#include <MKL46Z4.h>

#include <stdint.h>
#include <stdio.h>
#include "serial_api.h"
#include "serial_irq.h"
#include "timer_dma.h"

/* Defines */
#define SIRQ_LEN  1024

/* Port structure */
typedef struct {
	int     rix;
	int     wix;
	uint8_t buf[SIRQ_LEN];
} queue_t;

struct sirq_t {
	serial_t uart;
	queue_t  xmt;
	queue_t  rcv;
	int      irq;
	int      buffered;
};

/* Port data */
static sirq_t sirq_ports[SIRQ_NUM_UART];

/* Receive handler */
void sirq_handler(uint32_t _port, SerialIrq event)
{
	sirq_t *port = (sirq_t *)_port;

	// Handle transmit
	//   note: mbed seems to call TxIrq even it is not enabled,
	//   so we need to manually prevent transmitting when the
	//   port is set to buffered mode.
	if (event == TxIrq && (port->irq || !port->buffered)) {
		if (port->xmt.rix != port->xmt.wix) {
			int byte = port->xmt.buf[port->xmt.rix];
			serial_putc(&port->uart, byte);
			port->xmt.rix = (port->xmt.rix+1) % SIRQ_LEN;
		} else {
			serial_irq_set(&port->uart, TxIrq, 0);
			port->irq = 0;
		}
	}

	// Handle receive
	if (event == RxIrq) {
		int byte = serial_getc(&port->uart);
		port->rcv.buf[port->rcv.wix] = byte;
		port->rcv.wix = (port->rcv.wix+1) % SIRQ_LEN;
	}
}

/* Open port */
sirq_t *sirq_open(sirq_uart_t uart, PinName tx, PinName rx, int baud, int buffered)
{
	// Allocate port
	sirq_t *port = &sirq_ports[uart];

	// Buffered ports only transmit on demand
	port->buffered = buffered;

	// Configure port
	serial_init(&port->uart, tx, rx);
	serial_baud(&port->uart, baud);

	// Set IRQ handlers
	serial_irq_handler(&port->uart, sirq_handler, (uint32_t)port);
	serial_irq_set(&port->uart, RxIrq, 1);

	return port;
}

/* Write byte to the port */
void sirq_putc(sirq_t *port, int byte)
{
	port->xmt.buf[port->xmt.wix] = byte;
	port->xmt.wix = (port->xmt.wix+1) % SIRQ_LEN;
	if (!port->buffered)
		sirq_transmit(port);
}

/* Read byte from the port */
int sirq_getc(sirq_t *port)
{
	int byte = 0;
	if (port->rcv.rix != port->rcv.wix) {
		byte = port->rcv.buf[port->rcv.rix];
		port->rcv.rix = (port->rcv.rix+1) % SIRQ_LEN;
	}
	return byte;
}

/* Enable transmitter */
void sirq_transmit(sirq_t *port)
{
	if (port->xmt.rix != port->xmt.wix && !port->irq) {
		port->irq = 1;
		serial_irq_set(&port->uart, TxIrq, 1);
	}
}

/* Buffered write */
void sirq_write(sirq_t *port, void *data, int len)
{
	uint8_t *bytes = (uint8_t*)data;
	for (int i = 0; i < len; i++)
		sirq_putc(port, bytes[i]);
}

/* Check if port is writable */
int sirq_ready(sirq_t *port)
{
	return port->rcv.rix != port->rcv.wix;
}

/* Debug print */
void sirq_debug(sirq_t *port)
{
	sirq_printf("xmt  - wix:%03x rix:%03x\r\n", port->xmt.wix, port->xmt.rix);
	sirq_printf("rcv  - wix:%03x rix:%03x\r\n", port->rcv.wix, port->rcv.rix);
	sirq_printf("irq  - ??\r\n");
	sirq_printf("uart - ??\r\n");
}

/* Write ASCII data to the output queue */
void sirq_vprintf(const char *fmt, va_list ap)
{
	static char buf[512];
	int len = vsnprintf(buf, sizeof(buf), fmt, ap);
	for (int i = 0; i < len; i++)
		sirq_putc(&sirq_ports[0], buf[i]);
}

void sirq_printf(const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	sirq_vprintf(fmt, ap);
	va_end(ap);
}