#include "TokenStream.h"

#include <iostream>
#include <fstream>

TokenPoint::TokenPoint(TokenStream& S)
: Stream(S), Pos(S.Index)
{
}

TokenPoint::~TokenPoint()
{
	Stream.Index = Pos;
}

bool TokenPoint::accept()
{
	Pos = Stream.Index;
	return true;
}

bool TokenPoint::reject()
{
	Stream.Index = Pos;
	return false;
}

TokenStream::TokenStream()
: Index(0), Errors(0)
{
}

TokenStream::TokenStream(const std::string& Name)
: Index(0), Errors(0)
{
	char buffer[1024];
	std::ifstream ifs(Name.c_str());
	// better
	while (ifs)
	{
		ifs.get(buffer,1024,0);
		Content += std::string(buffer,ifs.gcount());
	}
	Index = 0;
	for (unsigned int i=0, Line=0; i<Content.length(); ++i)
	{
		LineNo.push_back(Line);
		if (Content[i] == '\n')
			++Line;
	}

//	std::cout << Name << "=" << Content << std::endl;
}

void TokenStream::error(const std::string& Err)
{
	std::cout << "Error at line " << LineNo[Index] << " : " << Err << std::endl;
	++Errors;
}

unsigned int TokenStream::errors() const
{
	return Errors;
}

bool TokenStream::eosButWhite()
{
	whiteSpace();
	return eos();
}

bool TokenStream::eos() const
{
	return Index == Content.length();
}

bool TokenStream::whiteSpace()
{
	bool Found = false;
	while (!eos())
	{
		if (Content[Index] == '/')
		{
			++Index;
			if (!eos() && Content[Index] == '/')
			{
				while (!eos())
				{
					if ( (Content[Index] == 10) || (Content[Index] == 11) || (Content[Index] == 13) )
						break;
					++Index;
				}
				if (eos()) return true;
			}
			else
				--Index;
		}
		if ( (Content[Index] != ' ') &&
			(Content[Index] != '\t') &&
			(Content[Index] != 10) &&
			(Content[Index] != 11) &&
			(Content[Index] != 13) )
			break;
		Found = true;
		++Index;
	}
	return Found;
}

bool TokenStream::literal(const std::string& S)
{
	whiteSpace();
	for (unsigned int i=0; i<S.length(); ++i)
		if ( ((Index+i) >= Content.length()) ||
			(Content[Index+i] != S[i]) )
			return false;
	Index += S.length();
	return true;
}

bool TokenStream::literal(char c)
{
	if (Content[Index] == c)
	{
		++Index;
		return true;
	}
	return false;
}

bool TokenStream::alpha()
{
	char c = Content[Index];
	if ( ( (c>='a') && (c<='z') ) ||
	     ( (c>='A') && (c<='Z') ) || (c=='_') )
	{
		++Index;
		return true;
	}
	return false;
}

bool TokenStream::numeric()
{
	char c = Content[Index];
	if ( (c>='0') && (c<='9') )
	{
		++Index;
		return true;
	}
	return false;
}

std::string TokenStream::cIdentifier()
{
	whiteSpace();
	unsigned int Start = Index;
	if (!alpha()) return "";
	while (!eos())
	{
		if (!alpha() && !numeric())
			break;
	}
	return std::string(Content,Start,Index-Start);
}

std::string TokenStream::cToken()
{
	whiteSpace();
	if (eos()) return "";
	if (
		(Content[Index] == '(') ||
		(Content[Index] == ')') ||
		(Content[Index] == ',') ||
		(Content[Index] == '.') )
	{
		++Index;
		return std::string(Content,Index-1,1);
	}
	if (Content[Index] == ':')
	{
		++Index;
		if (!eos() && (Content[Index] == ':'))
		{
			++Index;
			return std::string(Content,Index-2,2);
		}
		return std::string(Content,Index-1,1);
	}
	if (Content[Index] == '=')
	{
		++Index;
		if (!eos() && (Content[Index] == '='))
		{
			++Index;
			return std::string(Content,Index-2,2);
		}
		return std::string(Content,Index-1,1);
	}
	std::string id = cIdentifier();
	if (id != "") return id;
	++Index;
	return std::string(Content,Index-1,1);
}

std::string TokenStream::cString()
{
	whiteSpace();
	if (eos()) return "";
	if (Content[Index] != '"') return "";
	std::string Result("\"");
	for (++Index; !eos(); ++Index)
	{
		if (Content[Index] == '"')
		{
			++Index;
			if (eos() || (Content[Index] != '"') )
			{
				--Index;
				break;
			}
		}
		Result += Content[Index];
	}
	if (eos())
	{
		error("Unended string");
		return Result;
	}
	else
		++Index;
	return Result;
}

std::string TokenStream::makeFileName()
{
	whiteSpace();
	if (eos()) return "";
	std::string Result;
	if (Content[Index] == '"')
	{
		++Index;
		while (!eos())
		{
			++Index;
			if (Content[Index-1] == '"')
				return Result;
			Result += Content[Index-1];
		}
		return Result;
	}
	unsigned int Start = Index;
	while (!eos())
	{
		if (alpha() || numeric() || literal('.') || literal('/') || /* literal(':') || */ literal('\\'))
			Result += Content[Index-1];
	/*	else if (literal('\\'))
		{
			if (eos() || (Content[Index] == 10) || (Content[Index] == 13))
			{
				--Index;
				break;
			}
			Result += Content[Index];
			++Index;
		} */
		else
			break;
	}
	return Result;
}