#include <doctest/doctest.h>

#include "fgc/Logger.h"

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

using namespace fgc;

namespace {

// Run a callable with std::cout redirected to a buffer; return what was written.
template <typename F>
std::string captureCout(F&& f) {
    std::ostringstream oss;
    std::streambuf* old = std::cout.rdbuf(oss.rdbuf());
    f();
    std::cout.rdbuf(old);
    return oss.str();
}

unsigned bits(LogCat c) { return static_cast<unsigned>(c); }

}  // namespace

TEST_CASE("parseCategories maps names, all/none, and flags unknown tokens") {
    bool ok = true;

    CHECK(Logger::parseCategories("serial,mqtt", &ok) == (bits(LogCat::Serial) | bits(LogCat::Mqtt)));
    CHECK(ok);

    CHECK(Logger::parseCategories("all", &ok) == bits(LogCat::All));
    CHECK(ok);

    CHECK(Logger::parseCategories("none", &ok) == 0u);
    CHECK(ok);
    CHECK(Logger::parseCategories("", &ok) == 0u);
    CHECK(ok);

    // Case- and whitespace-insensitive.
    CHECK(Logger::parseCategories("  SeRiAl , Camera ", &ok)
          == (bits(LogCat::Serial) | bits(LogCat::Camera)));
    CHECK(ok);

    // Unknown token: ok=false, but recognized tokens still apply.
    ok = true;
    CHECK(Logger::parseCategories("serial,bogus", &ok) == bits(LogCat::Serial));
    CHECK_FALSE(ok);
}

TEST_CASE("catFromString round-trips and flags unknown") {
    bool ok = true;
    CHECK(Logger::catFromString("control", &ok) == LogCat::Control);
    CHECK(ok);
    CHECK(Logger::catFromString("nope", &ok) == LogCat::None);
    CHECK_FALSE(ok);
}

TEST_CASE("category enable/disable/set round-trip") {
    Logger::setCategories(0);
    CHECK(Logger::categories() == 0u);
    CHECK_FALSE(Logger::categoryEnabled(LogCat::Serial));

    Logger::enableCategory(LogCat::Serial);
    Logger::enableCategory(LogCat::Mqtt);
    CHECK(Logger::categoryEnabled(LogCat::Serial));
    CHECK(Logger::categoryEnabled(LogCat::Mqtt));
    CHECK_FALSE(Logger::categoryEnabled(LogCat::Camera));

    Logger::disableCategory(LogCat::Serial);
    CHECK_FALSE(Logger::categoryEnabled(LogCat::Serial));
    CHECK(Logger::categoryEnabled(LogCat::Mqtt));

    Logger::setCategories(bits(LogCat::All));
    CHECK(Logger::categoryEnabled(LogCat::Camera));
    CHECK(Logger::categoryEnabled(LogCat::Control));

    Logger::setCategories(0);  // leave global state clean for other tests
}

TEST_CASE("LOG_TRACE_CAT gating is independent of the linear level") {
    Logger::setCategories(0);

    SUBCASE("suppressed when category off (even at trace level)") {
        Logger::setLevel(LogLevel::Trace);
        std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Serial) << "TX kd180"; });
        CHECK(out.empty());
    }

    SUBCASE("emitted with [SERIAL] tag when category on, at default info level") {
        Logger::setLevel(LogLevel::Info);  // NOT trace
        Logger::enableCategory(LogCat::Serial);
        std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Serial) << "TX kd180"; });
        CHECK(out.find("[SERIAL]") != std::string::npos);
        CHECK(out.find("TX kd180") != std::string::npos);
    }

    SUBCASE("a different category stays silent") {
        Logger::setLevel(LogLevel::Info);
        Logger::enableCategory(LogCat::Serial);  // serial on, mqtt off
        std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Mqtt) << "PUB t p"; });
        CHECK(out.empty());
    }

    SUBCASE("level Off silences categories too") {
        Logger::setLevel(LogLevel::Off);
        Logger::enableCategory(LogCat::Serial);
        std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Serial) << "TX x"; });
        CHECK(out.empty());
    }

    // Restore defaults so test ordering can't leak state.
    Logger::setCategories(0);
    Logger::setLevel(LogLevel::Info);
}

// --- the file sink: a second, independent destination ----------------------

namespace {
// Logger state is process-global and doctest runs every case in one process, so
// a case that leaks a file sink makes LATER cases write into a deleted temp dir.
// Restoring at the end of the body is not enough: a failed REQUIRE skips it.
struct LoggerStateGuard {
    fgc::LogLevel console = fgc::Logger::level();
    fgc::LogLevel file    = fgc::Logger::fileLevel();
    unsigned      cats    = fgc::Logger::categories();
    ~LoggerStateGuard() {
        fgc::Logger::setFileSink({});
        fgc::Logger::setLevel(console);
        fgc::Logger::setFileLevel(file);
        fgc::Logger::setCategories(cats);
    }
};

