#include <dio.h>
#include <stdio.h>
#include <display.h>

uint32_t read_capacitance(dio_t *dio) {
    uint32_t i;

    dio_set_direction(dio, LINE_OUT);
    dio_set(dio, 1);

    i = 0;
    dio_set_direction(dio, LINE_IN);
    while (dio_read(dio) > 0) i++;
    return i;
}

uint32_t calibrate(dio_t *dio) {
    uint32_t max = 0;

    for (uint8_t i = 0; i < 100; i++) {
        uint8_t cap = read_capacitance(dio);
        max = cap > max ? cap : max;
        _delay_ms(10);
    }

    return max;
}

int main(void) {
    dio_t sensor = (dio_t){ .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 0 };
    display_t display = {
        .reg = {
            .output         = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 4 },
            .shift_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 3 },
            .latch_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 2 },
        },
    };
    display_init(&display);

    display_enable(&display);
    display_clear(&display);

    // calibration
    //
    // 100 times:
    //  Output 1
    //  Switch to Input
    //  measure in a loop until the input is 0
    //  save the measurement
    //
    // normal function
    //  Output 1
    //  Switch to input
    //  measure in a loop until the input is 0
    //  check against the saved measurement
    //  enable pin if significantly higher than the saved measurement
    //  update the average

    MCUCR |= _BV(PUD);


    uint8_t calibration_countdown = 0;
    uint32_t calibration = 0;
    bool touch = false;
    while (1) {
        if (calibration_countdown == 0 && !touch) {
            calibration = calibrate(&sensor);
            calibration_countdown = 100;

            char msg[20];
            snprintf(msg, 20, "calib: %6ld", calibration);
            display_set_location(&display, 0, 0);
            display_write_message(&display, msg);
        }

        uint32_t cap = read_capacitance(&sensor);

        if (cap > calibration) {
            display_set_location(&display, 1, 0);
            display_write_message(&display, "touch!");
            touch = true;
        } else if (touch) {
            display_set_location(&display, 1, 0);
            display_write_message(&display, "      ");
            touch = false;
        }

        if (calibration_countdown > 0) {
            calibration_countdown--;
        }
        _delay_ms(100);
    }

}