/* Copyright 2016 Adobe Systems Incorporated (http://www.adobe.com/). All Rights Reserved.
   This software is licensed as OpenSource, under the Apache License, Version 2.0.
   This license is available at: http://opensource.org/licenses/Apache-2.0. */

#include "ctlshare.h"
#include "nameread.h"
#include "varread.h"
#include "dynarr.h"
#include "sha1.h"
#include "supportexcept.h"

#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>

/* --------------------------- Constants  --------------------------- */

#define MAX_FAMILY_NAME_LENGTH 64
#define MAX_COORD_STRING_LENGTH 16

/* --------------------------- type Definitions  --------------------------- */

typedef struct /* bsearch id match record */
{
    unsigned short platformId;
    unsigned short platspecId;
    unsigned short languageId;
    unsigned short nameId;
} MatchIds;

struct nam_name_ /* name table */
{
    unsigned short format; /* =0 */
    unsigned short count;
    unsigned short stringOffset;
    dnaDCL(nam_NameRecord, records);
};

/* --------------------------- Functions  --------------------------- */

/* Load the name table. */
nam_name nam_loadname(sfrCtx sfr, ctlSharedStmCallbacks *sscb) {
    nam_name nameTbl = NULL;
    int success = 0;
    int i;

    sfrTable *table = sfrGetTableByTag(sfr, CTL_TAG('n', 'a', 'm', 'e'));
    if (table == NULL) {
        sscb->message(sscb, "name table missing");
        return NULL;
    }
    DURING
    sscb->seek(sscb, table->offset);

    nameTbl = (nam_name)sscb->memNew(sscb, sizeof(*nameTbl));
    if (!nameTbl)
        goto cleanup;

    /* Read and validate table format */
    nameTbl->format = sscb->read2(sscb);
    if (nameTbl->format != 0) {
        sscb->message(sscb, "invalid name table format");
        goto cleanup;
    }

    /* Read rest of header */
    nameTbl->count = sscb->read2(sscb);
    nameTbl->stringOffset = sscb->read2(sscb);

    /* Read name records */
    dnaINIT(sscb->dna, nameTbl->records, nameTbl->count, nameTbl->count);
    dnaSET_CNT(nameTbl->records, nameTbl->count);
    for (i = 0; i < nameTbl->records.cnt; i++) {
        nam_NameRecord *rec = &nameTbl->records.array[i];
        rec->platformId = sscb->read2(sscb);
        rec->platspecId = sscb->read2(sscb);
        rec->languageId = sscb->read2(sscb);
        rec->nameId = sscb->read2(sscb);
        rec->length = sscb->read2(sscb);
        rec->offset = table->offset + nameTbl->stringOffset + sscb->read2(sscb);
    }
    success = 1;

cleanup:;
    HANDLER
    END_HANDLER

    if (!success) {
        nam_freename(sscb, nameTbl);
        nameTbl = NULL;
    }

    return nameTbl;
}

void nam_freename(ctlSharedStmCallbacks *sscb, nam_name tbl) {
    if (tbl) {
        dnaFREE(tbl->records);
        sscb->memFree(sscb, tbl);
    }
}

/* Match ids. */
static int CTL_CDECL matchIds(const void *key, const void *value) {
    MatchIds *a = (MatchIds *)key;
    nam_NameRecord *b = (nam_NameRecord *)value;
    if (a->platformId < b->platformId)
        return -1;
    else if (a->platformId > b->platformId)
        return 1;
    else if (a->platspecId < b->platspecId)
        return -1;
    else if (a->platspecId > b->platspecId)
        return 1;
    else if (a->languageId < b->languageId)
        return -1;
    else if (a->languageId > b->languageId)
        return 1;
    else if (a->nameId < b->nameId)
        return -1;
    else if (a->nameId > b->nameId)
        return 1;
    else
        return 0;
}

