/**
 * test_ldf_parser.cpp — Tests for the LDF parsing module (Step 2, C++).
 *
 * C++ equivalent of python/tests/test_ldf_handler.py.
 * Tests the custom LDF parser against resources/sample.ldf.
 *
 * COMPILE-TIME DEFINES vs PYTHON PATH RESOLUTION:
 * ================================================
 * In Python, we resolve the path at runtime:
 *   SAMPLE_LDF = str(Path(__file__).parent.parent.parent / "resources" / "sample.ldf")
 *
 * In C++, CMakeLists.txt injects the path at compile time:
 *   target_compile_definitions(test_ldf_parser PRIVATE
 *       LDF_SAMPLE_PATH="${CMAKE_CURRENT_SOURCE_DIR}/../resources/sample.ldf"
 *   )
 *
 * This becomes a #define that the preprocessor substitutes before compilation.
 * The #ifndef / #define fallback below provides a default if CMake doesn't set it.
 *
 * STD::FIND_IF — C++ ALGORITHM:
 * =============================
 * Several tests need to find a specific frame by name. In Python:
 *   frame = next(f for f in result.tx_frames if f.name == "Motor_Command")
 *
 * In C++, we use std::find_if from the <algorithm> header:
 *   auto it = std::find_if(frames.begin(), frames.end(),
 *       [](const FrameInfo& f) { return f.name == "Motor_Command"; });
 *
 * The [](const FrameInfo& f) { ... } is a LAMBDA — an anonymous function.
 *   Python lambda: lambda f: f.name == "Motor_Command"
 *   C++ lambda:    [](const FrameInfo& f) { return f.name == "Motor_Command"; }
 *
 * The [] is the "capture list" — it specifies which local variables the lambda
 * can access. Empty [] means "capture nothing" (our lambda only uses its parameter).
 *
 * std::find_if returns an ITERATOR — a pointer-like object that points to the
 * found element. We use -> to access its members (like it->frame_id).
 */

#include <QtTest/QtTest>
#include "ldf_parser.h"

// Path to sample LDF — CMakeLists.txt defines LDF_SAMPLE_PATH at compile time.
// The #ifndef provides a fallback if CMake doesn't set it (shouldn't happen).
#ifndef LDF_SAMPLE_PATH
#define LDF_SAMPLE_PATH "../../resources/sample.ldf"
#endif

class TestLdfParser : public QObject
{
    Q_OBJECT

private:
    LdfData m_data;  // Parsed once, shared by all tests (read-only)

private slots:
    // initTestCase() runs ONCE before all tests (like pytest's session fixture).
    // This is different from init() which runs before EACH test.
    // Since our tests only read m_data and never modify it, parsing once is safe.
    void initTestCase()
    {
        m_data = parseLdf(QString(LDF_SAMPLE_PATH));
    }

    // ─── Basic Parsing ───────────────────────────────────────────

    void test_protocolVersion()
    {
        QCOMPARE(m_data.protocol_version, QString("2.1"));
    }

    void test_languageVersion()
    {
        QCOMPARE(m_data.language_version, QString("2.1"));
    }

    void test_baudrate()
    {
        QCOMPARE(m_data.baudrate, 19200);
    }

    void test_masterName()
    {
        QCOMPARE(m_data.master_name, QString("ECU_Master"));
    }

    void test_slaveNames()
    {
        QVERIFY(m_data.slave_names.contains("Motor_Control"));
        QVERIFY(m_data.slave_names.contains("Door_Module"));
    }

    void test_filePathStored()
    {
        QCOMPARE(m_data.file_path, QString(LDF_SAMPLE_PATH));
    }

    // ─── Frame Classification ────────────────────────────────────

    void test_txFrameCount()
    {
        QCOMPARE(m_data.tx_frames.size(), 2);
    }

    void test_rxFrameCount()
    {
        QCOMPARE(m_data.rx_frames.size(), 2);
    }

    void test_txFramesAreMaster()
    {
        for (const auto& frame : m_data.tx_frames)
            QVERIFY(frame.is_master_tx);
    }

    void test_rxFramesAreSlave()
    {
        for (const auto& frame : m_data.rx_frames)
            QVERIFY(!frame.is_master_tx);
    }

    void test_txFrameNames()
    {
        QStringList names;
        for (const auto& f : m_data.tx_frames) names << f.name;
        QVERIFY(names.contains("Motor_Command"));
        QVERIFY(names.contains("Door_Command"));
    }

    void test_rxFrameNames()
    {
        QStringList names;
        for (const auto& f : m_data.rx_frames) names << f.name;
        QVERIFY(names.contains("Motor_Status"));
        QVERIFY(names.contains("Door_Status"));
    }

