/*
 * Unicode Hexadecimal mode for QEmacs.
 *
 * Copyright (c) 2000-2001 Fabrice Bellard.
 * Copyright (c) 2002-2024 Charlie Gordon.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qe.h"

enum {
    UNIHEX_STYLE_OFFSET = QE_STYLE_COMMENT,
    UNIHEX_STYLE_DUMP   = QE_STYLE_FUNCTION,
};

static int unihex_mode_init(EditState *s, EditBuffer *b, int flags)
{
    if (s) {
        int offset, max_offset, w;
        char32_t c, maxc;

        /* unihex mode is incompatible with EOL_DOS eol type */
        eb_set_charset(s->b, s->b->charset, EOL_UNIX);

        /* Compute max width of character in hex dump (limit to first 64K) */
        maxc = 0xFFFF;
        max_offset = min_offset(65536, s->b->total_size);
        for (offset = 0; offset < max_offset;) {
            c = eb_nextc(s->b, offset, &offset);
            if (maxc < c)
                maxc = c;
        }

        s->hex_mode = 1;
        s->hex_nibble = 0;
        s->unihex_mode = w = snprintf(NULL, 0, "%x", maxc);
        s->dump_width = clamp_int((s->width - 8 - 2 - 2 - 1) / (w + 3), 8, 16);
        s->overwrite = 1;
        /* XXX: should come from mode.default_wrap */
        s->wrap = WRAP_TRUNCATE;
    }
    return 0;
}

static int unihex_to_disp(char32_t c) {
    /* Prevent display of C0 and C1 control codes and invalid code points */
    if (c < ' ' || c == 127 || (c >= 128 && c < 160)
    ||  (c >= 0xD800 && c <= 0xDFFF) || c > 0x10FFFF)
        c = '.';
    return c;
}

static int unihex_backward_offset(EditState *s, int offset)
{
    int pos;

    /* CG: beware: offset may fall inside a character */
    pos = eb_get_char_offset(s->b, offset);
    pos = align(pos, s->dump_width);
    return eb_goto_char(s->b, pos);
}

static int unihex_display_line(EditState *s, DisplayState *ds, int offset)
{
    int j, len, ateof, dump_width, w;
    int offset1, offset2;
    char32_t c, maxc, b;
    /* CG: array size is incorrect, should be smaller */
    char32_t buf[LINE_MAX_SIZE];
    char32_t pos[LINE_MAX_SIZE];

    display_bol(ds);

    ds->style = UNIHEX_STYLE_OFFSET;
    display_printf(ds, -1, -1, "%08x ", (unsigned)offset);
    //int charpos = eb_get_char_offset(s->b, offset);
    //display_printf(ds, -1, -1, "%08x ", charpos);
    //display_printf(ds, -1, -1, "%08x %08x ", charpos, offset);

    dump_width = min_int(LINE_MAX_SIZE - 1, s->dump_width);
    ateof = 0;
    len = 0;
    maxc = 0;
    for (j = 0; j < dump_width && offset < s->b->total_size; j++) {
        pos[len] = offset;
        buf[len] = c = eb_nextc(s->b, offset, &offset);
        if (maxc < c)
            maxc = c;
        len++;
    }
    pos[len] = offset;

    /* adjust s->unihex_mode if a larger character has been found */
    while (s->unihex_mode < 8 && maxc >> (s->unihex_mode * 4) != 0)
        s->unihex_mode++;

    ds->style = UNIHEX_STYLE_DUMP;

    for (j = 0; j < dump_width; j++) {
        display_char(ds, -1, -1, ' ');
        offset1 = pos[j];
        offset2 = pos[j + 1];
        if (j < len) {
            display_printhex(ds, offset1, offset2, buf[j], s->unihex_mode);
            //ds->cur_hex_mode = 1;
            //display_printf(ds, offset1, offset2, "%0*x", s->unihex_mode, buf[j]);
            //ds->cur_hex_mode = 0;
        } else {
            if (!ateof) {
                ateof = 1;
                offset2 = offset1 + 1;
            } else {
                offset2 = offset1 = -1;
            }
            ds->cur_hex_mode = s->hex_mode;
            display_printf(ds, offset1, offset2, "%*c", s->unihex_mode, ' ');
            ds->cur_hex_mode = 0;
        }
        if ((j & 7) == 7)
            display_char(ds, -1, -1, ' ');
    }
    display_char(ds, -1, -1, ' ');

