#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange
//
// Copyright (c) 2005-2017 empira Software GmbH, Cologne Area (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Collections.Generic;
using System.Diagnostics;
using PdfSharp.Pdf.Annotations;

namespace PdfSharp.Pdf.AcroForms
{
    /// <summary>
    /// Represents the base class for all button fields.
    /// </summary>
    public abstract class PdfButtonField : PdfAcroField
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="PdfButtonField"/> class.
        /// </summary>
        protected PdfButtonField(PdfDocument document)
            : base(document)
        { }

        /// <summary>
        /// Initializes a new instance of the <see cref="PdfButtonField"/> class.
        /// </summary>
        protected PdfButtonField(PdfDictionary dict)
            : base(dict)
        { }

        /// <summary>
        /// Gets the name which represents the opposite of /Off.
        /// </summary>
        protected string GetNonOffValue()
        {
            // Try to get the information from the appearance dictionaray.
            // Just return the first key that is not /Off.
            // I'm not sure what is the right solution to get this value.
            PdfDictionary ap = Elements[PdfAnnotation.Keys.AP] as PdfDictionary;
            if (ap != null)
            {
                PdfDictionary n = ap.Elements["/N"] as PdfDictionary;
                if (n != null)
                {
                    foreach (string name in n.Elements.Keys)
                        if (name != "/Off")
                            return name;
                }
            }
            return null;
        }

        internal override void GetDescendantNames(ref List<string> names, string partialName)
        {
            string t = Elements.GetString(PdfAcroField.Keys.T);
            // HACK: ??? 
            if (t == "")
                t = "???";
            Debug.Assert(t != "");
            if (t.Length > 0)
            {
                if (!String.IsNullOrEmpty(partialName))
                    names.Add(partialName + "." + t);
                else
                    names.Add(t);
            }
        }

        /// <summary>
        /// Predefined keys of this dictionary. 
        /// The description comes from PDF 1.4 Reference.
        /// </summary>
        public new class Keys : PdfAcroField.Keys
        {
            // Pushbuttons have no additional entries.
        }
    }
}
