/*
 * Copyright (C) 2004-2015 ZNC, see the NOTICE file for details.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <znc/Config.h>
#include <znc/FileUtils.h>
#include <stack>
#include <sstream>

struct ConfigStackEntry {
	CString sTag;
	CString sName;
	CConfig Config;

	ConfigStackEntry(const CString& Tag, const CString Name) {
		sTag = Tag;
		sName = Name;
	}
};

CConfigEntry::CConfigEntry()
	: m_pSubConfig(nullptr) {
}

CConfigEntry::CConfigEntry(const CConfig& Config)
	: m_pSubConfig(new CConfig(Config)) {
}

CConfigEntry::CConfigEntry(const CConfigEntry& other)
	: m_pSubConfig(nullptr) {
	if (other.m_pSubConfig)
		m_pSubConfig = new CConfig(*other.m_pSubConfig);
}

CConfigEntry::~CConfigEntry()
{
	delete m_pSubConfig;
}

CConfigEntry& CConfigEntry::operator=(const CConfigEntry& other) {
	delete m_pSubConfig;
	if (other.m_pSubConfig)
		m_pSubConfig = new CConfig(*other.m_pSubConfig);
	else
		m_pSubConfig = nullptr;
	return *this;
}

bool CConfig::Parse(CFile& file, CString& sErrorMsg)
{
	CString sLine;
	unsigned int uLineNum = 0;
	CConfig *pActiveConfig = this;
	std::stack<ConfigStackEntry> ConfigStack;
	bool bCommented = false;     // support for /**/ style comments

	if (!file.Seek(0)) {
		sErrorMsg = "Could not seek to the beginning of the config.";
		return false;
	}

	while (file.ReadLine(sLine)) {
		uLineNum++;

#define ERROR(arg) do { \
	std::stringstream stream; \
	stream << "Error on line " << uLineNum << ": " << arg; \
	sErrorMsg = stream.str(); \
	m_SubConfigs.clear(); \
	m_ConfigEntries.clear(); \
	return false; \
} while (0)

		// Remove all leading spaces and trailing line endings
		sLine.TrimLeft();
		sLine.TrimRight("\r\n");

		if (bCommented || sLine.Left(2) == "/*") {
			/* Does this comment end on the same line again? */
			bCommented = (sLine.Right(2) != "*/");

			continue;
		}

		if ((sLine.empty()) || (sLine[0] == '#') || (sLine.Left(2) == "//")) {
			continue;
		}

		if ((sLine.Left(1) == "<") && (sLine.Right(1) == ">")) {
			sLine.LeftChomp();
			sLine.RightChomp();
			sLine.Trim();

			CString sTag = sLine.Token(0);
			CString sValue = sLine.Token(1, true);

			sTag.Trim();
			sValue.Trim();

			if (sTag.Left(1) == "/") {
				sTag = sTag.substr(1);

				if (!sValue.empty())
					ERROR("Malformated closing tag. Expected \"</" << sTag << ">\".");
				if (ConfigStack.empty())
					ERROR("Closing tag \"" << sTag << "\" which is not open.");

				const struct ConfigStackEntry& entry = ConfigStack.top();
				CConfig myConfig(entry.Config);
				CString sName(entry.sName);

				if (!sTag.Equals(entry.sTag))
					ERROR("Closing tag \"" << sTag << "\" which is not open.");

				// This breaks entry
				ConfigStack.pop();

				if (ConfigStack.empty())
					pActiveConfig = this;
				else
					pActiveConfig = &ConfigStack.top().Config;

				SubConfig &conf = pActiveConfig->m_SubConfigs[sTag.AsLower()];
				SubConfig::const_iterator it = conf.find(sName);

				if (it != conf.end())
					ERROR("Duplicate entry for tag \"" << sTag << "\" name \"" << sName << "\".");

				conf[sName] = CConfigEntry(myConfig);
			} else {
				if (sValue.empty())
					ERROR("Empty block name at begin of block.");
				ConfigStack.push(ConfigStackEntry(sTag.AsLower(), sValue));
				pActiveConfig = &ConfigStack.top().Config;
			}

			continue;
		}

		// If we have a regular line, figure out where it goes
		CString sName = sLine.Token(0, false, "=");
		CString sValue = sLine.Token(1, true, "=");

		// Only remove the first space, people might want
		// leading spaces (e.g. in the MOTD).
		if (sValue.Left(1) == " ")
			sValue.LeftChomp();

		// We don't have any names with spaces, trim all
		// leading/trailing spaces.
		sName.Trim();

		if (sName.empty() || sValue.empty())
			ERROR("Malformed line");

		CString sNameLower = sName.AsLower();
		pActiveConfig->m_ConfigEntries[sNameLower].push_back(sValue);
	}

	if (bCommented)
		ERROR("Comment not closed at end of file.");

	if (!ConfigStack.empty()) {
		const CString& sTag = ConfigStack.top().sTag;
		ERROR("Not all tags are closed at the end of the file. Inner-most open tag is \"" << sTag << "\".");
	}

	return true;
}

void CConfig::Write(CFile& File, unsigned int iIndentation) {
	CString sIndentation = CString(iIndentation, '\t');

	for (EntryMapIterator it = m_ConfigEntries.begin(); it != m_ConfigEntries.end(); ++it) {
		for (VCString::const_iterator it2 = it->second.begin(); it2 != it->second.end(); ++it2) {
			File.Write(sIndentation + it->first + " = " + *it2 + "\n");
		}
	}

	for (SubConfigMapIterator it = m_SubConfigs.begin(); it != m_SubConfigs.end(); ++it) {
		for (SubConfig::const_iterator it2 = it->second.begin(); it2 != it->second.end(); ++it2) {
			File.Write("\n");

			File.Write(sIndentation + "<" + it->first + " " + it2->first + ">\n");
			it2->second.m_pSubConfig->Write(File, iIndentation + 1);
			File.Write(sIndentation + "</" + it->first + ">\n");
		}
	}
}