    ds->style = 0;

    display_char(ds, -1, -1, ' ');

    ateof = 0;
    for (j = 0; j < dump_width; j++) {
        offset1 = pos[j];
        offset2 = pos[j + 1];
        if (j < len) {
            b = buf[j];
            b = unihex_to_disp(b);
        } else {
            b = ' ';
            if (!ateof) {
                ateof = 1;
                offset2 = offset1 + 1;
            } else {
                offset2 = offset1 = -1;
            }
        }
        w = qe_wcwidth(b);
        if (w == 0) {
            /* insert space to make accent stand on its own */
            display_char(ds, offset1, offset2, ' ');
            display_char(ds, -1, -1, b);
        } else {
            display_char(ds, offset1, offset2, b);
        }
        /* spacing out single width glyphs may be less readable */
        if (w < 2) {
            display_char(ds, -1, -1, ' ');
        }
    }
    display_eol(ds, -1, -1);

    if (len >= dump_width)
        return offset;
    else
        return -1;
}

static void unihex_move_bol(EditState *s)
{
    int pos;

    pos = eb_get_char_offset(s->b, s->offset);
    pos = align(pos, s->dump_width);
    s->offset = eb_goto_char(s->b, pos);
}

static void unihex_move_eol(EditState *s)
{
    int pos;

    pos = eb_get_char_offset(s->b, s->offset);

    /* CG: should include the last character! */
    pos = align(pos, s->dump_width) + s->dump_width - 1;

    s->offset = eb_goto_char(s->b, pos);
}

static void unihex_move_left_right(EditState *s, int dir)
{
    if (dir > 0) {
        s->offset = eb_next(s->b, s->offset);
    } else {
        s->offset = eb_prev(s->b, s->offset);
    }
}

static void unihex_move_up_down(EditState *s, int dir)
{
    int pos;

    pos = eb_get_char_offset(s->b, s->offset);

    pos += dir * s->dump_width;

    s->offset = eb_goto_char(s->b, pos);
}

static void unihex_mode_line(EditState *s, buf_t *out)
{
    basic_mode_line(s, out, '-');
    buf_printf(out, "--0x%x--0x%x--%s",
               (unsigned)eb_get_char_offset(s->b, s->offset),
               (unsigned)s->offset, s->b->charset->name);
    buf_printf(out, "--%d%%", compute_percent(s->offset, s->b->total_size));
}

static int unihex_mode_probe(ModeDef *mode, ModeProbeData *p)
{
    /* XXX: should check for non 8 bit characters */
    /* XXX: should auto-detect if content has non ASCII utf8 contents */
    return 1;
}

/* additional mode specific bindings */
static const char * const unihex_bindings[] = {
    // XXX: Should use fallback mode for these bindings
    "C-left", "decrease-width",
    "C-right", "increase-width",
    "TAB, S-TAB", "toggle-hex",
    NULL
};

static ModeDef unihex_mode = {
    .name = "unihex",
    .mode_probe = unihex_mode_probe,
    .mode_init = unihex_mode_init,
    .display_line = unihex_display_line,
    .backward_offset = unihex_backward_offset,
    .move_up_down = unihex_move_up_down,
    .move_left_right = unihex_move_left_right,
    .move_bol = unihex_move_bol,
    .move_eol = unihex_move_eol,
    .move_bof = text_move_bof,
    .move_eof = text_move_eof,
    .scroll_up_down = text_scroll_up_down,
    .mouse_goto = text_mouse_goto,
    .write_char = hex_write_char,
    .get_mode_line = unihex_mode_line,
    .bindings = unihex_bindings,
    // XXX: Should use fallback mode for other bindings
    //.fallback = &binary_mode,
};

static int unihex_init(QEmacsState *qs) {
    qe_register_mode(qs, &unihex_mode, MODEF_VIEW);
    return 0;
}

qe_module_init(unihex_init);