//
// RegularExpression.h
//
// Library: Foundation
// Package: RegExp
// Module:  RegularExpression
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#include "Poco/RegularExpression.h"
#include "Poco/Exception.h"
#include <sstream>

#define PCRE2_CODE_UNIT_WIDTH 8
#include <pcre2.h>


namespace
{
	class MatchData
	{
	public:
		MatchData(pcre2_code* code):
			_match(pcre2_match_data_create_from_pattern(reinterpret_cast<pcre2_code*>(code), nullptr))
		{
			if (!_match) throw Poco::RegularExpressionException("cannot create match data");
		}

		~MatchData()
		{
			if (_match) pcre2_match_data_free(_match);
		}

		std::uint32_t count() const
		{
			return pcre2_get_ovector_count(_match);
		}

		const PCRE2_SIZE* data() const
		{
			return pcre2_get_ovector_pointer(_match);
		}

		operator pcre2_match_data*()
		{
			return _match;
		}

	private:
		pcre2_match_data* _match;
	};
}


namespace Poco {


RegularExpression::RegularExpression(const std::string& pattern, int options, bool /*study*/): _pcre(nullptr)
{
	int errorCode;
	PCRE2_SIZE errorOffset;
	unsigned nameCount;
	unsigned nameEntrySize;
	unsigned char* nameTable;

	pcre2_compile_context* context = pcre2_compile_context_create(nullptr);
	if (!context) throw Poco::RegularExpressionException("cannot create compile context");

	const unsigned RE_NEWLINE_MASK = 0x00f00000;
	if ((options & RE_NEWLINE_MASK) == RE_NEWLINE_LF)
		pcre2_set_newline(context, PCRE2_NEWLINE_LF);
	else if ((options & RE_NEWLINE_MASK) == RE_NEWLINE_CRLF)
		pcre2_set_newline(context, PCRE2_NEWLINE_CRLF);
	else if ((options & RE_NEWLINE_MASK) == RE_NEWLINE_ANY)
		pcre2_set_newline(context, PCRE2_NEWLINE_ANY);
	else if ((options & RE_NEWLINE_MASK) == RE_NEWLINE_ANYCRLF)
		pcre2_set_newline(context, PCRE2_NEWLINE_ANYCRLF);
	else // default RE_NEWLINE_CR
		pcre2_set_newline(context, PCRE2_NEWLINE_CR);

	_pcre = pcre2_compile(reinterpret_cast<PCRE2_SPTR>(pattern.c_str()), pattern.length(), compileOptions(options), &errorCode, &errorOffset, context);
	pcre2_compile_context_free(context);

	if (!_pcre)
	{
		PCRE2_UCHAR buffer[256];
		pcre2_get_error_message(errorCode, buffer, sizeof(buffer));
		std::ostringstream msg;
		msg << reinterpret_cast<char*>(buffer) << " (at offset " << errorOffset << ")";
		throw RegularExpressionException(msg.str());
	}

	pcre2_pattern_info(reinterpret_cast<pcre2_code*>(_pcre), PCRE2_INFO_NAMECOUNT, &nameCount);
	pcre2_pattern_info(reinterpret_cast<pcre2_code*>(_pcre), PCRE2_INFO_NAMEENTRYSIZE, &nameEntrySize);
	pcre2_pattern_info(reinterpret_cast<pcre2_code*>(_pcre), PCRE2_INFO_NAMETABLE, &nameTable);

	for (unsigned i = 0; i < nameCount; i++)
	{
		unsigned char* group = nameTable + 2 + (nameEntrySize * i);
		int n = pcre2_substring_number_from_name(reinterpret_cast<pcre2_code*>(_pcre), group);
		_groups[n] = std::string(reinterpret_cast<char*>(group));
	}
}


RegularExpression::~RegularExpression()
{
	if (_pcre) pcre2_code_free(reinterpret_cast<pcre2_code*>(_pcre));
}


int RegularExpression::match(const std::string& subject, std::string::size_type offset, Match& mtch, int options) const
{
	poco_assert (offset <= subject.length());