// Collects what the file sink is handed.
struct Captured {
    std::vector<std::string> lines;
    std::vector<fgc::LogCat> cats;
    bool has(const std::string& needle) const {
        for (const auto& l : lines)
            if (l.find(needle) != std::string::npos) return true;
        return false;
    }
};
}  // namespace

TEST_CASE("the file is more verbose than the console, independently") {
    LoggerStateGuard guard;
    Captured cap;
    Logger::setFileSink([&](LogLevel, LogCat c, const std::string& l) {
        cap.lines.push_back(l);
        cap.cats.push_back(c);
    });
    Logger::setLevel(LogLevel::Info);       // console
    Logger::setFileLevel(LogLevel::Debug);  // file

    // The macros must gate on the MORE verbose of the two, or the debug line
    // would never be built at all.
    CHECK(Logger::effectiveLevel() == LogLevel::Debug);
    CHECK(Logger::enabled(LogLevel::Debug));

    const std::string out = captureCout([] {
        LOG_DEBUG << "detail-for-file";
        LOG_INFO  << "for-both";
    });

    CHECK(cap.has("detail-for-file"));            // file got it
    CHECK(out.find("detail-for-file") == std::string::npos);  // console did not
    CHECK(cap.has("for-both"));
    CHECK(out.find("for-both") != std::string::npos);
}

TEST_CASE("a wire trace reaches the file even though its level is below the threshold") {
    // The regression this design is most likely to introduce. A category line
    // carries level == Trace; filtering it against file_level (debug) would drop
    // every wire trace silently, and `--trace serial` would write nothing.
    LoggerStateGuard guard;
    Captured cap;
    Logger::setFileSink([&](LogLevel, LogCat c, const std::string& l) {
        cap.lines.push_back(l);
        cap.cats.push_back(c);
    });
    Logger::setLevel(LogLevel::Info);
    Logger::setFileLevel(LogLevel::Debug);

    SUBCASE("category off: nowhere") {
        Logger::setCategories(0);
        const std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Serial) << "TX ping"; });
        CHECK_FALSE(cap.has("TX ping"));
        CHECK(out.find("TX ping") == std::string::npos);
    }
    SUBCASE("category on: both, and the file is told which category") {
        Logger::setCategories(static_cast<unsigned>(LogCat::Serial));
        const std::string out = captureCout([] { LOG_TRACE_CAT(LogCat::Serial) << "TX ping"; });
        CHECK(cap.has("TX ping"));
        CHECK(cap.has("[SERIAL]"));
        CHECK(out.find("TX ping") != std::string::npos);
        REQUIRE_FALSE(cap.cats.empty());
        CHECK(cap.cats.front() == LogCat::Serial);
    }
}

TEST_CASE("the console can be silenced without silencing the file") {
    // `--log-level off` now means the CONSOLE is off. A tower quietened on
    // screen must still be writing its record.
    LoggerStateGuard guard;
    Captured cap;
    Logger::setFileSink([&](LogLevel, LogCat, const std::string& l) { cap.lines.push_back(l); });
    Logger::setLevel(LogLevel::Off);
    Logger::setFileLevel(LogLevel::Info);

    const std::string out = captureCout([] { LOG_ERROR << "still-recorded"; });
    CHECK(cap.has("still-recorded"));
    CHECK(out.find("still-recorded") == std::string::npos);
}

TEST_CASE("with no file sink the logger behaves exactly as before") {
    LoggerStateGuard guard;
    Logger::setFileSink({});
    Logger::setFileLevel(LogLevel::Off);
    Logger::setLevel(LogLevel::Info);

    // Off is the identity for the min(), so the gate is bit-identical to the
    // pre-change behaviour.
    CHECK(Logger::effectiveLevel() == LogLevel::Info);
    CHECK_FALSE(Logger::enabled(LogLevel::Debug));
    CHECK(Logger::enabled(LogLevel::Info));

    const std::string out = captureCout([] { LOG_INFO << "unchanged"; });
    CHECK(out.find("unchanged") != std::string::npos);
}

TEST_CASE("setFileLevelFromString accepts the same words as the console one") {
    LoggerStateGuard guard;
    CHECK(Logger::setFileLevelFromString("debug"));
    CHECK(Logger::fileLevel() == LogLevel::Debug);
    CHECK(Logger::setFileLevelFromString("WARNING"));
    CHECK(Logger::fileLevel() == LogLevel::Warn);
    CHECK(Logger::setFileLevelFromString("off"));
    CHECK(Logger::fileLevel() == LogLevel::Off);
    // A bad word leaves it untouched rather than guessing.
    CHECK_FALSE(Logger::setFileLevelFromString("loud"));
    CHECK(Logger::fileLevel() == LogLevel::Off);
}