#include "fesa/assembly/surface_pressure_assembler.h"

#include <gtest/gtest.h>

#include <array>
#include <cstddef>
#include <cstdint>
#include <filesystem>
#include <memory>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>

#include "fesa/analysis/analysis_model.h"
#include "fesa/assembly/parallel_for.h"
#include "fesa/fem/dof_manager.h"
#include "fesa/model/domain.h"

namespace {

struct PressureFixture {
  std::unique_ptr<fesa::Domain> domain;
  std::unique_ptr<fesa::AnalysisModel> model;
  std::unique_ptr<fesa::DofManager> dofs;
};

PressureFixture MakeFixture(const std::vector<double>& magnitudes) {
  const std::filesystem::path source{"surface-pressure-assembly.inp"};
  fesa::ModelDefinition definition{};
  definition.source_path = source;
  definition.source_content_identity = "fnv1a64:surfacepressure";
  definition.nodes = {
      {{"Shell-1", 1, "1"}, {0.0, 0.0, 0.0}, {source, 2U}},
      {{"Shell-1", 2, "2"}, {1.0, 0.0, 0.0}, {source, 3U}},
      {{"Shell-1", 3, "3"}, {1.0, 1.0, 0.0}, {source, 4U}},
      {{"Shell-1", 4, "4"}, {0.0, 1.0, 0.0}, {source, 5U}}};
  definition.materials = {{"Steel", 1000.0, 0.25, {source, 6U}}};
  definition.shell_sections = {{"Shell", 0.1, 0U, {source, 7U}}};
  definition.shell_elements = {{{"Shell-1", 1, "1"},
                                fesa::ShellSourceElementType::kS4,
                                {0U, 1U, 2U, 3U},
                                0U,
                                0U,
                                {source, 8U}}};
  for (std::size_t node = 0U; node < definition.nodes.size(); ++node) {
    definition.shell_node_initial_frames.push_back(
        {static_cast<fesa::EntityIndex>(node),
         {0.0, 0.0, 1.0},
         {1.0, 0.0, 0.0},
         {0.0, 1.0, 0.0}});
  }
  definition.element_surfaces = {
      {"Pressure-Surface",
       "PRESSURE-SURFACE",
       {{0U,
         0U,
         "ShellPart",
         "SHELLPART",
         "Shell-1",
         "SHELL-1",
         1,
         "1",
         "S4",
         fesa::ShellSurfaceSide::kSpos,
         {source, 12U},
         0U,
         fesa::SurfaceMemberKind::kDirect,
         "",
         ""}},
       {source, 11U},
       0U}};

  std::vector<fesa::SurfacePressureLoadDefinition> pressure_loads;
  pressure_loads.reserve(magnitudes.size());
  for (std::size_t ordinal = 0U; ordinal < magnitudes.size(); ++ordinal) {
    pressure_loads.push_back({"Step-1",
                              "STEP-1",
                              0U,
                              "Pressure-Surface",
                              "PRESSURE-SURFACE",
                              "P",
                              magnitudes[ordinal],
                              std::to_string(magnitudes[ordinal]),
                              {source, 20U + ordinal},
                              {source, 21U + ordinal},
                              ordinal,
                              ordinal});
  }
  definition.steps.emplace_back(
      "Step-1", std::vector<fesa::PrescribedDisplacementDefinition>{},
      std::vector<fesa::NodalLoad>{}, std::move(pressure_loads),
      fesa::StaticProcedureKind::kLinearSmallDisplacement, false, 0.1, 1.0,
      0.01, 1.0, fesa::SourceLocation{source, 19U});

  auto domain_result = fesa::Domain::Create(std::move(definition));
  if (!domain_result.HasValue()) {
    throw std::runtime_error{"Unable to construct pressure Domain fixture."};
  }
  auto domain =
      std::make_unique<fesa::Domain>(std::move(domain_result.Value()));
  auto model_result = fesa::AnalysisModel::Create(*domain);
  if (!model_result.HasValue()) {
    throw std::runtime_error{"Unable to construct pressure AnalysisModel."};
  }
  auto model =
      std::make_unique<fesa::AnalysisModel>(std::move(model_result.Value()));
  auto dofs_result = fesa::DofManager::Create(*model);
  if (!dofs_result.HasValue()) {
    throw std::runtime_error{"Unable to construct pressure DofManager."};
  }
  auto dofs =
      std::make_unique<fesa::DofManager>(std::move(dofs_result.Value()));
  return {std::move(domain), std::move(model), std::move(dofs)};
}

std::vector<double> Values(const fesa::Vector& vector) {
  return {vector.Data(), vector.Data() + vector.Size()};
}

