/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *                    > www.orxonox.net <
 *
 *
 *   License notice:
 *
 *   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 2
 *   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, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 *   Author:
 *      Fabian 'x3n' Landau
 *   Co-authors:
 *      Benjamin Grauer
 *
 */

/**
    @file
    @brief Implementation of several string manipulation functions.
*/

#include "StringUtils.h"

#include <cctype>
#include <boost/scoped_array.hpp>
#include "Convert.h"
#include "Math.h"

namespace orxonox
{
    std::string BLANKSTRING;

    std::string getUniqueNumberString()
    {
        return multi_cast<std::string>(getUniqueNumber());
    }

    /**
        @brief Removes all whitespaces from a string.
        @param str The string to strip
    */
    void strip(std::string* str)
    {
        size_t pos;
        while ((pos = str->find(' ')) < str->length())
            str->erase(pos, 1);
        while ((pos = str->find('\t')) < str->length())
            str->erase(pos, 1);
        while ((pos = str->find('\n')) < str->length())
            str->erase(pos, 1);
    }

    /**
        @brief Returns a copy of a string without whitespaces.
        @param str The string to strip
        @return The stripped line
    */
    std::string getStripped(const std::string& str)
    {
        std::string output(str);
        strip(&output);
        return output;
    }

    /**
        @brief Returns a copy of a string without trailing whitespaces.
        @param str The string
        @return The modified copy
    */
    std::string removeTrailingWhitespaces(const std::string& str)
    {
        size_t pos1 = 0;
        int pos2 = static_cast<int>(str.size() - 1);
        for (; pos1 < str.size() && (str[pos1] == ' ' || str[pos1] == '\t' || str[pos1] == '\n'); pos1++);
        for (; pos2 > 0         && (str[pos2] == ' ' || str[pos2] == '\t' || str[pos2] == '\n'); pos2--);
        return str.substr(pos1, pos2 - pos1 + 1);
    }

    /**
        @brief Returns the position of the next quote in the string, starting with start.
        @param str The string
        @param start The startposition
        @return The position of the next quote (std::string::npos if there is no next quote)
    */
    size_t getNextQuote(const std::string& str, size_t start)
    {
        size_t quote = start - 1;

        while ((quote = str.find('"', quote + 1)) != std::string::npos)
        {
            size_t backslash = quote;
            size_t numbackslashes = 0;
            for (; backslash > 0; backslash--, numbackslashes++)
                if (str[backslash - 1] != '\\')
                    break;

            if (numbackslashes % 2 == 0)
                break;
        }

        return quote;
    }

    /**
        @brief Returns true if pos is between two quotes.
        @param str The string
        @param pos The position to check
        @return True if pos is between two quotes
    */
    bool isBetweenQuotes(const std::string& str, size_t pos)
    {
        if (pos == std::string::npos)
            return false;

        size_t quotecount = 0;
        size_t quote = static_cast<size_t>(-1);
        while ((quote = getNextQuote(str, quote + 1)) < pos)
        {
            if (quote == pos)
                return false;
            quotecount++;
        }

        if (quote == std::string::npos)
            return false;

        return ((quotecount % 2) == 1);
    }

    /**
        @brief Returns true if the string contains something like '..."between quotes"...'.
        @param str The string
        @return True if there is something between quotes
    */
    bool hasStringBetweenQuotes(const std::string& str)
    {
        size_t pos1 = getNextQuote(str, 0);
        size_t pos2 = getNextQuote(str, pos1 + 1);
        return (pos1 != std::string::npos && pos2 != std::string::npos && pos2 > pos1 + 1);
    }

    /**
        @brief If the string contains something like '..."between quotes"...' then 'between quotes' gets returned (without quotes).
        @param str The string between the quotes
    */
    std::string getStringBetweenQuotes(const std::string& str)
    {
        size_t pos1 = getNextQuote(str, 0);
        size_t pos2 = getNextQuote(str, pos1 + 1);
        if (pos1 != std::string::npos && pos2 != std::string::npos)
            return str.substr(pos1, pos2 - pos1 + 1);
        else
            return "";
    }

