#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/pwm.h" //import file

#define PIR_PIN 2
#define BUZZER_PIN 3
#define BUTTON_PIN 4

/* PWM mode – WOKWI only has a passive buzzer (DC), 
which, in comparison to an active buzzer (AC), is 
missing important bits that help it function like a buzzer! 
You'd think this is a downside, but it actually 
makes the passive buzzer more 'customisable' 
using PWM. IRL PWM is controlled using MOSFET transistors, 
but in WOKWI it's an import file and a few functions 
(where you manually code its On/Off function). */

// start buzzer
void buzzer_on() {
    gpio_set_function(BUZZER_PIN, GPIO_FUNC_PWM); //PWM mode
    uint slice_num = pwm_gpio_to_slice_num(BUZZER_PIN);
    pwm_set_wrap(slice_num, 2500);    //frequency (~1kHz)
    pwm_set_gpio_level(BUZZER_PIN, 1250); //duty-cycle... not sure how it works but in needs to be 50%; 1250/2500
    pwm_set_enabled(slice_num, true);
}

//stop buzzer
void buzzer_off() {
    pwm_set_gpio_level(BUZZER_PIN, 0); //duty-cycle 0% = off
}

int main() {
    stdio_init_all();

    gpio_init(PIR_PIN);
    gpio_set_dir(PIR_PIN, GPIO_IN);

    gpio_init(BUTTON_PIN);
    gpio_set_dir(BUTTON_PIN, GPIO_IN);
    gpio_pull_up(BUTTON_PIN); 

    while (true) {
        if (gpio_get(PIR_PIN)) { // Motion detected
            buzzer_on();
            printf("Motion detected!\n");

            // Wait until button is pressed
            while (gpio_get(BUTTON_PIN)) {
                sleep_ms(10);
            }

            buzzer_off();
            printf("Buzzer turned off.\n");
        }
        sleep_ms(100);
    }
}