PdfPig/src/UglyToad.PdfPig/AcroForms/Fields/AcroFieldCommonInformation.cs

namespace UglyToad.PdfPig.AcroForms.Fields
{
    using Util.JetBrains.Annotations;

    /// <summary>
    /// Information from the field dictionary which is common across all field types.
    /// All of this information is optional.
    /// </summary>
    public class AcroFieldCommonInformation
    {
        /// <summary>
        /// The reference to the field which is the parent of this one, if applicable.
        /// </summary>
        public IndirectReference? Parent { get; set; }

        /// <summary>
        /// The partial field name for this field. The fully qualified field name is the
        /// period '.' joined name of all parents' partial names and this field's partial name.
        /// </summary>
        [CanBeNull]
        public string PartialName { get; }

        /// <summary>
        /// The alternate field name to be used instead of the fully qualified field name where
        /// the field is being identified on the user interface or by screen readers.
        /// </summary>
        [CanBeNull]
        public string AlternateName { get; }

        /// <summary>
        /// The mapping name used when exporting form field data from the document.
        /// </summary>
        [CanBeNull]
        public string MappingName { get; }

        /// <summary>
        /// Create a new <see cref="AcroFieldCommonInformation"/>.
        /// </summary>
        public AcroFieldCommonInformation(IndirectReference? parent, string partialName, string alternateName, string mappingName)
        {
            Parent = parent;
            PartialName = partialName;
            AlternateName = alternateName;
            MappingName = mappingName;
        }

        /// <inheritdoc />
        public override string ToString()
        {
            string AppendIfNotNull(string val, string label, string result)
            {
                if (val == null)
                {
                    return result;
                }

                if (result.Length > 0)
                {
                    result += " ";
                }

                result += $"{label}: {val}.";

                return result;
            }

            var s = string.Empty;
            
            if (Parent != null)
            {
                s += $"Parent: {Parent}.";
            }

            s = AppendIfNotNull(PartialName, "Partial Name", s);
            s = AppendIfNotNull(AlternateName, "Alternate Name", s);
            s = AppendIfNotNull(MappingName, "Mapping Name", s);

            return s;
        }
    }
}