    /**
        @brief Removes enclosing quotes if available (including whitespaces at the outside of the quotes).
        @param str The string to strip
        @return The string with removed quotes
    */
    std::string stripEnclosingQuotes(const std::string& str)
    {
        size_t start = std::string::npos;
        size_t end = 0;

        for (size_t pos = 0; (pos < str.size()) && (pos < std::string::npos); pos++)
        {
            if (str[pos] == '"')
            {
                start = pos;
                break;
            }

            if ((str[pos] != ' ') && (str[pos] != '\t') && (str[pos] != '\n'))
                return str;
        }

        for (size_t pos = str.size() - 1; pos < std::string::npos; pos--)
        {
            if (str[pos] == '"')
            {
                end = pos;
                break;
            }

            if ((str[pos] != ' ') && (str[pos] != '\t') && (str[pos] != '\n'))
                return str;
        }

        if ((start != std::string::npos) && (end != 0))
            return str.substr(start + 1, end - start - 1);
        else
            return str;
    }

    /**
        @brief Removes enclosing {braces} (braces must be exactly on the beginning and the end of the string).
        @param str The string to strip
        @return The striped string
    */
    std::string stripEnclosingBraces(const std::string& str)
    {
        std::string output = str;

        while (output.size() >= 2 && output[0] == '{' && output[output.size() - 1] == '}')
            output = output.substr(1, output.size() - 2);

        return output;
    }

    /**
        @brief Determines if a string is a comment (starts with a comment-symbol).
        @param str The string to check
        @return True = it's a comment

        A comment is defined by a leading '#', '%', ';' or '//'.
    */
    bool isComment(const std::string& str)
    {
        // Strip the line, whitespaces are disturbing
        const std::string& teststring = getStripped(str);

        // There are four possible comment-symbols:
        //  1) #comment in script-language style
        //  2) %comment in matlab style
        //  3) ;comment in unreal tournament config-file style
        //  4) //comment in code style
        if (teststring.size() >= 2)
        {
            if (teststring[0] == '#' || teststring[0] == '%' || teststring[0] == ';' || (teststring[0] == '/' && teststring[1] == '/'))
                return true;
        }
        else if (teststring.size() == 1)
        {
            if (teststring[0] == '#' || teststring[0] == '%' || teststring[0] == ';')
                return true;
        }

        return false;
    }

    /**
        @brief Determines if a string is empty (contains only whitespaces).
        @param str The string to check
        @return True = it's empty
    */
    bool isEmpty(const std::string& str)
    {
        return getStripped(str).empty();
    }

    /**
        @brief Determines if a string contains only numbers and maximal one '.'.
        @param str The string to check
        @return True = it's a number
    */
    bool isNumeric(const std::string& str)
    {
        bool foundPoint = false;

        for (std::string::const_iterator it = str.begin(); it != str.end(); ++it)
        {
            if (((*it) < '0' || (*it) > '9'))
            {
                if ((*it) != '.' && !foundPoint)
                    foundPoint = true;
                else
                    return false;
            }
        }

