// Copyright (C) 2013 The Android Open Source Project
//
// 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.

import com.google.common.io.ByteStreams;

import org.asciidoctor.Asciidoctor;
import org.asciidoctor.AttributesBuilder;
import org.asciidoctor.Options;
import org.asciidoctor.OptionsBuilder;
import org.asciidoctor.SafeMode;
import org.asciidoctor.internal.JRubyAsciidoctor;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.CmdLineParser;
import org.kohsuke.args4j.Option;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class AsciiDoctor {

  private static final String DOCTYPE = "article";
  private static final String ERUBY = "erb";

  @Option(name = "-b", usage = "set output format backend")
  private String backend = "html5";

  @Option(name = "-z", usage = "output zip file")
  private String zipFile;

  @Option(name = "--in-ext", usage = "extension for input files")
  private String inExt = ".txt";

  @Option(name = "--out-ext", usage = "extension for output files")
  private String outExt = ".html";

  @Option(name = "--base-dir", usage = "base directory")
  private File basedir;

  @Option(name = "--tmp", usage = "temporary output path")
  private File tmpdir;

  @Option(name = "-a", usage =
      "a list of attributes, in the form key or key=value pair")
  private List<String> attributes = new ArrayList<>();

  @Argument(usage = "input files")
  private List<String> inputFiles = new ArrayList<>();

  public static String mapInFileToOutFile(
      String inFile, String inExt, String outExt) {
    String basename = new File(inFile).getName();
    if (basename.endsWith(inExt)) {
      basename = basename.substring(0, basename.length() - inExt.length());
    } else {
      // Strip out the last extension
      int pos = basename.lastIndexOf('.');
      if (pos > 0) {
        basename = basename.substring(0, pos);
      }
    }
    return basename + outExt;
  }

  private Options createOptions(File outputFile) {
    OptionsBuilder optionsBuilder = OptionsBuilder.options();

    optionsBuilder.backend(backend).docType(DOCTYPE).eruby(ERUBY)
      .safe(SafeMode.UNSAFE).baseDir(basedir);
    // XXX(fishywang): ideally we should just output to a string and add the
    // content into zip. But asciidoctor will actually ignore all attributes if
    // not output to a file. So we *have* to output to a file then read the
    // content of the file into zip.
    optionsBuilder.toFile(outputFile);

    AttributesBuilder attributesBuilder = AttributesBuilder.attributes();
    attributesBuilder.attributes(getAttributes());
    optionsBuilder.attributes(attributesBuilder.get());

    return optionsBuilder.get();
  }

  private Map<String, Object> getAttributes() {
    Map<String, Object> attributeValues = new HashMap<>();

    for (String attribute : attributes) {
      int equalsIndex = attribute.indexOf('=');
      if (equalsIndex > -1) {
        String name = attribute.substring(0, equalsIndex);
        String value = attribute.substring(equalsIndex + 1, attribute.length());

        attributeValues.put(name, value);
      } else {
        attributeValues.put(attribute, "");
      }
    }

    return attributeValues;
  }

  private void invoke(String... parameters) throws IOException {
    CmdLineParser parser = new CmdLineParser(this);
    try {
      parser.parseArgument(parameters);
      if (inputFiles.isEmpty()) {
        throw new CmdLineException(parser,
            "asciidoctor: FAILED: input file missing");
      }
    } catch (CmdLineException e) {
      System.err.println(e.getMessage());
      parser.printUsage(System.err);
      System.exit(1);
      return;
    }

    try (ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(zipFile))) {
      for (String inputFile : inputFiles) {
        if (!inputFile.endsWith(inExt)) {
          // We have to use UNSAFE mode in order to make embedding work. But in
          // UNSAFE mode we'll also need css file in the same directory, so we
          // have to add css files into the SRCS.
          continue;
        }

        String outName = mapInFileToOutFile(inputFile, inExt, outExt);
        File out = new File(tmpdir, outName);
        out.getParentFile().mkdirs();
        Options options = createOptions(out);
        renderInput(options, new File(inputFile));
        zipFile(out, outName, zip);
      }

      File[] cssFiles = tmpdir.listFiles(new FilenameFilter() {
        @Override
        public boolean accept(File dir, String name) {
          return name.endsWith(".css");
        }
      });
      for (File css : cssFiles) {
        zipFile(css, css.getName(), zip);
      }
    }
  }

  public static void zipFile(File file, String name, ZipOutputStream zip)
      throws IOException {
    zip.putNextEntry(new ZipEntry(name));
    try (FileInputStream input = new FileInputStream(file)) {
      ByteStreams.copy(input, zip);
    }
    zip.closeEntry();
  }

  private void renderInput(Options options, File inputFile) {
    Asciidoctor asciidoctor = JRubyAsciidoctor.create();
    asciidoctor.renderFile(inputFile, options);
  }

  public static void main(String[] args) {
    try {
      new AsciiDoctor().invoke(args);
    } catch (IOException e) {
      System.err.println(e.getMessage());
      System.exit(1);
    }
  }
}