/* Return name record match specified ids or NULL if no match. */
nam_NameRecord *nam_nameFind(nam_name tbl,
                             unsigned short platformId,
                             unsigned short platspecId,
                             unsigned short languageId,
                             unsigned short nameId) {
    MatchIds match;

    if (tbl->records.cnt == 0)
        return NULL; /* name table missing */

    /* Initialize match record */
    match.platformId = platformId;
    match.platspecId = platspecId;
    match.languageId = languageId;
    match.nameId = nameId;

    return (nam_NameRecord *)
        bsearch(&match, tbl->records.array, tbl->records.cnt,
                sizeof(nam_NameRecord), matchIds);
}

static int checkNameChar(unsigned char ch, int isPS) {
    if (isPS) {
        switch (ch) {
            case '[':
            case ']':
            case '(':
            case ')':
            case '{':
            case '}':
            case '<':
            case '>':
            case '/':
            case '%':
                return 0;
            default:
                return (ch >= 33 && ch <= 126);
        }
    } else
        return (ch >= 32) && (ch <= 126);
}

long nam_getASCIIName(nam_name nameTbl, ctlSharedStmCallbacks *sscb, char *buffer, unsigned long bufferLen, unsigned short nameId, int isPS) {
    unsigned long i;
    long nameLen;
    unsigned char ch1, ch2;
    nam_NameRecord *rec;

    if (!nameTbl)
        return NAME_READ_NAME_NOT_FOUND;
    rec = nam_nameFind(nameTbl, NAME_WIN_PLATFORM, NAME_WIN_UGL, NAME_WIN_ENGLISH, nameId);
    if (rec && rec->length > 0) {
        nameLen = 0;
        sscb->seek(sscb, rec->offset);
        for (i = 0; i + 1 < (unsigned long)rec->length; i += 2) {
            ch1 = sscb->read1(sscb);
            ch2 = sscb->read1(sscb);
            if (ch1 == 0 && checkNameChar(ch2, isPS)) {
                if ((unsigned long)nameLen + 1 >= bufferLen) {
                    sscb->message(sscb, "a name in the name table is longer than the given buffer");
                    return NAME_READ_NAME_TOO_LONG;
                }
                buffer[nameLen++] = (char)ch2;
            }
        }
        buffer[nameLen] = 0;
        return nameLen;
    }
    rec = nam_nameFind(nameTbl, NAME_MAC_PLATFORM, NAME_MAC_ROMAN, NAME_MAC_ENGLISH, nameId);
    if (rec) {
        nameLen = 0;
        sscb->seek(sscb, rec->offset);
        for (i = 0; i < (unsigned long)rec->length; i++) {
            ch1 = sscb->read1(sscb);
            if (checkNameChar(ch1, isPS)) {
                if ((unsigned long)nameLen + 1 >= bufferLen) {
                    sscb->message(sscb, "a name in the name table is longer than the given buffer");
                    return NAME_READ_NAME_TOO_LONG;
                }
                buffer[nameLen++] = (char)ch1;
            }
        }
        buffer[nameLen] = 0;
        return nameLen;
    }
    return NAME_READ_NAME_NOT_FOUND;
}

static long getPSName(nam_name nameTbl,
                      ctlSharedStmCallbacks *sscb,
                      char *nameBuffer, unsigned long nameBufferLen) {
    return nam_getASCIIName(nameTbl, sscb, nameBuffer, nameBufferLen, NAME_ID_POSTSCRIPT, 1);
}

static unsigned long removeNonAlphanumChar(char *buffer, unsigned long len) {
    unsigned long i, j;

    for (i = j = 0; i < len; i++) {
        if (isalnum((unsigned char)buffer[i])) {
            buffer[j++] = buffer[i];
        }
    }
    buffer[j] = 0;
    return j;
}

