// Copyright 2014 Google Inc. 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.docgen;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMap.Builder;
import com.google.common.io.ByteStreams;
import com.google.common.io.Files;
import com.google.devtools.build.lib.Constants;

import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Map;

/**
 * A class to contain the base definition of common BUILD rule attributes.
 * 
 * <p>See {@link Constants#COMMON_ATTRIBUTES_DOCFILES}, {@link Constants#BINARY_ATTRIBUTES_DOCFILES}
 * and {@link Constants#TEST_ATTRIBUTES_DOCFILES} for the list of files containing the attributes
 * description.
 */
public class PredefinedAttributes {

  private static ImmutableMap<String, RuleDocumentationAttribute> generateAttributeMap(
      String commonType, ImmutableList<String> filenames) {
    Builder<String, RuleDocumentationAttribute> builder =
        ImmutableMap.<String, RuleDocumentationAttribute>builder();
    for (String filename : filenames) {
      String name = Files.getNameWithoutExtension(filename);
      try {
        InputStream stream = PredefinedAttributes.class.getResourceAsStream(filename);
        if (stream == null) {
          throw new IllegalStateException("Resource " + filename + " not found");
        }
        String content = new String(ByteStreams.toByteArray(stream), StandardCharsets.UTF_8);
        builder.put(name, RuleDocumentationAttribute.create(name, commonType, content));
      } catch (IOException e) {
        throw new IllegalStateException("Exception while reading " + filename, e);
      }
    }
    return builder.build();
  }

  public static final Map<String, RuleDocumentationAttribute> COMMON_ATTRIBUTES =
      generateAttributeMap(DocgenConsts.COMMON_ATTRIBUTES, Constants.COMMON_ATTRIBUTES_DOCFILES);

  public static final Map<String, RuleDocumentationAttribute> BINARY_ATTRIBUTES =
      generateAttributeMap(DocgenConsts.BINARY_ATTRIBUTES, Constants.BINARY_ATTRIBUTES_DOCFILES);

  public static final Map<String, RuleDocumentationAttribute> TEST_ATTRIBUTES =
      generateAttributeMap(DocgenConsts.TEST_ATTRIBUTES, Constants.TEST_ATTRIBUTES_DOCFILES);
}