//===--- AnnotateHighlightings.cpp -------------------------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "SemanticHighlighting.h"
#include "refactor/Tweak.h"

namespace clang {
namespace clangd {
namespace {

/// Annotate all highlighting tokens in the current file. This is a hidden tweak
/// which is used to debug semantic highlightings.
/// Before:
///   void f() { int abc; }
///   ^^^^^^^^^^^^^^^^^^^^^
/// After:
///   void /* entity.name.function.cpp */ f() { int /* variable.cpp */ abc; }
class AnnotateHighlightings : public Tweak {
public:
  const char *id() const override final;

  bool prepare(const Selection &Inputs) override {
    for (auto N = Inputs.ASTSelection.commonAncestor(); N && !InterestedDecl;
         N = N->Parent)
      InterestedDecl = N->ASTNode.get<Decl>();
    return InterestedDecl;
  }
  Expected<Effect> apply(const Selection &Inputs) override;

  std::string title() const override { return "Annotate highlighting tokens"; }
  Intent intent() const override { return Refactor; }
  bool hidden() const override { return true; }

private:
  const Decl *InterestedDecl = nullptr;
};
REGISTER_TWEAK(AnnotateHighlightings)

Expected<Tweak::Effect> AnnotateHighlightings::apply(const Selection &Inputs) {
  // Store the existing scopes.
  const auto &BackupScopes = Inputs.AST.getASTContext().getTraversalScope();
  // Narrow the traversal scope to the selected node.
  Inputs.AST.getASTContext().setTraversalScope(
      {const_cast<Decl *>(InterestedDecl)});
  auto HighlightingTokens = getSemanticHighlightings(Inputs.AST);
  // Restore the traversal scope.
  Inputs.AST.getASTContext().setTraversalScope(BackupScopes);

  auto &SM = Inputs.AST.getSourceManager();
  tooling::Replacements Result;
  for (const auto &Token : HighlightingTokens) {
    assert(Token.R.start.line == Token.R.end.line &&
           "Token must be at the same line");
    auto InsertOffset = positionToOffset(Inputs.Code, Token.R.start);
    if (!InsertOffset)
      return InsertOffset.takeError();

    auto InsertReplacement = tooling::Replacement(
        SM.getFileEntryForID(SM.getMainFileID())->getName(), *InsertOffset, 0,
        ("/* " + toTextMateScope(Token.Kind) + " */").str());
    if (auto Err = Result.add(InsertReplacement))
      return std::move(Err);
  }
  return Effect::applyEdit(Result);
}

} // namespace
} // namespace clangd
} // namespace clang
