/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 <log4cxx/pattern/nameabbreviator.h>
#include <log4cxx/helpers/exception.h>
#include <log4cxx/helpers/stringhelper.h>
#include <vector>
#include <limits.h>

using namespace log4cxx;
using namespace log4cxx::pattern;
using namespace log4cxx::helpers;

IMPLEMENT_LOG4CXX_OBJECT(NameAbbreviator)

NameAbbreviator::NameAbbreviator()
{
}

NameAbbreviator::~NameAbbreviator()
{
}

namespace log4cxx
{
namespace pattern
{
/**
 * Abbreviator that simply appends full name to buffer.
 */
class NOPAbbreviator : public NameAbbreviator
{
	public:
		DECLARE_ABSTRACT_LOG4CXX_OBJECT(NOPAbbreviator)
		BEGIN_LOG4CXX_CAST_MAP()
		LOG4CXX_CAST_ENTRY(NOPAbbreviator)
		LOG4CXX_CAST_ENTRY_CHAIN(NameAbbreviator)
		END_LOG4CXX_CAST_MAP()

		/**
		 * Constructor.
		 */
		NOPAbbreviator()
		{
		}

		/**
		 * {@inheritDoc}
		 */
		void abbreviate(LogString::size_type /* nameStart */, LogString& /* buf */) const
		{
		}
};


/**
 * Abbreviator that drops starting path elements.
 */
class MaxElementAbbreviator : public NameAbbreviator
{
		/**
		 * Maximum number of path elements to output.
		 */
		const int count;

	public:
		DECLARE_ABSTRACT_LOG4CXX_OBJECT(MaxElementAbbreviator)
		BEGIN_LOG4CXX_CAST_MAP()
		LOG4CXX_CAST_ENTRY(MaxElementAbbreviator)
		LOG4CXX_CAST_ENTRY_CHAIN(NameAbbreviator)
		END_LOG4CXX_CAST_MAP()
		/**
		 * Create new instance.
		 * @param count maximum number of path elements to output.
		 */
		MaxElementAbbreviator(const int count1) : count(count1)
		{
		}

		/**
		 * Abbreviate name.
		 * @param buf buffer to append abbreviation.
		 * @param nameStart start of name to abbreviate.
		 */
		void abbreviate(LogString::size_type nameStart, LogString& buf) const
		{
			// We substract 1 from 'len' when assigning to 'end' to avoid out of
			// bounds exception in return r.substring(end+1, len). This can happen if
			// precision is 1 and the logger name ends with a dot.
			LogString::size_type end = buf.length() - 1;

			for (LogString::size_type i = count; i > 0; i--)
			{
				end = buf.rfind(0x2E /* '.' */, end - 1);

				if ((end == LogString::npos) || (end < nameStart))
				{
					return;
				}
			}

			buf.erase(buf.begin() + nameStart, buf.begin() + (end + 1));
		}
};

/**
 * Fragment of an pattern abbreviator.
 *
 */
class PatternAbbreviatorFragment
{
		/**
		 * Count of initial characters of element to output.
		 */
		LogString::size_type charCount;

		/**
		 *  Character used to represent dropped characters.
		 * '\0' indicates no representation of dropped characters.
		 */
		logchar ellipsis;

	public:
		/**
		 * Creates a PatternAbbreviatorFragment.
		 * @param charCount number of initial characters to preserve.
		 * @param ellipsis character to represent elimination of characters,
		 *    '\0' if no ellipsis is desired.
		 */
		PatternAbbreviatorFragment(
			const int charCount1, const logchar ellipsis1)
			: charCount(charCount1), ellipsis(ellipsis1)
		{
		}
		PatternAbbreviatorFragment() : charCount(0), ellipsis(0)
		{
		}

		PatternAbbreviatorFragment(const PatternAbbreviatorFragment& src)
			: charCount(src.charCount), ellipsis(src.ellipsis)
		{
		}

		PatternAbbreviatorFragment& operator=(const PatternAbbreviatorFragment& src)
		{
			charCount = src.charCount;
			ellipsis = src.ellipsis;
			return *this;
		}

		/**
		 * Abbreviate element of name.
		 * @param buf buffer to receive element.
		 * @param startPos starting index of name element.
		 * @return starting index of next element.
		 */
		LogString::size_type abbreviate(LogString& buf, LogString::size_type startPos) const
		{
			LogString::size_type nextDot = buf.find(0x2E /* '.' */, startPos);

			if (nextDot != LogString::npos)
			{
				if ((nextDot - startPos) > charCount)
				{
					buf.erase(buf.begin() + (startPos + charCount), buf.begin() + nextDot);
					nextDot = startPos + charCount;

					if (ellipsis != 0x00)
					{
						buf.insert(nextDot, 1, ellipsis);
						nextDot++;
					}
				}

				nextDot++;
			}

			return nextDot;
		}
};

