// text.cpp

/*    Copyright 2009 10gen Inc.
 *
 *    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 "mongo/util/text.h"

#include <boost/integer_traits.hpp>
#include <boost/smart_ptr/scoped_array.hpp>
#include <errno.h>
#include <sstream>

#ifdef _WIN32
#include <io.h>
#endif

#include "mongo/platform/basic.h"
#include "mongo/util/mongoutils/str.h"

using namespace std;

namespace mongo {

    // --- StringSplitter ----

    /** get next split string fragment */
    string StringSplitter::next() {
        const char * foo = strstr( _big , _splitter );
        if ( foo ) {
            string s( _big , foo - _big );
            _big = foo + strlen( _splitter );
            while ( *_big && strstr( _big , _splitter ) == _big )
                _big++;
            return s;
        }
        
        string s = _big;
        _big += strlen( _big );
        return s;
    }


    void StringSplitter::split( vector<string>& l ) {
        while ( more() ) {
            l.push_back( next() );
        }
    }

    vector<string> StringSplitter::split() {
        vector<string> l;
        split( l );
        return l;
    }

    string StringSplitter::join( const vector<string>& l , const string& split ) {
        stringstream ss;
        for ( unsigned i=0; i<l.size(); i++ ) {
            if ( i > 0 )
                ss << split;
            ss << l[i];
        }
        return ss.str();
    }

    vector<string> StringSplitter::split( const string& big , const string& splitter ) {
        StringSplitter ss( big.c_str() , splitter.c_str() );
        return ss.split();
    }
    


    // --- utf8 utils ------

    inline int leadingOnes(unsigned char c) {
        if (c < 0x80) return 0;
        static const char _leadingOnes[128] = {
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x80 - 0x8F
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x90 - 0x99
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0xA0 - 0xA9
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0xB0 - 0xB9
            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 0xC0 - 0xC9
            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 0xD0 - 0xD9
            3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // 0xE0 - 0xE9
            4, 4, 4, 4, 4, 4, 4, 4,                         // 0xF0 - 0xF7
            5, 5, 5, 5,             // 0xF8 - 0xFB
            6, 6,       // 0xFC - 0xFD
            7,    // 0xFE
            8, // 0xFF
        };
        return _leadingOnes[c & 0x7f];

    }

    bool isValidUTF8(const std::string& s) { 
        return isValidUTF8(s.c_str()); 
    }

    bool isValidUTF8(const char *s) {
        int left = 0; // how many bytes are left in the current codepoint
        while (*s) {
            const unsigned char c = (unsigned char) *(s++);
            const int ones = leadingOnes(c);
            if (left) {
                if (ones != 1) return false; // should be a continuation byte
                left--;
            }
            else {
                if (ones == 0) continue; // ASCII byte
                if (ones == 1) return false; // unexpected continuation byte
                if (c > 0xF4) return false; // codepoint too large (< 0x10FFFF)
                if (c == 0xC0 || c == 0xC1) return false; // codepoints <= 0x7F shouldn't be 2 bytes

                // still valid
                left = ones-1;
            }
        }
        if (left!=0) return false; // string ended mid-codepoint
        return true;
    }

    long long parseLL( const char *n ) {
        long long ret;
        uassert( 13307, "cannot convert empty string to long long", *n != 0 );
#if !defined(_WIN32)
        char *endPtr = 0;
        errno = 0;
        ret = strtoll( n, &endPtr, 10 );
        uassert( 13305, "could not convert string to long long", *endPtr == 0 && errno == 0 );
#elif _MSC_VER>=1600    // 1600 is VS2k10 1500 is VS2k8
        size_t endLen = 0;
        try {
            ret = stoll( n, &endLen, 10 );
        }
        catch ( ... ) {
            endLen = 0;
        }
        uassert( 13306, "could not convert string to long long", endLen != 0 && n[ endLen ] == 0 );
#else // stoll() wasn't introduced until VS 2010.
        char* endPtr = 0;
        ret = _strtoi64( n, &endPtr, 10 );
        uassert( 13310, "could not convert string to long long", (*endPtr == 0) && (ret != _I64_MAX) && (ret != _I64_MIN) );
#endif // !defined(_WIN32)
        return ret;
    }


