#include "dbc_decoder.h"

#include <QtTest>
#include <cmath>
#include <limits>
#include <sstream>
#include <stdexcept>

struct DecodeCase {
    const char *name;
    ByteOrder byteOrder;
    std::uint32_t startBit;
    std::uint32_t length;
    ValueType valueType;
    std::vector<std::uint8_t> data;
    bool valid;
    std::int64_t rawValue;
    double factor;
    double offset;
    double physicalValue;
};

Q_DECLARE_METATYPE(DecodeCase)

class DbcDecoderTest : public QObject {
    Q_OBJECT
private Q_SLOTS:
    void decode_data();
    void decode();
    void boundaries();
    void payloadPolicy_data();
    void payloadPolicy();
    void invalidDefinitions_data();
    void invalidDefinitions();
    void physicalConversion_data();
    void physicalConversion();
    void selectorConversionFailure();
    void zeroDlc();
};

void DbcDecoderTest::decode_data() {
    QTest::addColumn<DecodeCase>("test");
    const DecodeCase cases[] = {
            {"Motorola reproduction", ByteOrder::Motorola, 7U, 16U, ValueType::Unsigned, {0x12, 0x34}, true, 0x1234, 1.0, 0.0, 4660.0},
            {"Motorola within byte", ByteOrder::Motorola, 5U, 4U, ValueType::Unsigned, {0xAC}, true, 11, 1.0, 0.0, 11.0},
            {"Motorola unaligned crossing", ByteOrder::Motorola, 3U, 12U, ValueType::Unsigned, {0xAB, 0xCD}, true, 0xBCD, 1.0, 0.0, 3021.0},
            {"Motorola starts at bit zero", ByteOrder::Motorola, 0U, 2U, ValueType::Unsigned, {0x01, 0x80}, true, 3, 1.0, 0.0, 3.0},
            {"Motorola second byte", ByteOrder::Motorola, 15U, 16U, ValueType::Unsigned, {0xFF, 0x12, 0x34}, true, 0x1234, 1.0, 0.0, 4660.0},
            {"Motorola signed scaled", ByteOrder::Motorola, 7U, 16U, ValueType::Signed, {0xFF, 0xFE}, true, -2, 0.5, 10.0, 9.0},
            {"Motorola 64 bits", ByteOrder::Motorola, 7U, 64U, ValueType::Unsigned, {0, 0, 0, 0, 0, 0, 0x12, 0x34}, true, 0x1234, 1.0, 0.0, 4660.0},
            {"Motorola 64 bits high bit", ByteOrder::Motorola, 7U, 64U, ValueType::Unsigned, {0x40, 0, 0, 0, 0, 0, 0, 0}, true, 0x4000000000000000LL, 1.0, 0.0, 4611686018427387904.0},
            {"Motorola short payload", ByteOrder::Motorola, 7U, 16U, ValueType::Unsigned, {0x12}, false, 0, 1.0, 0.0, 0.0},
            {"Motorola empty payload", ByteOrder::Motorola, 7U, 8U, ValueType::Unsigned, {}, false, 0, 1.0, 0.0, 0.0},
            {"Motorola large start", ByteOrder::Motorola, std::numeric_limits<std::uint32_t>::max(), 8U, ValueType::Unsigned, {0xFF}, false, 0, 1.0, 0.0, 0.0},
            {"Motorola zero length", ByteOrder::Motorola, 7U, 0U, ValueType::Unsigned, {0xFF}, false, 0, 1.0, 0.0, 0.0},
            {"Motorola excessive length", ByteOrder::Motorola, 7U, 65U, ValueType::Unsigned,
             std::vector<std::uint8_t>(9U, 0xFF), false, 0, 1.0, 0.0, 0.0},
            {"Intel regression", ByteOrder::Intel, 0U, 16U, ValueType::Unsigned, {0x12, 0x34}, true, 0x3412, 1.0, 0.0, 13330.0},
            {"Intel signed regression", ByteOrder::Intel, 0U, 16U, ValueType::Signed, {0xFE, 0xFF}, true, -2, 0.5, 10.0, 9.0},
            {"Intel short payload", ByteOrder::Intel, 0U, 16U, ValueType::Unsigned, {0x12}, false, 0, 1.0, 0.0, 0.0}};

