#include "battery.h"
#include <driver/adc.h>
#include <esp_adc_cal.h>
#include <esp_log.h>
#include <soc/adc_channel.h>


static const char* LOG_TAG = "OdroidBattery";

static const adc1_channel_t BATTERY_READ_PIN = ADC1_GPIO36_CHANNEL;
static const gpio_num_t BATTERY_LED_PIN = GPIO_NUM_2;

static esp_adc_cal_characteristics_t gCharacteristics;

void Odroid_InitializeBatteryReader()
{
	// Configure LED
	{
		gpio_config_t gpioConfig = {};

		gpioConfig.mode = GPIO_MODE_OUTPUT;
		gpioConfig.pin_bit_mask = 1ULL << BATTERY_LED_PIN;

		ESP_ERROR_CHECK(gpio_config(&gpioConfig));
	}

	// Configure ADC
	{
		adc1_config_width(ADC_WIDTH_BIT_12);
		adc1_config_channel_atten(BATTERY_READ_PIN, ADC_ATTEN_DB_11);
		adc1_config_channel_atten(BATTERY_READ_PIN, ADC_ATTEN_DB_11);

		esp_adc_cal_value_t type = esp_adc_cal_characterize(
			ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, 1100, &gCharacteristics);

		// The ESP32 in the Odroid Go should have its fuse set with a pre-calibrated vref
		assert(type == ESP_ADC_CAL_VAL_EFUSE_VREF);
	}

	ESP_LOGI(LOG_TAG, "Battery reader initialized");
}

uint32_t Odroid_ReadBatteryLevel(void)
{
	const int SAMPLE_COUNT = 20;


	uint32_t raw = 0;

	for (int sampleIndex = 0; sampleIndex < SAMPLE_COUNT; ++sampleIndex)
	{
		raw += adc1_get_raw(BATTERY_READ_PIN);
	}

	raw /= SAMPLE_COUNT;


	// Voltage divider reports half actual voltage
	uint32_t voltage = 2 * esp_adc_cal_raw_to_voltage(raw, &gCharacteristics);

	return voltage;
}

void Odroid_EnableBatteryLight(void)
{
	gpio_set_level(BATTERY_LED_PIN, 1);
}

void Odroid_DisableBatteryLight(void)
{
	gpio_set_level(BATTERY_LED_PIN, 0);
}