#if defined(_WIN32)

    std::string toUtf8String(const std::wstring& wide) {
        if (wide.size() > boost::integer_traits<int>::const_max)
            throw std::length_error(
                "Wide string cannot be more than INT_MAX characters long.");
        if (wide.size() == 0)
            return "";

        // Calculate necessary buffer size
        int len = ::WideCharToMultiByte(
                      CP_UTF8, 0, wide.c_str(), static_cast<int>(wide.size()),
                      NULL, 0, NULL, NULL);

        // Perform actual conversion
        if (len > 0) {
            std::vector<char> buffer(len);
            len = ::WideCharToMultiByte(
                      CP_UTF8, 0, wide.c_str(), static_cast<int>(wide.size()),
                      &buffer[0], static_cast<int>(buffer.size()), NULL, NULL);
            if (len > 0) {
                verify(len == static_cast<int>(buffer.size()));
                return std::string(&buffer[0], buffer.size());
            }
        }

        msgasserted( 16091 ,
                     mongoutils::str::stream() << "can't wstring to utf8: " << ::GetLastError() );
        return "";
    }

    std::wstring toWideString(const char *utf8String) {
        int bufferSize = MultiByteToWideChar(
                CP_UTF8,            // Code page
                0,                  // Flags
                utf8String,         // Input string
                -1,                 // Count, -1 for NUL-terminated
                NULL,               // No output buffer
                0                   // Zero means "compute required size"
        );
        if ( bufferSize == 0 ) {
            return std::wstring();
        }
        boost::scoped_array< wchar_t > tempBuffer( new wchar_t[ bufferSize ] );
        tempBuffer[0] = 0;
        MultiByteToWideChar(
                CP_UTF8,            // Code page
                0,                  // Flags
                utf8String,         // Input string
                -1,                 // Count, -1 for NUL-terminated
                tempBuffer.get(),   // UTF-16 output buffer
                bufferSize          // Buffer size in wide characters
        );
        return std::wstring( tempBuffer.get() );
    }

    /**
     * Write a UTF-8 string to the Windows console in Unicode (UTF-16)
     *
     * @param utf8String        UTF-8 input string
     * @param utf8StringSize    Number of bytes in UTF-8 string, no NUL terminator assumed
     * @return                  true if all characters were displayed (including zero characters)
     */
    bool writeUtf8ToWindowsConsole( const char* utf8String, unsigned int utf8StringSize ) {
        int bufferSize = MultiByteToWideChar(
                CP_UTF8,            // Code page
                0,                  // Flags
                utf8String,         // Input string
                utf8StringSize,     // Input string length
                NULL,               // No output buffer
                0                   // Zero means "compute required size"
        );
        if ( bufferSize == 0 ) {
            return true;
        }
        boost::scoped_array<wchar_t> utf16String( new wchar_t[ bufferSize ] );
        MultiByteToWideChar(
                CP_UTF8,            // Code page
                0,                  // Flags
                utf8String,         // Input string
                utf8StringSize,     // Input string length
                utf16String.get(),  // UTF-16 output buffer
                bufferSize          // Buffer size in wide characters
        );
        const wchar_t* utf16Pointer = utf16String.get();
        size_t numberOfCharactersToWrite = bufferSize;
        HANDLE consoleHandle = GetStdHandle( STD_OUTPUT_HANDLE );
        while ( numberOfCharactersToWrite > 0 ) {
            static const DWORD MAXIMUM_CHARACTERS_PER_PASS = 8 * 1024;
            DWORD numberOfCharactersThisPass = static_cast<DWORD>( numberOfCharactersToWrite );
            if ( numberOfCharactersThisPass > MAXIMUM_CHARACTERS_PER_PASS ) {
                numberOfCharactersThisPass = MAXIMUM_CHARACTERS_PER_PASS;
            }
            DWORD numberOfCharactersWritten;
            BOOL success = WriteConsoleW( consoleHandle,
                                          utf16Pointer,
                                          numberOfCharactersThisPass,
                                          &numberOfCharactersWritten,
                                          NULL );
            if ( 0 == success ) {
                DWORD dosError = GetLastError();
                static bool errorMessageShown = false;
                if ( ERROR_GEN_FAILURE == dosError ) {
                    if ( ! errorMessageShown ) {
                        std::cout << "\n---\nUnicode text could not be correctly displayed.\n"
                                "Please change your console font to a Unicode font "
                                "(e.g. Lucida Console).\n---\n" << std::endl;
                        errorMessageShown = true;
                    }
                    // we can't display the text properly using a raster font,
                    // but we can display the bits that will display ...
                    _write( 1, utf8String, utf8StringSize );
                }
                return false;
            }
            numberOfCharactersToWrite -= numberOfCharactersWritten;
            utf16Pointer += numberOfCharactersWritten;
        }
        return true;
    }

