/******************************************************************************

	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.

	This file is part of LibMaxsi.

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

	LibMaxsi 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 Lesser General Public License for
	more details.

	You should have received a copy of the GNU Lesser General Public License
	along with LibMaxsi. If not, see <http://www.gnu.org/licenses/>.

	format.cpp
	Provides printf formatting functions that uses callbacks.

******************************************************************************/

#include <libmaxsi/platform.h>
#include <libmaxsi/string.h>
#include <libmaxsi/format.h>

namespace Maxsi
{
	namespace String
	{
		int ConvertInt32(int32_t num, char* dest)
		{
			int result = 0;
			int32_t copy = num;

			if ( num < 0 )
			{
				*dest++ = '-';
				result++;

				int offset = 0;
				while ( copy < -9 ) { copy /= 10; offset++; }
				result += offset;
				while ( offset >= 0 )
				{
					dest[offset] = '0' - num % 10; num /= 10; offset--;
				}
			}
			else
			{
				int offset = 0;
				while ( copy > 9 ) { copy /= 10; offset++; }
				result += offset;
				while ( offset >= 0 )
				{
					dest[offset] = '0' + num % 10; num /= 10; offset--;
				}
			}

			return result + 1;
		}

		int ConvertInt64(int64_t num, char* dest)
		{
			int result = 0;
			int64_t copy = num;

			if ( num < 0 )
			{
				*dest++ = '-';
				result++;

				int offset = 0;
				while ( copy < -9 ) { copy /= 10; offset++; }
				result += offset;
				while ( offset >= 0 )
				{
					dest[offset] = '0' - num % 10; num /= 10; offset--;
				}
			}
			else
			{
				int offset = 0;
				while ( copy > 9 ) { copy /= 10; offset++; }
				result += offset;
				while ( offset >= 0 )
				{
					dest[offset] = '0' + num % 10; num /= 10; offset--;
				}
			}

			return result + 1;
		}

		int ConvertUInt32(uint32_t num, char* dest)
		{
			int result = 0;
			uint32_t copy = num;
			int offset = 0;
			while ( copy > 9 ) { copy /= 10; offset++; }
			result += offset;
			while ( offset >= 0 )
			{
				dest[offset] = '0' + num % 10; num /= 10; offset--;
			}

			return result + 1;
		}

		int ConvertUInt64(uint64_t num, char* dest)
		{
			int result = 0;
			uint64_t copy = num;
			int offset = 0;
			while ( copy > 9 ) { copy /= 10; offset++; }
			result += offset;
			while ( offset >= 0 )
			{
				dest[offset] = '0' + num % 10; num /= 10; offset--;
			}

			return result + 1;
		}

		int ConvertUInt32Hex(uint32_t num, char* dest)
		{
			char chars[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
			                   'A', 'B', 'C', 'D', 'E', 'F' };
			int result = 0;
			uint32_t copy = num;
			int offset = 0;
			while ( copy > 15 ) { copy /= 16; offset++; }
			result += offset;
			while ( offset >= 0 )
			{
				dest[offset] = chars[num % 16]; num /= 16; offset--;
			}

			return result + 1;
		}

		int ConvertUInt64Hex(uint64_t num, char* dest)
		{
			char chars[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
			                   'A', 'B', 'C', 'D', 'E', 'F' };
			int result = 0;
			uint64_t copy = num;
			int offset = 0;
			while ( copy > 15 ) { copy /= 16; offset++; }
			result += offset;
			while ( offset >= 0 )
			{
				dest[offset] = chars[num % 16]; num /= 16; offset--;
			}

			return result + 1;
		}
	}

	namespace Format
	{
		#define READY_SIZE 128

		#define READY_FLUSH() \
			ready[readylen] = '\0'; \
			if ( 0 < readylen && callback && callback(user, ready, readylen) != readylen ) { return SIZE_MAX; } \
			written += readylen; readylen = 0;

		size_t Virtual(Callback callback, void* user, const char* format, va_list parameters)
		{
			size_t written = 0;
			size_t readylen = 0;
			char ready[READY_SIZE + 1];

