/* This is dvipdfmx, an eXtended version of dvipdfm by Mark A. Wicks.

   Copyright (C) 2002-2018 by Jin-Hwan Cho and Shunsaku Hirata,
   the dvipdfmx project team.

   This program 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.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/

#include "dpx-subfont.h"

#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "tectonic_bridge_core.h"
#include "dpx-dpxconf.h"
#include "dpx-dpxfile.h"
#include "dpx-error.h"
#include "dpx-mem.h"
#include "dpx-mfileio.h"

/* Don't forget fontmap reading now requires information
 * from SFD files. You must initialize at least sfd_file_
 * cache before starting loading of fontmaps.
 */

/* Subfont Definition File:
 *  struct sfd_file_ is for storing subfont identifiers
 *  contained in a SFD file and for mapping string pair
 *  <SFD_file, Subfont_id> to internal code mapping table
 *  ID which is index within an array of struct sfd_rec_.
 *  We store code mapping tables in different place than
 *  struct sfd_file_.
 */
struct sfd_file_
{
    char  *ident;  /* SFD file name */
    char **sub_id; /* Subfont IDs   */

    int   *rec_id; /* indices within struct sfd_rec_ array "sfd_record" */

    int    max_subfonts;
    int    num_subfonts;
};

/* Mapping table */
struct sfd_rec_
{
    /* unsigned char  misbit[32]; */
    unsigned short vector[256]; /* 0 for undefined */
};

static void
init_sfd_file_ (struct sfd_file_ *sfd)
{
    sfd->ident  = NULL;
    sfd->sub_id = NULL;
    sfd->rec_id = NULL;
    sfd->max_subfonts = sfd->num_subfonts = 0;
}

static void
clean_sfd_file_ (struct sfd_file_ *sfd)
{
    int  i;
    free(sfd->ident);
    if (sfd->sub_id) {
        for (i = 0; i < sfd->num_subfonts; i++) {
            free(sfd->sub_id[i]);
        }
        free(sfd->sub_id);
    }
    free(sfd->rec_id);
    init_sfd_file_(sfd);
}

static struct sfd_file_ *sfd_files = NULL;
static int num_sfd_files = 0, max_sfd_files = 0;

static struct sfd_rec_ *sfd_record = NULL;
static int num_sfd_records = 0, max_sfd_records = 0;



/* Another buffer...
 * We want buffer size at least 7 x 256 + a
 * 4096 is usually enough.
 */
#define LINE_BUF_SIZE 4096
static char line_buf[LINE_BUF_SIZE];

/* Each lines describes character code mapping for each
 * subfonts. '#' is start of comment.
 * SFD file format uses a '\' before newline sequence
 * for line-continuation.
 */
static char *
readline (char *buf, int buf_len, rust_input_handle_t handle)
{
    char  *r, *q, *p = buf;
    int    n = 0, c = 0;

    while (buf_len - n > 0 && (q = tt_mfgets(p, buf_len - n, handle))) {
        c++;
        r = strchr(q, '#');
        /* Comment is converted to single wsp (followed by a newline). */
        if (r) {
            *r = ' ';
            *(r + 1) = '\0';
        }
        if (strlen(q) == 0)
            break; /* empty line */
        n += strlen(q);
        q += strlen(q) - 1;
        if (*q != '\\')
            break;
        else { /* line continued */
            n -= 1;
            p  = buf + n;
        }
    }
    if (n >= buf_len - 1) {
        dpx_warning("Possible buffer overflow in reading SFD file (buffer full, size=%d bytes)",
                    buf_len - 1);
    }

    return  (c > 0 ? buf : NULL);
}

#define clear_vector(v) if ((v)) {              \
        int __i;                                \
        for (__i = 0; __i < 256; __i++)         \
            (v)[__i] = 0;                       \
    }

/* subfont_id ( integer ':' | integer '_' integer | integer )*
 *
 *  0x32: ==> Subsequent integers are place into slots starting at 0x32.
 *    0x32: 0xA1A1 0xA1A2 ... ==> 0x32 is mappned to 0xA1A1, 0x33 to 0xA1A2
 *  0xA1A1_0xA1A5 ==> Expanded to 0xA1A1 0xA1A2 ... 0xA1A5
 */

/* subfont_id is already consumed here. */
static int
read_sfd_record (struct sfd_rec_ *rec, const char *lbuf)
{
    const char *p = lbuf, *q;
    char  *r;
    int    repos  = 0;
    int    c,  v1 = 0, v2 = 0;
    int    curpos = 0;
    int    error  = 0;

