/*
 * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
 *
 * This file is part of libass.
 *
 * libass 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.
 *
 * libass 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 libass; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <inttypes.h>
#include <ft2build.h>
#include FT_FREETYPE_H

#include "ass_utils.h"
#include "ass.h"
#include "ass_library.h"
#include "ass_fontconfig.h"

#ifdef CONFIG_FONTCONFIG
#include <fontconfig/fontconfig.h>
#include <fontconfig/fcfreetype.h>
#endif

struct fc_instance {
#ifdef CONFIG_FONTCONFIG
    FcConfig *config;
#endif
    char *family_default;
    char *path_default;
    int index_default;
};

#ifdef CONFIG_FONTCONFIG

/**
 * \brief Case-insensitive match ASS/SSA font family against full name. (also
 * known as "name for humans")
 *
 * \param lib library instance
 * \param priv fontconfig instance
 * \param family font fullname
 * \param bold weight attribute
 * \param italic italic attribute
 * \return font set
 */
static FcFontSet *
match_fullname(ASS_Library *lib, FCInstance *priv, const char *family,
               unsigned bold, unsigned italic)
{
    FcFontSet *sets[2];
    FcFontSet *result = FcFontSetCreate();
    int nsets = 0;
    int i, fi;

    if ((sets[nsets] = FcConfigGetFonts(priv->config, FcSetSystem)))
        nsets++;
    if ((sets[nsets] = FcConfigGetFonts(priv->config, FcSetApplication)))
        nsets++;

    // Run over font sets and patterns and try to match against full name
    for (i = 0; i < nsets; i++) {
        FcFontSet *set = sets[i];
        for (fi = 0; fi < set->nfont; fi++) {
            FcPattern *pat = set->fonts[fi];
            char *fullname;
            int pi = 0, at;
            FcBool ol;
            while (FcPatternGetString(pat, FC_FULLNAME, pi++,
                   (FcChar8 **) &fullname) == FcResultMatch) {
                if (FcPatternGetBool(pat, FC_OUTLINE, 0, &ol) != FcResultMatch
                    || ol != FcTrue)
                    continue;
                if (FcPatternGetInteger(pat, FC_SLANT, 0, &at) != FcResultMatch
                    || at < italic)
                    continue;
                if (FcPatternGetInteger(pat, FC_WEIGHT, 0, &at) != FcResultMatch
                    || at < bold)
                    continue;
                if (strcasecmp(fullname, family) == 0) {
                    FcFontSetAdd(result, FcPatternDuplicate(pat));
                    break;
                }
            }
        }
    }

    return result;
}

/**
 * \brief Low-level font selection.
 * \param priv private data
 * \param family font family
 * \param treat_family_as_pattern treat family as fontconfig pattern
 * \param bold font weight value
 * \param italic font slant value
 * \param index out: font index inside a file
 * \param code: the character that should be present in the font, can be 0
 * \return font file path
*/
static char *select_font(ASS_Library *library, FCInstance *priv,
                          const char *family, int treat_family_as_pattern,
                          unsigned bold, unsigned italic, int *index,
                          uint32_t code)
{
    FcBool rc;
    FcResult result;
    FcPattern *pat = NULL, *rpat = NULL;
    int r_index, r_slant, r_weight;
    FcChar8 *r_family, *r_style, *r_file, *r_fullname;
    FcBool r_outline, r_embolden;
    FcCharSet *r_charset;
    FcFontSet *ffullname = NULL, *fsorted = NULL, *fset = NULL;
    int curf;
    char *retval = NULL;
    int family_cnt = 0;

    *index = 0;

    if (treat_family_as_pattern)
        pat = FcNameParse((const FcChar8 *) family);
    else
        pat = FcPatternCreate();

    if (!pat)
        goto error;

    if (!treat_family_as_pattern) {
        FcPatternAddString(pat, FC_FAMILY, (const FcChar8 *) family);