			while ( *format != '\0' )
			{
				char c = *(format++);

				if ( c != '%' )
				{
					if ( READY_SIZE <= readylen ) { READY_FLUSH(); }
					ready[readylen++] = c;
					continue;
				}

				if ( *format == '%' ) { continue; }

				const nat UNSIGNED = 0;
				const nat INTEGER = (1<<0);
				const nat BIT64 = (1<<1);
				const nat HEX = (1<<2);
				const nat STRING = 8;
				const nat CHARACTER = 9;
			#ifdef PLATFORM_X64
				const nat WORDWIDTH = BIT64;
			#else
				const nat WORDWIDTH = 0;
			#endif

				// TODO: Support signed datatypes!

				nat type = 0;

				bool scanning = true;
				while ( scanning )
				{
					switch( *(format++) )
					{
						case '3':
						case '2':
							break;
						case '6':
						case '4':
							type |= BIT64;
							break;
						case 'p':
							type = WORDWIDTH | HEX;
							scanning = false;
							break;
						case 't':
							type |= INTEGER;
						case 'z':
						case 'l':
							if ( type & WORDWIDTH ) { type |= BIT64; }
							type |= WORDWIDTH;
							break;
						case 'j':
							type |= BIT64;
							break;
						case 'u':
							type |= UNSIGNED;
							scanning = false;
							break;
						case 'd':
						case 'i':
							type |= INTEGER;
							scanning = false;
							break;
						case 'x':
						case 'X':
							type |= HEX;
							scanning = false;
							break;
						case 's':
							type = STRING;
							scanning = false;
							break;
						case 'c':
							type = CHARACTER;
							scanning = false;
							break;
						default:
							return SIZE_MAX;
					}
				}

				switch ( type )
				{
					case INTEGER:
					{
						if ( READY_SIZE - readylen < 10 ) { READY_FLUSH(); }
						int32_t num = va_arg(parameters, int32_t);
						readylen += String::ConvertInt32(num, ready + readylen);
						break;
					}
					case UNSIGNED:
					{
						if ( READY_SIZE - readylen < 10 ) { READY_FLUSH(); }
						uint32_t num = va_arg(parameters, uint32_t);
						readylen += String::ConvertUInt32(num, ready + readylen);
						break;
					}
					case INTEGER | BIT64:
					{
						if ( READY_SIZE - readylen < 10 ) { READY_FLUSH(); }
						int64_t num = va_arg(parameters, int64_t);
						readylen += String::ConvertInt64(num, ready + readylen);
						break;
					}
					case UNSIGNED | BIT64:
					{
						if ( READY_SIZE - readylen < 20 ) { READY_FLUSH(); }
						uint64_t num = va_arg(parameters, uint64_t);
						readylen += String::ConvertUInt64(num, ready + readylen);
						break;
					}
					case INTEGER | HEX:
					case UNSIGNED | HEX:
					{
						if ( READY_SIZE - readylen < 8 ) { READY_FLUSH(); }
						uint32_t num = va_arg(parameters, uint32_t);
						readylen += String::ConvertUInt32Hex(num, ready + readylen);
						break;
					}
					case INTEGER | BIT64 | HEX:
					case UNSIGNED | BIT64 | HEX:
					{
						if ( READY_SIZE - readylen < 16 ) { READY_FLUSH(); }
						uint64_t num = va_arg(parameters, uint64_t);
						readylen += String::ConvertUInt64Hex(num, ready + readylen);
						break;
					}
					case STRING:
					{
						READY_FLUSH();
						const char* str = va_arg(parameters, const char*);
						size_t len = String::Length(str);
						if ( callback && callback(user, str, len) != len ) { return SIZE_MAX; }
						written += len;
						break;
					}
					case CHARACTER:
					{
						int c = va_arg(parameters, int);
						if ( READY_SIZE <= readylen ) { READY_FLUSH(); }
						ready[readylen++] = c;
						break;
					}
				}
			}

			READY_FLUSH();

			return written;
		}
	}
}