        return true;
    }

    /**
        @brief Adds backslashes to the given string which makes special chars visible. Existing slashes will be doubled.
        @param str The string to manipulate
        @return The string with added slashes
    */
    std::string addSlashes(const std::string& str)
    {
        std::string output(str.size() * 2, ' ');
        size_t i = 0;
        for (size_t pos = 0; pos < str.size(); ++pos)
        {
            switch (str[pos])
            {
            case '\\': output[i] = '\\'; output[i + 1] = '\\'; break;
            case '\n': output[i] = '\\'; output[i + 1] =  'n'; break;
            case '\t': output[i] = '\\'; output[i + 1] =  't'; break;
            case '\v': output[i] = '\\'; output[i + 1] =  'v'; break;
            case '\b': output[i] = '\\'; output[i + 1] =  'b'; break;
            case '\r': output[i] = '\\'; output[i + 1] =  'r'; break;
            case '\f': output[i] = '\\'; output[i + 1] =  'f'; break;
            case '\a': output[i] = '\\'; output[i + 1] =  'a'; break;
            case  '"': output[i] = '\\'; output[i + 1] =  '"'; break;
            case '\0': output[i] = '\\'; output[i + 1] =  '0'; break;
            default  : output[i] = str[pos]; ++i; continue;
            }
            i += 2;
        }
        output.resize(i);

        return output;
    }

    /**
        @brief Removes backslashes from the given string. Double backslashes are interpreted as one backslash.
        @param str The string to manipulate
        @return The string with removed slashes
    */
    std::string removeSlashes(const std::string& str)
    {
        if (str.size() <= 1)
            return str;

        std::string output(str.size(), ' ');
        size_t i = 0;
        size_t pos = 0;
        while (pos < str.size() - 1)
        {
            if (str[pos] == '\\')
            {
                switch (str[pos + 1])
                {
                case '\\': output[i] = '\\'; break;
                case  'n': output[i] = '\n'; break;
                case  't': output[i] = '\t'; break;
                case  'v': output[i] = '\v'; break;
                case  'b': output[i] = '\b'; break;
                case  'r': output[i] = '\r'; break;
                case  'f': output[i] = '\f'; break;
                case  'a': output[i] = '\a'; break;
                case  '"': output[i] =  '"'; break;
                case  '0': output[i] = '\0'; break;
                default: ++pos; continue;
                }
                pos += 2; ++i;
            }
            else
                output[i++] = str[pos++];
        }
        if (pos < str.size())
            output[i++] = str[pos];
        output.resize(i);

        return output;
    }

    /**
        @brief Replaces each char between A and Z with its lowercase equivalent.
        @param str The string to convert
    */
    void lowercase(std::string* str)
    {
        for (size_t i = 0; i < str->size(); ++i)
        {
            (*str)[i] = static_cast<char>(tolower((*str)[i]));
        }
    }

    /**
        @brief Returns a copy of the given string without uppercase chars.
        @param str The string
        @return The copy
    */
    std::string getLowercase(const std::string& str)
    {
        std::string output(str);
        lowercase(&output);
        return output;
    }

    /**
        @brief Replaces each char between a and z with its uppercase equivalent.
        @param str The string to convert
    */
    void uppercase(std::string* str)
    {
        for (size_t i = 0; i < str->size(); ++i)
        {
            (*str)[i] = static_cast<char>(toupper((*str)[i]));
        }
    }

    /**
        @brief Returns a copy of the given string without lowercase chars.
        @param str The string
        @return The copy
    */
    std::string getUppercase(const std::string& str)
    {
        std::string output(str);
        uppercase(&output);
        return output;
    }

    /**
        @brief Compares two strings ignoring different casing.
        @param s1 First string
        @param s2 Second string
    */
    int nocaseCmp(const std::string& s1, const std::string& s2)
    {
        std::string::const_iterator it1=s1.begin();
        std::string::const_iterator it2=s2.begin();

        //stop when either string's end has been reached
        while ( (it1!=s1.end()) && (it2!=s2.end()) )
        {
            if(::toupper(*it1) != ::toupper(*it2)) //letters differ?
                // return -1 to indicate smaller than, 1 otherwise
                return (::toupper(*it1)  < ::toupper(*it2)) ? -1 : 1;
            //proceed to the next character in each string
            ++it1;
            ++it2;
        }
        size_t size1=s1.size(), size2=s2.size();// cache lengths
        //return -1,0 or 1 according to strings' lengths
        if (size1==size2)
            return 0;
        return (size1<size2) ? -1 : 1;
    }


