// Part of the Crubit project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "lifetime_analysis/test/lifetime_analysis_test.h"

#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <ostream>
#include <string>
#include <utility>
#include <variant>

#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "lifetime_analysis/analyze.h"
#include "lifetime_annotations/function_lifetimes.h"
#include "lifetime_annotations/lifetime_annotations.h"
#include "lifetime_annotations/test/named_func_lifetimes.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/raw_ostream.h"

#include "lifetime_annotations/test/run_on_code.h"

namespace clang {
namespace tidy {
namespace lifetimes {
namespace {

void SaveDotFile(absl::string_view dot, absl::string_view filename_base,
                 absl::string_view test_name, absl::string_view description) {
  std::string base_path =
      absl::StrCat(testing::TempDir(), "/", test_name, ".", filename_base);
  std::ofstream out(absl::StrCat(base_path, ".dot"));
  if (!out) {
    llvm::errs() << "Error opening dot file: " << strerror(errno) << "\n";
    return;
  }
  out << dot;
  if (!out) {
    llvm::errs() << "Error writing dot file: " << strerror(errno) << "\n";
    return;
  }
  out.close();
  if (system(
          absl::StrCat("dot ", base_path, ".dot -T svg -o ", base_path, ".svg")
              .c_str()) != 0) {
    llvm::errs() << "Error invoking graphviz. dot file can be found at: "
                 << base_path << ".dot\n";
    return;
  }
}

}  // namespace

void LifetimeAnalysisTest::TearDown() {
  if (HasFailure()) {
    for (const auto& [func, debug_info] : debug_info_map_) {
      std::cerr << debug_info.ast << "\n";

      std::cerr << debug_info.object_repository << "\n";

      const char* test_name =
          testing::UnitTest::GetInstance()->current_test_info()->name();

      SaveDotFile(debug_info.points_to_map_dot,
                  absl::StrCat(func, "_points_to"), test_name,
                  "Points-to map of exit block");
      SaveDotFile(debug_info.constraints_dot,
                  absl::StrCat(func, "_constraints"), test_name,
                  "Constraint set at exit block");
      SaveDotFile(debug_info.cfg_dot, absl::StrCat(func, "_cfg"), test_name,
                  "Control-flow graph");
    }
    std::cerr << "Debug graphs can be found in " << testing::TempDir()
              << std::endl;
  }
}

std::string LifetimeAnalysisTest::QualifiedName(
    const clang::FunctionDecl* func) {
  // TODO(veluca): figure out how to name overloaded functions.
  std::string str;
  llvm::raw_string_ostream ostream(str);
  func->printQualifiedName(ostream);
  ostream.flush();
  return str;
}

NamedFuncLifetimes LifetimeAnalysisTest::GetLifetimes(
    llvm::StringRef source_code, const GetLifetimesOptions& options) {
  NamedFuncLifetimes tu_lifetimes;

  auto test = [&tu_lifetimes, &options, this](
                  clang::ASTContext& ast_context,
                  const LifetimeAnnotationContext& lifetime_context) {
    // This will get called even if the code contains compilation errors.
    // So we need to check to avoid performing an analysis on code that
    // doesn't compile.
    if (ast_context.getDiagnostics().hasUncompilableErrorOccurred() &&
        !analyze_broken_code_) {
      tu_lifetimes.Add("", "Compilation error -- see log for details");
      return;
    }

    auto result_callback = [&tu_lifetimes, &options](
                               const clang::FunctionDecl* func,
                               const FunctionLifetimesOrError&
                                   lifetimes_or_error) {
      if (std::holds_alternative<FunctionAnalysisError>(lifetimes_or_error)) {
        tu_lifetimes.Add(
            QualifiedName(func),
            absl::StrCat(
                "ERROR: ",
                std::get<FunctionAnalysisError>(lifetimes_or_error).message));
        return;
      }
      const auto& func_lifetimes =
          std::get<FunctionLifetimes>(lifetimes_or_error);

      // Do not insert in the result set implicitly-defined constructors or
      // assignment operators.
      if (auto* constructor =
              clang::dyn_cast<clang::CXXConstructorDecl>(func)) {
        if (constructor->isImplicit() && !options.include_implicit_methods) {
          return;
        }
      }
      if (auto* method = clang::dyn_cast<clang::CXXMethodDecl>(func)) {
        if (method->isImplicit() && !options.include_implicit_methods) {
          return;
        }
      }

      tu_lifetimes.Add(QualifiedName(func), NameLifetimes(func_lifetimes));
    };

    FunctionDebugInfoMap func_ptr_debug_info_map;
    llvm::DenseMap<const clang::FunctionDecl*, FunctionLifetimesOrError>
        analysis_result;
    if (options.with_template_placeholder) {
      AnalyzeTranslationUnitWithTemplatePlaceholder(
          ast_context.getTranslationUnitDecl(), lifetime_context,
          result_callback,
          /*diag_reporter=*/{}, &func_ptr_debug_info_map);
    } else {
      analysis_result = AnalyzeTranslationUnit(
          ast_context.getTranslationUnitDecl(), lifetime_context,
          /*diag_reporter=*/{}, &func_ptr_debug_info_map);

      for (const auto& [func, lifetimes_or_error] : analysis_result) {
        result_callback(func, lifetimes_or_error);
      }
    }

    for (auto& [func, debug_info] : func_ptr_debug_info_map) {
      debug_info_map_.try_emplace(func->getDeclName().getAsString(),
                                  std::move(debug_info));
    }
  };

  if (!runOnCodeWithLifetimeHandlers(source_code, test,
                                     {"-fsyntax-only", "-std=c++17"})) {
    // We need to disambiguate between two cases:
    // - We were unable to run the analysis at all (because there was some
    //   internal error)
    //   In this case, `tu_lifetimes` will be empty, so add a corresponding
    //   note here.
    // - The analysis emitted an error diagnostic, which will also cause us to
    //   end up here.
    //   In this case, `tu_lifetimes` already contains an error empty, so we
    //   don't need to do anything.
    if (tu_lifetimes.Entries().empty()) {
      tu_lifetimes.Add("", "Error running dataflow analysis");
    }
  }

  return tu_lifetimes;
}

NamedFuncLifetimes LifetimeAnalysisTest::GetLifetimesWithPlaceholder(
    llvm::StringRef source_code) {
  GetLifetimesOptions options;
  options.with_template_placeholder = true;
  return GetLifetimes(source_code, options);
}

}  // namespace lifetimes
}  // namespace tidy
}  // namespace clang