#include "gtest/gtest.h"

#define FASTMOUSE_IMPL
#include "fastmouse.h"
#undef FASTMOUSE_IMPL

#include <cmath>

// Wrappers to avoid specifying params we do not use here.
static void input_emit() {
    fastmouse_input_emit(nullptr);
}
static void input_event(movement_type m, const int value) {
    input_event_fastmouse_log(nullptr, EV_REL, m, value);
}

class FastmouseTest : public ::testing::Test {
protected:
    void SetUp() override {
        static auto fp = fastmouse;
        static auto mp = movement;
        fastmouse = fp;
        movement = mp;
    }
};

TEST_F(FastmouseTest, test_noop) {
    EXPECT_EQ(movement.x, 0);
    EXPECT_EQ(movement.y, 0);
    
    input_event(REL_X, 1);
    input_event(REL_Y, 1);
    input_emit();

    EXPECT_EQ(movement.x, 1);
    EXPECT_EQ(movement.y, 1);
}

TEST_F(FastmouseTest, simple_division) {
    fastmouse.division = 2;
    input_event(REL_X, 1);
    input_emit();

    EXPECT_EQ(movement.x, 0);
    EXPECT_EQ(movement.y, 0);

    // 'Loss of 'precision' shows immediately here, it's not a big issue that the first
    // two dots do not emit an event, it only occurs again after the next INT_MAX dots.
    // All tests will exhibit this behaviour where the first division dots do not emit an event
    // as expected unless INT_MAX % division == 0.
    // We do not actually lose precision, it's just that we can only emit events in
    // discreet intervals.
    input_event(REL_X, 2);
    input_emit();

    EXPECT_EQ(movement.x, 1);
    EXPECT_EQ(movement.y, 0);
    
    input_event(REL_Y, 3);
    input_emit();
    EXPECT_EQ(movement.x, 1);
    EXPECT_EQ(movement.y, 1);
}

TEST_F(FastmouseTest, high_division) {
    fastmouse.division = 20;
    for (auto i = 0; i < 20; ++i) {
        input_event(REL_X, 1);
        input_emit();
        EXPECT_EQ(movement.x, 0);
        EXPECT_EQ(movement.y, 0);
    }
    input_event(REL_X, 1);
    input_emit();
    EXPECT_EQ(movement.x, 1);
}

TEST_F(FastmouseTest, different_axis_division) {
    fastmouse.division = 10;

    input_event(REL_X, 201);
    input_event(REL_Y, 51);
    input_emit();
    EXPECT_EQ(movement.x, 20);
    EXPECT_EQ(movement.y, 5);
}

TEST_F(FastmouseTest, simple_rotation) {
    // scripts/set_rotation.sh 45
    fastmouse.rise = 1518500249;
    fastmouse.run = 1518500249;

    input_event(REL_X, 10'000);
    input_emit();
    EXPECT_EQ(movement.x, 7071);
    EXPECT_EQ(movement.y, 7071);
    // It's important we do not add distance when calculating rotation!
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 9999);
}

TEST_F(FastmouseTest, simple_y_rotation) {
    // scripts/set_rotation.sh 45
    fastmouse.rise = 1518500249;
    fastmouse.run = 1518500249;

    input_event(REL_Y, 10'000);
    input_emit();
    EXPECT_EQ(movement.x, -7071);
    EXPECT_EQ(movement.y, 7071);
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 9999);
}

TEST_F(FastmouseTest, negative_rotation) {
    // scripts/set_rotation.sh -120
    fastmouse.rise = -1859775393;
    fastmouse.run = -1073741824;

    input_event(REL_X, 500);
    input_emit();
    EXPECT_EQ(movement.x, -250);
    EXPECT_EQ(movement.y, -433);
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 499);
}

TEST_F(FastmouseTest, inversion_rotation) {
    // scripts/set_rotation.sh 180
    fastmouse.rise = 0;
    fastmouse.run = -2147483648;

    input_event(REL_X, 500);
    input_emit();
    EXPECT_EQ(movement.x, -500);
    EXPECT_EQ(movement.y, 0);
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 500);
}

TEST_F(FastmouseTest, sideways_rotation) {
    // scripts/set_rotation.sh 90
    fastmouse.rise = 2147483647;
    fastmouse.run = 0;

    input_event(REL_X, 500);
    input_emit();
    EXPECT_EQ(movement.x, 0);
    EXPECT_EQ(movement.y, 500);
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 500);
}

TEST_F(FastmouseTest, rotation_with_division) {
    fastmouse.division = 10;
    // scripts/set_rotation.sh 10
    fastmouse.rise = 372906621;
    fastmouse.run = 2114858545;

    input_event(REL_X, 100'000);
    input_emit();
    EXPECT_EQ(movement.x, 9848);
    EXPECT_EQ(movement.y, 1736);
    EXPECT_EQ(static_cast<int>(std::sqrt(movement.x * movement.x + movement.y * movement.y)), 9999);
}