/*-
 * #%L
 * FontAwesome Iron Iconset
 * %%
 * Copyright (C) 2019 - 2023 Flowing Code
 * %%
 * 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.
 * #L%
 */


import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.NoSuchElementException;
import java.util.Optional;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import net.sf.saxon.TransformerFactoryImpl;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.output.StringBuilderWriter;

/**
 * @author Javier Godoy / Flowing Code
 */
public class BuildSprites {

  private static String tagName;

  private static String repositoryName;

  private static File spritesDirectory;

  private static File iconsDirectory;


  public static void main(String[] args) throws IOException {

    iconsDirectory = new File(getRequiredProperty("codegen.icons")); // the location of the icons
    spritesDirectory = new File(getRequiredProperty("codegen.sprites")); // the location of the sprites

    if (!iconsDirectory.exists()) {
      System.out.println("Skipping build-sprites phase");
      return;
    }

    createDirectory(spritesDirectory);
    execute();

  }

  private static String getRequiredProperty(String name) {
    return Optional.ofNullable(System.getProperty(name))
        .orElseThrow(() -> new NoSuchElementException("Missing system property -D" + name));
  }

  private static File createDirectory(File directory) {
    if (!directory.isDirectory() && !directory.mkdir()) {
      System.err.println("Output directory " + directory + " does not exist and cannot be created");
      System.exit(1);
    }
    return directory;
  }

  private static void execute() throws IOException {
    for (File directory : iconsDirectory.listFiles(File::isDirectory)) {
      String family = directory.getName();
      File files[] = directory.listFiles(file -> file.getName().endsWith(".svg"));
      if (files.length == 0) {
        continue;
      }

      System.out.println("Creating sprite for " + family + " (" + files.length + " icons)");

      StringBuilderWriter out = new StringBuilderWriter();
      out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n");
      out.write("<svg xmlns=\"http://www.w3.org/2000/svg\">\r\n");

      for (File file : files) {
        String data = FileUtils.readFileToString(file, StandardCharsets.UTF_8);
        data = data.replace(
            "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">",
            "");
        data = data.replace("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>", "");
        String name = FilenameUtils.getBaseName(file.getName());
        out.write("<symbol id=\"" + name + "\">\r\n");
        out.write(data);
        out.write("\r\n</symbol>\r\n");
      }
      out.write("</svg>");

      File iconset = new File(spritesDirectory, family + ".svg");
      FileUtils.writeStringToFile(iconset, out.toString(), StandardCharsets.UTF_8);
      transform(iconset);
    }
  }

  private static void transform(File file) throws IOException {
    File dst = new File(file.getParent(), file.getName() + ".2");
    try (InputStream in = new FileInputStream(file);
        InputStream xslt = new FileInputStream("build-sprites.xslt");
        OutputStream out = new FileOutputStream(dst)) {
      Transformer t = new TransformerFactoryImpl().newTransformer(new StreamSource(xslt));
      Result outputTarget = new StreamResult(out);
      t.transform(new StreamSource(in), outputTarget);
    } catch (TransformerException e) {
      throw new IOException(e);
    }
    file.delete();
    dst.renameTo(file);
  }

}