}  // namespace

TEST(SurfacePressureAssembly, AssemblesFullDofsInPressureFacetAndRecordOrder) {
  auto fixture = MakeFixture({2.0});
  fesa::Vector coordinates{fixture.dofs->FullDofCount()};
  coordinates[2U] = 11.0;
  fesa::SerialParallelFor serial;

  const auto result = fesa::AssembleSurfacePressure(
      *fixture.model, *fixture.dofs, coordinates, 1.0,
      fesa::SurfacePressureConfiguration::kReference, serial);

  ASSERT_TRUE(result.HasValue());
  EXPECT_TRUE(result.Value().diagnostics.empty());
  ASSERT_EQ(result.Value().full_external_force.Size(), 24U);
  for (std::size_t node = 0U; node < 4U; ++node) {
    const std::size_t offset = node * 6U;
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset], 0.0);
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset + 1U], 0.0);
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset + 2U], -0.5);
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset + 3U], 0.0);
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset + 4U], 0.0);
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[offset + 5U], 0.0);
  }
  EXPECT_EQ(result.Value().full_external_tangent.Rows(), 24U);
  EXPECT_EQ(result.Value().full_external_tangent.Columns(), 24U);
  for (const double value : result.Value().full_external_tangent.Values()) {
    EXPECT_EQ(value, 0.0);
  }
}

TEST(SurfacePressureAssembly,
     AddsRepeatedRecordsAndAppliesUnitFactorExactlyOnce) {
  auto fixture = MakeFixture({6.0, 2.0});
  fesa::Vector coordinates{fixture.dofs->FullDofCount()};
  fesa::SerialParallelFor serial;

  const auto result = fesa::AssembleSurfacePressure(
      *fixture.model, *fixture.dofs, coordinates, 0.5,
      fesa::SurfacePressureConfiguration::kReference, serial);

  ASSERT_TRUE(result.HasValue());
  for (std::size_t node = 0U; node < 4U; ++node) {
    EXPECT_DOUBLE_EQ(result.Value().full_external_force[node * 6U + 2U],
                     -1.0);
  }
}

TEST(SurfacePressureAssembly,
     IsBitwiseStableForSerialAndParallelLocalEvaluation) {
  auto fixture = MakeFixture({1.0e16, -1.0e16, 3.5});
  fesa::Vector coordinates{fixture.dofs->FullDofCount()};
  fesa::SerialParallelFor serial;
  fesa::TbbParallelFor parallel;

  const auto serial_result = fesa::AssembleSurfacePressure(
      *fixture.model, *fixture.dofs, coordinates, 1.0,
      fesa::SurfacePressureConfiguration::kReference, serial);
  const auto parallel_result = fesa::AssembleSurfacePressure(
      *fixture.model, *fixture.dofs, coordinates, 1.0,
      fesa::SurfacePressureConfiguration::kReference, parallel);

  ASSERT_TRUE(serial_result.HasValue());
  ASSERT_TRUE(parallel_result.HasValue());
  EXPECT_EQ(Values(serial_result.Value().full_external_force),
            Values(parallel_result.Value().full_external_force));
  EXPECT_EQ(serial_result.Value().full_external_tangent.RowOffsets(),
            parallel_result.Value().full_external_tangent.RowOffsets());
  EXPECT_EQ(serial_result.Value().full_external_tangent.ColumnIndices(),
            parallel_result.Value().full_external_tangent.ColumnIndices());
  EXPECT_EQ(serial_result.Value().full_external_tangent.Values(),
            parallel_result.Value().full_external_tangent.Values());
  EXPECT_TRUE(serial_result.Value().diagnostics.empty());
  EXPECT_TRUE(parallel_result.Value().diagnostics.empty());
}