#include "dbc_parser.h"
#include "dbc_statement_handler.h"

#include <chrono>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <stdexcept>

struct Fixture {
    std::filesystem::path path = std::filesystem::temp_directory_path() /
                                 ("dbc_parser_test_" + std::to_string(std::chrono::steady_clock::now().time_since_epoch().count()) + ".dbc");
    ~Fixture() {
        std::error_code error;
        std::filesystem::remove(path, error);
    }
    void Write(const std::string &text) const {
        std::ofstream output(path);
        output << text;
        if (!output)
            throw std::runtime_error("Cannot write test fixture.");
    }
};

class CountingHandler : public DbcStatementHandler {
public:
    inline static int instances = 0;
    inline static int calls = 0;
    CountingHandler() { ++instances; }
    void Handle(const std::string &, DbcParseContext &context) const override {
        ++calls;
        context.database.frames.emplace_back();
    }
};

int main() {
    Fixture fixture;
    int failures = 0;
    std::size_t count = 0U;
    const auto check = [&](bool passed, const std::string &name) {
        ++count;
        if (!passed) {
            ++failures;
            std::cerr << "FAIL: " << name << '\n';
        }
    };
    struct ValidCase {
        const char *line;
        std::uint32_t id;
        bool extended;
        unsigned length;
    };
    const ValidCase valid[] = {
            {"BO_ 0 Frame: 0 ECU", 0U, false, 0U},
            {"BO_ 2047 Frame: 8 ECU", 2047U, false, 8U},
            {"BO_ 2048 Frame: 64 ECU", 2048U, true, 64U},
            {"BO_ 536870911 Frame: 255 ECU", 0x1FFFFFFFU, true, 255U},
            {"BO_ 2147483649 Frame: 8 ECU", 1U, true, 8U},
            {"BO_ 2684354559 Frame: 8 ECU", 0x1FFFFFFFU, true, 8U},
            {"  BO_\t256\tFrame :\t8\tECU  \r", 256U, false, 8U}};
    for (const auto &test: valid) {
        fixture.Write(std::string(test.line) + '\n');
        try {
            const auto database = DbcParser().ParseFile(fixture.path.string());
            check(database.frames.size() == 1U && database.frames[0].name == "Frame" &&
                          database.frames[0].canId == test.id &&
                          database.frames[0].isExtended == test.extended &&
                          database.frames[0].dlc == test.length &&
                          database.frames[0].transmitter == "ECU",
                  test.line);
        } catch (const std::exception &error) { check(false, error.what()); }
    }
    const char *invalid[] = {
            "BO_ invalid", "BO_", "BO_ 1", "BO_ 1 : 8 ECU", "BO_ 1 Frame 8 ECU",
            "BO_ 1 Frame:", "BO_ 1 Frame: 8", "BO_ 1 Frame: 8 ECU extra",
            "BO_ 1 Two Names: 8 ECU", "BO_ -1 Frame: 8 ECU", "BO_ +1 Frame: 8 ECU",
            "BO_ 1x Frame: 8 ECU", "BO_ 0x123 Frame: 8 ECU", "BO_ 1.5 Frame: 8 ECU",
            "BO_ 4294967296 Frame: 8 ECU", "BO_ 999999999999999999999 Frame: 8 ECU",
            "BO_ 536870912 Frame: 8 ECU", "BO_ 1073741824 Frame: 8 ECU",
            "BO_ 2684354560 Frame: 8 ECU", "BO_ 4294967295 Frame: 8 ECU",
            "BO_ 1 Frame: -1 ECU", "BO_ 1 Frame: +8 ECU", "BO_ 1 Frame: 8x ECU",
            "BO_ 1 Frame: 8.5 ECU", "BO_ 1 Frame: 256 ECU",
            "BO_ 1 Frame: 4294967296 ECU", "BO_\tinvalid"};
    for (const auto *line: invalid) {
        fixture.Write(std::string("VERSION \"test\"\n\n") + line + '\n');
        try {
            DbcParser().ParseFile(fixture.path.string());
            check(false, line);
        } catch (const std::runtime_error &error) {
            const std::string prefix = fixture.path.string() + ":3: ";
            check(std::string(error.what()).find(prefix) == 0U &&
                          std::string(error.what()).size() > prefix.size(),
                  line);
        }
    }
    fixture.Write(
            "BO_TX_BU_ 256 : ECU;\nBO_ 256 Frame: 8 ECU\n"
            " SG_ Speed : 0|16@1+ (0.5,1) [0|100] \"rpm\" ECU\n"
            "CM_ BO_ 256 \"Frame comment\";\nCM_ SG_ 256 Speed \"Signal comment\";\n"
            "BO_ 257 Second: 8 ECU\n");
    const auto database = DbcParser().ParseFile(fixture.path.string());
    check(database.frames.size() == 2U && database.frames[0].signals.size() == 1U &&
