/*
***************************************************************************
* Copyright (C) 2008-2009, International Business Machines Corporation
* and others. All Rights Reserved.
***************************************************************************
*   file name:  uspoof.cpp
*   encoding:   US-ASCII
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2008Feb13
*   created by: Andy Heninger
*
*   Unicode Spoof Detection
*/
#include "unicode/utypes.h"
#include "unicode/uspoof.h"
#include "unicode/unorm.h"
#include "unicode/ustring.h"
#include "cmemory.h"
#include "uspoof_impl.h"
#include "uassert.h"

#include <stdio.h>      // debug

U_NAMESPACE_USE


U_CAPI USpoofChecker * U_EXPORT2
uspoof_open(UErrorCode *status) {
    if (U_FAILURE(*status)) {
        return NULL;
    }
    SpoofImpl *si = new SpoofImpl(SpoofData::getDefault(*status), *status);
    if (U_FAILURE(*status)) {
        delete si;
        si = NULL;
    }
    return (USpoofChecker *)si;
}


U_CAPI USpoofChecker * U_EXPORT2
uspoof_openFromSerialized(const void *data, int32_t length, int32_t *pActualLength,
                          UErrorCode *status) {
    if (U_FAILURE(*status)) {
        return NULL;
    }
    SpoofData *sd = new SpoofData(data, length, *status);
    SpoofImpl *si = new SpoofImpl(sd, *status);
    if (U_FAILURE(*status)) {
        delete sd;
        delete si;
        return NULL;
    }
    if (sd == NULL || si == NULL) {
        *status = U_MEMORY_ALLOCATION_ERROR;
        delete sd;
        delete si;
        return NULL;
    }
        
    if (pActualLength != NULL) {
        *pActualLength = sd->fRawData->fLength;
    }
    return reinterpret_cast<USpoofChecker *>(si);
}


U_CAPI USpoofChecker * U_EXPORT2
uspoof_clone(const USpoofChecker *sc, UErrorCode *status) {
    const SpoofImpl *src = SpoofImpl::validateThis(sc, *status);
    if (src == NULL) {
        return NULL;
    }
    SpoofImpl *result = new SpoofImpl(*src, *status);   // copy constructor
    if (U_FAILURE(*status)) {
        delete result;
        result = NULL;
    }
    return (USpoofChecker *)result;
}


U_CAPI void U_EXPORT2
uspoof_close(USpoofChecker *sc) {
    UErrorCode status = U_ZERO_ERROR;
    SpoofImpl *This = SpoofImpl::validateThis(sc, status);
    delete This;
}


U_CAPI void U_EXPORT2
uspoof_setChecks(USpoofChecker *sc, int32_t checks, UErrorCode *status) {
    SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return;
    }

    // Verify that the requested checks are all ones (bits) that 
    //   are acceptable, known values.
    if (checks & ~USPOOF_ALL_CHECKS) {
        *status = U_ILLEGAL_ARGUMENT_ERROR; 
        return;
    }

    This->fChecks = checks;
}


U_CAPI int32_t U_EXPORT2
uspoof_getChecks(const USpoofChecker *sc, UErrorCode *status) {
    const SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return 0;
    }
    return This->fChecks;
}

U_CAPI void U_EXPORT2
uspoof_setAllowedLocales(USpoofChecker *sc, const char * /*localesList*/, UErrorCode *status) {
    SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return;
    }
    // TODO:
}


U_CAPI const USet * U_EXPORT2
uspoof_getAllowedChars(const USpoofChecker *sc, UErrorCode *status) {
    const UnicodeSet *result = uspoof_getAllowedUnicodeSet(sc, status);
    return reinterpret_cast<const USet *>(result);
}

U_CAPI const UnicodeSet * U_EXPORT2
uspoof_getAllowedUnicodeSet(const USpoofChecker *sc, UErrorCode *status) {
    const SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return NULL;
    }
    return This->fAllowedCharsSet;
}


U_CAPI void U_EXPORT2
uspoof_setAllowedChars(USpoofChecker *sc, const USet *chars, UErrorCode *status) {
    const UnicodeSet *set = reinterpret_cast<const UnicodeSet *>(chars);
    uspoof_setAllowedUnicodeSet(sc, set, status);
}


U_CAPI void U_EXPORT2
uspoof_setAllowedUnicodeSet(USpoofChecker *sc, const UnicodeSet *chars, UErrorCode *status) {
    SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return;
    }
    if (chars->isBogus()) {
        *status = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
    UnicodeSet *clonedSet = static_cast<UnicodeSet *>(chars->clone());
    if (clonedSet == NULL || clonedSet->isBogus()) {
        *status = U_MEMORY_ALLOCATION_ERROR;
        return;
    }
    clonedSet->freeze();
    delete This->fAllowedCharsSet;
    This->fAllowedCharsSet = clonedSet;
    This->fChecks |= USPOOF_CHAR_LIMIT;
}


