#include <bits/types/struct_timeval.h>
#include <cstdlib>
#include <ctime>
#include <fstream>
#include <iostream>
using namespace std;

struct input_event {
    timeval         time;
    unsigned short  type;
    unsigned short  code;
    unsigned int    value;
};

enum button_code {
    BTN_LEFT            = 272,
    BTN_TOUCH           = 330,
    BTN_TOOL_FINGER     = 325,
    BTN_TOOL_DOUBLETAP  = 333,
    BTN_TOOL_TRIPLETAP  = 334,
    BTN_TOOL_QUADTAP    = 335,
    BTN_TOOL_QUINTTAP   = 328,
};

float operator-(timeval a, timeval b) {
    return 0;
}

void adjustVolume (float diff) {
    char cmd[45];
    if (diff >= 0)
        sprintf(cmd, "pactl set-sink-volume @DEFAULT_SINK@ +%d%%", abs((int) diff));
    else
        sprintf(cmd, "pactl set-sink-volume @DEFAULT_SINK@ -%d%%", abs((int) diff));
    system(cmd);
}

void adjustBrightness (float diff) {
    char cmd[45];
    if (diff > 0)
        sprintf(cmd, "brightnessctl set +%d > /dev/null", (int) diff);
    else
        sprintf(cmd, "brightnessctl set %d- -n 1 > /dev/null", (int) diff * -1);
    system(cmd);
}

void adjust(int y, bool side) {
    if (y == 0) return;
    if (side)
        adjustBrightness (y*8);
    else
        adjustVolume     ((float)y/8);
}

int main(int argc, char** argv) {
    ifstream        device (
        "/dev/input/by-path/pci-0000:00:15.0-platform-i2c_designware.0-event-mouse",
        ios_base::binary
    );
    input_event     event;
    button_code     button;
    bool            down;
    time_t          tv_sec  = 0;
    long int        tv_usec = 0;
    int             y_value = 0;
    int             y_diff;
    bool            side;        // False is left, true is right

    while (device.read(reinterpret_cast<char*>(&event), sizeof(input_event))) {
        if (event.type == 1) {
            if (event.code == button_code::BTN_TOUCH)
                down = false;
            button = (button_code) event.code;
        }
        if (button == button_code::BTN_TOOL_FINGER) {
            if (event.type == 0 &&
                event.code == 0 &&
                event.time.tv_sec - tv_sec
                + (float)(event.time.tv_usec - tv_usec)/1000000 > 0.03
            ) {
                tv_sec  = event.time.tv_sec;
                tv_usec = event.time.tv_usec;
                if (down) {
                    adjust(y_diff, side);
                }
                y_diff = 0;
                down = true;
            }

            if (event.type == 3) {
                if (event.code == 0) {
                    side = (event.value > 1682); // Trackpad resolution is 3364x1669
                }
                if (event.code == 1) {
                    y_diff += y_value - event.value;
                    y_value = event.value;
                }
            }
        }
    }
}