#define IS_TOKSEP(c) ((c) == '\0' || isspace((unsigned char)(c)))
    for ( ; *p && isspace((unsigned char)*p); p++);
    while (!error && *p) {
        repos = 0; q = p;
        v1    = strtol(p, &r, 0);
        q = r;
        if (q == p ||
            (!IS_TOKSEP(*q) && *q != ':' && *q != '_')) {
            dpx_warning("Unknown token in subfont mapping table: %c", *q);
            return  -1;
        }

        switch (*q) {
        case  ':':
            if (v1 < 0 || v1 > 0xff) {
                dpx_warning("Invalud value for subfont table offset: %d", v1);
                return  -1;
            }
            repos = 1;
            q++;
            break;
        case  '_':
            p  = q + 1;
            v2 = strtol(p, &r, 0);
            q = r;
            if (v1 < 0 || v1 > 0xffffL ||
                v2 < 0 || v2 > 0xffffL) {
                dpx_warning("Invalid value in subfont mapping table: 0x%x_0x%x", v1, v2);
                return -1;
            } else if (q == p || !IS_TOKSEP(*q)) {
                dpx_warning("Invalid char in subfont mapping table: %c", *q);
                return  -1;
            }
            break;
        default:
            if (v1 < 0 || v1 > 0xffffL) {
                dpx_warning("Invalid character code in subfont mapping table: 0x%x", v1);
                return -1;
            }
            v2 = v1;
            break;
        }

        if (repos)
            curpos = v1;
        else {
            if (v2 < v1 || curpos + (v2 - v1) > 0xff) {
                dpx_warning("Invalid range in subfont mapping: curpos=\"0x%02x\" range=\"0x%04x,0x%04x\"",
                            curpos, v1, v2);
                return  -1;
            }
            for (c = v1; c <= v2; c++) {
                if (rec->vector[curpos] != 0) {
                    dpx_warning("Subfont mapping for slot=\"0x%02x\" already defined...", curpos);
                    return  -1;
                }
                assert( curpos >= 0 && curpos <= 255 );
                rec->vector[curpos++] = (unsigned short) c;
            }
        }
        for (p = q; *p && isspace((unsigned char)*p); p++);
    }

    return  error;
}

/* Scan for subfont IDs */
static int
scan_sfd_file (struct sfd_file_ *sfd, rust_input_handle_t handle)
{
    char  *id;
    char  *q, *p;
    int    n, lpos = 0;

    assert( sfd && handle );

    if (dpx_conf.verbose_level > 3) {
        dpx_message("\nsubfont>> Scanning SFD file \"%s\"...\n", sfd->ident);
    }

    ttstub_input_seek(handle, 0, SEEK_SET);

    sfd->max_subfonts = sfd->num_subfonts = 0;
    while ((p = readline(line_buf, LINE_BUF_SIZE, handle)) != NULL) {
        lpos++;
        for ( ; *p && isspace((unsigned char)*p); p++);
        if (*p == 0)
            continue; /* empty */

        /* Saw non-wsp here */
        for (n = 0, q = p; *p && !isspace((unsigned char)*p); p++, n++);
        id = NEW(n + 1, char);
        memcpy(id, q, n); id[n] = '\0';
        if (sfd->num_subfonts >= sfd->max_subfonts) {
            sfd->max_subfonts += 16;
            sfd->sub_id = RENEW(sfd->sub_id, sfd->max_subfonts, char *);
        }

        if (dpx_conf.verbose_level > 3) {
            dpx_message("subfont>>   id=\"%s\" at line=\"%d\"\n", id, lpos);
        }
        sfd->sub_id[sfd->num_subfonts] = id;
        sfd->num_subfonts++;
    }

    sfd->rec_id = NEW(sfd->num_subfonts, int);
    for (n = 0; n < sfd->num_subfonts; n++) {
        sfd->rec_id[n] = -1; /* Not loaded yet. We do lazy loading of map definitions. */
    }

    if (dpx_conf.verbose_level > 3) {
        dpx_message("subfont>> %d entries found in SFD file \"%s\".\n", sfd->num_subfonts, sfd->ident);
    }

    return  0;
}


/* Open SFD file and gather subfont IDs. We do not read mapping tables
 * here but only read subfont IDs used in SFD file.
 */
static int
find_sfd_file (const char *sfd_name)
{
    int    id = -1;
    int    i, error = -1;

    /* Check if we already opened SFD file */
    for (i = 0; i < num_sfd_files; i++) {
        if (streq_ptr(sfd_files[i].ident, sfd_name)) {
            id = i;
            break;
        }
    }

    if (id < 0) {
        struct sfd_file_ *sfd = NULL;
        rust_input_handle_t handle = NULL;

        if (num_sfd_files >= max_sfd_files) {
            max_sfd_files += 8;
            sfd_files = RENEW(sfd_files, max_sfd_files, struct sfd_file_);
        }
        sfd = &sfd_files[num_sfd_files];
        init_sfd_file_(sfd);
        sfd->ident = NEW(strlen(sfd_name) + 1, char);
        strcpy(sfd->ident, sfd_name);
        handle = ttstub_input_open(sfd->ident, TTBC_FILE_FORMAT_SFD, 0);
        if (handle == NULL) {
            clean_sfd_file_(sfd);
            return  -1;
        }
        error = scan_sfd_file(sfd, handle);
        ttstub_input_close(handle);
        if (!error)
            id = num_sfd_files++;
        else {
            dpx_warning("Error occured while reading SFD file \"%s\"", sfd_name);
            clean_sfd_file_(sfd);
            id = -1;
        }
    }

