//------------------------------------------------------------------------------
// <copyright file="ChildTable.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//------------------------------------------------------------------------------

namespace System.Web.UI.WebControls {

    using System;
    using System.ComponentModel;
    using System.Web.UI;
    using System.Web.Util;

    [
    ToolboxItem(false),
    SupportsEventValidation,
    ]

    /// <internalonly/>
    /// <devdoc>
    ///   Used by composite controls that are based on a table, that only render
    ///   their contents.
    ///   Used to render out an ID attribute representing the parent composite control
    ///   if an ID is not actually set on this table.
    /// </devdoc>
    internal class ChildTable : Table {

        private int _parentLevel;
        private string _parentID;
        private bool _parentIDSet;


        /// <internalonly/>
        internal ChildTable() : this(1) {
        }


        /// <internalonly/>
        internal ChildTable(int parentLevel) {
            Debug.Assert(parentLevel >= 1);
            _parentLevel = parentLevel;
            _parentIDSet = false;
        }

        internal ChildTable(string parentID) {
            _parentID = parentID;
            _parentIDSet = true;
        }


        /// <internalonly/>
        protected override void AddAttributesToRender(HtmlTextWriter writer) {
            base.AddAttributesToRender(writer);
            string parentID = _parentID;

            if (!_parentIDSet) {
                parentID = GetParentID();
            }

            if (parentID != null) {
                writer.AddAttribute(HtmlTextWriterAttribute.Id, parentID);
            }
        }


        /// <devdoc>
        /// Gets the ClientID of the parent whose ID is supposed to be used in the rendering.
        /// </devdoc>
        private string GetParentID() {
            if (ID != null) {
                return null;
            }

            Control parent = this;
            for (int i = 0; i < _parentLevel; i++) {
                parent = parent.Parent;
                if (parent == null) {
                    break;
                }
            }

            Debug.Assert(parent != null);
            if (parent != null) {
                string id = parent.ID;
                if (!String.IsNullOrEmpty(id)) {
                    return parent.ClientID;
                }
            }

            return null;
        }
    }
}