                  database.frames[0].comment == "Frame comment" &&
                  database.frames[0].signals[0].comment == "Signal comment",
          "Integration");
    fixture.Write("\nSG_ Speed : invalid\n");
    try {
        DbcParser().ParseFile(fixture.path.string());
        check(false, "Signal error location");
    } catch (const std::runtime_error &error) {
        check(std::string(error.what()).find(fixture.path.string() + ":2: ") == 0U,
              "Signal error location");
    }
    const DbcParser signalParser;
    const auto signalLine = [](const std::string &start, const std::string &length,
                               const std::string &order, const std::string &factor,
                               const std::string &offset, const std::string &minimum,
                               const std::string &maximum) {
        return "SG_ Value : " + start + "|" + length + "@" + order +
               " (" + factor + "," + offset + ") [" + minimum + "|" + maximum + "] \"\" ECU";
    };
    const auto rejectSignal = [&](const std::string &line, unsigned payload = 8U) {
        fixture.Write("BO_ 1 Frame: " + std::to_string(payload) + " ECU\n\n" + line + "\n");
        try {
            signalParser.ParseFile(fixture.path.string());
            check(false, "Reject " + line);
        } catch (const std::runtime_error &error) {
            const std::string prefix = fixture.path.string() + ":3: ";
            check(std::string(error.what()).find(prefix) == 0U &&
                          std::string(error.what()).size() > prefix.size(),
                  "Reject " + line);
        }
    };
    const std::string ordinary = signalLine("0", "8", "1+", "1", "0", "0", "255");
    for (const std::string value: {"-1", "+1", "0junk", "0x10", "1.5",
                                   "4294967296", "999999999999999999999"}) {
        rejectSignal(signalLine(value, "8", "1+", "1", "0", "0", "255"));
        rejectSignal(signalLine("0", value, "1+", "1", "0", "0", "255"));
    }
    for (const std::string length: {"0", "65"})
        rejectSignal(signalLine("0", length, "1+", "1", "0", "0", "255"));
    for (const std::string order: {"2+", "9-", "1", "1x", "1++", "01+"})
        rejectSignal(signalLine("0", "8", order, "1", "0", "0", "255"));
    for (const std::string value: {"1junk", "nan", "NaN", "inf", "-inf", "1e999", "1e-999", "0x1p2", "", "1e", "1.2.3"}) {
        rejectSignal(signalLine("0", "8", "1+", value, "0", "0", "255"));
        rejectSignal(signalLine("0", "8", "1+", "1", value, "0", "255"));
        rejectSignal(signalLine("0", "8", "1+", "1", "0", value, "255"));
        rejectSignal(signalLine("0", "8", "1+", "1", "0", "0", value));
    }
    rejectSignal(signalLine("0", "8", "1+", "1", "0", "2", "1"));
    for (const std::string name: {"", "Two Names", "Value M", "Value m1", "Value m1M"}) {
        std::string line = ordinary;
        line.replace(4U, 5U, name);
        rejectSignal(line);
    }
    for (const std::string broken: {
                 "SG_", "SG_ Value", "SG_ Value : 0|8@1+ (1,0) [0|255] ECU",
                 "SG_ Value : 0|8@1+ (1,0) [0|255] \"\"",
                 "SG_ Value : 0|8@1+ (1,0) [0|255] \"\" ECU,",
                 "SG_ Value : 0|8@1+ (1,0) [0|255] \"\" ECU extra"})
        rejectSignal(broken);
    rejectSignal(signalLine("64", "1", "1+", "1", "0", "0", "1"));
    rejectSignal(signalLine("63", "2", "1+", "1", "0", "0", "3"));
    rejectSignal(signalLine("56", "2", "0+", "1", "0", "0", "3"));
    rejectSignal(signalLine("4294967295", "64", "1+", "1", "0", "0", "1"));
    rejectSignal(ordinary, 0U);
    for (const char delimiter: {'|', '@', '(', ')', '[', ']', '"'}) {
        std::string line = ordinary;
        line.erase(line.find(delimiter), 1U);
        rejectSignal(line);
    }
    fixture.Write("BO_ 1 Frame: 8 ECU\n" +
                  signalLine("0", "8", "1+", "0", "0", "0", "0") + "\n" +
                  signalLine("8", "8", "1-", "-1", "0", "-255", "0") + "\n");
    const auto factors = signalParser.ParseFile(fixture.path.string());
    check(factors.frames[0].signals.size() == 2U &&
                  factors.frames[0].signals[0].factor == 0.0 &&
                  factors.frames[0].signals[1].factor == -1.0,
          "Zero and negative factors and equal range boundaries");

