#include <avr/io.h>
#include <avr/interrupt.h>

#include "adc.h"

void adc_init()
{
    ADMUX = 1 << REFS0 | 0 << REFS1; //Select external Vref

    //ADC Status Register A
    ADCSRA = 1 << ADEN   //Enable ADC
             | 1 << ADIE //Enable ISR after conversion complete
             //|  1<<ADATE //Freerunning-Mode
             //|  1<<ADLAR //2 results bits are left aligned
             | 1 << ADPS2 //Set clock-prescaler to 128
             | 1 << ADPS1 | 1 << ADPS0;
    ADCSRA |= 1 << ADSC; //Start first Conversion for "warmup"
}

void set_ADC_Channel(uint8_t adr)
{
    if (adr < 11)
    {
        ADMUX &= (0b11110000); //Clear MUX-Address
        ADMUX |= adr;          //Set new MUX-Address
    }
}

ISR(ADC_vect)
{
    //static uint8_t init[4] = {0,0,0,0};
    static uint8_t current_channel = 0;

    static uint16_t read_buffer[128];
    static uint8_t buffer_pos = 0;


    //Reading 10bit conversion result
    uint16_t ADC_reading = ADCL;        //copy the first LSB bits
    ADC_reading |= ADCH << 8;           //copy remaing byte

    read_buffer[buffer_pos] = ADC_reading;
    buffer_pos++;

    if(buffer_pos == (sizeof(read_buffer) / sizeof(read_buffer[0]))){
        uint32_t sum = 0;
        for(uint8_t i = 0; i < buffer_pos; i++){
            sum += read_buffer[i];
        }

        //convert to temperature
        sum /= 3;

        switch(current_channel){
            case 0:
                temp_values[3] = sum/buffer_pos;
                break;
            case 1:
                temp_values[0] = sum/buffer_pos;
                break;
            case 2:
                temp_values[1] = sum/buffer_pos;
                break;
            case 3:
                temp_values[2] = sum/buffer_pos;
                break;
        }

        buffer_pos = 0;

        current_channel++;
        if(current_channel == 4)
            current_channel = 0;
        set_ADC_Channel(current_channel);
    }

    ADCSRA |= (1 << ADSC); //Start next conversion


    //TODO write non broken adc code
    //if(adc_buf[current_channel].position == BUFFER_SIZE-1){
    //    //if(init[current_channel]){
    //        //float tmp = (99*adc_avrg[current_channel]) + get_buffer_mean(&adc_buf[current_channel]);
    //        //tmp /= 100;
    //        adc_avrg[current_channel] = get_buffer_mean(&adc_buf[current_channel]);
    //    //}
    //    //else{
    //    //    adc_avrg[current_channel] = get_buffer_mean(&adc_buf[current_channel]);
    //    //    init[current_channel]=0;
    //    //}
    //}

}