    for (const DecodeCase &test: cases)
        QTest::newRow(test.name) << test;
}

void DbcDecoderTest::decode() {
    QFETCH(DecodeCase, test);
    DecodeSignal signal;
    signal.name = test.name;
    signal.byteOrder = test.byteOrder;
    signal.startBit = test.startBit;
    signal.length = test.length;
    signal.valueType = test.valueType;
    signal.factor = test.factor;
    signal.offset = test.offset;

    DecodeFrame definition;
    definition.canId = 0x123U;
    definition.dlc = 8U;
    definition.signals.push_back(signal);
    if (test.length == 0U || test.length > 64U || test.startBit > 64U) {
        QVERIFY_THROWS_EXCEPTION(std::invalid_argument, (void) DecodeDatabase({definition}));
        return;
    }
    const DecodeDatabase database({definition});

    RawCanFrame frame;
    frame.canId = definition.canId;
    frame.data = test.data;
    const DecodedFrameValue result = DbcDecoder().Decode(database, frame);
    QVERIFY2(result.valid, test.name);
    QCOMPARE(result.definition.get(), &database.GetFrames()[0]);
    QCOMPARE(result.signals.size(), std::size_t(1U));
    const DecodedSignalValue &decoded = result.signals[0];
    QCOMPARE(decoded.definition.get(), &database.GetFrames()[0].signals[0]);
    QCOMPARE(decoded.valid, test.valid);
    if (!test.valid)
        return;

    if (test.valueType == ValueType::Signed) {
        const std::int64_t *raw = std::get_if<std::int64_t>(&decoded.rawValue);
        QVERIFY(raw != nullptr);
        QCOMPARE(*raw, test.rawValue);
    } else {
        const std::uint64_t *raw = std::get_if<std::uint64_t>(&decoded.rawValue);
        QVERIFY(raw != nullptr);
        QCOMPARE(*raw, static_cast<std::uint64_t>(test.rawValue));
    }
    QCOMPARE(decoded.physicalValue, test.physicalValue);
}

void DbcDecoderTest::boundaries() {
    for (ByteOrder order: {ByteOrder::Intel, ByteOrder::Motorola}) {
        for (ValueType type: {ValueType::Unsigned, ValueType::Signed}) {
            for (std::uint64_t bits: {std::uint64_t(0U), std::uint64_t(0x7FFFFFFFFFFFFFFFULL),
                                      std::uint64_t(0x8000000000000000ULL),
                                      std::uint64_t(0x8000000000000001ULL),
                                      std::uint64_t(0xFFFFFFFFFFFFFFFFULL)}) {
                DecodeFrame definition;
                definition.dlc = 8U;
                DecodeSignal signal;
                signal.startBit = order == ByteOrder::Intel ? 0U : 7U;
                signal.length = 64U;
                signal.byteOrder = order;
                signal.valueType = type;
                signal.factor = 0.5;
                signal.offset = 10.0;
                definition.signals.push_back(signal);
                const DecodeDatabase database({definition});
                RawCanFrame frame;
                for (unsigned byte = 0U; byte < 8U; ++byte) {
                    const unsigned shift = (order == ByteOrder::Intel ? byte : 7U - byte) * 8U;
                    frame.data.push_back(static_cast<std::uint8_t>(bits >> shift));
                }
                const DecodedFrameValue result = DbcDecoder().Decode(database, frame);
                const std::int64_t signedExpected = bits <= 0x7FFFFFFFFFFFFFFFULL
                                                            ? static_cast<std::int64_t>(bits)
                                                            : std::numeric_limits<std::int64_t>::min() +
                                                                      static_cast<std::int64_t>(bits - 0x8000000000000000ULL);
                const DecodedSignalValue &decoded = result.signals.at(0U);
                const RawSignalValue expected = type == ValueType::Unsigned
                                              ? std::variant<std::int64_t, std::uint64_t>(bits)
                                              : std::variant<std::int64_t, std::uint64_t>(signedExpected);
                const double physical = (type == ValueType::Unsigned
                                                 ? static_cast<double>(bits)
                                                 : static_cast<double>(signedExpected)) *
                                                0.5 +
                                        10.0;
                std::ostringstream actualText;
                std::ostringstream expectedText;
                if (const std::int64_t *signedValue = std::get_if<std::int64_t>(&decoded.rawValue))
                    actualText << *signedValue;
                else
                    actualText << std::get<std::uint64_t>(decoded.rawValue);
                if (type == ValueType::Unsigned)
                    expectedText << bits;
                else
                    expectedText << signedExpected;
                QVERIFY(decoded.valid);
                QVERIFY(decoded.rawValue == expected);
                QCOMPARE(decoded.physicalValue, physical);
                QCOMPARE(actualText.str(), expectedText.str());
            }
        }
    }
}

