#include <stdbool.h>
#include <am335x_gpio.h>
#include "wheel.h"

#define CHA_GPIO    AM335X_GPIO2
#define CHA_PIN     1
#define CHB_GPIO    AM335X_GPIO1
#define CHB_PIN     29

static struct listener{
    wheel_handler_t routine;
    void* param;
}  listener;

static void wheel_handler(void* param){
    (void)param;
    enum wheel_direction dir = WHEEL_RIGHT;
    bool cha = am335x_gpio_get_state(CHA_GPIO, CHA_PIN);
    bool chb = am335x_gpio_get_state(CHB_GPIO, CHB_PIN);
    if (cha == chb) dir = WHEEL_LEFT;
    if (listener.routine != 0){
        listener.routine(dir, listener.param);
    }
}

void wheel_init(){
    am335x_gpio_init(CHA_GPIO);
    am335x_gpio_init(CHB_GPIO);

    am335x_gpio_setup_pin(CHA_GPIO, CHA_PIN, AM335X_GPIO_PULL_NONE, true);
    am335x_gpio_setup_pin(CHB_GPIO, CHB_PIN, AM335X_GPIO_PULL_NONE, true);

    gpio_on_event(CHA_GPIO, CHA_PIN, GPIO_FALLING | GPIO_RISING | GPIO_DEBOUNCED, wheel_handler, 0);
}

int wheel_on_event(wheel_handler_t, routine, void* param){
    if (routine == 0){
        listener.routine = 0;
        listener.param = 0;
        return 0;
    }
    if (listener.routine == 0){
        listener.routine = routine;
        listener.param = param;
        return 0;
    }
    return -1;
}