#include <BAN/Errors.h>
#include <kernel/IO.h>

#define COM1_PORT 0x3f8

namespace Serial
{

	static bool s_initialized = false;

	void initialize()
	{
		IO::outb(COM1_PORT + 1, 0x00);    // Disable all interrupts
		IO::outb(COM1_PORT + 3, 0x80);    // Enable DLAB (set baud rate divisor)
		IO::outb(COM1_PORT + 0, 0x03);    // Set divisor to 3 (lo byte) 38400 baud
		IO::outb(COM1_PORT + 1, 0x00);    //                  (hi byte)
		IO::outb(COM1_PORT + 3, 0x03);    // 8 bits, no parity, one stop bit
		IO::outb(COM1_PORT + 2, 0xC7);    // Enable FIFO, clear them, with 14-byte threshold
		IO::outb(COM1_PORT + 4, 0x0B);    // IRQs enabled, RTS/DSR set
		IO::outb(COM1_PORT + 4, 0x1E);    // Set in loopback mode, test the serial chip
		IO::outb(COM1_PORT + 0, 0xAE);    // Test serial chip (send byte 0xAE and check if serial returns same byte)

		// Check if serial is faulty (i.e: not same byte as sent)
		if(IO::inb(COM1_PORT + 0) != 0xAE)
			return;

		// If serial is not faulty set it in normal operation mode
		// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
		IO::outb(COM1_PORT + 4, 0x0F);
		s_initialized = true;
	}

	bool is_initialized()
	{
		return s_initialized;
	}

	static int is_transmit_empty() {
		return IO::inb(COM1_PORT + 5) & 0x20;
	}
 
	void putchar(char c)
	{
		ASSERT(s_initialized);
		while (is_transmit_empty() == 0);
		IO::outb(COM1_PORT, c);
	}

}