/**
 * Pattern abbreviator.
 *
 *
 */
class PatternAbbreviator : public NameAbbreviator
{
		/**
		 * Element abbreviation patterns.
		 */
		std::vector<PatternAbbreviatorFragment> fragments;

	public:
		DECLARE_ABSTRACT_LOG4CXX_OBJECT(PatternAbbreviator)
		BEGIN_LOG4CXX_CAST_MAP()
		LOG4CXX_CAST_ENTRY(PatternAbbreviator)
		LOG4CXX_CAST_ENTRY_CHAIN(NameAbbreviator)
		END_LOG4CXX_CAST_MAP()
		/**
		 * Create PatternAbbreviator.
		 *
		 * @param fragments element abbreviation patterns.
		 */
		PatternAbbreviator(const std::vector<PatternAbbreviatorFragment>& fragments1) :
			fragments(fragments1)
		{
			if (fragments1.size() == 0)
			{
				throw IllegalArgumentException(LOG4CXX_STR("fragments parameter must contain at least one element"));
			}
		}

		/**
		 * Abbreviate name.
		 * @param buf buffer that abbreviated name is appended.
		 * @param nameStart start of name.
		 */
		void abbreviate(LogString::size_type nameStart, LogString& buf) const
		{
			//
			//  all non-terminal patterns are executed once
			//
			LogString::size_type pos = nameStart;

			for (LogString::size_type i = 0; (i < (fragments.size() - 1)) && (pos < buf.length());
				i++)
			{
				pos = fragments[i].abbreviate(buf, pos);
			}

			//
			//   last pattern in executed repeatedly
			//
			PatternAbbreviatorFragment terminalFragment =
				fragments[fragments.size() - 1];

			while (pos < buf.length())
			{
				pos = terminalFragment.abbreviate(buf, pos);
			}
		}
};
}
}

IMPLEMENT_LOG4CXX_OBJECT(NOPAbbreviator)
IMPLEMENT_LOG4CXX_OBJECT(MaxElementAbbreviator)
IMPLEMENT_LOG4CXX_OBJECT(PatternAbbreviator)


NameAbbreviatorPtr NameAbbreviator::getAbbreviator(const LogString& pattern)
{
	if (pattern.length() > 0)
	{
		//  if pattern is just spaces and numbers then
		//     use MaxElementAbbreviator
		LogString trimmed(StringHelper::trim(pattern));

		if (trimmed.length() == 0)
		{
			return getDefaultAbbreviator();
		}

		LogString::size_type i = 0;

		while (
			(i < trimmed.length()) && (trimmed[i] >= 0x30 /* '0' */)
			&& (trimmed[i] <= 0x39 /* '9' */))
		{
			i++;
		}

		//
		//  if all blanks and digits
		//
		if (i == trimmed.length())
		{
			return new MaxElementAbbreviator(StringHelper::toInt(trimmed));
		}

		std::vector<PatternAbbreviatorFragment> fragments;
		logchar ellipsis;
		int charCount;
		LogString::size_type pos = 0;

		while (pos < trimmed.length())
		{
			LogString::size_type ellipsisPos = pos;

			if (trimmed[pos] == 0x2A /* '*' */)
			{
				charCount = INT_MAX;
				ellipsisPos++;
			}
			else
			{
				if ((trimmed[pos] >= 0x30 /* '0' */)
					&& (trimmed[pos] <= 0x39 /* '9' */))
				{
					charCount = trimmed[pos] - 0x30 /* '0' */;
					ellipsisPos++;
				}
				else
				{
					charCount = 0;
				}
			}

			ellipsis = 0;

			if (ellipsisPos < trimmed.length())
			{
				ellipsis = trimmed[ellipsisPos];

				if (ellipsis == 0x2E /* '.' */)
				{
					ellipsis = 0;
				}
			}

			fragments.push_back(PatternAbbreviatorFragment(charCount, ellipsis));
			pos = trimmed.find(0x2E /* '.' */, pos);

			if (pos == LogString::npos)
			{
				break;
			}

			pos++;
		}

		NameAbbreviatorPtr abbrev(new PatternAbbreviator(fragments));
		return abbrev;
	}

	//
	//  no matching abbreviation, return defaultAbbreviator
	//
	return getDefaultAbbreviator();
}

/**
 * Gets default abbreviator.
 *
 * @return default abbreviator.
 */
NameAbbreviatorPtr NameAbbreviator::getDefaultAbbreviator()
{
	static NameAbbreviatorPtr def(new NOPAbbreviator());
	return def;
}