void DbcDecoderTest::payloadPolicy_data() {
    QTest::addColumn<unsigned>("bytes");
    QTest::addColumn<FrameDecodeStatus>("status");
    QTest::newRow("empty") << 0U << FrameDecodeStatus::InsufficientPayload;
    QTest::newRow("partial") << 1U << FrameDecodeStatus::InsufficientPayload;
    QTest::newRow("short-with-all-signals") << 2U << FrameDecodeStatus::InsufficientPayload;
    QTest::newRow("exact") << 3U << FrameDecodeStatus::Valid;
    QTest::newRow("long") << 4U << FrameDecodeStatus::Valid;
}

void DbcDecoderTest::payloadPolicy() {
    QFETCH(unsigned, bytes);
    QFETCH(FrameDecodeStatus, status);
    for (ByteOrder order: {ByteOrder::Intel, ByteOrder::Motorola}) {
        DecodeFrame definition;
        definition.canId = 17U;
        definition.dlc = 3U;
        DecodeSignal signal;
        signal.name = "First";
        signal.length = 8U;
        signal.byteOrder = order;
        signal.startBit = order == ByteOrder::Intel ? 0U : 7U;
        definition.signals.push_back(signal);
        signal.name = "Second";
        signal.startBit += 8U;
        definition.signals.push_back(signal);
        const DecodeDatabase database({definition});
        RawCanFrame raw;
        raw.canId = 17U;
        raw.data.assign(bytes, 42U);
        const DecodedFrameValue result = DbcDecoder().Decode(database, raw);
        QVERIFY(result.valid);
        QCOMPARE(result.status, status);
        QCOMPARE(result.signals.size(), std::size_t(2U));
        for (std::size_t index = 0U; index < result.signals.size(); ++index) {
            const DecodedSignalValue &value = result.signals[index];
            QCOMPARE(value.status, bytes > index ? SignalDecodeStatus::Valid : SignalDecodeStatus::InsufficientPayload);
            QCOMPARE(value.valid, bytes > index);
            if (value.valid) {
                QCOMPARE(std::get<std::uint64_t>(value.rawValue), std::uint64_t(42U));
                QCOMPARE(value.physicalValue, 42.0);
            }
        }
        raw.isExtended = true;
        const DecodedFrameValue unknown = DbcDecoder().Decode(database, raw);
        QVERIFY(!unknown.valid && !unknown.definition && unknown.signals.empty());
        QCOMPARE(unknown.status, FrameDecodeStatus::UnknownFrame);
        QVERIFY(unknown.key == FrameKey(17U, true));
        QCOMPARE(DbcDecoder().Decode(DecodeDatabase(), raw).status, FrameDecodeStatus::UnknownFrame);

