#include "temperature.hpp"

#include <Arduino.h>

TemperatureSensor::TemperatureSensor(uint8_t pin) noexcept : _pin(pin)
{
	pinMode(_pin, OUTPUT);
}

auto TemperatureSensor::read_temperature() noexcept -> TemperatureSensorStatus
{
	// Send start signal and wait
	digitalWrite(_pin, LOW);
	delay(TemperatureSensorTiming::START_SIGNAL_TIME_MILLIS);

	// Pull up and wait for response
	digitalWrite(_pin, HIGH);
	delayMicroseconds(TemperatureSensorTiming::RESPONSE_SIGNAL_WAIT_TIME_MICROS);

	pinMode(_pin, INPUT);

	// The sensor sends a LOW signal and keeps it for 80us
	if (!_wait_read(LOW, TemperatureSensorTiming::RESPONSE_SIGNAL_TIME_MICROS))
	{
		return TemperatureSensorStatus::TIMEOUT;
	}

	// The sensor sends a HIGH signal and keeps it for 80us
	if (!_wait_read(HIGH, TemperatureSensorTiming::RESPONSE_SIGNAL_TIME_MICROS))
	{
		return TemperatureSensorStatus::TIMEOUT;
	}

	uint8_t data_bytes[TEMPERATURE_SENSOR_RESPONSE_DATA_BYTE_CNT] = { 0U,
																	  0U,
																	  0U,
																	  0U,
																	  0U };

	uint8_t bit_index = BITS_IN_BYTE - 1U;
	uint8_t byte_index = 0U;

	for (uint16_t index = 0U;
		 index < (BITS_IN_BYTE * TEMPERATURE_SENSOR_RESPONSE_DATA_BYTE_CNT);
		 index++)
	{
		// Wait for the start to transmit signal
		if (!_wait_read(
				LOW,
				TemperatureSensorTiming::START_TO_TRANSMIT_SIGNAL_TIME_MICROS + 5U
			))
		{
			return TemperatureSensorStatus::TIMEOUT;
		}

		const auto start_time = micros();

		if (!_wait_read(HIGH, TemperatureSensorTiming::DATA_TRANSMIT_TIMEOUT_MICROS))
		{
			return TemperatureSensorStatus::TIMEOUT;
		}

		// A voltage length greater than 40 means the bit is a 1
		if ((micros() - start_time) > 40U)
		{
			data_bytes[byte_index] |= static_cast<uint8_t>(1U << bit_index);
		}

		// Continue to the next byte if it's the last bit
		if (bit_index == 0U)
		{
			// Restart at the MSB
			bit_index = BITS_IN_BYTE - 1U;

			byte_index++;
			continue;
		}

		bit_index--;
	}

	// Restore pin to initial state
	pinMode(_pin, OUTPUT);
	digitalWrite(_pin, HIGH);

	_temperature = data_bytes[2];

	auto sum = data_bytes[0] + data_bytes[2];

	if (data_bytes[4] != sum)
	{
		return TemperatureSensorStatus::CHECKSUM_ERROR;
	}

	return TemperatureSensorStatus::OK;
}

auto TemperatureSensor::temperature() const noexcept -> uint8_t
{
	return _temperature;
}

// NOLINTNEXTLINE(bugprone-easily-swappable-parameters)
auto TemperatureSensor::_wait_read(uint8_t level, size_t timeout_micros) noexcept -> bool
{
	const auto start_time = micros();

	while (digitalRead(_pin) == level)
	{
		if ((start_time + timeout_micros) < micros())
		{
			return false;
		}
	}

	return true;
}