#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (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.Diagnostics;
using System.Collections;
using PdfSharp.Pdf;
using PdfSharp.Internal;
using PdfSharp.Drawing;

namespace PdfSharp.Pdf.Annotations
{
  /// <summary>
  /// Represents the base class of all annotations.
  /// </summary>
  public abstract class PdfAnnotation : PdfDictionary
  {
    /// <summary>
    /// Initializes a new instance of the <see cref="PdfAnnotation"/> class.
    /// </summary>
    protected PdfAnnotation()
    {
      Initialize();
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfAnnotation"/> class.
    /// </summary>
    protected PdfAnnotation(PdfDocument document)
      : base(document)
    {
      Initialize();
    }

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

    void Initialize()
    {
      Elements.SetName(Keys.Type, "/Annot");
      Elements.SetString(Keys.NM, Guid.NewGuid().ToString("D"));
      Elements.SetDateTime(Keys.M, DateTime.Now);
    }

    //dmh - 6/7/06 added delete method
    /// <summary>
    /// Removes an annotation from the document
    /// <seealso cref="PdfAnnotations.Remove(PdfAnnotation)"/>
    /// </summary>
    [Obsolete("Use 'Parent.Remove(this)'")]
    public void Delete()
    {
      Parent.Remove(this);
    }

    /// <summary>
    /// Gets or sets the annotation flags of this instance.
    /// </summary>
    public PdfAnnotationFlags Flags
    {
      get { return (PdfAnnotationFlags)Elements.GetInteger(Keys.F); }
      set
      {
        Elements.SetInteger(Keys.F, (int)value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets the PdfAnnotations object that this annoation belongs to.
    /// </summary>
    public PdfAnnotations Parent
    {
      get { return this.parent; }
      set { this.parent = value; }
    }
    PdfAnnotations parent;

    /// <summary>
    /// Gets or sets the annotation rectangle, defining the location of the annotation
    /// on the page in default user space units.
    /// </summary>
    public PdfRectangle Rectangle
    {
      get { return Elements.GetRectangle(Keys.Rect, true); }
      set
      {
        Elements.SetRectangle(Keys.Rect, value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets the text label to be displayed in the title bar of the annotation’s
    /// pop-up window when open and active. By convention, this entry identifies
    /// the user who added the annotation.
    /// </summary>
    public string Title
    {
      get { return Elements.GetString(Keys.T, true); }
      set
      {
        Elements.SetString(Keys.T, value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets text representing a short description of the subject being
    /// addressed by the annotation.
    /// </summary>
    public string Subject
    {
      get { return Elements.GetString(Keys.Subj, true); }
      set
      {
        Elements.SetString(Keys.Subj, value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets the text to be displayed for the annotation or, if this type of
    /// annotation does not display text, an alternate description of the annotation’s
    /// contents in human-readable form.
    /// </summary>
    public string Contents
    {
      get { return Elements.GetString(Keys.Contents, true); }
      set
      {
        Elements.SetString(Keys.Contents, value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets the color representing the components of the annotation. If the color
    /// has an alpha value other than 1, it is ignored. Use property Opacity to get or set the
    /// opacity of an annotation.
    /// </summary>
    public XColor Color
    {
      get
      {
        PdfItem item = Elements[Keys.C];
        if (item is PdfArray)  // TODO: check for iref?
        {
          PdfArray array = (PdfArray)item;
          if (array.Elements.Count == 3)
          {
            // TODO: an array.GetColor() function may be useful here
            return XColor.FromArgb(
              (int)(array.Elements.GetReal(0) * 255),
              (int)(array.Elements.GetReal(1) * 255),
              (int)(array.Elements.GetReal(2) * 255));
          }
        }
        return XColors.Black;
      }
      set
      {
        // TODO: an array.SetColor(clr) function may be useful here
        PdfArray array = new PdfArray(this.Owner, new PdfReal[] 
          { new PdfReal(value.R / 255.0), new PdfReal(value.G / 255.0), new PdfReal(value.B / 255.0) });
        Elements[Keys.C] = array;
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Gets or sets the constant opacity value to be used in painting the annotation.
    /// This value applies to all visible elements of the annotation in its closed state
    /// (including its background and border) but not to the popup window that appears when
    /// the annotation is opened.
    /// </summary>
    public double Opacity
    {
      get
      {
        if (!Elements.Contains(Keys.CA))
          return 1;
        return Elements.GetReal(Keys.CA, true);
      }
      set
      {
        if (value < 0 || value > 1)
          throw new ArgumentOutOfRangeException("value", value, "Opacity must be a value in the range from 0 to 1.");
        Elements.SetReal(Keys.CA, value);
        Elements.SetDateTime(Keys.M, DateTime.Now);
      }
    }

