/*

Copyright 2006-2010 Taco Hoekwater <taco@luatex.org>

This file is part of LuaTeX.

LuaTeX 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.

LuaTeX 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 Lesser General Public
License for more details.

You should have received a copy of the GNU General Public License along
with LuaTeX; if not, see <http://www.gnu.org/licenses/>.

*/

#include "ptexlib.h"
#include "lua/luatex-api.h"

/*tex

    A bit more interfacing is needed for proper error reporting.

*/

static char *font_error_message(pointer u, char *nom, scaled s)
{
    char *str = xmalloc(256);
    char *c = makecstring(cs_text(u));
    const char *extra = "metric data not found or bad";
    if (s >= 0) {
        snprintf(str, 255, "Font \\%s=%s at %gpt not loadable: %s", c, nom, (double) s / 65536, extra);
    } else if (s != -1000) {
        snprintf(str, 255, "Font \\%s=%s scaled %d not loadable: %s", c, nom, (int) (-s), extra);
    } else {
        snprintf(str, 255, "Font \\%s=%s not loadable: %s", c, nom, extra);
    }
    free(c);
    return str;
}

static int do_define_font(int f, const char *cnom, scaled s, int natural_dir)
{
    boolean res = 0;
    char *cnam;
    int r, t;
    int callback_id = callback_defined(define_font_callback);
    if (callback_id > 0) {
        cnam = xstrdup(cnom);
        callback_id = run_and_save_callback(callback_id, "Sdd->", cnam, s, f);
        free(cnam);
        if (callback_id > 0) {
            /*tex Success. */
            luaL_checkstack(Luas, 1, "out of stack space");
            lua_rawgeti(Luas, LUA_REGISTRYINDEX, callback_id);
            t = lua_type(Luas, -1);
            if (t == LUA_TTABLE) {
                res = font_from_lua(Luas, f);
                destroy_saved_callback(callback_id);
            } else if (t == LUA_TNUMBER) {
                r = (int) lua_tointeger(Luas, -1);
                destroy_saved_callback(callback_id);
                delete_font(f);
                lua_pop(Luas, 1);
                return r;
            } else {
                lua_pop(Luas, 1);
                delete_font(f);
                return 0;
            }
        }
    } else if (callback_id == 0) {
        res = read_tfm_info(f, cnom, s);
        if (res) {
            set_hyphen_char(f, default_hyphen_char_par);
            set_skew_char(f, default_skew_char_par);
        }
    }
    if (font_name(f) && strlen(font_name(f)) > 255) {
        /*tex

            The font name has to fit in the dvi file's single byte storage. There
            is no need to test area, as we are never using it.

            If we have an error in DVI mode we just abort as the DVI file is unuseable
            anyway then.
        */
        if (get_o_mode() == OMODE_DVI) {
            formatted_error("backend","font name too long for DVI: %s",font_name(f));
        }
    }
    if (res) {
        if (font_type(f) != virtual_font_type) {
            /*tex This implies \LUA. */
            do_vf(f);
            set_font_natural_dir(f, natural_dir);
        }
        return f;
    } else {
        delete_font(f);
        return 0;
    }

}

int read_font_info(pointer u, char *cnom, scaled s, int natural_dir)
{
    int f;
    char *msg;

    f = new_font();
    if ((f = do_define_font(f, cnom, s, natural_dir))) {
        return f;
    } else {
        const char *help[] = {
            "I wasn't able to read the size data for this font,",
            "so I will ignore the font specification.",
            "[Wizards can fix TFM files using TFtoPL/PLtoTF.]",
            "You might try inserting a different font spec;",
            "e.g., type `I\\font<same font id>=<substitute font name>'.",
            NULL
        };
        if (suppress_fontnotfound_error_par == 0) {
            msg = font_error_message(u, cnom, s);
            tex_error(msg, help);
            free(msg);
        }
        return 0;
    }
}

int find_font_id(const char *nom, scaled s)
{
    int f;
    f = new_font();
    if ((f = do_define_font(f, nom, s, -1))) {
        return f;
    } else {
        return 0;
    }
}
