#include "token.h"

void gen_tokens(std::string filename, std::vector<Token> & tokens){ std::ifstream input_file(filename.c_str());
	if (!input_file)
	{
		std::cerr << "I can't read " << filename << "." << std::endl;
		abort();
	}
	std::string line;
	for (int line_no = 1; std::getline(input_file, line); ++line_no)
	{
		for (size_t i = 0; i < line.size();)
		{
			// comments
			if (line[i] == '/')
			{
				++i;
				if ((i == line.size()) || (line[i] != '/'))
				{
					std::cerr << "LINE " << line_no
						<< ": a single / is not allowed" << std::endl;
					abort();
				}
				break; // skip the rest of the line by exiting the loop
			}

			// spaces
			if ((line[i] == ' ') || (line[i] == '\t')
					|| (line[i] == '\r') || (line[i] == '\n'))
			{
				++i; // skip this space character
				continue; // skip the rest of the iteration
			}

			// SINGLE
			if ((line[i] == '(') || (line[i] == ')')
					|| (line[i] == '[') || (line[i] == ']')
					|| (line[i] == ':') || (line[i] == ';')
					|| (line[i] == ','))
			{
				tokens.push_back(Token(Token::SINGLE, std::string(&(line[i]),1)));
				++i; // we consumed this character
				continue; // skip the rest of the iteration
			}

			// NAME
			if (((line[i] >= 'a') && (line[i] <= 'z'))       // a to z
					|| ((line[i] >= 'A') && (line[i] <= 'Z'))    // A to Z
					|| (line[i] == '_'))
			{
				size_t name_begin = i;
				for (++i; i < line.size(); ++i)
				{
					if (!(((line[i] >= 'a') && (line[i] <= 'z'))
								|| ((line[i] >= 'A') && (line[i] <= 'Z'))
								|| ((line[i] >= '0') && (line[i] <= '9'))
								|| (line[i] == '_') || (line[i] == '$')))
					{
						break; // [name_begin, i) is the range for the token
					}
				}
				tokens.push_back(Token(Token::NAME, line.substr(name_begin, i - name_begin)));
			}
			else {
				// NUMBER
				if ((line[i] >= '0') && (line[i] <= '9')) // 0-9
				{
					char * begin = &(line[i]);
					char * end = NULL;

					//used to find the 
					//start and end of the number;
					strtoll(begin, &end, 10);
					i+= end - begin;
					tokens.push_back(Token(Token::NUMBER, std::string(begin, end - begin)));
					continue;
				}
				else
				{
					std::cerr << "LINE " << line_no
						<< ": invalid character" << std::endl;
					abort();
				}
			}
		}
	}

}