/*
 * Copyright 2009 Google Inc.
 *
 * 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.
 */

package com.google.template.soy;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.collect.ImmutableMap;
import com.google.common.io.Files;
import com.google.template.soy.base.internal.BaseUtils;
import java.io.File;
import java.io.IOException;
import java.util.Map;
import org.kohsuke.args4j.Option;

/**
 * Executable for generating Java classes containing Soy parse info.
 *
 * <p> The command-line arguments should contain command-line flags and the list of paths to the
 * Soy files.
 *
 */
public final class SoyParseInfoGenerator extends AbstractSoyCompiler {

  @Option(name = "--allowExternalCalls",
          usage = "Whether to allow external calls. New projects should set this to false, and" +
                  " existing projects should remove existing external calls and then set this" +
                  " to false. It will save you a lot of headaches. Currently defaults to true" +
                  " for backward compatibility.")
  private boolean allowExternalCalls = true;

  @Option(name = "--outputDirectory",
          required = true,
          usage = "[Required] The path to the output directory. If files with the same names" +
                  " already exist at this location, they will be overwritten.")
  private String outputDirectory = "";

  @Option(name = "--javaPackage",
          required = true,
          usage = "[Required] The Java package name to use for the generated classes.")
  private String javaPackage = "";

  @Option(name = "--javaClassNameSource",
          required = true,
          usage = "[Required] The source for the generated class names. Valid values are" +
                  " \"filename\", \"namespace\", and \"generic\". Option \"filename\" turns" +
                  " a Soy file name AaaBbb.soy or aaa_bbb.soy into AaaBbbSoyInfo. Option" +
                  " \"namespace\" turns a namespace aaa.bbb.cccDdd into CccDddSoyInfo (note" +
                  " it only uses the last part of the namespace). Option \"generic\" generates" +
                  " class names such as File1SoyInfo, File2SoyInfo.")
  private String javaClassNameSource = "";

  /**
   * Generates Java classes containing Soy parse info.
   *
   * <p>If syntax errors are encountered, no output is generated and the process terminates with a
   * non-zero exit status. On successful parse, the process terminates with a zero exit status.
   *
   * @param args Should contain command-line flags and the list of paths to the Soy files.
   * @throws IOException If there are problems reading the input files or writing the output file.
   */
  public static void main(final String[] args) throws IOException {
    new SoyParseInfoGenerator().runMain(args);
  }

  @Override
  void validateFlags() {
    if (outputDirectory.length() == 0) {
      exitWithError("Must provide output directory.");
    }
    if (javaPackage.length() == 0) {
      exitWithError("Must provide Java package.");
    }
    if (javaClassNameSource.length() == 0) {
      exitWithError("Must provide Java class name source.");
    }
  }

  @Override
  void compile(SoyFileSet.Builder sfsBuilder) throws IOException {
    sfsBuilder.setAllowExternalCalls(allowExternalCalls);

    SoyFileSet sfs = sfsBuilder.build();

    ImmutableMap<String, String> parseInfo =
        sfs.generateParseInfo(javaPackage, javaClassNameSource);

    for (Map.Entry<String, String> entry : parseInfo.entrySet()) {
      File outputFile = new File(outputDirectory, entry.getKey());
      BaseUtils.ensureDirsExistInPath(outputFile.getPath());
      Files.write(entry.getValue(), outputFile, UTF_8);
    }
  }
}