#include <gtest/gtest.h>
#include <hdf5.h>

#include <atomic>
#include <chrono>
#include <filesystem>
#include <fstream>
#include <iterator>
#include <stdexcept>
#include <string>

#include "fesa/app/fesa_application.h"

namespace {

class EigenApplicationTest : public ::testing::Test {
 protected:
  void SetUp() override {
    static std::atomic<unsigned long long> sequence{0U};
    folder_ =
        std::filesystem::temp_directory_path() /
        ("fesa-eigen-app-" +
         std::to_string(
             std::chrono::steady_clock::now().time_since_epoch().count()) +
         "-" + std::to_string(sequence.fetch_add(1U)));
    ASSERT_TRUE(std::filesystem::create_directory(folder_));
    input_ = folder_ / "Panel.Modes.inp";
    output_ = folder_ / "Panel.Modes_results.h5";
    log_ = folder_ / "Panel.Modes_log.txt";
  }

  void TearDown() override {
    std::error_code ignored;
    std::filesystem::remove_all(folder_, ignored);
  }

  void WriteDeck(const bool empty = false) {
    std::ofstream file{input_};
    file << R"inp(*Part, name=Panel
*Node
11,0,0,0
22,1,0,0
33,1,1,0
44,0,1,0
*Element,type=S4
71,11,22,33,44
*Elset,elset=Shell
71
*Shell Section,elset=Shell,material=Steel
0.5
*End Part
*Assembly,name=Assembly
*Instance,name=Panel-1,part=Panel
*End Instance
*Nset,nset=Fixed,instance=Panel-1
11,22,33
*Nset,nset=Tip,instance=Panel-1
44
*End Assembly
*Material,name=Steel
*Density
1.
*Elastic
12.,0.
*Boundary
Fixed,1,6
Tip,1,2
Tip,4,6
)inp";
    if (empty) file << "Tip,3,3\n";
    file << R"inp(*Step,name=Step-2,nlgeom=NO,perturbation
*Frequency,eigensolver=Lanczos,normalization=mass
1
*End Step
)inp";
    ASSERT_TRUE(file.good());
  }

  std::filesystem::path folder_, input_, output_, log_;
};

TEST_F(EigenApplicationTest, DispatchesFrequencyAndWritesModalSibling) {
  WriteDeck();
  ASSERT_EQ(fesa::FesaApplication{}.Run({input_.string()}), 0);
  ASSERT_TRUE(std::filesystem::exists(output_));
  ASSERT_TRUE(std::filesystem::exists(log_));
  EXPECT_EQ(std::filesystem::file_size(log_), 0U);
  const hid_t file =
      H5Fopen(output_.string().c_str(), H5F_ACC_RDONLY, H5P_DEFAULT);
  ASSERT_GE(file, 0);
  EXPECT_GT(H5Lexists(file, "/steps/Step-1/eigen/modes", H5P_DEFAULT), 0);
  EXPECT_GT(H5Lexists(file, "/steps/Step-1/eigen/vectors", H5P_DEFAULT), 0);
  EXPECT_EQ(H5Lexists(file, "/steps/Step-1/frames", H5P_DEFAULT), 0);
  EXPECT_GE(H5Fclose(file), 0);
}

TEST_F(EigenApplicationTest, EmptyPencilPreservesPreviousFinalAndEmptyLog) {
  WriteDeck(true);
  const std::string original = "previous authoritative file";
  {
    std::ofstream previous{output_, std::ios::binary};
    previous << original;
  }
  EXPECT_EQ(fesa::FesaApplication{}.Run({input_.string()}), 4);
  std::ifstream previous{output_, std::ios::binary};
  EXPECT_TRUE(std::string(std::istreambuf_iterator<char>{previous}, {}) ==
              original);
  EXPECT_EQ(std::filesystem::file_size(log_), 0U);
}

}  // namespace