	MatchData matchData(reinterpret_cast<pcre2_code*>(_pcre));
	int rc = pcre2_match(reinterpret_cast<pcre2_code*>(_pcre), reinterpret_cast<PCRE2_SPTR>(subject.c_str()), subject.size(), offset, matchOptions(options), matchData, nullptr);
	if (rc == PCRE2_ERROR_NOMATCH)
	{
		mtch.offset = std::string::npos;
		mtch.length = 0;
		return 0;
	}
	else if (rc == PCRE2_ERROR_BADOPTION)
	{
		throw RegularExpressionException("bad option");
	}
	else if (rc == 0)
	{
		throw RegularExpressionException("too many captured substrings");
	}
	else if (rc < 0)
	{
		PCRE2_UCHAR buffer[256];
		pcre2_get_error_message(rc, buffer, sizeof(buffer));
		throw RegularExpressionException(std::string(reinterpret_cast<char*>(buffer)));
	}
	const PCRE2_SIZE* ovec = matchData.data();
	mtch.offset = (ovec[0] == PCRE2_UNSET) ? std::string::npos : ovec[0];
	mtch.length = ovec[1] - mtch.offset;
	return rc;
}


int RegularExpression::match(const std::string& subject, std::string::size_type offset, MatchVec& matches, int options) const
{
	poco_assert (offset <= subject.length());

	matches.clear();

	MatchData matchData(reinterpret_cast<pcre2_code*>(_pcre));
	int rc = pcre2_match(reinterpret_cast<pcre2_code*>(_pcre), reinterpret_cast<PCRE2_SPTR>(subject.c_str()), subject.size(), offset, matchOptions(options), matchData, nullptr);
	if (rc == PCRE2_ERROR_NOMATCH)
	{
		return 0;
	}
	else if (rc == PCRE2_ERROR_BADOPTION)
	{
		throw RegularExpressionException("bad option");
	}
	else if (rc == 0)
	{
		throw RegularExpressionException("too many captured substrings");
	}
	else if (rc < 0)
	{
		PCRE2_UCHAR buffer[256];
		pcre2_get_error_message(rc, buffer, sizeof(buffer));
		throw RegularExpressionException(std::string(reinterpret_cast<char*>(buffer)));
	}
	matches.reserve(rc);
	const PCRE2_SIZE* ovec = matchData.data();
	for (int i = 0; i < rc; ++i)
	{
		Match m;
		GroupMap::const_iterator it;

		m.offset = (ovec[i*2] == PCRE2_UNSET) ? std::string::npos : ovec[i*2];
		m.length = ovec[i*2 + 1] - m.offset;

		it = _groups.find(i);
		if (it != _groups.end())
		{
			m.name = (*it).second;
		}

		matches.push_back(m);
	}
	return rc;
}


bool RegularExpression::match(const std::string& subject, std::string::size_type offset) const
{
	Match mtch;
	match(subject, offset, mtch, RE_ANCHORED | RE_NOTEMPTY);
	return mtch.offset == offset && mtch.length == subject.length() - offset;
}


bool RegularExpression::match(const std::string& subject, std::string::size_type offset, int options) const
{
	Match mtch;
	match(subject, offset, mtch, options);
	return mtch.offset == offset && mtch.length == subject.length() - offset;
}


int RegularExpression::extract(const std::string& subject, std::string& str, int options) const
{
	Match mtch;
	int rc = match(subject, 0, mtch, options);
	if (mtch.offset != std::string::npos)
		str.assign(subject, mtch.offset, mtch.length);
	else
		str.clear();
	return rc;
}


int RegularExpression::extract(const std::string& subject, std::string::size_type offset, std::string& str, int options) const
{
	Match mtch;
	int rc = match(subject, offset, mtch, options);
	if (mtch.offset != std::string::npos)
		str.assign(subject, mtch.offset, mtch.length);
	else
		str.clear();
	return rc;
}


int RegularExpression::split(const std::string& subject, std::string::size_type offset, std::vector<std::string>& strings, int options) const
{
	MatchVec matches;
	strings.clear();
	int rc = match(subject, offset, matches, options);
	strings.reserve(matches.size());
	for (const auto& m: matches)
	{
		if (m.offset != std::string::npos)
			strings.push_back(subject.substr(m.offset, m.length));
		else
			strings.push_back(std::string());
	}
	return rc;
}


int RegularExpression::subst(std::string& subject, std::string::size_type offset, const std::string& replacement, int options) const
{
	if (options & RE_GLOBAL)
	{
		int rc = 0;
		std::string::size_type pos = substOne(subject, offset, replacement, options);
		while (pos != std::string::npos)
		{
			++rc;
			pos = substOne(subject, pos, replacement, options);
		}
		return rc;
	}
	else
	{
		return substOne(subject, offset, replacement, options) != std::string::npos ? 1 : 0;
	}
}


std::string::size_type RegularExpression::substOne(std::string& subject, std::string::size_type offset, const std::string& replacement, int options) const
{
	if (offset >= subject.length()) return std::string::npos;