U_CAPI int32_t U_EXPORT2
uspoof_check(const USpoofChecker *sc,
             const UChar *text, int32_t length,
             int32_t *position,
             UErrorCode *status) {
             
    const SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        return 0;
    }
    if (length < -1) {
        *status = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }
    if (length == -1) {
        // It's not worth the bother to handle nul terminated strings everywhere.
        //   Just get the length and be done with it.
        length = u_strlen(text);
    }

    int32_t result = 0;
    int32_t failPos = 0x7fffffff;   // TODO: do we have a #define for max int32?

    // A count of the number of non-Common or inherited scripts.
    // Needed for both the SINGLE_SCRIPT and the WHOLE/MIXED_SCIRPT_CONFUSABLE tests.
    // Share the computation when possible.  scriptCount == -1 means that we haven't
    // done it yet.
    int32_t scriptCount = -1;

    if ((This->fChecks) & USPOOF_SINGLE_SCRIPT) {
        scriptCount = This->scriptScan(text, length, failPos, *status);
        // printf("scriptCount (clipped to 2) = %d\n", scriptCount);
        if ( scriptCount >= 2) {
            // Note: scriptCount == 2 covers all cases of the number of scripts >= 2
            result |= USPOOF_SINGLE_SCRIPT;
        }
    }

    if (This->fChecks & USPOOF_CHAR_LIMIT) {
        int32_t i;
        UChar32 c;
        for (i=0; i<length ;) {
            U16_NEXT(text, i, length, c);
            if (!This->fAllowedCharsSet->contains(c)) {
                result |= USPOOF_CHAR_LIMIT;
                if (i < failPos) {
                    failPos = i;
                }
                break;
            }
        }
    }

    // TODO:  add USPOOF_INVISIBLE check
    
    if (This->fChecks & (USPOOF_WHOLE_SCRIPT_CONFUSABLE | USPOOF_MIXED_SCRIPT_CONFUSABLE)) {
        // The basic test is the same for both whole and mixed script confusables.
        // Compute the set of scripts that every input character has a confusable in.
        // For this computation an input character is always considered to be
        //    confusable with itself in its own script.
        // If the number of such scripts is two or more, and the input consisted of
        //   characters all from a single script, we have a whole script confusable.
        //   (The two scripts will be the original script and the one that is confusable)
        // If the number of such scripts >= one, and the original input contained characters from
        //   more than one script, we have a mixed script confusable.  (We can transform
        //   some of the characters, and end up with a visually similar string all in
        //   one script.)

        NFKDBuffer   normalizedInput(text, length, *status);
        const UChar  *nfkdText = normalizedInput.getBuffer();
        int32_t      nfkdLength = normalizedInput.getLength();

        if (scriptCount == -1) {
        int32_t t;
            scriptCount = This->scriptScan(text, length, t, *status);
        }
        
        ScriptSet scripts;
        This->wholeScriptCheck(nfkdText, nfkdLength, &scripts, *status);
        int32_t confusableScriptCount = scripts.countMembers();
        //printf("confusableScriptCount = %d\n", confusableScriptCount);
        
        if ((This->fChecks & USPOOF_WHOLE_SCRIPT_CONFUSABLE) &&
            confusableScriptCount >= 2 &&
            scriptCount == 1) {
            result |= USPOOF_WHOLE_SCRIPT_CONFUSABLE;
        }
    
        if ((This->fChecks & USPOOF_MIXED_SCRIPT_CONFUSABLE) &&
            confusableScriptCount >= 1 &&
            scriptCount > 1) {
            result |= USPOOF_MIXED_SCRIPT_CONFUSABLE;
        }
    }

    if (position != NULL && failPos != 0x7fffffff) {
        *position = failPos;
    }
    return result;
}


