// 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.buildjar.javac.plugins.processing;

import com.google.devtools.build.buildjar.javac.plugins.BlazeJavaCompilerPlugin;
import com.google.devtools.build.buildjar.proto.JavaCompilation.CompilationUnit;

import com.sun.tools.javac.comp.AttrContext;
import com.sun.tools.javac.comp.Env;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.HashSet;

/**
 * A plugin that records information about sources generated during annotation
 * processing.
 */
public class AnnotationProcessingPlugin extends BlazeJavaCompilerPlugin {

  private final HashSet<JCCompilationUnit> toplevels = new HashSet<>();
  private final AnnotationProcessingModule processingModule;

  public AnnotationProcessingPlugin(AnnotationProcessingModule processingModule) {
    this.processingModule = processingModule;
  }

  @Override
  public void postAttribute(Env<AttrContext> env) {
    if (toplevels.add(env.toplevel)) {
      recordInfo(env.toplevel);
    }
  }

  private void recordInfo(JCCompilationUnit toplevel) {
    CompilationUnit.Builder builder = CompilationUnit.newBuilder();

    if (toplevel.sourcefile != null) {
      // FileObject#getName() returns the original exec root-relative path of
      // the source file, which is want we want.
      // Paths.get(sourcefile.toUri()) would absolutize the path.
      Path path = Paths.get(toplevel.sourcefile.getName());
      builder.setPath(processingModule.stripSourceRoot(path).toString());
      builder.setGeneratedByAnnotationProcessor(processingModule.isGenerated(path));
    }

    if (toplevel.getPackageName() != null) {
      builder.setPkg(toplevel.getPackageName().toString());
    }

    for (JCTree decl : toplevel.defs) {
      if (decl instanceof JCClassDecl) {
        builder.addTopLevel(((JCClassDecl) decl).getSimpleName().toString());
      }
    }

    processingModule.recordUnit(builder.build());
  }
}