	MatchData matchData(reinterpret_cast<pcre2_code*>(_pcre));
	int rc = pcre2_match(reinterpret_cast<pcre2_code*>(_pcre), reinterpret_cast<PCRE2_SPTR>(subject.c_str()), subject.size(), offset, matchOptions(options), matchData, nullptr);
	if (rc == PCRE2_ERROR_NOMATCH)
	{
		return std::string::npos;
	}
	else if (rc == PCRE2_ERROR_BADOPTION)
	{
		throw RegularExpressionException("bad option");
	}
	else if (rc == 0)
	{
		throw RegularExpressionException("too many captured substrings");
	}
	else if (rc < 0)
	{
		PCRE2_UCHAR buffer[256];
		pcre2_get_error_message(rc, buffer, sizeof(buffer));
		throw RegularExpressionException(std::string(reinterpret_cast<char*>(buffer)));
	}
	const PCRE2_SIZE* ovec = matchData.data();
	std::string result;
	std::string::size_type len = subject.length();
	std::string::size_type pos = 0;
	std::string::size_type rp = std::string::npos;
	while (pos < len)
	{
		if (ovec[0] == pos)
		{
			std::string::const_iterator it  = replacement.begin();
			std::string::const_iterator end = replacement.end();
			while (it != end)
			{
				if (*it == '$' && !(options & RE_NO_VARS))
				{
					++it;
					if (it != end)
					{
						char d = *it;
						if (d >= '0' && d <= '9')
						{
							int c = d - '0';
							if (c < rc)
							{
								std::size_t o = ovec[c*2];
								std::size_t l = ovec[c*2 + 1] - o;
								result.append(subject, o, l);
							}
						}
						else
						{
							result += '$';
							result += d;
						}
						++it;
					}
					else result += '$';
				}
				else result += *it++;
			}
			pos = ovec[1];
			rp = result.length();
		}
		else result += subject[pos++];
	}
	subject = result;
	return rp;
}


bool RegularExpression::match(const std::string& subject, const std::string& pattern, int options)
{
	int ctorOptions = options & (RE_CASELESS | RE_MULTILINE | RE_DOTALL | RE_EXTENDED | RE_ANCHORED | RE_DOLLAR_ENDONLY | RE_EXTRA | RE_UNGREEDY | RE_UTF8 | RE_NO_AUTO_CAPTURE);
	int mtchOptions = options & (RE_ANCHORED | RE_NOTBOL | RE_NOTEOL | RE_NOTEMPTY | RE_NO_AUTO_CAPTURE | RE_NO_UTF8_CHECK);
	RegularExpression re(pattern, ctorOptions, false);
	return re.match(subject, 0, mtchOptions);
}


int RegularExpression::compileOptions(int options)
{
	int pcreOptions = 0;

	if (options & RE_CASELESS)
		pcreOptions |= PCRE2_CASELESS;
	if (options & RE_MULTILINE)
		pcreOptions |= PCRE2_MULTILINE;
	if (options & RE_DOTALL)
		pcreOptions |= PCRE2_DOTALL;
	if (options & RE_EXTENDED)
		pcreOptions |= PCRE2_EXTENDED;
	if (options & RE_ANCHORED)
		pcreOptions |= PCRE2_ANCHORED;
	if (options & RE_DOLLAR_ENDONLY)
		pcreOptions |= PCRE2_DOLLAR_ENDONLY;
	if (options & RE_UNGREEDY)
		pcreOptions |= PCRE2_UNGREEDY;
	if (options & RE_UTF8)
		pcreOptions |= PCRE2_UTF | PCRE2_UCP;
	if (options & RE_NO_AUTO_CAPTURE)
		pcreOptions |= PCRE2_NO_AUTO_CAPTURE;
	if (options & RE_FIRSTLINE)
		pcreOptions |= PCRE2_FIRSTLINE;
	if (options & RE_DUPNAMES)
		pcreOptions |= PCRE2_DUPNAMES;

	return pcreOptions;
}


int RegularExpression::matchOptions(int options)
{
	int pcreOptions = 0;

	if (options & RE_ANCHORED)
		pcreOptions |= PCRE2_ANCHORED;
	if (options & RE_NOTBOL)
		pcreOptions |= PCRE2_NOTBOL;
	if (options & RE_NOTEOL)
		pcreOptions |= PCRE2_NOTEOL;
	if (options & RE_NOTEMPTY)
		pcreOptions |= PCRE2_NOTEMPTY;
	if (options & RE_NO_AUTO_CAPTURE)
		pcreOptions |= PCRE2_NO_AUTO_CAPTURE;
	if (options & RE_NO_UTF8_CHECK)
		pcreOptions |= PCRE2_NO_UTF_CHECK;

	return pcreOptions;
}


} // namespace Poco
