#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/gpio.h"
#include "hardware/irq.h"

// Declare the main assembly code entry point.
void main_asm();

// Initialise a GPIO pin – see SDK for detail on gpio_init()
void asm_gpio_init(uint pin) {
    gpio_init(pin);
}

// Set direction of a GPIO pin – see SDK for detail on gpio_set_dir()
void asm_gpio_set_dir(uint pin, bool out) {
    gpio_set_dir(pin, out);
}

// Get the value of a GPIO pin – see SDK for detail on gpio_get()
bool asm_gpio_get(uint pin) {
    return gpio_get(pin);
}

// Set the value of a GPIO pin – see SDK for detail on gpio_put()
void asm_gpio_put(uint pin, bool value) {
    gpio_put(pin, value);
}

// Enable falling-edge interrupt – see SDK for detail on gpio_set_irq_enabled()
void asm_gpio_set_irq(uint pin) {
    gpio_set_irq_enabled(pin, GPIO_IRQ_EDGE_FALL, true);
}

// GPIO Interrupt Handler for all buttons
void gpio_callback(uint gpio, uint32_t events) {
    printf("Interrupt on GPIO %d!\n", gpio);
}

// Setup GPIO and interrupts
void setup_gpio() {
    // LED Setup
    asm_gpio_init(25);                // Built-in LED on GP25
    asm_gpio_set_dir(25, true);        // Set GP25 as output

    // Button Setup
    asm_gpio_init(20);                 // Button for halving rate
    asm_gpio_set_dir(20, false);       // Set GP20 as input
    asm_gpio_set_irq(20);              // Enable interrupt for GP20

    asm_gpio_init(21);                 // Button for toggling LED state
    asm_gpio_set_dir(21, false);       // Set GP21 as input
    asm_gpio_set_irq(21);              // Enable interrupt for GP21

    asm_gpio_init(22);                 // Button for doubling rate
    asm_gpio_set_dir(22, false);       // Set GP22 as input
    asm_gpio_set_irq(22);              // Enable interrupt for GP22

    // Attach interrupt handler
    gpio_set_irq_enabled_with_callback(20, GPIO_IRQ_EDGE_FALL, true, &gpio_callback);
    gpio_set_irq_enabled_with_callback(21, GPIO_IRQ_EDGE_FALL, true, &gpio_callback);
    gpio_set_irq_enabled_with_callback(22, GPIO_IRQ_EDGE_FALL, true, &gpio_callback);
}

// Main entry point of the application
int main() {
    stdio_init_all();                  // Initialise all basic IO
    printf("Assignment #1...\n");      // Basic print to console

    setup_gpio();                      // Setup GPIO pins and interrupts

    main_asm();                        // Jump into the ASM code
    return 0;                          // Application return code
}