    /// <summary>
    /// Predefined keys of this dictionary.
    /// </summary>
    public class Keys : KeysBase
    {
      /// <summary>
      /// (Optional) The type of PDF object that this dictionary describes; if present,
      /// must be Annot for an annotation dictionary.
      /// </summary>
      [KeyInfo(KeyType.Name | KeyType.Optional, FixedValue = "Annot")]
      public const string Type = "/Type";

      /// <summary>
      /// (Required) The type of annotation that this dictionary describes.
      /// </summary>
      [KeyInfo(KeyType.Name | KeyType.Required)]
      public const string Subtype = "/Subtype";

      /// <summary>
      /// (Required) The annotation rectangle, defining the location of the annotation
      /// on the page in default user space units.
      /// </summary>
      [KeyInfo(KeyType.Rectangle | KeyType.Required)]
      public const string Rect = "/Rect";

      /// <summary>
      /// (Optional) Text to be displayed for the annotation or, if this type of annotation
      /// does not display text, an alternate description of the annotation’s contents
      /// in human-readable form. In either case, this text is useful when
      /// extracting the document’s contents in support of accessibility to users with
      /// disabilities or for other purposes.
      /// </summary>
      [KeyInfo(KeyType.TextString | KeyType.Optional)]
      public const string Contents = "/Contents";

      // P

      /// <summary>
      /// (Optional; PDF 1.4) The annotation name, a text string uniquely identifying it
      /// among all the annotations on its page.
      /// </summary>
      [KeyInfo(KeyType.TextString | KeyType.Optional)]
      public const string NM = "/NM";

      /// <summary>
      /// (Optional; PDF 1.1) The date and time when the annotation was most recently
      /// modified. The preferred format is a date string, but viewer applications should be 
      /// prepared to accept and display a string in any format.
      /// </summary>
      [KeyInfo(KeyType.Date | KeyType.Optional)]
      public const string M = "/M";

      /// <summary>
      /// (Optional; PDF 1.1) A set of flags specifying various characteristics of the annotation.
      /// Default value: 0.
      /// </summary>
      [KeyInfo("1.1", KeyType.Integer | KeyType.Optional)]
      public const string F = "/F";

      /// <summary>
      /// (Optional; PDF 1.2) A border style dictionary specifying the characteristics of
      /// the annotation’s border.
      /// </summary>
      [KeyInfo("1.2", KeyType.Dictionary | KeyType.Optional)]
      public const string BS = "/BS";

      /// <summary>
      /// (Optional; PDF 1.2) An appearance dictionary specifying how the annotation
      /// is presented visually on the page. Individual annotation handlers may ignore
      /// this entry and provide their own appearances.
      /// </summary>
      [KeyInfo("1.2", KeyType.Dictionary | KeyType.Optional)]
      public const string AP = "/AP";

      /// <summary>
      /// (Required if the appearance dictionary AP contains one or more subdictionaries; PDF 1.2)
      /// The annotation’s appearance state, which selects the applicable appearance stream from 
      /// an appearance subdictionary.
      /// </summary>
      [KeyInfo("1.2", KeyType.Dictionary | KeyType.Optional)]
      public const string AS = "/AS";