U_CAPI int32_t U_EXPORT2
uspoof_checkUTF8(const USpoofChecker *sc,
                 const char *text, int32_t length,
                 int32_t *position,
                 UErrorCode *status) {

    if (U_FAILURE(*status)) {
        return 0;
    }
    UChar stackBuf[USPOOF_STACK_BUFFER_SIZE];
    UChar* text16 = stackBuf;
    int32_t len16;
    
    u_strFromUTF8(text16, USPOOF_STACK_BUFFER_SIZE, &len16, text, length, status);
    if (U_FAILURE(*status) && *status != U_BUFFER_OVERFLOW_ERROR) {
        return 0;
    }
    if (*status == U_BUFFER_OVERFLOW_ERROR) {
        text16 = static_cast<UChar *>(uprv_malloc(len16 * sizeof(UChar) + 2));
        if (text16 == NULL) {
            *status = U_MEMORY_ALLOCATION_ERROR;
            return 0;
        }
        *status = U_ZERO_ERROR;
        u_strFromUTF8(text16, len16+1, NULL, text, length, status);
    }

    int32_t position16 = -1;
    int32_t result = uspoof_check(sc, text16, len16, &position16, status);
    if (U_FAILURE(*status)) {
        return 0;
    }

    if (position16 > 0) {
        // Translate a UTF-16 based error position back to a UTF-8 offset.
        // u_strToUTF8() in preflight mode is an easy way to do it.
        U_ASSERT(position16 <= len16);
        u_strToUTF8(NULL, 0, position, text16, position16, status);
    }

    if (text16 != stackBuf) {
        uprv_free(text16);
    }
    return result;
    
}


U_CAPI int32_t U_EXPORT2
uspoof_checkUnicodeString(const USpoofChecker *sc,
                          const U_NAMESPACE_QUALIFIER UnicodeString &text, 
                          int32_t *position,
                          UErrorCode *status) {
    int32_t result = uspoof_check(sc, text.getBuffer(), text.length(), position, status);
    return result;
}


U_CAPI int32_t U_EXPORT2
uspoof_getSkeleton(const USpoofChecker *sc,
                   uint32_t type,
                   const UChar *s,  int32_t length,
                   UChar *dest, int32_t destCapacity,
                   UErrorCode *status) {

    const SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (U_FAILURE(*status)) {
        return 0;
    }
    if (length<-1 || destCapacity<0 || (destCapacity==0 && dest!=NULL) ||
        (type & ~(USPOOF_SINGLE_SCRIPT_CONFUSABLE | USPOOF_ANY_CASE)) != 0) {
        *status = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }

   int32_t tableMask = 0;
   switch (type) {
      case 0:
        tableMask = USPOOF_ML_TABLE_FLAG;
        break;
      case USPOOF_SINGLE_SCRIPT_CONFUSABLE:
        tableMask = USPOOF_SL_TABLE_FLAG;
        break;
      case USPOOF_ANY_CASE:
        tableMask = USPOOF_MA_TABLE_FLAG;
        break;
      case USPOOF_SINGLE_SCRIPT_CONFUSABLE | USPOOF_ANY_CASE:
        tableMask = USPOOF_SA_TABLE_FLAG;
        break;
      default:
        *status = U_ILLEGAL_ARGUMENT_ERROR;
        return 0;
    }

    // NFKD transform of the user supplied input
    
    UChar nfkdBuf[USPOOF_STACK_BUFFER_SIZE];
    UChar *nfkdInput = nfkdBuf;
    int32_t normalizedLen = unorm_normalize(
        s, length, UNORM_NFKD, 0, nfkdInput, USPOOF_STACK_BUFFER_SIZE, status);
    if (*status == U_BUFFER_OVERFLOW_ERROR) {
        nfkdInput = (UChar *)uprv_malloc((normalizedLen+1)*sizeof(UChar));
        if (nfkdInput == NULL) {
            *status = U_MEMORY_ALLOCATION_ERROR;
            return 0;
        }
        normalizedLen = unorm_normalize(s, length, UNORM_NFKD, 0,
                                        nfkdInput, normalizedLen+1, status);
    }
    if (U_FAILURE(*status)) {
        return 0;
    }

    // buffer to hold the Unicode defined mappings for a single code point
    UChar buf[USPOOF_MAX_SKELETON_EXPANSION];

    // Apply the mapping to the NFKD form string
    
    int32_t inputIndex = 0;
    int32_t resultLen = 0;
    while (inputIndex < normalizedLen) {
        UChar32 c;
        U16_NEXT(nfkdInput, inputIndex, normalizedLen, c);
        int32_t replaceLen = This->confusableLookup(c, tableMask, buf);
        if (resultLen + replaceLen < destCapacity) {
            int i;
            for (i=0; i<replaceLen; i++) {
                dest[resultLen++] = buf[i];
            }
        } else {
            // Storing the transformed string would overflow the dest buffer.
            //   Don't bother storing anything, just sum up the required buffer size.
            //   (We dont guarantee that a truncated buffer is filled to it's end)
            resultLen += replaceLen;
        }
    }
    
    if (resultLen < destCapacity) {
        dest[resultLen] = 0;
    } else if (resultLen == destCapacity) {
        *status = U_STRING_NOT_TERMINATED_WARNING;
    } else {
        *status = U_BUFFER_OVERFLOW_ERROR;
    }
    if (nfkdInput != nfkdBuf) {
        uprv_free(nfkdInput);
    }
    return resultLen;
}