/* get the family name prefix for a variable font instance name */
long nam_getFamilyNamePrefix(nam_name nameTbl,
                             ctlSharedStmCallbacks *sscb,
                             char *buffer, unsigned long bufferLen) {
    long nameLen;

    nameLen = nam_getASCIIName(nameTbl, sscb, buffer, bufferLen, NAME_ID_POSTSCRIPT_PREFIX, 1);
    if (nameLen == NAME_READ_NAME_NOT_FOUND)
        nameLen = nam_getASCIIName(nameTbl, sscb, buffer, bufferLen, NAME_ID_TYPO_FAMILY, 1);
    if (nameLen == NAME_READ_NAME_NOT_FOUND)
        nameLen = nam_getASCIIName(nameTbl, sscb, buffer, bufferLen, NAME_ID_FAMILY, 1);
    if (nameLen > 0)
        nameLen = removeNonAlphanumChar(buffer, nameLen);

    if (nameLen > MAX_FAMILY_NAME_LENGTH) {
        sscb->message(sscb, "too long family name prefix");
        nameLen = NAME_READ_NAME_TOO_LONG;
    }
    return nameLen;
}

/* allocate a temporary buffer long enough to hold a generated instance name */
static char *allocNameBuffer(ctlSharedStmCallbacks *sscb, long axisCount, unsigned long *bufferLen) {
    char *buffer;

    *bufferLen = MAX_FAMILY_NAME_LENGTH + 10 + (MAX_COORD_STRING_LENGTH * axisCount);
    buffer = (char *)sscb->memNew(sscb, *bufferLen);
    if (buffer == 0) {
        sscb->message(sscb, "failed to allocate memory");
        return NULL;
    }
    return buffer;
}

long nam_getNamedInstancePSName(nam_name nameTbl,
                                var_axes axesTbl,
                                ctlSharedStmCallbacks *sscb,
                                float *coords,
                                unsigned short axisCount,
                                int instanceIndex,
                                char *instanceName, unsigned long instanceNameLen) {
    unsigned long familyNameLen = 0;
    long nameLen = NAME_READ_NAME_NOT_FOUND;
    unsigned short subfamilyID = 0, postscriptID = 0;
    char *buffer = 0;
    unsigned long bufferLen;

    /* if the font is not a variable font or no coordinates are specified, return the default PS name */
    if (!axesTbl || !coords || !axisCount) {
        return getPSName(nameTbl, sscb, instanceName, instanceNameLen);
    }

    /* find a matching named instance in the fvar table */
    if (instanceIndex < 0)
        instanceIndex = var_findInstance(axesTbl, coords, axisCount, &subfamilyID, &postscriptID);
    if ((instanceIndex >= 0) && (postscriptID == 6 || ((postscriptID > 255) && (postscriptID < 32768)))) {
        nameLen = nam_getASCIIName(nameTbl, sscb, instanceName, instanceNameLen, postscriptID, 1);
        if (nameLen > 0)
            return nameLen;
    }

    /* allocate a temporary buffer long enough to hold a generated instance name */
    buffer = allocNameBuffer(sscb, axisCount, &bufferLen);
    if (buffer == NULL)
        return NAME_READ_FAILED;

    /* get the family name prefix */
    nameLen = nam_getFamilyNamePrefix(nameTbl, sscb, buffer, bufferLen);
    if (nameLen <= 0)
        goto cleanup;

    familyNameLen = (unsigned long)nameLen;

    /* append the style name from the instance if there is a matching one */
    if (instanceIndex >= 0) {
        char *styleName = &buffer[nameLen];
        unsigned long styleBufferLen = bufferLen - nameLen;
        long styleLen;

        styleLen = nam_getASCIIName(nameTbl, sscb, styleName, styleBufferLen, subfamilyID, 0);
        if (styleLen < 0)
            nameLen = styleLen;
        else {
            styleLen = removeNonAlphanumChar(styleName, styleLen);
            nameLen = nameLen + styleLen;
            if ((unsigned long)nameLen + 1 > instanceNameLen)
                nameLen = NAME_READ_NAME_TOO_LONG;
            else
                STRCPY_S(instanceName, instanceNameLen, buffer);
        }
    } else
        nameLen = NAME_READ_NAME_NOT_FOUND;