      /// <summary>
      /// (Optional) An array specifying the characteristics of the annotation’s border.
      /// The border is specified as a rounded rectangle.
      /// In PDF 1.0, the array consists of three numbers defining the horizontal corner 
      /// radius, vertical corner radius, and border width, all in default user space units.
      /// If the corner radii are 0, the border has square (not rounded) corners; if the border 
      /// width is 0, no border is drawn.
      /// In PDF 1.1, the array may have a fourth element, an optional dash array defining a 
      /// pattern of dashes and gaps to be used in drawing the border. The dash array is 
      /// specified in the same format as in the line dash pattern parameter of the graphics state.
      /// For example, a Border value of [0 0 1 [3 2]] specifies a border 1 unit wide, with
      /// square corners, drawn with 3-unit dashes alternating with 2-unit gaps. Note that no
      /// dash phase is specified; the phase is assumed to be 0.
      /// Note: In PDF 1.2 or later, this entry may be ignored in favor of the BS entry.
      /// </summary>
      [KeyInfo(KeyType.Array | KeyType.Optional)]
      public const string Border = "/Border";

      /// <summary>
      /// (Optional; PDF 1.1) An array of three numbers in the range 0.0 to 1.0, representing
      /// the components of a color in the DeviceRGB color space. This color is used for the
      /// following purposes:
      /// • The background of the annotation’s icon when closed
      /// • The title bar of the annotation’s pop-up window
      /// • The border of a link annotation
      /// </summary>
      [KeyInfo("1.1", KeyType.Array | KeyType.Optional)]
      public const string C = "/C";

      /// <summary>
      /// (Optional; PDF 1.1) An action to be performed when the annotation is activated.
      /// Note: This entry is not permitted in link annotations if a Dest entry is present.
      /// Also note that the A entry in movie annotations has a different meaning.
      /// </summary>
      [KeyInfo("1.1", KeyType.Dictionary | KeyType.Optional)]
      public const string A = "/A";

      // AA
      // StructParent
      // OC

      // ----- Excerpt of entries specific to markup annotations ----------------------------------

      /// <summary>
      /// (Optional; PDF 1.1) The text label to be displayed in the title bar of the annotation’s
      /// pop-up window when open and active. By convention, this entry identifies
      /// the user who added the annotation.
      /// </summary>
      [KeyInfo(KeyType.TextString | KeyType.Optional)]
      public const string T = "/T";

      /// <summary>
      /// (Optional; PDF 1.3) An indirect reference to a pop-up annotation for entering or
      /// editing the text associated with this annotation.
      /// </summary>
      [KeyInfo(KeyType.Dictionary | KeyType.Optional)]
      public const string Popup = "/Popup";

      /// <summary>
      /// (Optional; PDF 1.4) The constant opacity value to be used in painting the annotation.
      /// This value applies to all visible elements of the annotation in its closed state
      /// (including its background and border) but not to the popup window that appears when
      /// the annotation is opened.
      /// The specified value is not used if the annotation has an appearance stream; in that
      /// case, the appearance stream must specify any transparency. (However, if the viewer
      /// regenerates the annotation’s appearance stream, it may incorporate the CA value
      /// into the stream’s content.)
      /// The implicit blend mode is Normal.
      /// Default value: 1.0.
      /// </summary>
      [KeyInfo(KeyType.Real | KeyType.Optional)]
      public const string CA = "/CA";

      //RC
      //CreationDate
      //IRT

      /// <summary>
      /// (Optional; PDF 1.5) Text representing a short description of the subject being
      /// addressed by the annotation.
      /// </summary>
      [KeyInfo("1.5", KeyType.TextString | KeyType.Optional)]
      public const string Subj = "/Subj";

      //RT
      //IT
    }
  }
}