        // In SSA/ASS fonts are sometimes referenced by their "full name",
        // which is usually a concatenation of family name and font
        // style (ex. Ottawa Bold). Full name is available from
        // FontConfig pattern element FC_FULLNAME, but it is never
        // used for font matching.
        // Therefore, I'm removing words from the end of the name one
        // by one, and adding shortened names to the pattern. It seems
        // that the first value (full name in this case) has
        // precedence in matching.
        // An alternative approach could be to reimplement FcFontSort
        // using FC_FULLNAME instead of FC_FAMILY.
        family_cnt = 1;
        {
            char *s = strdup(family);
            char *p = s + strlen(s);
            while (--p > s)
                if (*p == ' ' || *p == '-') {
                    *p = '\0';
                    FcPatternAddString(pat, FC_FAMILY, (const FcChar8 *) s);
                    ++family_cnt;
                }
            free(s);
        }
    }
    FcPatternAddBool(pat, FC_OUTLINE, FcTrue);
    FcPatternAddInteger(pat, FC_SLANT, italic);
    FcPatternAddInteger(pat, FC_WEIGHT, bold);

    FcDefaultSubstitute(pat);

    rc = FcConfigSubstitute(priv->config, pat, FcMatchPattern);
    if (!rc)
        goto error;

    fsorted = FcFontSort(priv->config, pat, FcTrue, NULL, &result);
    ffullname = match_fullname(library, priv, family, bold, italic);
    if (!fsorted || !ffullname)
        goto error;

    fset = FcFontSetCreate();
    for (curf = 0; curf < ffullname->nfont; ++curf) {
        FcPattern *curp = ffullname->fonts[curf];
        FcPatternReference(curp);
        FcFontSetAdd(fset, curp);
    }
    for (curf = 0; curf < fsorted->nfont; ++curf) {
        FcPattern *curp = fsorted->fonts[curf];
        FcPatternReference(curp);
        FcFontSetAdd(fset, curp);
    }

    for (curf = 0; curf < fset->nfont; ++curf) {
        FcPattern *curp = fset->fonts[curf];

        result = FcPatternGetBool(curp, FC_OUTLINE, 0, &r_outline);
        if (result != FcResultMatch)
            continue;
        if (r_outline != FcTrue)
            continue;
        if (!code)
            break;
        result = FcPatternGetCharSet(curp, FC_CHARSET, 0, &r_charset);
        if (result != FcResultMatch)
            continue;
        if (FcCharSetHasChar(r_charset, code))
            break;
    }

    if (curf >= fset->nfont)
        goto error;

    if (!treat_family_as_pattern) {
        // Remove all extra family names from original pattern.
        // After this, FcFontRenderPrepare will select the most relevant family
        // name in case there are more than one of them.
        for (; family_cnt > 1; --family_cnt)
            FcPatternRemove(pat, FC_FAMILY, family_cnt - 1);
    }

    rpat = FcFontRenderPrepare(priv->config, pat, fset->fonts[curf]);
    if (!rpat)
        goto error;

    result = FcPatternGetInteger(rpat, FC_INDEX, 0, &r_index);
    if (result != FcResultMatch)
        goto error;
    *index = r_index;

    result = FcPatternGetString(rpat, FC_FILE, 0, &r_file);
    if (result != FcResultMatch)
        goto error;
    retval = strdup((const char *) r_file);

    result = FcPatternGetString(rpat, FC_FAMILY, 0, &r_family);
    if (result != FcResultMatch)
        r_family = NULL;

    result = FcPatternGetString(rpat, FC_FULLNAME, 0, &r_fullname);
    if (result != FcResultMatch)
        r_fullname = NULL;

    if (!treat_family_as_pattern &&
        !(r_family && strcasecmp((const char *) r_family, family) == 0) &&
        !(r_fullname && strcasecmp((const char *) r_fullname, family) == 0))
        ass_msg(library, MSGL_WARN,
               "fontconfig: Selected font is not the requested one: "
               "'%s' != '%s'",
               (const char *) (r_fullname ? r_fullname : r_family), family);

    result = FcPatternGetString(rpat, FC_STYLE, 0, &r_style);
    if (result != FcResultMatch)
        r_style = NULL;

    result = FcPatternGetInteger(rpat, FC_SLANT, 0, &r_slant);
    if (result != FcResultMatch)
        r_slant = 0;