cleanup:
    if (buffer)
        sscb->memFree(sscb, buffer);

    return nameLen;
}

/* convert a fractional number to a string in the buffer.
 * function returns the length of the string.
 * the buffer is assumed to be long enough.
 */
static unsigned long stringizeNum(char *buffer, unsigned long bufferLen, float value) {
    unsigned long i = 0;
    float eps = 0.5f / (1 << 16);
    float hi, lo;
    int intPart;
    float fractPart;
    int neg = 0;
    int power10;
    int digit;

    if (value < 0.0f) {
        neg = 1;
        value = -value;
    }

    hi = value + eps;
    lo = value - eps;

    intPart = (int)floor(hi);
    if (intPart != (int)floor(lo)) {
        fractPart = 0.0f;
    } else {
        fractPart = hi - intPart;
    }

    if ((intPart == 0) && (fractPart == 0.0f)) {
        buffer[i++] = '0';
        return i;
    }

    if (neg) {
        if (i + 1 >= bufferLen) return 0;
        buffer[i++] = '-';
    }

    /* integer part */
    for (digit = 0, power10 = 1; intPart >= power10;) {
        digit++;
        power10 *= 10;
    }
    while (digit-- > 0) {
        power10 /= 10;
        buffer[i++] = (char)('0' + (intPart / power10));
        intPart %= power10;
    }

    /* fractional part */
    if (fractPart >= eps) {
        buffer[i++] = '.';

        do {
            fractPart *= 10;
            eps *= 10;
            intPart = (int)fractPart;
            buffer[i++] = (char)('0' + intPart);
            fractPart -= intPart;
        } while (fractPart >= eps);
    }

    return i;
}

long nam_generateArbitraryInstancePSName(nam_name nameTbl,
                                         var_axes axesTbl,
                                         ctlSharedStmCallbacks *sscb,
                                         float *coords,
                                         unsigned short axisCount,
                                         char *instanceName, unsigned long instanceNameLen) {
    unsigned long familyNameLen = 0;
    long nameLen;
    unsigned short axis;
    char *buffer = 0;
    unsigned long bufferLen;

    /* if the font is not a variable font or no coordinates are specified, return the default PS name */
    if (!axesTbl || !coords || !axisCount) {
        return getPSName(nameTbl, sscb, instanceName, instanceNameLen);
    }

    /* allocate a temporary buffer long enough to hold a generated instance name */
    buffer = allocNameBuffer(sscb, axisCount, &bufferLen);
    if (buffer == NULL)
        return NAME_READ_FAILED;

    /* get the family name prefix */
    nameLen = nam_getFamilyNamePrefix(nameTbl, sscb, buffer, bufferLen);
    if (nameLen <= 0)
        goto cleanup;

    familyNameLen = (unsigned long)nameLen;

    /* create an arbitrary instance name from the coordinates */
    for (axis = 0; axis < axisCount; axis++) {
        unsigned long coordStrLen;
        int i;
        unsigned long tag;

        /* value range check */
        if (fabs(coords[axis]) > 32768.0f) {
            sscb->message(sscb, "coordinates value out of range: %f", coords[axis]);
            nameLen = 0;
            goto cleanup;
        }

        /* convert a coordinates value to string */
        buffer[nameLen++] = '_';
        coordStrLen = stringizeNum(&buffer[nameLen], bufferLen - nameLen, coords[axis]);
        nameLen += coordStrLen;

