//              Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
//   (See accompanying file LICENSE_1_0.txt or copy at
//        https://www.boost.org/LICENSE_1_0.txt)

// SPDX-License-Identifier: BSL-1.0

#include <catch2/catch_tag_alias_autoregistrar.hpp>
#include <catch2/reporters/catch_reporter_event_listener.hpp>
#include <catch2/internal/catch_enforce.hpp>
#include <catch2/catch_test_case_info.hpp>
#include <catch2/reporters/catch_reporter_registrars.hpp>


// Some example tag aliases
CATCH_REGISTER_TAG_ALIAS("[@nhf]", "[failing]~[.]")
CATCH_REGISTER_TAG_ALIAS("[@tricky]", "[tricky]~[.]")

#ifdef __clang__
#   pragma clang diagnostic ignored "-Wpadded"
#   pragma clang diagnostic ignored "-Wweak-vtables"
#   pragma clang diagnostic ignored "-Wc++98-compat"
#endif

/**
 * Event listener that internally counts and validates received events.
 *
 * Currently only performs validation by counting received events, rather
 * than performing full matching. This means that it won't fail if the *Ended
 * events are provided in wrong order, as long as they come in the right amount
 * and with the right nesting.
 */
class ValidatingTestListener : public Catch::EventListenerBase {
    struct EventCounter {
        int starting = 0;
        int ended = 0;

        bool hasActiveEvent() const {
            return starting > ended;
        }
        bool hasSingleActiveEvent() const {
            return starting - 1 == ended;
        }
        bool allEventsEnded() const {
            return starting == ended;
        }
    };

public:
    static std::string getDescription() {
        return "Validates ordering of Catch2's listener events";
    }

    ValidatingTestListener(Catch::IConfig const* config) :
        EventListenerBase(config) {
        m_preferences.shouldReportAllAssertions = true;
    }

    void testRunStarting( Catch::TestRunInfo const& ) override {
        CATCH_ENFORCE( m_testRunCounter.starting == 0,
                       "Test run can only start once" );
        ++m_testRunCounter.starting;
    }
    void testCaseStarting(Catch::TestCaseInfo const&) override {
        CATCH_ENFORCE( m_testRunCounter.hasActiveEvent(),
                       "Test case can only be started if the test run has already started" );
        CATCH_ENFORCE( m_testCaseCounter.allEventsEnded(),
                       "Test case cannot start if there is an unfinished one" );

        ++m_testCaseCounter.starting;

        // Reset the part tracking for partial test case events
        m_lastSeenPartNumber = uint64_t(-1);
    }

    void testCasePartialStarting(Catch::TestCaseInfo const&,
                                 uint64_t partNumber) override {
        CATCH_ENFORCE( m_testCaseCounter.hasSingleActiveEvent(),
                       "Test case can only be partially started if the test case has fully started already" );
        CATCH_ENFORCE( m_lastSeenPartNumber + 1 == partNumber,
                       "Partial test case started out of order" );

        ++m_testCasePartialCounter.starting;
        m_lastSeenPartNumber = partNumber;
    }

    void sectionStarting(Catch::SectionInfo const&) override {
        CATCH_ENFORCE( m_testCaseCounter.hasSingleActiveEvent(),
                       "Section can only start in a test case" );
        CATCH_ENFORCE( m_testCasePartialCounter.hasSingleActiveEvent(),
                       "Section can only start in a test case" );

        ++m_sectionCounter.starting;
    }

    void assertionStarting(Catch::AssertionInfo const&) override {
        CATCH_ENFORCE( m_testCaseCounter.hasSingleActiveEvent(),
                       "Assertion can only start if test case is started" );

        ++m_assertionCounter.starting;
    }
    void assertionEnded(Catch::AssertionStats const&) override {
        // todo:
        //  * Check that assertions are balanced
        //  * Check that assertions has started
        ++m_assertionCounter.ended;
    }

    void sectionEnded(Catch::SectionStats const&) override {
        CATCH_ENFORCE( m_sectionCounter.hasActiveEvent(),
                       "Section ended without corresponding start" );
        // TODO: Check that all assertions ended

        ++m_sectionCounter.ended;
    }


    void testCasePartialEnded(Catch::TestCaseStats const&,
                              uint64_t partNumber) override {
        CATCH_ENFORCE( m_lastSeenPartNumber == partNumber,
                       "Partial test case ended out of order" );
        CATCH_ENFORCE( m_testCasePartialCounter.hasSingleActiveEvent(),
                       "Partial test case ended without corresponding start" );
        CATCH_ENFORCE( m_sectionCounter.allEventsEnded(),
                       "Partial test case ended with unbalanced sections" );
        // TODO: Check that all assertions ended

        ++m_testCasePartialCounter.ended;
    }


    void testCaseEnded(Catch::TestCaseStats const&) override {
        CATCH_ENFORCE( m_testCaseCounter.hasSingleActiveEvent(),
                       "Test case end is not matched with test case start" );
        CATCH_ENFORCE( m_testCasePartialCounter.allEventsEnded(),
                       "A partial test case has not ended" );
        CATCH_ENFORCE( m_sectionCounter.allEventsEnded(),
                       "Test case ended with unbalanced sections" );

        // TODO: Check that all assertions ended

        ++m_testCaseCounter.ended;
    }
    void testRunEnded( Catch::TestRunStats const& ) override {
        CATCH_ENFORCE( m_testRunCounter.hasSingleActiveEvent(),
                       "Test run end is not matched with test run start" );
        CATCH_ENFORCE( m_testRunCounter.ended == 0,
                       "Test run can only end once" );

        ++m_testRunCounter.ended;
    }

    ~ValidatingTestListener() override;

private:
    EventCounter m_testRunCounter;
    EventCounter m_testCaseCounter;
    EventCounter m_testCasePartialCounter;
    uint64_t m_lastSeenPartNumber = 0;
    EventCounter m_sectionCounter;
    EventCounter m_assertionCounter;
};


ValidatingTestListener::~ValidatingTestListener() {
    // Throwing from noexcept destructor terminates, but we don't mind
    // because this is test-only check and we don't need to try and recover
    // from assumption violation here.

    CATCH_ENFORCE( m_testRunCounter.ended < 2,
                   "Test run should be started at most once" );
    CATCH_ENFORCE( m_testRunCounter.allEventsEnded(),
                   "The test run has not finished" );
    CATCH_ENFORCE( m_testCaseCounter.allEventsEnded(),
                   "A test case did not finish" );

    // TODO: other counters being balanced?
}

CATCH_REGISTER_LISTENER( ValidatingTestListener )