/*
	This file is part of Fennix Kernel.

	Fennix Kernel is free software: you can redistribute it and/or
	modify it under the terms of the GNU General Public License as
	published by the Free Software Foundation, either version 3 of
	the License, or (at your option) any later version.

	Fennix Kernel is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/

#include <uart.hpp>

#include <debug.h>
#include <vector>

bool serialports[8] = {false, false, false, false, false, false, false, false};
std::vector<UniversalAsynchronousReceiverTransmitter::Events *> RegisteredEvents;

#if defined(a86)
NIF __always_inline inline uint8_t NoProfiler_inportb(uint16_t Port)
{
	uint8_t Result;
	asm("in %%dx, %%al"
		: "=a"(Result)
		: "d"(Port));
	return Result;
}

NIF __always_inline inline void NoProfiler_outportb(uint16_t Port, uint8_t Data)
{
	asmv("out %%al, %%dx"
		 :
		 : "a"(Data), "d"(Port));
}
#endif

namespace UniversalAsynchronousReceiverTransmitter
{
#define SERIAL_ENABLE_DLAB 0x80
#define SERIAL_RATE_115200_LO 0x01
#define SERIAL_RATE_115200_HI 0x00
#define SERIAL_RATE_57600_LO 0x02
#define SERIAL_RATE_57600_HI 0x00
#define SERIAL_RATE_38400_LO 0x03
#define SERIAL_RATE_38400_HI 0x00
#define SERIAL_BUFFER_EMPTY 0x20

	/* TODO: Serial Port implementation needs reword. https://wiki.osdev.org/Serial_Ports */

	nsa NIF UART::UART(SerialPorts Port)
	{
#if defined(a86)
		if (Port == COMNULL)
			return;

		uint8_t com = NoProfiler_inportb(Port);
		if (com == 0xFF)
		{
			error("Serial port %#lx is not available.", Port);
			return;
		}

		this->Port = Port;
		int PortNumber = 0;

		switch (Port)
		{
		case COM1:
			PortNumber = 0;
			break;
		case COM2:
			PortNumber = 1;
			break;
		case COM3:
			PortNumber = 2;
			break;
		case COM4:
			PortNumber = 3;
			break;
		case COM5:
			PortNumber = 4;
			break;
		case COM6:
			PortNumber = 5;
			break;
		case COM7:
			PortNumber = 6;
			break;
		case COM8:
			PortNumber = 7;
			break;
		default:
			return;
		}

		if (serialports[PortNumber])
			return;

		// Initialize the serial port
		NoProfiler_outportb(s_cst(uint16_t, Port + 1), 0x00);				   // Disable all interrupts
		NoProfiler_outportb(s_cst(uint16_t, Port + 3), SERIAL_ENABLE_DLAB);	   // Enable DLAB (set baud rate divisor)
		NoProfiler_outportb(s_cst(uint16_t, Port + 0), SERIAL_RATE_115200_LO); // Set divisor to 1 (lo byte) 115200 baud
		NoProfiler_outportb(s_cst(uint16_t, Port + 1), SERIAL_RATE_115200_HI); //                  (hi byte)
		NoProfiler_outportb(s_cst(uint16_t, Port + 3), 0x03);				   // 8 bits, no parity, one stop bit
		NoProfiler_outportb(s_cst(uint16_t, Port + 2), 0xC7);				   // Enable FIFO, clear them, with 14-byte threshold
		NoProfiler_outportb(s_cst(uint16_t, Port + 4), 0x0B);				   // IRQs enabled, RTS/DSR set

		/* FIXME  https://wiki.osdev.org/Serial_Ports */
		// NoProfiler_outportb(s_cst(uint16_t, Port + 0), 0x1E);
		// NoProfiler_outportb(s_cst(uint16_t, Port + 0), 0xAE);
		// Check if the serial port is faulty.
		// if (NoProfiler_inportb(s_cst(uint16_t, Port + 0)) != 0xAE)
		// {
		//     static int once = 0;
		//     if (!once++)
		//         warn("Serial port %#lx is faulty.", Port);
		//     // serialports[Port] = false; // ignore for now
		//     // return;
		// }

		// Set to normal operation mode.
		NoProfiler_outportb(s_cst(uint16_t, Port + 4), 0x0F);
		serialports[PortNumber] = true;
		this->IsAvailable = true;
#endif
	}

	nsa NIF UART::~UART() {}

	nsa NIF void UART::Write(uint8_t Char)
	{
		if (!this->IsAvailable)
			return;
#if defined(a86)
		while ((NoProfiler_inportb(s_cst(uint16_t, Port + 5)) & SERIAL_BUFFER_EMPTY) == 0)
			;
		NoProfiler_outportb(Port, Char);
#endif
		foreach (auto e in RegisteredEvents)
			if (e->GetRegisteredPort() == Port || e->GetRegisteredPort() == COMNULL)
				e->OnSent(Char);
	}

	nsa NIF uint8_t UART::Read()
	{
		if (!this->IsAvailable)
			return 0;
#if defined(a86)
		while ((NoProfiler_inportb(s_cst(uint16_t, Port + 5)) & 1) == 0)
			;
		return NoProfiler_inportb(Port);
#endif
		foreach (auto e in RegisteredEvents)
		{
			if (e->GetRegisteredPort() == Port || e->GetRegisteredPort() == COMNULL)
			{
#if defined(a86)
				e->OnReceived(NoProfiler_inportb(Port));
#endif
			}
		}
	}

	nsa NIF Events::Events(SerialPorts Port)
	{
		this->Port = Port;
		RegisteredEvents.push_back(this);
	}

	nsa NIF Events::~Events()
	{
		forItr(itr, RegisteredEvents)
		{
			if (*itr == this)
			{
				RegisteredEvents.erase(itr);
				return;
			}
		}
	}
}