        /* append a axis name */
        if (var_getAxis(axesTbl, axis, &tag, NULL, NULL, NULL, NULL)) {
            sscb->message(sscb, "failed to get axis information");
            nameLen = 0;
            goto cleanup;
        }
        for (i = 3; i >= 0; i--) {
            char ch = (char)((tag >> (i * 8)) & 0xff);
            if (ch < 32 || ch > 126) {
                sscb->message(sscb, "invalid character found in an axis tag");
                continue;
            }
            if (ch == ' ') continue;
            buffer[nameLen++] = ch;
        }
    }
    buffer[nameLen++] = 0;
    if (nameLen <= (long)instanceNameLen) {
        STRNCPY_S(instanceName, instanceNameLen, buffer, nameLen);
        instanceName[nameLen] = 0;
    } else
        nameLen = NAME_READ_NAME_TOO_LONG;

cleanup:
    if (buffer)
        sscb->memFree(sscb, buffer);

    return nameLen;
}

static void *nam_sha1_malloc(size_t size, void *hook) {
    ctlSharedStmCallbacks *sscb = (ctlSharedStmCallbacks *)hook;
    return sscb->memNew(sscb, size);
}

static void nam_sha1_free(sha1_pctx ctx, void *hook) {
    ctlSharedStmCallbacks *sscb = (ctlSharedStmCallbacks *)hook;
    sscb->memFree(sscb, ctx);
}

long nam_generateLastResortInstancePSName(nam_name nameTbl,
                                          var_axes axesTbl,
                                          ctlSharedStmCallbacks *sscb,
                                          float *coords,
                                          unsigned short axisCount,
                                          char *instanceName, unsigned long instanceNameLen) {
    unsigned long familyNameLen = 0;
    long nameLen;
    char *buffer = 0;
    unsigned long bufferLen;
    unsigned long hashLen;
    unsigned long i;

    /* if the font is not a variable font or no coordinates are specified, return the default PS name */
    if (!axesTbl || !coords || !axisCount) {
        return getPSName(nameTbl, sscb, instanceName, instanceNameLen);
    }

    /* allocate a temporary buffer long enough to hold a generated instance name */
    buffer = allocNameBuffer(sscb, axisCount, &bufferLen);
    if (buffer == NULL)
        return NAME_READ_FAILED;

    /* get the family name prefix */
    nameLen = nam_getFamilyNamePrefix(nameTbl, sscb, buffer, bufferLen);
    if (nameLen <= 0)
        goto cleanup;

    familyNameLen = (unsigned long)nameLen;

    /* generate a SHA1 value of the generated name as the identififier in a last resort name.
     */
    hashLen = sizeof(sha1_hash);
    for (i = 0; i < 2; i++) {
        if (familyNameLen + hashLen * 2 + 5 < instanceNameLen)
            break;

        if (i >= 1) {
            sscb->message(sscb, "name buffer not long enough to generate a last resort variable font instance name");
            nameLen = -2;
            goto cleanup;
        }
        hashLen /= 2; /* give it another chance by halvening the hash length */
    }
    nameLen = familyNameLen;
    STRNCPY_S(instanceName, instanceNameLen, buffer, nameLen);
    instanceName[nameLen++] = '-';

    {
        sha1_pctx sha1_ctx = sha1_init(nam_sha1_malloc, sscb);
        sha1_hash hash;
        int error;

        if (!sha1_ctx) {
            nameLen = 0;
            goto cleanup;
        }

        error = sha1_update(sha1_ctx, (unsigned char *)buffer, nameLen - 1);
        error |= sha1_finalize(sha1_ctx, nam_sha1_free, hash, sscb);

        if (error) {
            sscb->message(sscb, "failed to generate hash during a last resort variable font instance name generation");
            nameLen = 0;
            goto cleanup;
        }

        /* append the hash value has a hex string */
        for (i = 0; i < hashLen; i++) {
            static const char hexChar[] = "0123456789ABCDEF";
            unsigned char byte = hash[i];
            instanceName[nameLen++] = hexChar[byte >> 4];
            instanceName[nameLen++] = hexChar[byte & 0xF];
        }

        instanceName[nameLen++] = '.';
        instanceName[nameLen++] = '.';
        instanceName[nameLen++] = '.';
        instanceName[nameLen++] = 0;

        sscb->message(sscb, "last resort variable font instance name %s generated for %s",
                      instanceName, buffer);
    }

cleanup:
    if (buffer)
        sscb->memFree(sscb, buffer);

    return nameLen;
}
