// Copyright 2015 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.android;

import com.google.devtools.common.options.Converter;
import com.google.devtools.common.options.OptionsParsingException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;

/**
 * Some convenient converters used by android actions. Note: These are specific to android actions.
 */
public final class Converters {
  private static final Converter<String> IDENTITY_CONVERTER =
      new Converter<String>() {
        @Override
        public String convert(String input) {
          return input;
        }

        @Override
        public String getTypeDescription() {
          return "a string";
        }
      };

  /** Validating converter for Paths. A Path is considered valid if it resolves to a file. */
  public static class PathConverter implements Converter<Path> {

    private final boolean mustExist;

    public PathConverter() {
      this.mustExist = false;
    }

    protected PathConverter(boolean mustExist) {
      this.mustExist = mustExist;
    }

    @Override
    public Path convert(String input) throws OptionsParsingException {
      try {
        Path path = FileSystems.getDefault().getPath(input);
        if (mustExist && !Files.exists(path)) {
          throw new OptionsParsingException(
              String.format("%s is not a valid path: it does not exist.", input));
        }
        return path;
      } catch (InvalidPathException e) {
        throw new OptionsParsingException(
            String.format("%s is not a valid path: %s.", input, e.getMessage()), e);
      }
    }

    @Override
    public String getTypeDescription() {
      return "a valid filesystem path";
    }
  }

  /**
   * Validating converter for Paths. A Path is considered valid if it resolves to a file and exists.
   */
  public static class ExistingPathConverter extends PathConverter {
    public ExistingPathConverter() {
      super(true);
    }
  }
}