#include "ph.h"

ADC_HandleTypeDef hadc;
DMA_HandleTypeDef hdma_adc;

uint32_t adc_reading;
float ph_readings[10] = {0};
uint8_t ph_i = 0;

void ph_init(void)
{
    __HAL_RCC_ADC1_CLK_ENABLE();
    __HAL_RCC_DMA1_CLK_ENABLE();

    GPIO_InitTypeDef GPIO_InitStruct;

    GPIO_InitStruct.Pin = GPIO_PIN_0;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    ADC_ChannelConfTypeDef sConfig;

    hadc.Instance = ADC1;
    hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
    hadc.Init.Resolution = ADC_RESOLUTION_12B;
    hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
    hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
    hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
    hadc.Init.LowPowerAutoWait = DISABLE;
    hadc.Init.LowPowerAutoPowerOff = DISABLE;
    hadc.Init.ContinuousConvMode = ENABLE;
    hadc.Init.DiscontinuousConvMode = DISABLE;
    hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
    hadc.Init.DMAContinuousRequests = ENABLE;
    hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
    HAL_ADC_Init(&hadc);


    // Configure DMA
    hdma_adc.Instance = DMA1_Channel1;
    hdma_adc.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
    hdma_adc.Init.Mode = DMA_CIRCULAR;
    hdma_adc.Init.Priority = DMA_PRIORITY_LOW;
    HAL_DMA_Init(&hdma_adc);

    __HAL_LINKDMA(&hadc, DMA_Handle, hdma_adc);

    sConfig.Channel = ADC_CHANNEL_0;
    sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
    sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
    HAL_ADC_ConfigChannel(&hadc, &sConfig);

    HAL_ADC_Start_DMA(&hadc, &adc_reading, 1);

    //fill the rolling average buffer with real readings so the first reading isn't ~0
	for (uint8_t i = 0; i < 10; i++)
	{
		ph_update();
		HAL_Delay(100);
	}
}

void ph_update(void)
{
	uint32_t ph_raw = adc_reading;
    ph_readings[ph_i] = ph_convert(ph_raw); //convert adc counts to pH
    ph_i = (ph_i + 1) % 10;
}

float ph_get(void)
{
    float ph = 0;

    for (uint8_t i = 0; i < 10; i++)
    {
    	ph += ph_readings[i];
    }
    ph = ph / 10;

    return ph;
}

float ph_convert(uint32_t ph_raw)
{
	float ph = (float)ph_raw;

	return ph;
}