/*
  http-adoc - Asciidoctor extensions to jdk.httpserver
  Copyright (C) 2021  Ulrich Hilger

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package de.uhilger.httpserver.adoc;

import com.sun.net.httpserver.HttpExchange;
import de.uhilger.httpserver.base.HttpResponder;
import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import static org.asciidoctor.Asciidoctor.Factory.create;
import org.asciidoctor.Asciidoctor;
import static org.asciidoctor.AttributesBuilder.attributes;
import static org.asciidoctor.OptionsBuilder.options;
import org.asciidoctor.SafeMode;

/**
 * Der AdocActor transformiert den Asciidoctor-Quellcode aus einer 
 * gegebenen Datei zu HTML oder PDF und legt das Ergebnis als HTML- oder 
 * PDF-Datei ab.
 * 
 * Der AdocActor benötigt AsciidoctorJ im Classpath.
 * 
 * @author Ulrich Hilger
 * @version 1, 16.06.2021
 */
public class AdocActor {
  
  private static final Logger logger = Logger.getLogger(AdocActor.class.getName());
  
  private static final String DOT = ".";
  public static final String HTML = "html";
  public static final String PDF = "pdf";
  
  public void handle(HttpExchange e, String fileBase, String fileName) throws IOException {
    File adocfile = new File(fileBase, fileName);
    logger.fine("adocfile: " + adocfile.getAbsolutePath());
    AdocActor actor = new AdocActor();
    File outfile = actor.getTargetFile(adocfile, AdocActor.HTML);
    logger.fine("outfile: " + outfile.getAbsolutePath());
    HttpResponder fs = new HttpResponder();
    fs.serveFile(e, outfile);
  }
  
  public File getTargetFile(File adocfile, String ext) {
    String nameext = adocfile.getName();
    String fname = nameext.substring(0, nameext.lastIndexOf(DOT));
    File outfile = new File(adocfile.getParentFile(), fname + DOT + ext);
    logger.log(Level.FINE, "out: {0}", outfile.getAbsolutePath());
    return outfile;
  }
  
  public void processAdocFile(File adocfile, String pdf) {
    
    String absname = adocfile.getAbsolutePath();
    logger.log(Level.FINE, "in: {0}", absname);
 
    // HTML-Datei ermitteln
    //String nameext = adocfile.getName();
    //String fname = nameext.substring(0, nameext.lastIndexOf(DOT));
    //File htmlfile = new File(adocfile.getParentFile(), fname + DOT + HTML);
    //File outfile = htmlfile; // Standardmaessig wird HTML zurueckgegeben
    //logger.fine("out: " + outfile.getAbsolutePath());
    //response.setCharacterEncoding("UTF-8");
    File outfile = getTargetFile(adocfile, HTML);
    File htmlfile = outfile;
    
    /*
      nach HTML transformieren, wenn die Quelle sich geandert hat oder 
      die HTML-Datei noch nicht existiert
    */
    if(!htmlfile.exists() || adocfile.lastModified() > htmlfile.lastModified()) {
      logger.fine("calling transform for " + absname);
      transform(absname);
    }
 
    /*
      nach PDF transformieren, wenn der Parameter pdf=true existiert und 
      wenn die Quelle sich geandert hat oder 
      die PDF-Datei noch nicht existiert
    */
    
    if(null != pdf && pdf.equalsIgnoreCase(Boolean.TRUE.toString())) {
      //File pdffile = new File(adocfile.getParentFile(), fname + DOT + PDF);
      File pdffile = getTargetFile(adocfile, PDF);
      outfile = pdffile; // PDF soll zurueckgegeben werden
      if(!pdffile.exists() || adocfile.lastModified() > pdffile.lastModified()) {
        //response.setContentType("application/pdf");
        transform(absname, PDF);
      }
      //ServletOutputStream os = response.getOutputStream();
      //InputStream bytes = new FileInputStream(outfile);
      //int b = bytes.read();
      //while(b > -1 ) {
      //  os.write(b);
      //  b = bytes.read();
      //}
    } else {
      //PrintWriter out = response.getWriter();
      //InputStreamReader in = new InputStreamReader(new FileInputStream(outfile), "UTF-8");
      //in.transferTo(out);
    }
  }
  
  /**
   * Nach HTML transformieren
   * @param fileName der Dateiname der Quelldatei samt absoluter Pfadangabe
   */
  private void transform(String fileName) {
    transform(fileName, null);
  }  
  
  /**
   * In ein Format transformieren, das von einem 'Backend' von Asciidoctor 
   * unterstuetzt wird
   * @param fileName der Dateiname der Quelldatei samt absoluter Pfadangabe
   * @param backend das Kuerzel des Backends, z.B. der String 'pdf', wenn 
   * nach PDF transformiert werden soll
   */
  private void transform(String fileName, String backend) {    
    logger.fine("fileName: " + fileName + ", backend: " + backend);
    Map<String, Object> attributes;
    File outFile = new File(fileName);
    String thisDirName = outFile.getParent();
    File pdfStyles = new File(outFile.getParentFile(), "custom-theme.yml");
    if(pdfStyles.exists()) {
      attributes = attributes()
              .attribute("pdf-themesdir", thisDirName)
              .attribute("pdf-theme","custom")
              .attribute("pdf-fontsdir", thisDirName + "/fonts")
              .attribute("allow-uri-read")
              .sourceHighlighter("highlightjs")
              .asMap();
    } else {
      attributes = attributes()
              .sourceHighlighter("highlightjs")
              .asMap();
    }
    Map<String, Object> options;
    if(null != backend) {
      options = options().inPlace(false)
              .safe(SafeMode.SERVER)
              .backend(backend).attributes(attributes).asMap();
      
    } else {
      options = options().inPlace(false)
              .safe(SafeMode.SERVER)
              .attributes(attributes).asMap();
    }
    
    File adcf = new File(fileName);
    logger.fine("before asciidoctor create, adcf: " + adcf.getAbsolutePath());
    Asciidoctor asciidoctor = create();    
    logger.fine("asciidoctor created.");
    asciidoctor.requireLibrary("asciidoctor-diagram");
    logger.fine("asciidoctor requireLibrary diagram passed.");
    logger.fine("calling asciidoctor.convert for file " + adcf.getAbsolutePath());
    asciidoctor.convertFile(adcf, options);    
  }
  
}