigger is active.
        /// </summary>
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public SetterBaseCollection Setters
        {
            get
            {
                // Verify Context Access
                VerifyAccess();
 
                if( _setters == null )
                {
                    _setters = new SetterBaseCollection();
                }
                return _setters;
            }
        }
 
        ///<summary>
        /// This method is called to Add a Setter object as a child of the Style.
        ///</summary>
        ///<param name="value">
        /// The object to add as a child; it must be a Setter or subclass.
        ///</param>
        void IAddChild.AddChild (Object value)
        {
            // Verify Context Access
            VerifyAccess();
 
            Setters.Add(Trigger.CheckChildIsSetter(value));
        }
 
        ///<summary>
        /// This method is called by the parser when text appears under the tag in markup.
        /// As default Styles do not support text, calling this method has no effect.
        ///</summary>
        ///<param name="text">
        /// Text to add as a child.
        ///</param>
        void IAddChild.AddText (string text)
        {
            // Verify Context Access
            VerifyAccess();
 
            XamlSerializerUtil.ThrowIfNonWhiteSpaceInAddText(text, this);
        }
 
        internal sealed override void Seal()
        {
            if (IsSealed)
            {
                return;
            }
 
            // Process the _setters collection: Copy values into PropertyValueList and seal the Setter objects.
            ProcessSettersCollection(_setters);
 
            // Freeze the value for the trigger
            StyleHelper.SealIfSealable(_value);
 
            // Build conditions array from collection
            TriggerConditions = new TriggerCondition[] {
                new TriggerCondition(
                    _binding,
                    LogicalOp.Equals,
                    _value) };
 
            // Set Condition for all data triggers
            for (int i = 0; i < PropertyValues.Count; i++)
            {
                PropertyValue propertyValue = PropertyValues[i];
 
                propertyValue.Conditions = TriggerConditions;
                switch (propertyValue.ValueType)
                {
                    case PropertyValueType.Trigger:
                        propertyValue.ValueType = PropertyValueType.DataTrigger;
                        break;
                    case PropertyValueType.PropertyTriggerResource:
                        propertyValue.ValueType = PropertyValueType.DataTriggerResource;
                        break;
                    default:
                        throw new InvalidOperationException(SR.Format(SR.UnexpectedValueTypeForDataTrigger, propertyValue.ValueType));
                }
 
                // Put back modified struct
                PropertyValues[i] = propertyValue;
            }
 
            base.Seal();
        }
 
        // evaluate the current state of the trigger
        internal override bool GetCurrentState(DependencyObject container, UncommonField<HybridDictionary[]> dataField)
        {
            Debug.Assert( TriggerConditions != null && TriggerConditions.Length == 1,
                "This method assumes there is exactly one TriggerCondition." );
 
            return TriggerConditions[0].ConvertAndMatch(StyleHelper.GetDataTriggerValue(dataField, container, TriggerConditions[0].Binding));
        }
 
        private BindingBase _binding;
        private object _value = DependencyProperty.UnsetValue;
        private SetterBaseCollection _setters = null;
 
        public static void ReceiveMarkupExtension(object targetObject, XamlSetMarkupExtensionEventArgs eventArgs)
        {
            ArgumentNullException.ThrowIfNull(targetObject);
            ArgumentNullException.ThrowIfNull(eventArgs);
 
            DataTrigger trigger = targetObject as DataTrigger;
            if (trigger != null && eventArgs.Member.Name == "Binding" && eventArgs.MarkupExtension is BindingBase)
            {
                trigger.Binding = eventArgs.MarkupExtension as BindingBase;
 
                eventArgs.Handled = true;
            }
            else
            {
                eventArgs.CallBase();
            }
        }
    }
}