        definition.signals.clear();
        raw.isExtended = false;
        const DecodedFrameValue empty = DbcDecoder().Decode(DecodeDatabase({definition}), raw);
        QVERIFY(empty.valid && empty.signals.empty());
        QCOMPARE(empty.status, status);
    }
}

void DbcDecoderTest::invalidDefinitions_data() {
    QTest::addColumn<int>("kind");
    QTest::newRow("zero-length") << 0;
    QTest::newRow("65-bits") << 1;
    QTest::newRow("outside-dlc") << 2;
    QTest::newRow("start-overflow") << 3;
    QTest::newRow("invalid-byte-order") << 4;
    QTest::newRow("invalid-value-type") << 5;
    QTest::newRow("invalid-multiplex-role") << 6;
    QTest::newRow("missing-selector") << 7;
}

void DbcDecoderTest::invalidDefinitions() {
    QFETCH(int, kind);
    for (ByteOrder order: {ByteOrder::Intel, ByteOrder::Motorola}) {
        DecodeFrame definition;
        definition.dlc = 1U;
        DecodeSignal good;
        good.name = "Good";
        good.length = 4U;
        good.byteOrder = order;
        good.startBit = order == ByteOrder::Intel ? 0U : 7U;
        DecodeSignal bad = good;
        bad.name = "Bad";
        switch (kind) {
        case 0: bad.length = 0U; break;
        case 1: bad.length = 65U; break;
        case 2: bad.startBit += 8U; break;
        case 3: bad.startBit = std::numeric_limits<std::uint32_t>::max(); break;
        case 4: bad.byteOrder = static_cast<ByteOrder>(99); break;
        case 5: bad.valueType = static_cast<ValueType>(99); break;
        case 6: bad.multiplexing.role = static_cast<MultiplexRole>(99); break;
        case 7: bad.multiplexing.role = MultiplexRole::Branch; break;
        }
        definition.signals = {bad, good};
        QVERIFY_THROWS_EXCEPTION(std::invalid_argument, (void) DecodeDatabase({definition}));
    }
}

void DbcDecoderTest::physicalConversion_data() {
    QTest::addColumn<double>("factor");
    QTest::addColumn<double>("offset");
    QTest::addColumn<bool>("finite");
    const double infinity = std::numeric_limits<double>::infinity();
    const double nan = std::numeric_limits<double>::quiet_NaN();
    const double maximum = std::numeric_limits<double>::max();
    QTest::newRow("nan-factor") << nan << 0.0 << false;
    QTest::newRow("nan-offset") << 1.0 << nan << false;
    QTest::newRow("infinite-factor") << infinity << 0.0 << false;
    QTest::newRow("negative-infinite-factor") << -infinity << 0.0 << false;
    QTest::newRow("infinite-offset") << 1.0 << infinity << false;
    QTest::newRow("negative-infinite-offset") << 1.0 << -infinity << false;
    QTest::newRow("multiply-overflow") << maximum << 0.0 << false;
    QTest::newRow("add-overflow") << maximum / 2.0 << maximum << false;
    QTest::newRow("finite-limit") << maximum / 2.0 << 0.0 << true;
    QTest::newRow("zero-factor") << 0.0 << 42.0 << true;
}

