/*
    Ousía
    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel

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

    This program 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 General Public License for more details.

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

#include <algorithm>
#include <cctype>
#include <string>

#include "Utils.hpp"

namespace ousia {

bool Utils::isIdentifier(const std::string &name)
{
	bool first = true;
	for (char c : name) {
		if (first && !isIdentifierStartCharacter(c)) {
			return false;
		}
		if (!first && !isIdentifierCharacter(c)) {
			return false;
		}
		first = false;
	}
	return !first && isIdentifierEndCharacter(name.back());
}

bool Utils::isIdentifierOrEmpty(const std::string &name)
{
	return name.empty() || isIdentifier(name);
}

bool Utils::isNamespacedIdentifier(const std::string &name)
{
	bool first = true;
	for (size_t i = 0; i < name.size(); i++) {
		const char c = name[i];
		if (first && !isIdentifierStartCharacter(c)) {
			return false;
		}
		if (!first && (!(isIdentifierCharacter(c) || c == ':') ||
		               (c == ':' && !isIdentifierEndCharacter(name[i - 1])))) {
			return false;
		}
		first = (c == ':');
	}
	return !first && isIdentifierEndCharacter(name.back());
}

bool Utils::hasNonWhitepaceChar(const std::string &s)
{
	for (char c : s) {
		if (!isWhitespace(c)) {
			return true;
		}
	}
	return false;
}

std::vector<std::string> Utils::split(const std::string &s, char delim)
{
	std::vector<std::string> res;
	const size_t totalLen = s.size();
	size_t start = 0;
	size_t len = 0;
	for (size_t i = 0; i <= totalLen; i++) {
		if (i == totalLen || s[i] == delim) {
			res.push_back(s.substr(start, len));
			start = i + 1;
			len = 0;
		} else {
			len++;
		}
	}
	return res;
}

std::string Utils::toLower(std::string s)
{
	std::transform(s.begin(), s.end(), s.begin(), tolower);
	return s;
}

std::string Utils::extractFileExtension(const std::string &filename)
{
	size_t n = 0;
	for (ssize_t i = filename.size() - 1; i >= 0; i--) {
		if (filename[i] == '/' || filename[i] == '\\') {
			return std::string{};
		}
		if (filename[i] == '.') {
			return toLower(filename.substr(i + 1, n));
		}
		n++;
	}
	return std::string{};
}

bool Utils::startsWith(const std::string &s, const std::string &prefix)
{
	return prefix.size() <= s.size() && s.substr(0, prefix.size()) == prefix;
}

bool Utils::endsWith(const std::string &s, const std::string &suffix)
{
	return suffix.size() <= s.size() &&
	       s.substr(s.size() - suffix.size(), suffix.size()) == suffix;
}

bool Utils::isUserDefinedToken(const std::string &token)
{
	// Make sure the token meets is neither empty, nor starts or ends with an
	// alphanumeric character
	const size_t len = token.size();
	if (len == 0 || isAlphanumeric(token[0]) ||
	    isAlphanumeric(token[len - 1])) {
		return false;
	}

	// Make sure the token is not any special OSML token
	if (token == "\\" || token == "%" || token == "%{" || token == "}%" ||
	    token == "{!" || token == "<\\" || token == "\\>") {
		return false;
	}

	// Make sure the token does not contain any whitespaces.
	for (char c : token) {
		if (isWhitespace(c)) {
			return false;
		}
	}

	// Make sure the token contains other characters but { and }
	for (char c : token) {
		if (c != '{' && c != '}') {
			return true;
		}
	}
	return false;
}
}