    return  id;
}

char **
sfd_get_subfont_ids (const char *sfd_name, int *num_ids)
{
    int  sfd_id;

    if (!sfd_name)
        return  NULL;

    sfd_id = find_sfd_file(sfd_name);
    if (sfd_id < 0)
        return  NULL;

    if (num_ids)
        *num_ids = sfd_files[sfd_id].num_subfonts;
    return  sfd_files[sfd_id].sub_id;
}

/* Make sure that sfd_name does not have the extension '.sfd'.
 * Mapping tables are actually read here.
 */
int
sfd_load_record (const char *sfd_name, const char *subfont_id)
{
    int               rec_id = -1;
    struct sfd_file_ *sfd;
    rust_input_handle_t handle;
    int               sfd_id, i, error = 0;
    char             *p, *q;

    if (!sfd_name || !subfont_id)
        return  -1;

    sfd_id = find_sfd_file(sfd_name);
    if (sfd_id < 0)
        return  -1;

    sfd = &sfd_files[sfd_id];
    /* Check if we already loaded mapping table. */
    for (i = 0;
         i < sfd->num_subfonts && strcmp(sfd->sub_id[i], subfont_id); i++);
    if (i == sfd->num_subfonts) {
        dpx_warning("Subfont id=\"%s\" not exist in SFD file \"%s\"...",
                    subfont_id, sfd->ident);
        return  -1;
    } else if (sfd->rec_id[i] >= 0) {
        return  sfd->rec_id[i];
    }

    if (dpx_conf.verbose_level > 3) {
        dpx_message("\nsubfont>> Loading SFD mapping table for <%s,%s>...",
                    sfd->ident, subfont_id);
    }

    /* reopen */
    handle = ttstub_input_open(sfd->ident, TTBC_FILE_FORMAT_SFD, 0);
    if (handle == NULL) {
        return  -1;
        /* _tt_abort("Could not open SFD file \"%s\"", sfd_name); */
    }

    /* Seek to record for 'sub_name'. */
    while ((p = readline(line_buf, LINE_BUF_SIZE, handle))) {
        for ( ; *p && isspace((unsigned char)*p); p++);
        if (*p == 0)
            continue; /* empty line */

        /* q = parse_ident(&p, p + strlen(p)); */
        for (q = p; *p && !isspace((unsigned char)*p); p++);
        *p = '\0'; p++;
        if (streq_ptr(q, subfont_id)) {
            if (num_sfd_records >= max_sfd_records) {
                max_sfd_records += 16;
                sfd_record = RENEW(sfd_record, max_sfd_records, struct sfd_rec_);
            }
            clear_vector(sfd_record[num_sfd_records].vector);
            error = read_sfd_record(&sfd_record[num_sfd_records], p);
            if (error)
                dpx_warning("Error occured while reading SFD file: file=\"%s\" subfont_id=\"%s\"",
                            sfd->ident, subfont_id);
            else {
                rec_id = num_sfd_records++;
            }
        }
    }
    if (rec_id < 0) {
        dpx_warning("Failed to load subfont mapping table for SFD=\"%s\" subfont_id=\"%s\"",
                    sfd->ident, subfont_id);
    }
    sfd->rec_id[i] = rec_id;
    ttstub_input_close(handle);

    if (dpx_conf.verbose_level > 3) {
        int __i;
        if (rec_id >= 0) {
            dpx_message(" at id=\"%d\"", rec_id);
            dpx_message("\nsubfont>> Content of mapping table:");
            for (__i = 0; __i < 256; __i++) {
                if (__i % 16 == 0)
                    dpx_message("\nsubfont>>  ");
                dpx_message(" %04x", sfd_record[rec_id].vector[__i]);
            }
        }
        dpx_message("\n");
    }

    return  rec_id;
}


/* Lookup mapping table */
unsigned short
lookup_sfd_record (int rec_id, unsigned char c)
{
    if (!sfd_record ||
        rec_id < 0 || rec_id >= num_sfd_records)
        _tt_abort("Invalid subfont_id: %d", rec_id);
    return sfd_record[rec_id].vector[c];
}

void
release_sfd_record (void)
{
    int  i;

    if (sfd_record) {
        free(sfd_record);
    }
    if (sfd_files) {
        for (i = 0; i < num_sfd_files; i++) {
            clean_sfd_file_(&sfd_files[i]);
        }
        free(sfd_files);
    }
    sfd_record = NULL;
    sfd_files  = NULL;
    num_sfd_records = max_sfd_records = 0;
    num_sfd_files = max_sfd_files = 0;
}