zaaReloaded2/zaaReloaded2/Formatter/DocumentWriter.cs

/* DocumentWriter.cs
 * part of zaaReloaded2
 * 
 * Copyright 2015 Daniel Kraus
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Interop.Word;

namespace zaaReloaded2.Formatter
{
    /// <summary>
    /// Helper class that serves to write text to a Word document or
    /// to a linked DocumentWriter. Provides a buffer that can be
    /// appended or prepended to, which facilitates conditional output
    /// depending on whether there is text in the buffer or not.
    /// </summary>
    /// <remarks>
    /// Linking several DocumentWriters permits a cascading work flow
    /// with several buffers.
    /// </remarks>
    class DocumentWriter
    {
        #region Properties

        /// <summary>
        /// Gets the Document associated with this DocumentWriter,
        /// or null if there is no associated Document.
        /// </summary>
        public Document Document { get; set; }

        /// <summary>
        /// Gets the parent DocumentWriter (if any).
        /// </summary>
        public DocumentWriter Parent { get; set; }

        /// <summary>
        /// Returns true if there is text in the buffer.
        /// </summary>
        public bool HasBufferedText { get { return _buffer.Length > 0; } }

        #endregion

        #region Constructors

        public DocumentWriter()
        {
            _buffer = new StringBuilder();
        }

        /// <summary>
        /// Creates a new DocumentWriter instance that is associated
        /// with a Word Document.
        /// </summary>
        /// <param name="document"></param>
        public DocumentWriter(Document document)
            : this()
        {
            Document = document;
        }

        /// <summary>
        /// Creates a new DocumentWriter instance that is associated
        /// with a parent DocumentWriter.
        /// </summary>
        /// <param name="parent"></param>
        public DocumentWriter(DocumentWriter parent)
            : this()
        {
            Parent = parent;
        }

        #endregion

        #region Overrides

        public override string ToString()
        {
            return _buffer.ToString();
        }

        #endregion

        #region Public methods

        /// <summary>
        /// Flushes the buffer to the associated Word document and/or the
        /// parent DocumentWriter.
        /// </summary>
        public void Flush()
        {
            if (!HasBufferedText) return;

            if (Document == null && Parent == null)
            {
                throw new InvalidOperationException(
                    "No document and no parent buffer to flush into.");
            }

            if (Document != null)
            {
                Document.Range().Text = _buffer.ToString();
            }
            if (Parent != null)
            {
                Parent.Write(_buffer.ToString());
            }

            _buffer.Clear();
        }

        /// <summary>
        /// Writes text to the buffer.
        /// </summary>
        /// <param name="text">Text to write to the buffer.</param>
        public void Write(string text)
        {
            _buffer.Append(text);
        }

        /// <summary>
        /// Appends a line of text to the buffer.
        /// </summary>
        /// <param name="text">Text to append.</param>
        public void WriteLine(string text)
        {
            _buffer.AppendLine(text);
        }

        /// <summary>
        /// Inserts text at the start of the buffer.
        /// </summary>
        /// <param name="text">Text to insert at the start of the
        /// buffer.</param>
        public void Prepend(string text)
        {
            _buffer.Insert(0, text);
        }

        #endregion

        #region Fields

        StringBuilder _buffer;

        #endregion
    }
}