#include "main.h"


const char* lm35_string = "LM35 Temp: ";
const struct {
    x = sizeof(lm35_string);
    y = 0;
} lm35_value_pos;

#ifdef CALIBRATION
const char* diode_string = "Diode Value: ";
#else
const char* diode_string = "Diode Temp: ";
#endif

const struct {
    x = sizeof(diode_string);
    y = 1;
} diode_value_pos;

/** @brief Initialises general pins for use.
 * 
 * @note Does not initialise LCD pins. That is handled by lcdlibrary
 */
void pin_init() {
    /* Pin Mappings:
     * PC0 -> ADC0 input for diode measurement
     * PC1 -> ADC1 input for LM35
     */

    // Pin Config for Diode ADC
    DDRC &= ~(1 << DDRC0);
    DIDR0 |= (1 << ADC0D); // Disable digital input

    // Pin Config for LM35 ADC
    DDRC &= ~(1 << DDRC1);
    DIDR0 |= (1 << ADC1D); // Disable digital input
}

/** @brief Initializes ADC with required settings
 */
void adc_init() {
    /* ADC Settings
     * Use Aref as Vref
     * Initially set input as GND
     * Data right-adjusted
     * No Interrupts
     */

    // Set MUX[3:0] to 0b1111 (GND reference)
    ADMUX |= (1 << MUX3) | (1 << MUX2) | (1 << MUX1) | (1 << MUX0);
    // Make sure data is right adjusted
    ADMUX &= ~(1 << ADLAR);

    // Set the clock prescaler to 128 (slower ADC means more accurate measurements)
    ADCSRA |= (1 << ADPS2) | (1 << ADPS1) (1 << ADPS0);
    // Enable ADC
    ADCSRA |= (1 << ADEN);
}

/** @brief Blocking function to read an ADC conversion from a selected ADC input.
 * 
 * @note Blocks until conversion finishes, so speed of this function is dependant
 *      on ADC prescaler.
 */
uint16_t adc_run_conversion(uint8_t adc_selection) {
    // Select ADC
    ADMUX &= 0xF0 | adc_selection;

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

    // Wait until conversion is complete
    while (ADCSRA & (1 << ADIF));

    // Read out conversion value
    // may not be correct
    return ADC;
}


/** @brief Converts an ADC value from a measurement on an LM35 into a temperature.
 */
float lm35_convert(uint16_t adc_reading) {
    return (float) (adc_reading * ADC_VREF / ADC_RESOLUTION) / LM35_SENSITIVITY;
}

/** @brief Converts and ADC value from a measurement on a diode into a temperature.
 * TODO
 */
float diode_convert(uint16_t adc_reading) {
    // Do some funky math here

    return 0;
}

int main() {
    // Initialise peripherals
    pin_init();
    adc_init();

    // Initialise display
    // NOTE: LCD uses PB0-PB6
    lcd_init(LCD_DISP_ON);

    // Write "base" strings to LCD
    lcd_puts(lm35_string);
    lcd_gotoxy(0, diode_value_pos.y); // Switch to bottom
    lcd_puts(diode_string);


    // Note that special compiler/linker flags have to be added to enable
    // printf-ing floats
    // See: https://startingelectronics.org/articles/atmel-AVR-8-bit/print-float-atmel-studio-7/
    while (1) {
        // Read LM35 value, and write to LCD
        float lm35_temp = lm35_convert(adc_run_conversion(1));
        // Convert measured value to string
        char[6] lm35_temp_str;
        sprintf(lm35_temp_str, "%3.1f", lm35_temp);

        // Display temp on LCD
        lcd_gotoxy(lm35_value_pos.x, lm35_value_pos.y);
        lcd_puts((const char*) lm35_temp_str);


        // Read diode value, and write to LCD
        #ifdef CALIBRATION
        uint16_t diode_value = adc_run_conversion(0);
        char[6] diode_str;
        sprintf(diode_str, "%d", diode_value);
        #else
        float diode_temp = diode_convert(adc_run_conversion(0));
        char[6] diode_str;
        sprintf(diode_str, "%3.1f", diode_temp);
        #endif

        // Display diode info on LCD
        lcd_gotoxy(diode_value_pos.x, diode_value_pos.y);
        lcd_puts((const char*) diode_str);
    }
    
}