    struct SignalCase {
        const char *start;
        const char *length;
        const char *order;
        unsigned payload;
    };
    const SignalCase validSignals[] = {
            {"0", "1", "1+", 1U},
            {"7", "1", "0-", 1U},
            {"0", "64", "1+", 8U},
            {"7", "64", "0-", 8U},
            {"63", "1", "1+", 8U},
            {"56", "1", "0+", 8U},
            {"3", "12", "0+", 2U},
            {"2039", "1", "1+", 255U}};
    for (const auto &test: validSignals) {
        fixture.Write("BO_ 1 Frame: " + std::to_string(test.payload) + " ECU\n" +
                      signalLine(test.start, test.length, test.order, ".5e+1", "-2.5E-1", "-1.", "+2e2") + "\n");
        try {
            const auto parsed = signalParser.ParseFile(fixture.path.string());
            const auto &signal = parsed.frames.at(0).signals.at(0);
            check(signal.startBit == std::stoul(test.start) &&
                          signal.length == std::stoul(test.length) &&
                          signal.isLittleEndian == (test.order[0] == '1') &&
                          signal.isSigned == (test.order[1] == '-') &&
                          signal.factor == 5.0 && signal.offset == -0.25 &&
                          signal.minimum == -1.0 && signal.maximum == 200.0,
                  "Valid signal boundary and numeric metadata");
        } catch (const std::exception &error) { check(false, error.what()); }
    }
    fixture.Write("BO_ 1 Frame: 8 ECU\n"
                  "SG_\tValue\t:\t0 | 8 @1+ ( 1 , 0 ) [ 0 | 255 ] \"rpm\" ECU1,\tECU2\n");
    try {
        const auto parsed = signalParser.ParseFile(fixture.path.string());
        const auto &signal = parsed.frames.at(0).signals.at(0);
        check(signal.name == "Value" && signal.unit == "rpm" &&
                      signal.receivers == std::vector<std::string>({"ECU1", "ECU2"}),
              "Signal tabs, spaces, and receiver list");
    } catch (const std::exception &error) { check(false, error.what()); }
    DbcDatabase dispatchDatabase;
    DbcParseContext context{dispatchDatabase, nullptr};
    DbcStatementDispatcher dispatcher;
    dispatcher.RegisterType<CountingHandler>("TEST_");
    check(dispatcher.Dispatch("TEST_ first", context) &&
                  dispatcher.Dispatch("TEST_ second", context) &&
                  CountingHandler::instances == 1 && CountingHandler::calls == 2 &&
                  dispatchDatabase.frames.size() == 2U,
          "Factory dispatch and handler reuse");
    check(!dispatcher.Dispatch("TEST_OTHER data", context) &&
                  !dispatcher.Dispatch("BO_TX_BU_ 1 : ECU;", context) &&
                  !dispatcher.Dispatch("VAL_ 1 Speed 0 \"Stopped\";", context) &&
                  CountingHandler::calls == 2,
          "Exact and unknown keyword dispatch");
    const DbcParser parser;
    fixture.Write("BO_ 1 First: 8 ECU\n");
    check(parser.ParseFile(fixture.path.string()).frames.size() == 1U, "First parse");
    fixture.Write("SG_ Speed : invalid\n");
    try {
        parser.ParseFile(fixture.path.string());
        check(false, "Independent parse context");
    } catch (const std::runtime_error &error) {
        check(std::string(error.what()).find("Signal found before any frame") !=
                      std::string::npos,
              "Independent parse context");
    }
    fixture.Write("BO_ 2 Second: 8 ECU\n");
    const auto recovered = parser.ParseFile(fixture.path.string());
    check(recovered.frames.size() == 1U && recovered.frames[0].canId == 2U,
          "Fresh parse after error");
    if (failures != 0) return 1;
    std::cout << "All " << count << " parser cases passed.\n";
    return 0;
}