void DbcDecoderTest::physicalConversion() {
    QFETCH(double, factor);
    QFETCH(double, offset);
    QFETCH(bool, finite);
    for (ValueType type: {ValueType::Signed, ValueType::Unsigned}) {
        DecodeFrame definition;
        definition.dlc = 1U;
        DecodeSignal signal;
        signal.name = "Scaled";
        signal.length = 4U;
        signal.valueType = type;
        signal.factor = factor;
        signal.offset = offset;
        signal.valueDescriptions.emplace(std::uint64_t(2U), "Two");
        definition.signals.push_back(signal);
        signal.name = "Good";
        signal.startBit = 4U;
        signal.factor = 1.0;
        signal.offset = 0.0;
        definition.signals.push_back(signal);
        RawCanFrame raw;
        raw.data = {0x32U};
        if (!std::isfinite(factor) || !std::isfinite(offset)) {
            QVERIFY_THROWS_EXCEPTION(std::invalid_argument, (void) DecodeDatabase({definition}));
            continue;
        }
        const DecodedFrameValue result = DbcDecoder().Decode(DecodeDatabase({definition}), raw);
        QVERIFY(result.valid);
        QCOMPARE(result.status, finite ? FrameDecodeStatus::Valid : FrameDecodeStatus::SignalErrors);
        const DecodedSignalValue &scaled = result.signals[0];
        QCOMPARE(scaled.valid, finite);
        QCOMPARE(scaled.status, finite ? SignalDecodeStatus::Valid : SignalDecodeStatus::PhysicalConversionFailed);
        QCOMPARE(std::isfinite(scaled.physicalValue), finite);
        if (type == ValueType::Signed)
            QCOMPARE(std::get<std::int64_t>(scaled.rawValue), std::int64_t(2));
        else
            QCOMPARE(std::get<std::uint64_t>(scaled.rawValue), std::uint64_t(2));
        QVERIFY(result.signals[1].valid);
        QCOMPARE(result.signals[1].physicalValue, 3.0);
        if (finite) {
            QVERIFY(scaled.GetValueDescription());
            QCOMPARE(*scaled.GetValueDescription(), std::string("Two"));
        } else {
            QVERIFY(!scaled.GetValueDescription());
        }
    }
}

void DbcDecoderTest::selectorConversionFailure() {
    DecodeFrame definition;
    definition.dlc = 1U;
    DecodeSignal selector;
    selector.name = "Selector";
    selector.length = 2U;
    selector.multiplexing.role = MultiplexRole::Selector;
    selector.factor = std::numeric_limits<double>::max();
    DecodeSignal branch;
    branch.name = "Branch";
    branch.startBit = 2U;
    branch.length = 6U;
    branch.multiplexing.role = MultiplexRole::Branch;
    branch.multiplexing.value = 2U;
    definition.signals = {branch, selector};
    RawCanFrame raw;
    raw.data = {170U};
    const DecodedFrameValue result = DbcDecoder().Decode(DecodeDatabase({definition}), raw);
    QCOMPARE(result.status, FrameDecodeStatus::SignalErrors);
    QVERIFY(result.signals[0].valid);
    QCOMPARE(result.signals[0].physicalValue, 42.0);
    QCOMPARE(result.signals[1].status, SignalDecodeStatus::PhysicalConversionFailed);
    QCOMPARE(std::get<std::uint64_t>(result.signals[1].rawValue), std::uint64_t(2U));
    raw.data = {168U};
    selector.factor = 1.0;
    definition.signals = {branch, selector};
    const DecodedFrameValue inactive = DbcDecoder().Decode(DecodeDatabase({definition}), raw);
    QCOMPARE(inactive.status, FrameDecodeStatus::Valid);
    QCOMPARE(inactive.signals[0].status, SignalDecodeStatus::Inactive);
}

void DbcDecoderTest::zeroDlc() {
    DecodeFrame definition;
    RawCanFrame raw;
    for (const std::vector<std::uint8_t> &data: {std::vector<std::uint8_t>(), std::vector<std::uint8_t>{42U}}) {
        raw.data = data;
        const DecodedFrameValue result = DbcDecoder().Decode(DecodeDatabase({definition}), raw);
        QVERIFY(result.valid && result.signals.empty());
        QCOMPARE(result.status, FrameDecodeStatus::Valid);
    }
    DecodeSignal signal;
    signal.length = 8U;
    definition.signals.push_back(signal);
    QVERIFY_THROWS_EXCEPTION(std::invalid_argument, (void) DecodeDatabase({definition}));
}

int RunDecoderTests(int argc, char **argv) {
    DbcDecoderTest tests;
    return QTest::qExec(&tests, argc, argv);
}

#include "dbc_decoder_test.moc"