#include "circbuff.h"

void circbuff_init(circbuff_t *circbuff) {
	circbuff->end_bit = 0;
	circbuff->end_byte = 0;
	circbuff->start_bit = 0;
	circbuff->start_byte = 0;
}

uint8_t circbuff_size(circbuff_t *circbuff) {
	if (circbuff->end_byte >= circbuff->start_byte) {
		return (circbuff->end_byte - circbuff->start_byte);
	} else {
		return CIRCBUFF_LENGTH -
		       (circbuff->start_byte - circbuff->end_byte);
	}
}

bool circbuff_is_full(circbuff_t *circbuff) {
	return (circbuff_size(circbuff) >= CIRCBUFF_LENGTH - 1);
}

bool circbuff_add_byte(circbuff_t *circbuff, uint8_t data) {
	bool status = false;
	if (circbuff_is_full(circbuff) == true) {
		circbuff->start_byte =
			(circbuff->start_byte + 1) % CIRCBUFF_LENGTH;
		circbuff->start_bit = 0;
		status = true;
	}
	circbuff->data[circbuff->end_byte] = data;
	circbuff->end_byte = (circbuff->end_byte + 1) % CIRCBUFF_LENGTH;
	circbuff->end_bit = 0;
	return status;
}

bool circbuff_is_empty(circbuff_t *circbuff) {
	return circbuff->start_byte == circbuff->end_byte;
}

uint8_t circbuff_pop_byte(circbuff_t *circbuff) {
	circbuff->start_bit = 0;
	if (circbuff_is_empty(circbuff) == false) {
		uint8_t data = circbuff->data[circbuff->start_byte];
		circbuff->start_byte =
			(circbuff->start_byte + 1) % CIRCBUFF_LENGTH;
		return data;
	}
	return 0;
}

bool circbuff_add_bit(circbuff_t *circbuff, uint8_t data) {
	bool status = false;

	circbuff->data[circbuff->end_byte] |= data << (7 - circbuff->end_bit);

	circbuff->end_bit++;
	if (circbuff->end_bit > 7) {
		if (circbuff_is_full(circbuff) == true) {
			circbuff->start_byte =
				(circbuff->start_byte + 1) % CIRCBUFF_LENGTH;
			circbuff->start_bit = 0;
			status = true;
		}
		circbuff->end_byte = (circbuff->end_byte + 1) % CIRCBUFF_LENGTH;
		circbuff->end_bit = 0;
		circbuff->data[circbuff->end_byte] = 0;
	}

	return status;
}

uint8_t circbuff_pop_bit(circbuff_t *circbuff) {
	uint8_t data;
	uint8_t bit;

	data = circbuff->data[circbuff->start_byte];
	bit = (data & (1 << (7 - circbuff->start_bit))) >>
	      (7 - circbuff->start_bit);

	circbuff->start_bit++;
	if (circbuff->start_bit > 7) {
		circbuff_pop_byte(circbuff);
	}

	return bit;
}