/*
 *  Copyright (C) 2008 Jürg Billeter <j@bitron.ch>
 *  Copyright (C) 2008 Dominik Röttsches <dominik.roettsches@access-company.com>
 *  Copyright (C) 2010 Igalia S.L.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "UnicodeGLib.h"

#include <wtf/Vector.h>
#include <wtf/unicode/UTF8.h>

#define UTF8_IS_SURROGATE(character) (character >= 0x10000 && character <= 0x10FFFF)

namespace WTF {
namespace Unicode {

UChar32 foldCase(UChar32 ch)
{
    GOwnPtr<GError> gerror;

    GOwnPtr<char> utf8char;
    utf8char.set(g_ucs4_to_utf8(reinterpret_cast<gunichar*>(&ch), 1, 0, 0, &gerror.outPtr()));
    if (gerror)
        return ch;

    GOwnPtr<char> utf8caseFolded;
    utf8caseFolded.set(g_utf8_casefold(utf8char.get(), -1));

    GOwnPtr<gunichar> ucs4Result;
    ucs4Result.set(g_utf8_to_ucs4_fast(utf8caseFolded.get(), -1, 0));

    return *ucs4Result;
}

static int getUTF16LengthFromUTF8(const gchar* utf8String, int length)
{
    int utf16Length = 0;
    const gchar* inputString = utf8String;

    while ((utf8String + length - inputString > 0) && *inputString) {
        gunichar character = g_utf8_get_char(inputString);

        utf16Length += UTF8_IS_SURROGATE(character) ? 2 : 1;
        inputString = g_utf8_next_char(inputString);
    }

    return utf16Length;
}

typedef gchar* (*UTF8CaseFunction)(const gchar*, gssize length);

static int convertCase(UChar* result, int resultLength, const UChar* src, int srcLength, bool* error, UTF8CaseFunction caseFunction)
{
    *error = false;

    // Allocate a buffer big enough to hold all the characters.
    Vector<char> buffer(srcLength * 3);
    char* utf8Target = buffer.data();
    const UChar* utf16Source = src;
    ConversionResult conversionResult = convertUTF16ToUTF8(&utf16Source, utf16Source + srcLength, &utf8Target, utf8Target + buffer.size(), true);
    if (conversionResult != conversionOK) {
        *error = true;
        return -1;
    }
    buffer.shrink(utf8Target - buffer.data());

    GOwnPtr<char> utf8Result(caseFunction(buffer.data(), buffer.size()));
    long utf8ResultLength = strlen(utf8Result.get());

    // Calculate the destination buffer size.
    int realLength = getUTF16LengthFromUTF8(utf8Result.get(), utf8ResultLength);
    if (realLength > resultLength) {
        *error = true;
        return realLength;
    }

    // Convert the result to UTF-16.
    UChar* utf16Target = result;
    const char* utf8Source = utf8Result.get();
    conversionResult = convertUTF8ToUTF16(&utf8Source, utf8Source + utf8ResultLength, &utf16Target, utf16Target + resultLength, true);
    long utf16ResultLength = utf16Target - result;
    if (conversionResult != conversionOK)
        *error = true;

    return utf16ResultLength <= 0 ? -1 : utf16ResultLength;
}
int foldCase(UChar* result, int resultLength, const UChar* src, int srcLength, bool* error)
{
    return convertCase(result, resultLength, src, srcLength, error, g_utf8_casefold);
}

int toLower(UChar* result, int resultLength, const UChar* src, int srcLength, bool* error)
{
    return convertCase(result, resultLength, src, srcLength, error, g_utf8_strdown);
}

int toUpper(UChar* result, int resultLength, const UChar* src, int srcLength, bool* error)
{
    return convertCase(result, resultLength, src, srcLength, error, g_utf8_strup);
}

Direction direction(UChar32 c)
{
    PangoBidiType type = pango_bidi_type_for_unichar(c);
    switch (type) {
    case PANGO_BIDI_TYPE_L:
        return LeftToRight;
    case PANGO_BIDI_TYPE_R:
        return RightToLeft;
    case PANGO_BIDI_TYPE_AL:
        return RightToLeftArabic;
    case PANGO_BIDI_TYPE_LRE:
        return LeftToRightEmbedding;
    case PANGO_BIDI_TYPE_RLE:
        return RightToLeftEmbedding;
    case PANGO_BIDI_TYPE_LRO:
        return LeftToRightOverride;
    case PANGO_BIDI_TYPE_RLO:
        return RightToLeftOverride;
    case PANGO_BIDI_TYPE_PDF:
        return PopDirectionalFormat;
    case PANGO_BIDI_TYPE_EN:
        return EuropeanNumber;
    case PANGO_BIDI_TYPE_AN:
        return ArabicNumber;
    case PANGO_BIDI_TYPE_ES:
        return EuropeanNumberSeparator;
    case PANGO_BIDI_TYPE_ET:
        return EuropeanNumberTerminator;
    case PANGO_BIDI_TYPE_CS:
        return CommonNumberSeparator;
    case PANGO_BIDI_TYPE_NSM:
        return NonSpacingMark;
    case PANGO_BIDI_TYPE_BN:
        return BoundaryNeutral;
    case PANGO_BIDI_TYPE_B:
        return BlockSeparator;
    case PANGO_BIDI_TYPE_S:
        return SegmentSeparator;
    case PANGO_BIDI_TYPE_WS:
        return WhiteSpaceNeutral;
    default:
        return OtherNeutral;
    }
}

int umemcasecmp(const UChar* a, const UChar* b, int len)
{
    GOwnPtr<char> utf8a;
    GOwnPtr<char> utf8b;

    utf8a.set(g_utf16_to_utf8(a, len, 0, 0, 0));
    utf8b.set(g_utf16_to_utf8(b, len, 0, 0, 0));

    GOwnPtr<char> foldedA;
    GOwnPtr<char> foldedB;

    foldedA.set(g_utf8_casefold(utf8a.get(), -1));
    foldedB.set(g_utf8_casefold(utf8b.get(), -1));

    // FIXME: umemcasecmp needs to mimic u_memcasecmp of icu
    // from the ICU docs:
    // "Compare two strings case-insensitively using full case folding.
    // his is equivalent to u_strcmp(u_strFoldCase(s1, n, options), u_strFoldCase(s2, n, options))."
    //
    // So it looks like we don't need the full g_utf8_collate here,
    // but really a bitwise comparison of casefolded unicode chars (not utf-8 bytes).
    // As there is no direct equivalent to this icu function in GLib, for now
    // we'll use g_utf8_collate():

    return g_utf8_collate(foldedA.get(), foldedB.get());
}

}
}