    result = FcPatternGetInteger(rpat, FC_WEIGHT, 0, &r_weight);
    if (result != FcResultMatch)
        r_weight = 0;

    result = FcPatternGetBool(rpat, FC_EMBOLDEN, 0, &r_embolden);
    if (result != FcResultMatch)
        r_embolden = 0;

    ass_msg(library, MSGL_V,
           "Font info: family '%s', style '%s', fullname '%s',"
           " slant %d, weight %d%s", (const char *) r_family,
           (const char *) r_style, (const char *) r_fullname, r_slant,
           r_weight, r_embolden ? ", embolden" : "");

  error:
    if (pat)
        FcPatternDestroy(pat);
    if (rpat)
        FcPatternDestroy(rpat);
    if (fsorted)
        FcFontSetDestroy(fsorted);
    if (ffullname)
        FcFontSetDestroy(ffullname);
    if (fset)
        FcFontSetDestroy(fset);
    return retval;
}

/**
 * \brief Find a font. Use default family or path if necessary.
 * \param priv_ private data
 * \param family font family
 * \param treat_family_as_pattern treat family as fontconfig pattern
 * \param bold font weight value
 * \param italic font slant value
 * \param index out: font index inside a file
 * \param code: the character that should be present in the font, can be 0
 * \return font file path
*/
char *fontconfig_select(ASS_Library *library, FCInstance *priv,
                        const char *family, int treat_family_as_pattern,
                        unsigned bold, unsigned italic, int *index,
                        uint32_t code)
{
    char *res = 0;
    if (!priv->config) {
        *index = priv->index_default;
        res = priv->path_default ? strdup(priv->path_default) : 0;
        return res;
    }
    if (family && *family)
        res =
            select_font(library, priv, family, treat_family_as_pattern,
                         bold, italic, index, code);
    if (!res && priv->family_default) {
        res =
            select_font(library, priv, priv->family_default, 0, bold,
                         italic, index, code);
        if (res)
            ass_msg(library, MSGL_WARN, "fontconfig_select: Using default "
                    "font family: (%s, %d, %d) -> %s, %d",
                    family, bold, italic, res, *index);
    }
    if (!res && priv->path_default) {
        res = strdup(priv->path_default);
        *index = priv->index_default;
        ass_msg(library, MSGL_WARN, "fontconfig_select: Using default font: "
                "(%s, %d, %d) -> %s, %d", family, bold, italic,
                res, *index);
    }
    if (!res) {
        res = select_font(library, priv, "Arial", 0, bold, italic,
                           index, code);
        if (res)
            ass_msg(library, MSGL_WARN, "fontconfig_select: Using 'Arial' "
                    "font family: (%s, %d, %d) -> %s, %d", family, bold,
                    italic, res, *index);
    }
    if (res)
        ass_msg(library, MSGL_V,
                "fontconfig_select: (%s, %d, %d) -> %s, %d", family, bold,
                italic, res, *index);
    return res;
}

/**
 * \brief Process memory font.
 * \param priv private data
 * \param library library object
 * \param ftlibrary freetype library object
 * \param idx index of the processed font in library->fontdata
 *
 * Builds a font pattern in memory via FT_New_Memory_Face/FcFreeTypeQueryFace.
*/
static void process_fontdata(FCInstance *priv, ASS_Library *library,
                             FT_Library ftlibrary, int idx)
{
    int rc;
    const char *name = library->fontdata[idx].name;
    const char *data = library->fontdata[idx].data;
    int data_size = library->fontdata[idx].size;

    FT_Face face;
    FcPattern *pattern;
    FcFontSet *fset;
    FcBool res;
    int face_index, num_faces = 1;

    for (face_index = 0; face_index < num_faces; ++face_index) {
        rc = FT_New_Memory_Face(ftlibrary, (unsigned char *) data,
                                data_size, face_index, &face);
        if (rc) {
            ass_msg(library, MSGL_WARN, "Error opening memory font: %s",
                   name);
            return;
        }
        num_faces = face->num_faces;