    // ─── Frame Details ───────────────────────────────────────────

    void test_motorCommandId()
    {
        auto it = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        QVERIFY(it != m_data.tx_frames.end());
        QCOMPARE(it->frame_id, 0x10);
    }

    void test_motorCommandLength()
    {
        auto it = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        QCOMPARE(it->length, 2);
    }

    void test_motorCommandPublisher()
    {
        auto it = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        QCOMPARE(it->publisher, QString("ECU_Master"));
    }

    // ─── Signal Extraction ───────────────────────────────────────

    void test_motorCommandSignals()
    {
        auto frame = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        QStringList sigNames;
        for (const auto& s : frame->signal_list) sigNames << s.name;
        QVERIFY(sigNames.contains("MotorEnable"));
        QVERIFY(sigNames.contains("MotorDirection"));
        QVERIFY(sigNames.contains("MotorSpeed"));
    }

    void test_signalBitOffset()
    {
        auto frame = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        auto sig = std::find_if(frame->signal_list.begin(), frame->signal_list.end(),
            [](const SignalInfo& s) { return s.name == "MotorEnable"; });
        QCOMPARE(sig->bit_offset, 0);
    }

    void test_signalWidth()
    {
        auto frame = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        auto sig = std::find_if(frame->signal_list.begin(), frame->signal_list.end(),
            [](const SignalInfo& s) { return s.name == "MotorSpeed"; });
        QCOMPARE(sig->width, 8);
    }

    void test_signalInitValue()
    {
        auto frame = std::find_if(m_data.tx_frames.begin(), m_data.tx_frames.end(),
            [](const FrameInfo& f) { return f.name == "Motor_Command"; });
        auto sig = std::find_if(frame->signal_list.begin(), frame->signal_list.end(),
            [](const SignalInfo& s) { return s.name == "MotorEnable"; });
        QCOMPARE(sig->init_value, 0);
    }

    // ─── Schedule Tables ─────────────────────────────────────────

    void test_scheduleCount()
    {
        QCOMPARE(m_data.schedule_tables.size(), 2);
    }

    void test_scheduleNames()
    {
        QStringList names;
        for (const auto& st : m_data.schedule_tables) names << st.name;
        QVERIFY(names.contains("NormalSchedule"));
        QVERIFY(names.contains("FastSchedule"));
    }

    void test_normalScheduleEntries()
    {
        auto st = std::find_if(m_data.schedule_tables.begin(), m_data.schedule_tables.end(),
            [](const ScheduleTableInfo& s) { return s.name == "NormalSchedule"; });
        QCOMPARE(st->entries.size(), 4);
    }

    void test_normalScheduleDelay()
    {
        auto st = std::find_if(m_data.schedule_tables.begin(), m_data.schedule_tables.end(),
            [](const ScheduleTableInfo& s) { return s.name == "NormalSchedule"; });
        for (const auto& entry : st->entries)
            QCOMPARE(entry.delay_ms, 10);
    }

    void test_fastScheduleDelay()
    {
        auto st = std::find_if(m_data.schedule_tables.begin(), m_data.schedule_tables.end(),
            [](const ScheduleTableInfo& s) { return s.name == "FastSchedule"; });
        for (const auto& entry : st->entries)
            QCOMPARE(entry.delay_ms, 5);
    }

    void test_frameEntriesHaveNoData()
    {
        auto st = std::find_if(m_data.schedule_tables.begin(), m_data.schedule_tables.end(),
            [](const ScheduleTableInfo& s) { return s.name == "NormalSchedule"; });
        for (const auto& entry : st->entries)
            QVERIFY(entry.data.isEmpty());
    }

    // ─── Error Handling ──────────────────────────────────────────

    void test_fileNotFound()
    {
        bool threw = false;
        try {
            parseLdf("/nonexistent/path/fake.ldf");
        } catch (const std::runtime_error&) {
            threw = true;
        }
        QVERIFY(threw);
    }

    void test_invalidFile()
    {
        // Create a temporary invalid file
        QTemporaryFile tmpFile;
        tmpFile.open();
        tmpFile.write("this is not a valid LDF file");
        tmpFile.close();

        bool threw = false;
        try {
            parseLdf(tmpFile.fileName());
        } catch (const std::runtime_error&) {
            threw = true;
        }
        QVERIFY(threw);
    }
};

QTEST_MAIN(TestLdfParser)
#include "test_ldf_parser.moc"