#include "csvparser.h"
#include <climits>


CsvParser::CsvParser(bool skip_hdr, char field_sep, char quote_ch, char line_sep, char line_sep2) {
	skip_header = skip_hdr;
	field_separator = field_sep;
	quote_character = quote_ch;
	line_separator = line_sep;
	line_separator2 = line_sep2;

	header_skiped = false;
}

MlValue CsvParser::parseCSV(const std::string &csvSource) {
	constexpr size_t INITIAL_PARSED_ROWS_SIZE = 128;
	constexpr size_t INITIAL_COLUMNS_SIZE = 32;
	constexpr size_t ROWS_READ_FOR_SIZE_ESTIMATION = 16;

    size_t linesRead = 0;
	bool inQuote(false);
	bool newLine(false);
	std::string field;

	std::vector<MlValue> parsed_rows;
	parsed_rows.reserve(INITIAL_PARSED_ROWS_SIZE);

	std::vector<MlValue> line;
	line.reserve(INITIAL_COLUMNS_SIZE);

	std::string::const_iterator aChar = csvSource.begin();
	std::string::const_iterator aEnd = csvSource.end();
	while (aChar != aEnd) {
		if (*aChar == quote_character) {
			newLine = false;
			inQuote = !inQuote;
		} else if (*aChar == field_separator) {
			newLine = false;
			if (inQuote) {
				field += *aChar;
			} else {
				line.push_back(ivalualize(field));
				field.clear();
			}
		} else if (*aChar == line_separator || *aChar == line_separator2) {
			if (inQuote) {
				field += *aChar;
			} else {
				if (!newLine) {
					line.push_back(ivalualize(field));
					add_row(line, parsed_rows);
					field.clear();
					line.clear();
					linesRead++;
					if (linesRead == ROWS_READ_FOR_SIZE_ESTIMATION) {
					    size_t linesEstimation = csvSource.size() / (std::distance(csvSource.begin(), aChar) / linesRead);
						if (linesEstimation > parsed_rows.capacity())
					    	parsed_rows.reserve(linesEstimation);
					}
					newLine = true;
				}
			}
		} else {
			newLine = false;
			field.push_back(*aChar);
		}

		aChar++;
	}

	if (!field.empty())
		line.push_back(ivalualize(field));

	add_row(line, parsed_rows);

	return parsed_rows;
}


void CsvParser::add_row(const std::vector<MlValue> &columns, std::vector<MlValue>  &rows) {
	if (skip_header && !header_skiped) {
		header_skiped = true;
	} else {
		if (!columns.empty())
			rows.emplace_back(columns);
	}
}

MlValue CsvParser::ivalualize(const std::string &value) {
	long int_val;
	double float_val;
	if (value.empty() || ((!isdigit(value[0])) && (value[0] != '-') && (value[0] != '+'))) {
		return MlValue::string(value);
	} else if (is_string_int(value, int_val)) {
		return MlValue(int_val);
	} else if (is_string_float(value, float_val)) {
		return MlValue(float_val);
	} else {
		return MlValue::string(value);
	}
}

// Is string representing int value
bool CsvParser::is_string_int(const std::string &s, long &val) {
    char *end_ptr;
    errno = 0;
	// if(s.empty() || ((!isdigit(s[0])) && (s[0] != '-') && (s[0] != '+'))) return false;
    val = strtol(s.c_str(), &end_ptr, 10);

    if ( *end_ptr != '\0' ) return false;
    if (errno == ERANGE && (val == LONG_MIN || val == LONG_MAX)) return false;
    if (val == 0 && errno != 0) return false;
    return true;
}

// Is string representing float value
bool CsvParser::is_string_float(const std::string &s, double &val) {
    char *end_ptr;
    errno = 0;
	// if(s.empty() || ((!isdigit(s[0])) && (s[0] != '-') && (s[0] != '+'))) return false;
    val = strtod(s.c_str(), &end_ptr);

    if ( *end_ptr != '\0' ) return false;
    if (errno == ERANGE && (val == HUGE_VAL || val == -HUGE_VAL)) return false;
    if (val == 0 && errno != 0) return false;
    return true;
}