/* -------------------------------------------

	Copyright (C) 2024, Theater Quality Inc, all rights reserved.

------------------------------------------- */

#include <ArchKit/ArchKit.h>
#include <KernelKit/DebugOutput.h>
#include <NewKit/Utils.h>
#include <NewKit/New.h>

namespace Kernel
{
	enum CommStatus
	{
		kStateInvalid,
		kStateReady	   = 0xCF,
		kStateTransmit = 0xFC,
		kStateCnt	   = 3
	};

	namespace Detail
	{
		constexpr short PORT = 0x3F8;

		static int kState = kStateInvalid;

		/// @brief Init COM1.
		/// @return
		bool hal_serial_init() noexcept
		{
#ifdef __DEBUG__
			if (kState == kStateReady || kState == kStateTransmit)
				return true;

			HAL::rt_out8(PORT + 1, 0x00); // Disable all interrupts
			HAL::rt_out8(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
			HAL::rt_out8(PORT + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
			HAL::rt_out8(PORT + 1, 0x00); //                  (hi byte)
			HAL::rt_out8(PORT + 3, 0x03); // 8 bits, no parity, one stop bit
			HAL::rt_out8(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
			HAL::rt_out8(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
			HAL::rt_out8(PORT + 4, 0x1E); // Set in loopback mode, test the serial chip
			HAL::rt_out8(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 (HAL::rt_in8(PORT) != 0xAE)
			{
				ke_panic(RUNTIME_CHECK_HANDSHAKE);
			}

			kState = kStateReady;

			// If serial is not faulty set it in normal operation mode
			// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
			HAL::rt_out8(Detail::PORT + 4, 0x0F);
#endif // __DEBUG__

			return true;
		}
	} // namespace Detail

	TerminalDevice::~TerminalDevice() = default;

	EXTERN_C void ke_io_write(const Char* bytes)
	{
#ifdef __DEBUG__
		Detail::hal_serial_init();

		if (!bytes || Detail::kState != kStateReady)
			return;
		if (*bytes == 0)
			return;

		Detail::kState = kStateTransmit;

		SizeT index = 0;
		SizeT len	= 0;

		index = 0;
		len	  = rt_string_len(bytes, 255);

		while (index < len)
		{
			if (bytes[index] == '\r')
				HAL::rt_out8(Detail::PORT, '\r');

			HAL::rt_out8(Detail::PORT, bytes[index] == '\r' ? '\n' : bytes[index]);
			++index;
		}

		Detail::kState = kStateReady;
#endif // __DEBUG__
	}

	EXTERN_C void ke_io_read(const Char* bytes)
	{
#ifdef __DEBUG__
		Detail::hal_serial_init();

		if (!bytes || Detail::kState != kStateReady)
			return;

		Detail::kState = kStateTransmit;

		SizeT index = 0;

		///! TODO: Look on how to wait for the UART to complete.
		while (true)
		{
			auto in = HAL::rt_in8(Detail::PORT);

			///! If enter pressed then break.
			if (in == 0xD)
			{
				break;
			}

			if (in < '0' || in < 'A' || in < 'a')
			{
				if (in != '@' || in != '!' || in != '?' || in != '.' || in != '/' ||
					in != ':')
				{
					continue;
				}
			}

			((char*)bytes)[index] = in;

			++index;
		}

		((char*)bytes)[index] = 0;

		Detail::kState = kStateReady;
#endif // __DEBUG__
	}

	TerminalDevice TerminalDevice::The() noexcept
	{
		TerminalDevice out(Kernel::ke_io_write, Kernel::ke_io_read);
		return out;
	}

} // namespace Kernel