/*
 * Hexadecimal modes 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 {
    HEX_STYLE_OFFSET = QE_STYLE_COMMENT,
    HEX_STYLE_DUMP   = QE_STYLE_FUNCTION,
};

static ModeDef hex_mode;

static int bin_to_disp(int c)
{
#if 0
    /* Allow characters in range 160-255 to show as graphics */
    // XXX: This causes alignment issues on screen remove sessions
    //      eg: C-x C-d C-s ligatures
    if ((c & 127) < ' ' || c == 127)
        c = '.';
#else
    if (c < ' ' || c >= 127)
        c = '.';
#endif
    return c;
}

static int hex_backward_offset(EditState *s, int offset)
{
    return align(offset, s->dump_width);
}

static int hex_display_line(EditState *s, DisplayState *ds, int offset)
{
    int j, len, ateof;
    int offset1, offset2;
    unsigned char b;

    display_bol(ds);

    ds->style = HEX_STYLE_OFFSET;
    display_printf(ds, -1, -1, "%08x ", (unsigned)offset);

    ateof = 0;
    len = s->b->total_size - offset;
    if (len > s->dump_width)
        len = s->dump_width;

    if (s->mode == &hex_mode) {

        ds->style = HEX_STYLE_DUMP;

        for (j = 0; j < s->dump_width; j++) {
            display_char(ds, -1, -1, ' ');
            offset1 = offset + j;
            offset2 = offset1 + 1;
            if (j < len) {
                eb_read(s->b, offset1, &b, 1);
                display_printhex(ds, offset1, offset2, b, 2);
            } else {
                if (!ateof) {
                    ateof = 1;
                } else {
                    offset1 = offset2 = -1;
                }
                ds->cur_hex_mode = s->hex_mode;
                display_printf(ds, offset1, offset2, "  ");
                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 < s->dump_width; j++) {
        offset1 = offset + j;
        offset2 = offset1 + 1;
        if (j < len) {
            eb_read(s->b, offset1, &b, 1);
        } else {
            b = ' ';
            if (!ateof) {
                ateof = 1;
            } else {
                offset1 = offset2 = -1;
            }
        }
        display_char(ds, offset1, offset2, bin_to_disp(b));
    }
    display_eol(ds, -1, -1);

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

static void do_set_width(EditState *s, int w)
{
    if (w >= 1) {
        s->dump_width = w;
        s->offset_top = s->mode->backward_offset(s, s->offset_top);
    }
}

static void do_increase_width(EditState *s, int n)
{
    do_set_width(s, s->dump_width + n);
}

static void do_toggle_hex(EditState *s)
{
    s->hex_mode = !s->hex_mode;
}

/* common binary and hex commands */
static const CmdDef binary_commands[] = {
    CMD2( "decrease-width", "C-left",
          "Decrease the number of bytes displayed on each row",
          do_increase_width, ESi, "q")
    CMD2( "increase-width", "C-right",
          "Increase the number of bytes displayed on each row",
          do_increase_width, ESi, "p")
    CMD2( "set-width", "",
          "Set the number of bytes displayed on each row",
          do_set_width, ESi,
          "N{Width: }")
    CMD3( "goto-byte", "M-g",
          "Move point to a specified location",
          do_goto, ESsi,
          "s{Goto byte: }"
          "v", 'b')
};

/* specific hex commands and bindings */
static const CmdDef hex_commands[] = {
    CMD0( "toggle-hex", "TAB, S-TAB",
          "Switch between the hex side and binary side",
          do_toggle_hex)
};

static int binary_mode_init(EditState *s, EditBuffer *b, int flags)
{
    if (s) {
        s->dump_width = s->screen->width / s->char_width;
        if (s->b->flags & BF_PREVIEW)
            s->dump_width = s->dump_width * 4 / 5;

        s->dump_width -= 10;
        /* align on 16 byte boundary */
        s->dump_width &= ~15;
        if (s->dump_width < 16)
            s->dump_width = 16;
        s->hex_mode = 0;
        s->unihex_mode = 0;
        s->overwrite = 1;
        /* XXX: should come from mode.default_wrap */
        s->wrap = WRAP_TRUNCATE;
    }
    return 0;
}

static int hex_mode_init(EditState *s, EditBuffer *b, int flags)
{
    if (s) {
        s->dump_width = 16;
        s->hex_mode = 1;
        s->hex_nibble = 0;
        s->unihex_mode = 0;
        s->overwrite = 1;
        /* XXX: should come from mode.default_wrap */
        s->wrap = WRAP_TRUNCATE;
    }
    return 0;
}

static int detect_binary(const unsigned char *buf, int size)
{
    const uint32_t magic = ((1U << '\b') | (1U << '\t') | (1U << '\f') |
                            (1U << '\n') | (1U << '\r') | (1U << '\033') |
                            (1U << 0x0e) | (1U << 0x0f) | (1U << 0x1a) |
                            (1U << '\a') | (1U << 0x1f));
    int i, c;