        pattern =
            FcFreeTypeQueryFace(face, (unsigned char *) name, face_index,
                                FcConfigGetBlanks(priv->config));
        if (!pattern) {
            ass_msg(library, MSGL_WARN, "%s failed", "FcFreeTypeQueryFace");
            FT_Done_Face(face);
            return;
        }

        fset = FcConfigGetFonts(priv->config, FcSetSystem);     // somehow it failes when asked for FcSetApplication
        if (!fset) {
            ass_msg(library, MSGL_WARN, "%s failed", "FcConfigGetFonts");
            FT_Done_Face(face);
            return;
        }

        res = FcFontSetAdd(fset, pattern);
        if (!res) {
            ass_msg(library, MSGL_WARN, "%s failed", "FcFontSetAdd");
            FT_Done_Face(face);
            return;
        }

        FT_Done_Face(face);
    }
}

/**
 * \brief Init fontconfig.
 * \param library libass library object
 * \param ftlibrary freetype library object
 * \param family default font family
 * \param path default font path
 * \param fc whether fontconfig should be used
 * \param config path to a fontconfig configuration file, or NULL
 * \param update whether the fontconfig cache should be built/updated
 * \return pointer to fontconfig private data
*/
FCInstance *fontconfig_init(ASS_Library *library,
                            FT_Library ftlibrary, const char *family,
                            const char *path, int fc, const char *config,
                            int update)
{
    int rc;
    FCInstance *priv = calloc(1, sizeof(FCInstance));
    const char *dir = library->fonts_dir;
    int i;

    if (!fc) {
        ass_msg(library, MSGL_WARN,
               "Fontconfig disabled, only default font will be used.");
        goto exit;
    }

    priv->config = FcConfigCreate();
    rc = FcConfigParseAndLoad(priv->config, (unsigned char *) config, FcTrue);
    if (!rc) {
        ass_msg(library, MSGL_WARN, "No usable fontconfig configuration "
                "file found, using fallback.");
        FcConfigDestroy(priv->config);
        priv->config = FcInitLoadConfig();
        rc++;
    }
    if (rc && update) {
        FcConfigBuildFonts(priv->config);
    }

    if (!rc || !priv->config) {
        ass_msg(library, MSGL_FATAL,
                "No valid fontconfig configuration found!");
        FcConfigDestroy(priv->config);
        goto exit;
    }

    for (i = 0; i < library->num_fontdata; ++i)
        process_fontdata(priv, library, ftlibrary, i);

    if (dir) {
        ass_msg(library, MSGL_V, "Updating font cache");

        rc = FcConfigAppFontAddDir(priv->config, (const FcChar8 *) dir);
        if (!rc) {
            ass_msg(library, MSGL_WARN, "%s failed", "FcConfigAppFontAddDir");
        }
    }

    priv->family_default = family ? strdup(family) : NULL;
exit:
    priv->path_default = path ? strdup(path) : NULL;
    priv->index_default = 0;

    return priv;
}

int fontconfig_update(FCInstance *priv)
{
        return FcConfigBuildFonts(priv->config);
}

#else                           /* CONFIG_FONTCONFIG */

char *fontconfig_select(ASS_Library *library, FCInstance *priv,
                        const char *family, int treat_family_as_pattern,
                        unsigned bold, unsigned italic, int *index,
                        uint32_t code)
{
    *index = priv->index_default;
    char* res = priv->path_default ? strdup(priv->path_default) : 0;
    return res;
}

FCInstance *fontconfig_init(ASS_Library *library,
                            FT_Library ftlibrary, const char *family,
                            const char *path, int fc, const char *config,
                            int update)
{
    FCInstance *priv;

    ass_msg(library, MSGL_WARN,
        "Fontconfig disabled, only default font will be used.");

    priv = calloc(1, sizeof(FCInstance));

    priv->path_default = path ? strdup(path) : 0;
    priv->index_default = 0;
    return priv;
}

int fontconfig_update(FCInstance *priv)
{
    // Do nothing
    return 1;
}

#endif

void fontconfig_done(FCInstance *priv)
{

    if (priv) {
#ifdef CONFIG_FONTCONFIG
        FcConfigDestroy(priv->config);
#endif
        free(priv->path_default);
        free(priv->family_default);
    }
    free(priv);
}