U_CAPI UnicodeString &  U_EXPORT2
uspoof_getSkeletonUnicodeString(const USpoofChecker *sc,
                                uint32_t type,
                                const UnicodeString &s,
                                UnicodeString &dest,
                                UErrorCode *status) {
    if (U_FAILURE(*status)) {
        return dest;
    }
    dest.remove();
    
    const UChar *str = s.getBuffer();
    int32_t      strLen = s.length();
    UChar        smallBuf[100];
    UChar       *buf = smallBuf;
    int32_t outputSize = uspoof_getSkeleton(sc, type, str, strLen, smallBuf, 100, status);
    if (*status == U_BUFFER_OVERFLOW_ERROR) {
        buf = static_cast<UChar *>(uprv_malloc(outputSize+1));
        if (buf == NULL) {
            *status = U_MEMORY_ALLOCATION_ERROR;
        }
        uspoof_getSkeleton(sc, type, str, strLen, buf, outputSize+1, status);
    }
    if (U_SUCCESS(*status)) {
        dest.setTo(buf, outputSize);
    }

    if (buf != smallBuf) {
        uprv_free(buf);
    }
    return dest;
}


U_CAPI int32_t U_EXPORT2
uspoof_getSkeletonUTF8(const USpoofChecker *sc,
                       uint32_t type,
                       const char *s,  int32_t length,
                       char *dest, int32_t destCapacity,
                       UErrorCode *status) {
    // Lacking a UTF-8 normalization API, just converting the input to
    // UTF-16 seems as good an approach as any.  In typical use, input will
    // be an identifier, which is to say not too long for stack buffers.
    if (U_FAILURE(*status)) {
        return 0;
    }
    // Buffers for the UChar form of the input and skeleton strings.
    UChar    smallInBuf[USPOOF_STACK_BUFFER_SIZE];
    UChar   *inBuf = smallInBuf;
    UChar    smallOutBuf[USPOOF_STACK_BUFFER_SIZE];
    UChar   *outBuf = smallOutBuf;

    int32_t  lengthInUChars = 0;
    int32_t  skelLengthInUChars = 0;
    int32_t  skelLengthInUTF8 = 0;
    
    u_strFromUTF8(inBuf, USPOOF_STACK_BUFFER_SIZE, &lengthInUChars,
                  s, length, status);
    if (*status == U_BUFFER_OVERFLOW_ERROR) {
        *status = U_ZERO_ERROR;
        inBuf = static_cast<UChar *>(uprv_malloc((lengthInUChars+1)*sizeof(UChar)));
        if (inBuf == NULL) {
            *status = U_MEMORY_ALLOCATION_ERROR;
            goto cleanup;
        }
        u_strFromUTF8(inBuf, USPOOF_STACK_BUFFER_SIZE, &lengthInUChars+1,
                      s, length, status);
    }
    
    skelLengthInUChars = uspoof_getSkeleton(sc, type, outBuf, lengthInUChars,
                                         outBuf, USPOOF_STACK_BUFFER_SIZE, status);
    if (*status == U_BUFFER_OVERFLOW_ERROR) {
        *status = U_ZERO_ERROR;
        outBuf = static_cast<UChar *>(uprv_malloc((skelLengthInUChars+1)*sizeof(UChar)));
        if (outBuf == NULL) {
            *status = U_MEMORY_ALLOCATION_ERROR;
            goto cleanup;
        }
        skelLengthInUChars = uspoof_getSkeleton(sc, type, outBuf, lengthInUChars,
                                         outBuf, USPOOF_STACK_BUFFER_SIZE, status);
    }

    u_strToUTF8(dest, destCapacity, &skelLengthInUTF8,
                outBuf, skelLengthInUChars, status);

  cleanup:
    if (inBuf != smallInBuf) {
        delete inBuf;
    }
    if (outBuf != smallOutBuf) {
        delete outBuf;
    }
    return skelLengthInUTF8;
}


U_CAPI int32_t U_EXPORT2
uspoof_serialize(USpoofChecker *sc,void *buf, int32_t capacity, UErrorCode *status) {
    SpoofImpl *This = SpoofImpl::validateThis(sc, *status);
    if (This == NULL) {
        U_ASSERT(U_FAILURE(*status));
        return 0;
    }
    int32_t dataSize = This->fSpoofData->fRawData->fLength;
    if (capacity < dataSize) {
        *status = U_BUFFER_OVERFLOW_ERROR;
        return dataSize;
    }
    uprv_memcpy(buf, This->fSpoofData->fRawData, dataSize);
    return dataSize;
}