using org.pdfclown.documents;

using org.pdfclown.documents.contents;

using org.pdfclown.documents.contents.fonts;

using org.pdfclown.documents.contents.objects;

using org.pdfclown.files;

using org.pdfclown.tools;



using System;

using System.Collections.Generic;



namespace org.pdfclown.samples.cli

{

  /**

    <summary>This sample demonstrates the low-level way to extract text from a PDF document.</summary>

    <remarks>In order to obtain richer information about the extracted text content,

    see the other available samples (<see cref="TextInfoExtractionSample"/>,

    <see cref="AdvancedTextExtractionSample"/>).</remarks>

  */

  public class BasicTextExtractionSample

    : Sample

  {

    public override void Run(

      )

    {

      // 1. Opening the PDF file...

      string filePath = PromptFileChoice("Please select a PDF file");

      using(File file = new File(filePath))

      {

        Document document = file.Document;



        // 2. Text extraction from the document pages.

        foreach(Page page in document.Pages)

        {

          if(!PromptNextPage(page, false))

          {

            Quit();

            break;

          }



          Extract(

            new ContentScanner(page) // Wraps the page contents into a scanner.

            );

        }

      }

    }



    /**

      <summary>Scans a content level looking for text.</summary>

    */

    /*

      NOTE: Page contents are represented by a sequence of content objects,

      possibly nested into multiple levels.

    */

    private void Extract(

      ContentScanner level

      )

    {

      if(level == null)

        return;



      while(level.MoveNext())

      {

        ContentObject content = level.Current;

        if(content is ShowText)

        {

          Font font = level.State.Font;

          // Extract the current text chunk, decoding it!

          Console.WriteLine(font.Decode(((ShowText)content).Text));

        }

        else if(content is Text

          || content is ContainerObject)

        {

          // Scan the inner level!

          Extract(level.ChildLevel);

        }

      }

    }

  }

}