#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/cm3/systick.h>

#include <stdio.h>
#include <errno.h>
#include <unistd.h>

// Configuration
// LED2 on PA5
// Debug: USART2, TX on PA2
// Bluetooth: USART3. TX PB10, RX PB11, CTS PB13 (in), RTS PB14 (out), N_SHUTDOWN PB15
#define GPIO_LED2 GPIO5
#define USART_CONSOLE USART2
#define GPIO_BT_N_SHUTDOWN GPIO15

// btstack code starts there
void btstack_main(void);

// hal_tick.h inmplementation
#include <btstack/hal_tick.h>

static void dummy_handler(void);
static void (*tick_handler)(void) = &dummy_handler;

static void dummy_handler(void){};

void hal_tick_init(void){
	/* clock rate / 1000 to get 1mS interrupt rate */
	systick_set_reload(8000);
	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
	systick_counter_enable();
	systick_interrupt_enable();
}

void hal_tick_set_handler(void (*handler)(void)){
    if (handler == NULL){
        tick_handler = &dummy_handler;
        return;
    }
    tick_handler = handler;
}

int  hal_tick_get_tick_period_in_ms(void){
    return 1;
}

void sys_tick_handler(void)
{
	(*tick_handler)();
}

// hal_cpu.h implementation
#include <btstack/hal_cpu.h>

void hal_cpu_disable_irqs(void){

}
void hal_cpu_enable_irqs(void){

}
void hal_cpu_enable_irqs_and_sleep(void){

}

//

/**
 * Use USART_CONSOLE as a console.
 * This is a syscall for newlib
 * @param file
 * @param ptr
 * @param len
 * @return
 */
int _write(int file, char *ptr, int len);
int _write(int file, char *ptr, int len)
{
	int i;

	if (file == STDOUT_FILENO || file == STDERR_FILENO) {
		for (i = 0; i < len; i++) {
			if (ptr[i] == '\n') {
				usart_send_blocking(USART_CONSOLE, '\r');
			}
			usart_send_blocking(USART_CONSOLE, ptr[i]);
		}
		return i;
	}
	errno = EIO;
	return -1;
}

static void clock_setup(void)
{
	/* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1 + USART2. */
	/* needs to be done before initializing other peripherals */
	rcc_periph_clock_enable(RCC_GPIOA);
	rcc_periph_clock_enable(RCC_GPIOB);
	rcc_periph_clock_enable(RCC_USART2);
	rcc_periph_clock_enable(RCC_USART3);
}

static void gpio_setup(void)
{
	/* Set GPIO5 (in GPIO port A) to 'output push-pull'. [LED] */
	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_LED2);
}

void usart_setup(void);
void usart_setup(void)
{
	/* Setup GPIO pin GPIO_USART2_TX/GPIO2 on GPIO port A for transmit. */
	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX);

	/* Setup UART parameters. */
	usart_set_baudrate(USART2, 9600);
	usart_set_databits(USART2, 8);
	usart_set_stopbits(USART2, USART_STOPBITS_1);
	usart_set_mode(USART2, USART_MODE_TX);
	usart_set_parity(USART2, USART_PARITY_NONE);
	usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);

	/* Finally enable the USART. */
	usart_enable(USART2);
}

int main(void)
{
	clock_setup();
	gpio_setup();
	usart_setup();
	hal_tick_init();

	// hand over to btstack embedded code 
	btstack_main();

	return 0;
}