//===- TreeTest.cpp -------------------------------------------------------===//
//
// 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 "clang/Tooling/Syntax/Tree.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/Decl.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendAction.h"
#include "clang/Lex/PreprocessorOptions.h"
#include "clang/Tooling/Syntax/BuildTree.h"
#include "clang/Tooling/Syntax/Nodes.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <cstdlib>

using namespace clang;

namespace {
class SyntaxTreeTest : public ::testing::Test {
protected:
  // Build a syntax tree for the code.
  syntax::TranslationUnit *buildTree(llvm::StringRef Code) {
    // FIXME: this code is almost the identical to the one in TokensTest. Share
    //        it.
    class BuildSyntaxTree : public ASTConsumer {
    public:
      BuildSyntaxTree(syntax::TranslationUnit *&Root,
                      std::unique_ptr<syntax::Arena> &Arena,
                      std::unique_ptr<syntax::TokenCollector> Tokens)
          : Root(Root), Arena(Arena), Tokens(std::move(Tokens)) {
        assert(this->Tokens);
      }

      void HandleTranslationUnit(ASTContext &Ctx) override {
        Arena = std::make_unique<syntax::Arena>(Ctx.getSourceManager(),
                                                 Ctx.getLangOpts(),
                                                 std::move(*Tokens).consume());
        Tokens = nullptr; // make sure we fail if this gets called twice.
        Root = syntax::buildSyntaxTree(*Arena, *Ctx.getTranslationUnitDecl());
      }

    private:
      syntax::TranslationUnit *&Root;
      std::unique_ptr<syntax::Arena> &Arena;
      std::unique_ptr<syntax::TokenCollector> Tokens;
    };

    class BuildSyntaxTreeAction : public ASTFrontendAction {
    public:
      BuildSyntaxTreeAction(syntax::TranslationUnit *&Root,
                            std::unique_ptr<syntax::Arena> &Arena)
          : Root(Root), Arena(Arena) {}

      std::unique_ptr<ASTConsumer>
      CreateASTConsumer(CompilerInstance &CI, StringRef InFile) override {
        // We start recording the tokens, ast consumer will take on the result.
        auto Tokens =
            std::make_unique<syntax::TokenCollector>(CI.getPreprocessor());
        return std::make_unique<BuildSyntaxTree>(Root, Arena,
                                                  std::move(Tokens));
      }

    private:
      syntax::TranslationUnit *&Root;
      std::unique_ptr<syntax::Arena> &Arena;
    };

    constexpr const char *FileName = "./input.cpp";
    FS->addFile(FileName, time_t(), llvm::MemoryBuffer::getMemBufferCopy(""));
    if (!Diags->getClient())
      Diags->setClient(new IgnoringDiagConsumer);
    // Prepare to run a compiler.
    std::vector<const char *> Args = {"syntax-test", "-std=c++11",
                                      "-fsyntax-only", FileName};
    auto CI = createInvocationFromCommandLine(Args, Diags, FS);
    assert(CI);
    CI->getFrontendOpts().DisableFree = false;
    CI->getPreprocessorOpts().addRemappedFile(
        FileName, llvm::MemoryBuffer::getMemBufferCopy(Code).release());
    CompilerInstance Compiler;
    Compiler.setInvocation(std::move(CI));
    Compiler.setDiagnostics(Diags.get());
    Compiler.setFileManager(FileMgr.get());
    Compiler.setSourceManager(SourceMgr.get());

    syntax::TranslationUnit *Root = nullptr;
    BuildSyntaxTreeAction Recorder(Root, this->Arena);
    if (!Compiler.ExecuteAction(Recorder)) {
      ADD_FAILURE() << "failed to run the frontend";
      std::abort();
    }
    return Root;
  }

  // Adds a file to the test VFS.
  void addFile(llvm::StringRef Path, llvm::StringRef Contents) {
    if (!FS->addFile(Path, time_t(),
                     llvm::MemoryBuffer::getMemBufferCopy(Contents))) {
      ADD_FAILURE() << "could not add a file to VFS: " << Path;
    }
  }

  // Data fields.
  llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
      new DiagnosticsEngine(new DiagnosticIDs, new DiagnosticOptions);
  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> FS =
      new llvm::vfs::InMemoryFileSystem;
  llvm::IntrusiveRefCntPtr<FileManager> FileMgr =
      new FileManager(FileSystemOptions(), FS);
  llvm::IntrusiveRefCntPtr<SourceManager> SourceMgr =
      new SourceManager(*Diags, *FileMgr);
  // Set after calling buildTree().
  std::unique_ptr<syntax::Arena> Arena;
};

TEST_F(SyntaxTreeTest, Basic) {
  std::pair</*Input*/ std::string, /*Expected*/ std::string> Cases[] = {
      {
          R"cpp(
int main() {}
void foo() {}
    )cpp",
          R"txt(
*: TranslationUnit
|-TopLevelDeclaration
| |-int
| |-main
| |-(
| |-)
| `-CompoundStatement
|   |-2: {
|   `-3: }
`-TopLevelDeclaration
  |-void
  |-foo
  |-(
  |-)
  `-CompoundStatement
    |-2: {
    `-3: }
)txt"},
  };

  for (const auto &T : Cases) {
    auto *Root = buildTree(T.first);
    std::string Expected = llvm::StringRef(T.second).trim().str();
    std::string Actual = llvm::StringRef(Root->dump(*Arena)).trim();
    EXPECT_EQ(Expected, Actual) << "the resulting dump is:\n" << Actual;
  }
}
} // namespace