#include "memecoder.h"
#include "ch32v20x.h"


int memecoder_prev_state = 0;
int memecoder_count = 0;


void memecoder_init() {
    // Enable GPIOB
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    // Set up GPIO on port B
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;

    // PHASE_A - PB12
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // PHASE_A - PB13
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // PHASE_A - PB14
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void memecoder_update() {
	u8 cur_state =
			GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_12) << 0 |
			GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_13) << 1 |
			GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_14) << 2;

	if(cur_state != memecoder_prev_state) {
		if(		(memecoder_prev_state == 1 && cur_state == 3) ||
				(memecoder_prev_state == 3 && cur_state == 2) ||
				(memecoder_prev_state == 2 && cur_state == 6) ||
				(memecoder_prev_state == 6 && cur_state == 4) ||
				(memecoder_prev_state == 4 && cur_state == 5) ||
				(memecoder_prev_state == 5 && cur_state == 1)) {
			memecoder_count++;
		} else {
			memecoder_count--;
		}

		memecoder_prev_state = cur_state;
	}
}

void memecoder_set(int value) {
	memecoder_count = value;
}

int memecoder_get() {
	return memecoder_count;
}

void memecoder_zero() {
	memecoder_count = 0;
}