    for (i = 0; i < size; i++) {
        c = buf[i];
        if (c < 32 && !(magic & (1U << c)))
            return 1;
    }
    return 0;
}

static int hex_mode_probe(ModeDef *mode, ModeProbeData *p)
{
    if (detect_binary(p->buf, p->buf_size))
        return 50;
    else
        return 10;
}

static void hex_move_bol(EditState *s)
{
    s->offset = align(s->offset, s->dump_width);
}

static void hex_move_eol(EditState *s)
{
    s->offset = min_offset(align(s->offset, s->dump_width) + s->dump_width - 1,
                           s->b->total_size);
}

static void hex_move_left_right(EditState *s, int dir)
{
    s->offset = clamp_offset(s->offset + dir, 0, s->b->total_size);
}

static void hex_move_up_down(EditState *s, int dir)
{
    s->offset = clamp_offset(s->offset + dir * s->dump_width, 0, s->b->total_size);
}

void hex_write_char(EditState *s, int key)
{
    char32_t cur_ch, ch;
    int hsize, shift, cur_len, len, h;
    int offset = s->offset;
    char buf[10];

    if (s->hex_mode) {
        if (s->unihex_mode)
            hsize = s->unihex_mode;
        else
            hsize = 2;
        h = qe_digit_value(key);
        if (h >= 16)
            return;
        if ((!s->overwrite || offset >= s->b->total_size) && s->hex_nibble == 0) {
            ch = h << ((hsize - 1) * 4);
            if (s->unihex_mode || s->b->charset->char_size > 1) {
                len = eb_encode_char32(s->b, buf, ch);
            } else {
                len = 1;
                buf[0] = ch;
            }
            eb_insert(s->b, offset, buf, len);
        } else {
            if (s->unihex_mode) {
                cur_ch = eb_nextc(s->b, offset, &cur_len);
                cur_len -= offset;
            } else {
                eb_read(s->b, offset, buf, 1);
                cur_ch = (u8)buf[0];
                cur_len = 1;
            }

            shift = (hsize - s->hex_nibble - 1) * 4;
            ch = (cur_ch & ~(0xf << shift)) | (h << shift);

            if (s->unihex_mode) {
                len = eb_encode_char32(s->b, buf, ch);
            } else {
                len = 1;
                buf[0] = ch;
            }
#if 1
            // XXX: offset and mark may be udated differently
            eb_replace(s->b, offset, cur_len, buf, len);
#else
            if (cur_len == len) {
                eb_write(s->b, offset, buf, len);
            } else {
                eb_delete(s->b, offset, cur_len);
                eb_insert(s->b, offset, buf, len);
            }
#endif
        }
        s->offset = offset;
        if (++s->hex_nibble == hsize) {
            s->hex_nibble = 0;
            if (offset < s->b->total_size)
                s->offset += len;
        }
    } else {
        // XXX: should use overwrite mode?
        text_write_char(s, key);
    }
}

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

static int binary_mode_probe(ModeDef *mode, ModeProbeData *p)
{
    return 5;
}

static ModeDef binary_mode = {
    .name = "binary",
    .mode_probe = binary_mode_probe,
    .mode_init = binary_mode_init,
    .display_line = hex_display_line,
    .backward_offset = hex_backward_offset,
    .move_up_down = hex_move_up_down,
    .move_left_right = hex_move_left_right,
    .move_bol = hex_move_bol,
    .move_eol = hex_move_eol,
    .move_bof = text_move_bof,
    .move_eof = text_move_eof,
    .move_word_left_right = text_move_word_left_right,
    .scroll_up_down = text_scroll_up_down,
    .mouse_goto = text_mouse_goto,
    .write_char = text_write_char,
    .get_mode_line = hex_mode_line,
};

static ModeDef hex_mode = {
    .name = "hex",
    .mode_probe = hex_mode_probe,
    .mode_init = hex_mode_init,
    .display_line = hex_display_line,
    .backward_offset = hex_backward_offset,
    .move_up_down = hex_move_up_down,
    .move_left_right = hex_move_left_right,
    .move_bol = hex_move_bol,
    .move_eol = hex_move_eol,
    .move_bof = text_move_bof,
    .move_eof = text_move_eof,
    .move_word_left_right = text_move_word_left_right,
    .scroll_up_down = text_scroll_up_down,
    .mouse_goto = text_mouse_goto,
    .write_char = hex_write_char,
    .get_mode_line = hex_mode_line,
    .fallback = &binary_mode,
};

static int hex_init(QEmacsState *qs)
{
    /* first register mode(s) */
    qe_register_mode(qs, &binary_mode, MODEF_VIEW);
    qe_register_mode(qs, &hex_mode, MODEF_VIEW);

    /* commands and default keys */
    qe_register_commands(qs, &binary_mode, binary_commands, countof(binary_commands));
    qe_register_commands(qs, &hex_mode, hex_commands, countof(hex_commands));

    return 0;
}

qe_module_init(hex_init);
