/*************************************************************************
 * Copyright (c) 2025 Advanced Micro Devices, Inc. All rights reserved.
 *
 * See LICENSE.txt for license information
 ************************************************************************/

/**
 * @file main_mpi.cpp
 * @brief Main entry point for Google Test-based MPI tests
 *
 * This file provides the main() function for running GTest-based MPI tests.
 * For standalone tests (performance benchmarks, etc.), each test should have
 * its own main() function and use MPIHelpers for common functionality.
 */

#include <cstdio>
#include <cstdlib>
#include <gtest/gtest.h>

#ifdef MPI_TESTS_ENABLED

    #include "MPIHelpers.hpp"
    #include "MPITestBase.hpp"
    #include "MPIEnvironment.hpp"

int main(int argc, char* argv[])
{
    // Initialize MPI using shared helper
    auto mpi_ctx = MPIHelpers::initializeMPI(&argc, &argv);

    const auto world_rank = mpi_ctx.world_rank;
    const auto world_size = mpi_ctx.world_size;

    // Setup per-rank logging using shared helper
    auto       rank_log_config          = MPIHelpers::setupRankLogging(world_rank);
    const auto per_rank_logging_enabled = rank_log_config && rank_log_config->logging_enabled;

    // Print initialization message
    if(world_rank == 0 && !per_rank_logging_enabled)
    {
        TEST_INFO("MPI initialized - World size: %d, Thread support: %d",
                  world_size,
                  mpi_ctx.thread_support);
    }

    // Initialize Google Test
    ::testing::InitGoogleTest(&argc, argv);

    // Suppress GTest output for non-zero ranks (unless per-rank logging is enabled)
    // This is done by deleting GTest listeners for non-zero ranks
    // Note: stdout/stderr are already redirected for non-zero ranks by setupRankLogging
    if(world_rank != 0 && !per_rank_logging_enabled)
    {
        auto& listeners = ::testing::UnitTest::GetInstance()->listeners();
        delete listeners.Release(listeners.default_result_printer());
        delete listeners.Release(listeners.default_xml_generator());
    }

    // Set up the RCCL MPI environment for all tests
    ::testing::AddGlobalTestEnvironment(new MPIEnvironment());

    // Run all tests
    const auto ret_code = RUN_ALL_TESTS();

    // Restore original output if per-rank logging was enabled
    if(rank_log_config)
    {
        MPIHelpers::restoreRankLogging(*rank_log_config);
    }

    // MPI_Finalize is called by:
    // 1. MPIEnvironment::TearDown() -> cleanup_mpi() (normal case)
    // 2. MPIEnvironment destructor (safety net if TearDown fails or no tests match)
    return ret_code;
}

#else // MPI_TESTS_ENABLED not defined

int main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[])
{
    std::fprintf(stderr,
                 "ERROR: MPI tests are not enabled. Please build with ENABLE_MPI_TESTS=ON\n");
    std::fprintf(stderr, "Usage: cmake -DENABLE_MPI_TESTS=ON -DMPI_PATH=/path/to/mpi ..\n");
    return 1;
}

#endif // MPI_TESTS_ENABLED
