namespace UnityEngine.Rendering
{
    public partial class DebugUI
    {
        /// <summary>
        /// Base class for "container" type widgets, although it can be used on its own (if a display name is set then it'll behave as a group with a header)
        /// </summary>
        public class Container : Widget, IContainer
        {
            /// <summary>
            /// List of children.
            /// </summary>
            public ObservableList<Widget> children { get; private set; }

            /// <summary>
            /// Panel the container is attached to.
            /// </summary>
            public override Panel panel
            {
                get { return m_Panel; }
                internal set
                {
                    m_Panel = value;

                    // Bubble down
                    foreach (var child in children)
                        child.panel = value;
                }
            }

            /// <summary>
            /// Constructor
            /// </summary>
            public Container()
            {
                displayName = "";
                children = new ObservableList<Widget>();
                children.ItemAdded += OnItemAdded;
                children.ItemRemoved += OnItemRemoved;
            }

            /// <summary>
            /// Constructor.
            /// </summary>
            /// <param name="displayName">Display name of the container.</param>
            /// <param name="children">List of attached children.</param>
            public Container(string displayName, ObservableList<Widget> children)
            {
                this.displayName = displayName;
                this.children = children;
                children.ItemAdded += OnItemAdded;
                children.ItemRemoved += OnItemRemoved;
            }

            internal override void GenerateQueryPath()
            {
                base.GenerateQueryPath();

                foreach (var child in children)
                    child.GenerateQueryPath();
            }

            /// <summary>
            /// Method called when a children is added.
            /// </summary>
            /// <param name="sender">Sender widget.</param>
            /// <param name="e">List of added children.</param>
            protected virtual void OnItemAdded(ObservableList<Widget> sender, ListChangedEventArgs<Widget> e)
            {
                if (e.item != null)
                {
                    e.item.panel = m_Panel;
                    e.item.parent = this;
                }

                if (m_Panel != null)
                    m_Panel.SetDirty();
            }

            /// <summary>
            /// Method called when a children is removed.
            /// </summary>
            /// <param name="sender">Sender widget.</param>
            /// <param name="e">List of removed children.</param>
            protected virtual void OnItemRemoved(ObservableList<Widget> sender, ListChangedEventArgs<Widget> e)
            {
                if (e.item != null)
                {
                    e.item.panel = null;
                    e.item.parent = null;
                }

                if (m_Panel != null)
                    m_Panel.SetDirty();
            }

            /// <summary>
            /// Returns the hash code of the widget.
            /// </summary>
            /// <returns>Hash code of the widget.</returns>
            public override int GetHashCode()
            {
                int hash = 17;
                hash = hash * 23 + queryPath.GetHashCode();

                foreach (var child in children)
                    hash = hash * 23 + child.GetHashCode();

                return hash;
            }
        }

        /// <summary>
        /// Unity-like foldout that can be collapsed.
        /// </summary>
        public class Foldout : Container, IValueField
        {
            /// <summary>
            /// Always false.
            /// </summary>
            public bool isReadOnly { get { return false; } }

            /// <summary>
            /// Opened state of the foldout.
            /// </summary>
            public bool opened;

            /// <summary>
            /// List of columns labels.
            /// </summary>
            public string[] columnLabels { get; set; } = null;

            /// <summary>
            /// Constructor.
            /// </summary>
            public Foldout() : base() { }
            /// <summary>
            /// Constructor.
            /// </summary>
            /// <param name="displayName">Display name of the foldout.</param>
            /// <param name="children">List of attached children.</param>
            /// <param name="columnLabels">Optional list of column names.</param>
            public Foldout(string displayName, ObservableList<Widget> children, string[] columnLabels = null)
                : base(displayName, children)
            {
                this.columnLabels = columnLabels;
            }

            /// <summary>
            /// Get the opened state of the foldout.
            /// </summary>
            /// <returns>True if the foldout is opened.</returns>
            public bool GetValue() => opened;

            /// <summary>
            /// Get the opened state of the foldout.
            /// </summary>
            /// <returns>True if the foldout is opened.</returns>
            object IValueField.GetValue() => GetValue();

            /// <summary>
            /// Set the opened state of the foldout.
            /// </summary>
            /// <param name="value">True to open the foldout, false to close it.</param>
            public void SetValue(object value) => SetValue((bool)value);

            /// <summary>
            /// Validates the value of the widget before setting it.
            /// </summary>
            /// <param name="value">Input value.</param>
            /// <returns>The validated value.</returns>
            public object ValidateValue(object value) => value;

            /// <summary>
            /// Set the value of the widget.
            /// </summary>
            /// <param name="value">Input value.</param>
            public void SetValue(bool value) => opened = value;
        }

        /// <summary>
        /// Horizontal Layout Container.
        /// </summary>
        public class HBox : Container
        {
            /// <summary>
            /// Constructor.
            /// </summary>
            public HBox()
            {
                displayName = "HBox";
            }
        }

        /// <summary>
        /// Vertical Layout Container.
        /// </summary>
        public class VBox : Container
        {
            /// <summary>
            /// Constructor.
            /// </summary>
            public VBox()
            {
                displayName = "VBox";
            }
        }
    }
}