// Copyright (2019-2024) Paul Scherrer Institute

#include <catch2/catch.hpp>
#include "../receiver/LossyFilter.h"

TEST_CASE("LossyFilterDisabled","[LossyFilter]") {
    LossyFilter filter(false, 0.0);

    DataMessage message{
        .number = 123,
        .indexing_result = 0
    };

    filter.ApplyFilter(message);
    REQUIRE(message.number == 123);
    REQUIRE(message.indexing_result == 0);

    filter.ApplyFilter(message);
    REQUIRE(message.number == 123);
    REQUIRE(message.indexing_result == 0);

    filter.ApplyFilter(message);
    REQUIRE(message.number == 123);
    REQUIRE(message.indexing_result == 0);
}

TEST_CASE("LossyFilterEnable","[LossyFilter]") {
    LossyFilter filter(true, 0.0);

    DataMessage message_1{
            .number = 123,
            .indexing_result = 1
    };

    DataMessage message_2{
            .number = 124,
            .indexing_result = 0
    };

    filter.ApplyFilter(message_1);
    REQUIRE(message_1.number == 0);

    filter.ApplyFilter(message_2);
    REQUIRE(message_2.number == -1);

    filter.ApplyFilter(message_1);
    REQUIRE(message_1.number == 1);

    filter.ApplyFilter(message_1);
    REQUIRE(message_1.number == 2);
}

TEST_CASE("LossyFilterEnable_Prob","[LossyFilter]") {
    LossyFilter filter(true, 0.5);

    int64_t accepted = 0;
    int64_t count = 0;
    for (int i = 0; i < 1000000; i++) {
        DataMessage message{
                .number = 124,
                .indexing_result = 0
        };
        filter.ApplyFilter(message);
        count++;
        if (message.number < 0)
            accepted++;
    }
    double frac = static_cast<double>(accepted) / static_cast<double>(count);
    REQUIRE(frac < 0.51);
    REQUIRE(frac > 0.49);
}