#include "Driver_GPIO.h"
#include "stm32f4xx.h"

#include "sram_vtor.h"
#include "debounce.h"

extern ARM_DRIVER_GPIO Driver_GPIOA, Driver_GPIOC;

volatile long gTicks;

void on_tick(void)
{
	gTicks++;
}

void delay(uint32_t t)
{
	uint32_t start = gTicks;
	// modular subtraction is resillient against
	// up to a single overflow in gTicks
	while (gTicks - start < t)
		__WFI();
}

void init_clock(void)
{
	SystemCoreClockUpdate();
	SysTick_Config(SystemCoreClock / 1000);
	NVIC_SetVector(SysTick_IRQn, (uintptr_t)on_tick);
	NVIC_EnableIRQ(SysTick_IRQn);

	RCC->AHB1ENR |=
		RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOCEN;
	(void)RCC->AHB1ENR;
	(void)RCC->AHB1ENR;
}

int main(void)
{
	ARM_DRIVER_GPIO *ioa = &Driver_GPIOA, *ioc = &Driver_GPIOC;

	NVIC_Relocate_VTOR();
	init_clock();

	ioa->Setup(5, NULL);
	ioa->SetDirection(5, ARM_GPIO_OUTPUT);
	ioc->Setup(13, NULL);

	sample_state button_samples;
	debounce_init(&button_samples, true, 5);
	bool led = true;
	ioa->SetOutput(5, led);

	while (1)
	{
		bool *stable;
		stable = debounce(
			&button_samples, ioc->GetInput(13));
		if (stable && !*stable)
		{
			led = !led;
			ioa->SetOutput(5, led);
		}
		delay(10);
	}
}