    /**
        @brief Compares the first 'len' chars of two strings ignoring different casing.
        @param s1 First string
        @param s2 Second string
        @param len Maximal number of chars to compare
    */
    int nocaseCmp(const std::string& s1, const std::string& s2, size_t len)
    {
        if (len == 0)
            return 0;
        std::string::const_iterator it1=s1.begin();
        std::string::const_iterator it2=s2.begin();

        //stop when either string's end has been reached
        while ( (it1!=s1.end()) && (it2!=s2.end()) && len-- > 0)
        {
            if(::toupper(*it1) != ::toupper(*it2)) //letters differ?
                // return -1 to indicate smaller than, 1 otherwise
                return (::toupper(*it1)  < ::toupper(*it2)) ? -1 : 1;
            //proceed to the next character in each string
            ++it1;
            ++it2;
        }
        return 0;
    }

    /**
        @brief Returns true if the string contains a comment, introduced by #, %, ; or //.
        @param str The string
        @return True if the string contains a comment
    */
    bool hasComment(const std::string& str)
    {
        return (getCommentPosition(str) != std::string::npos);
    }

    /**
        @brief If the string contains a comment, the comment gets returned (including the comment symbol), an empty string otherwise.
        @param str The string
        @return The comment
    */
    std::string getComment(const std::string& str)
    {
        return str.substr(getCommentPosition(str));
    }

    /**
        @brief If the string contains a comment, the position of the comment-symbol gets returned, std::string::npos otherwise.
        @param str The string
        @return The position
    */
    size_t getCommentPosition(const std::string& str)
    {
        return getNextCommentPosition(str, 0);
    }

    /**
        @brief Returns the position of the next comment-symbol, starting with start.
        @param str The string
        @param start The startposition
        @return The position
    */
    size_t getNextCommentPosition(const std::string& str, size_t start)
    {
        for (size_t i = start; i < str.size(); i++)
            if (isComment(str.substr(i)))
                return i;

        return std::string::npos;
    }

    /**
        @brief Replaces individual charaters
        @param str String to be manipulated
        @param target Character to be replaced
        @param replacement Replacement character
        @return Number of replacements
    */
    size_t replaceCharacters(std::string& str, char target, char replacement)
    {
        size_t j = 0;
        for (size_t i = 0; i < str.size(); ++i)
        {
            if (str[i] == target)
            {
                str[i] = replacement;
                ++j;
            }
        }
        return j;
    }

    /**
        @brief Calculates the Levenshtein distance between two strings.

        The Levenshtein distance is defined by the number of transformations needed to convert str1
        into str2. Possible transformations are substituted, added, or removed characters.
    */
    unsigned int getLevenshteinDistance(const std::string& str1, const std::string& str2)
    {
        size_t cols = str1.size() + 1;
        size_t rows = str2.size() + 1;
        boost::scoped_array<int> matrix(new int[rows * cols]);

        for (size_t r = 0; r < rows; ++r)
            for (size_t c = 0; c < cols; ++c)
                matrix[r*cols + c] = 0;

        for (size_t i = 1; i < cols; ++i)
            matrix[0*cols + i] = i;
        for (size_t i = 1; i < rows; ++i)
            matrix[i*cols + 0] = i;

        for (size_t r = 1; r < rows; ++r)
            for (size_t c = 1; c < cols; ++c)
                matrix[r*cols + c] = (str1[c-1] != str2[r-1]);

        for (size_t r = 1; r < rows; ++r)
            for (size_t c = 1; c < cols; ++c)
                matrix[r*cols + c] = std::min(std::min(matrix[(r-1)*cols + c] + 1,
                                                       matrix[r*cols + c-1] + 1),
                                              matrix[(r-1)*cols + c-1] + (str1[c-1] != str2[r-1]));

        return matrix[(rows-1)*cols + cols-1];
    }
}