    WindowsCommandLine::WindowsCommandLine(int argc, wchar_t* argvW[], wchar_t* envpW[]) :
            _argv(NULL), _envp(NULL) {

        // Construct UTF-8 copy of arguments
        vector<string> utf8args;
        vector<size_t> utf8argLength;
        size_t blockSize = argc * sizeof(char*);
        size_t blockPtr = blockSize;
        for (int i = 0; i < argc; ++i) {
            utf8args.push_back( toUtf8String(argvW[i]) );
            size_t argLength = utf8args[i].length() + 1;
            utf8argLength.push_back(argLength);
            blockSize += argLength;
        }
        _argv = static_cast<char**>(malloc(blockSize));
        for (int i = 0; i < argc; ++i) {
            _argv[i] = reinterpret_cast<char*>(_argv) + blockPtr;
            strcpy_s(_argv[i], utf8argLength[i], utf8args[i].c_str());
            blockPtr += utf8argLength[i];
        }

        // Construct UTF-8 copy of environment strings
        size_t envCount = 0;
        wchar_t** envpWptr = &envpW[0];
        while (*envpWptr++) {
            ++envCount;
        }
        vector<string> utf8envs;
        vector<size_t> utf8envLength;
        blockSize = (envCount + 1) * sizeof(char*);
        blockPtr = blockSize;
        for (size_t i = 0; i < envCount; ++i) {
            utf8envs.push_back( toUtf8String(envpW[i]) );
            size_t envLength = utf8envs[i].length() + 1;
            utf8envLength.push_back(envLength);
            blockSize += envLength;
        }
        _envp = static_cast<char**>(malloc(blockSize));
        size_t i;
        for (i = 0; i < envCount; ++i) {
            _envp[i] = reinterpret_cast<char*>(_envp) + blockPtr;
            strcpy_s(_envp[i], utf8envLength[i], utf8envs[i].c_str());
            blockPtr += utf8envLength[i];
        }
        _envp[i] = NULL;
    }

    WindowsCommandLine::~WindowsCommandLine() {
        free(_argv);
        free(_envp);
    }

#endif // #if defined(_WIN32)

    // See "Parsing C++ Command-Line Arguments (C++)"
    // http://msdn.microsoft.com/en-us/library/windows/desktop/17w5ykft(v=vs.85).aspx
    static void quoteForWindowsCommandLine(const std::string& arg, std::ostream& os) {
        if (arg.empty()) {
            os << "\"\"";
        }
        else if (arg.find_first_of(" \t\"") == std::string::npos) {
            os << arg;
        }
        else {
            os << '"';
            std::string backslashes = "";
            for (std::string::const_iterator iter = arg.begin(), end = arg.end();
                 iter != end; ++iter) {

                switch (*iter) {
                case '\\':
                    backslashes.push_back(*iter);
                    if (iter + 1 == end)
                        os << backslashes << backslashes;
                    break;
                case '"':
                    os << backslashes << backslashes << "\\\"";
                    break;
                default:
                    os << backslashes << *iter;
                    backslashes.clear();
                    break;
                }
            }
            os << '"';
        }
    }

    std::string constructUtf8WindowsCommandLine(const std::vector<std::string>& argv) {
        if (argv.empty())
            return "";

        std::ostringstream commandLine;
        std::vector<std::string>::const_iterator iter = argv.begin();
        std::vector<std::string>::const_iterator end = argv.end();
        quoteForWindowsCommandLine(*iter, commandLine);
        ++iter;
        for (; iter != end; ++iter) {
            commandLine << ' ';
            quoteForWindowsCommandLine(*iter, commandLine);
        }
        return commandLine.str();
    }
}