// SPDX-License-Identifier: LGPL-2.1-or-later

#include <gtest/gtest.h>

#include <Mod/Assembly/Solver/IKCSolver.h>
#include <Mod/Assembly/Solver/SolverRegistry.h>
#include <Mod/Assembly/Solver/Types.h>

#include <algorithm>

using namespace KCSolve;

// ── Minimal mock solver for registry tests ─────────────────────────

namespace
{

class MockSolver : public IKCSolver
{
public:
    std::string name() const override
    {
        return "MockSolver";
    }

    std::vector<BaseJointKind> supported_joints() const override
    {
        return {BaseJointKind::Fixed, BaseJointKind::Revolute};
    }

    SolveResult solve(const SolveContext& /*ctx*/) override
    {
        return SolveResult {SolveStatus::Success, {}, 0, {}, 0};
    }
};

}  // namespace


// ── Tests ──────────────────────────────────────────────────────────
//
// SolverRegistry is a singleton — tests use unique names to avoid
// interference across test cases.

TEST(SolverRegistryTest, GetUnknownReturnsNull)  // NOLINT
{
    auto solver = SolverRegistry::instance().get("nonexistent_solver_xyz");
    EXPECT_EQ(solver, nullptr);
}

TEST(SolverRegistryTest, RegisterAndGet)  // NOLINT
{
    auto& reg = SolverRegistry::instance();

    bool ok = reg.register_solver("test_reg_get",
                                  []() { return std::make_unique<MockSolver>(); });
    EXPECT_TRUE(ok);

    auto solver = reg.get("test_reg_get");
    ASSERT_NE(solver, nullptr);
    EXPECT_EQ(solver->name(), "MockSolver");
}

TEST(SolverRegistryTest, DuplicateRegistrationFails)  // NOLINT
{
    auto& reg = SolverRegistry::instance();

    bool first = reg.register_solver("test_dup",
                                     []() { return std::make_unique<MockSolver>(); });
    EXPECT_TRUE(first);

    bool second = reg.register_solver("test_dup",
                                      []() { return std::make_unique<MockSolver>(); });
    EXPECT_FALSE(second);
}

TEST(SolverRegistryTest, AvailableListsSolvers)  // NOLINT
{
    auto& reg = SolverRegistry::instance();

    reg.register_solver("test_avail_1",
                        []() { return std::make_unique<MockSolver>(); });
    reg.register_solver("test_avail_2",
                        []() { return std::make_unique<MockSolver>(); });

    auto names = reg.available();
    EXPECT_NE(std::find(names.begin(), names.end(), "test_avail_1"), names.end());
    EXPECT_NE(std::find(names.begin(), names.end(), "test_avail_2"), names.end());
}

TEST(SolverRegistryTest, SetDefaultAndGet)  // NOLINT
{
    auto& reg = SolverRegistry::instance();

    reg.register_solver("test_default",
                        []() { return std::make_unique<MockSolver>(); });

    bool ok = reg.set_default("test_default");
    EXPECT_TRUE(ok);

    // get() with no arg should return the default.
    auto solver = reg.get();
    ASSERT_NE(solver, nullptr);
    EXPECT_EQ(solver->name(), "MockSolver");
}

TEST(SolverRegistryTest, SetDefaultUnknownFails)  // NOLINT
{
    auto& reg = SolverRegistry::instance();
    bool ok = reg.set_default("totally_unknown_solver");
    EXPECT_FALSE(ok);
}

TEST(SolverRegistryTest, JointsForReturnsCapabilities)  // NOLINT
{
    auto& reg = SolverRegistry::instance();

    reg.register_solver("test_joints",
                        []() { return std::make_unique<MockSolver>(); });

    auto joints = reg.joints_for("test_joints");
    EXPECT_EQ(joints.size(), 2u);
    EXPECT_NE(std::find(joints.begin(), joints.end(), BaseJointKind::Fixed), joints.end());
    EXPECT_NE(std::find(joints.begin(), joints.end(), BaseJointKind::Revolute), joints.end());
}

TEST(SolverRegistryTest, JointsForUnknownReturnsEmpty)  // NOLINT
{
    auto joints = SolverRegistry::instance().joints_for("totally_unknown_solver_2");
    EXPECT_TRUE(joints.empty());
}