// Copyright 2020 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.lib.rules.proto;

import com.google.devtools.build.docgen.annot.DocCategory;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.collect.nestedset.Depset;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import com.google.devtools.build.lib.vfs.PathFragment;
import net.starlark.java.annot.StarlarkBuiltin;
import net.starlark.java.annot.StarlarkMethod;
import net.starlark.java.eval.EvalException;
import net.starlark.java.eval.StarlarkThread;
import net.starlark.java.eval.StarlarkValue;

/** Represents a single {@code .proto} source file. */
@Immutable
@StarlarkBuiltin(name = "ProtoSource", category = DocCategory.BUILTIN, documented = false)
final class ProtoSource implements StarlarkValue {
  public static final Depset.ElementType TYPE = Depset.ElementType.of(ProtoSource.class);

  private final Artifact sourceFile;
  private final Artifact originalSourceFile;
  private final PathFragment sourceRoot;

  public ProtoSource(Artifact sourceFile, PathFragment sourceRoot) {
    this(sourceFile, sourceFile, sourceRoot);
  }

  ProtoSource(Artifact sourceFile, Artifact originalSourceFile, PathFragment sourceRoot) {
    this.sourceFile = sourceFile;
    this.originalSourceFile = originalSourceFile;
    this.sourceRoot = ProtoCommon.memoryEfficientProtoSourceRoot(sourceRoot);
  }

  public Artifact getSourceFile() {
    return sourceFile;
  }

  @StarlarkMethod(name = "source_file", documented = false, useStarlarkThread = true)
  public Artifact getSourceFileForStarlark(StarlarkThread thread) throws EvalException {
    ProtoCommon.checkPrivateStarlarkificationAllowlist(thread);
    return sourceFile;
  }

  /** Returns the original source file. Only for forbidding protos! */
  @StarlarkMethod(name = "original_source_file", documented = false, useStarlarkThread = true)
  public Artifact getOriginalSourceFileForStarlark(StarlarkThread thread) throws EvalException {
    ProtoCommon.checkPrivateStarlarkificationAllowlist(thread);
    return originalSourceFile;
  }

  Artifact getOriginalSourceFile() {
    return originalSourceFile;
  }

  public PathFragment getSourceRoot() {
    return sourceRoot;
  }

  @StarlarkMethod(name = "import_path", documented = false, useStarlarkThread = true)
  public String getImportPathForStarlark(StarlarkThread thread) throws EvalException {
    ProtoCommon.checkPrivateStarlarkificationAllowlist(thread);
    return getImportPath().getPathString();
  }

  public PathFragment getImportPath() {
    return sourceFile.getExecPath().relativeTo(sourceRoot);
  }

  @Override
  public String toString() {
    return "ProtoSource('" + getImportPath() + "')";
  }

  @Override
  public boolean isImmutable() {
    return true;
  }
}