/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008-2009 Ed Schouten <ed@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

static void teken_subr_cursor_up(teken_t *, unsigned int);
static void teken_subr_erase_line(const teken_t *, unsigned int);
static void teken_subr_regular_character(teken_t *, teken_char_t);
static void teken_subr_reset_to_initial_state(teken_t *);
static void teken_subr_save_cursor(teken_t *);

static inline int
teken_tab_isset(const teken_t *t, unsigned int col)
{
        unsigned int b, o;

        if (col >= T_NUMCOL)
                return ((col % 8) == 0);

        b = col / (sizeof(unsigned int) * 8);
        o = col % (sizeof(unsigned int) * 8);

        return (t->t_tabstops[b] & (1U << o));
}

static inline void
teken_tab_clear(teken_t *t, unsigned int col)
{
        unsigned int b, o;

        if (col >= T_NUMCOL)
                return;

        b = col / (sizeof(unsigned int) * 8);
        o = col % (sizeof(unsigned int) * 8);

        t->t_tabstops[b] &= ~(1U << o);
}

static inline void
teken_tab_set(teken_t *t, unsigned int col)
{
        unsigned int b, o;

        if (col >= T_NUMCOL)
                return;

        b = col / (sizeof(unsigned int) * 8);
        o = col % (sizeof(unsigned int) * 8);

        t->t_tabstops[b] |= 1U << o;
}

static void
teken_tab_default(teken_t *t)
{
        unsigned int i;

        memset(t->t_tabstops, 0, T_NUMCOL / 8);

        for (i = 8; i < T_NUMCOL; i += 8)
                teken_tab_set(t, i);
}

static void
teken_subr_do_scroll(const teken_t *t, int amount)
{
        teken_rect_t tr;
        teken_pos_t tp;

        teken_assert(t->t_cursor.tp_row <= t->t_winsize.tp_row);
        teken_assert(t->t_scrollreg.ts_end <= t->t_winsize.tp_row);
        teken_assert(amount != 0);

        /* Copy existing data 1 line up. */
        if (amount > 0) {
                /* Scroll down. */

                /* Copy existing data up. */
                if (t->t_scrollreg.ts_begin + amount < t->t_scrollreg.ts_end) {
                        tr.tr_begin.tp_row = t->t_scrollreg.ts_begin + amount;
                        tr.tr_begin.tp_col = 0;
                        tr.tr_end.tp_row = t->t_scrollreg.ts_end;
                        tr.tr_end.tp_col = t->t_winsize.tp_col;
                        tp.tp_row = t->t_scrollreg.ts_begin;
                        tp.tp_col = 0;
                        teken_funcs_copy(t, &tr, &tp);

                        tr.tr_begin.tp_row = t->t_scrollreg.ts_end - amount;
                } else {
                        tr.tr_begin.tp_row = t->t_scrollreg.ts_begin;
                }

                /* Clear the last lines. */
                tr.tr_begin.tp_col = 0;
                tr.tr_end.tp_row = t->t_scrollreg.ts_end;
                tr.tr_end.tp_col = t->t_winsize.tp_col;
                teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
        } else {
                /* Scroll up. */
                amount = -amount;

                /* Copy existing data down. */
                if (t->t_scrollreg.ts_begin + amount < t->t_scrollreg.ts_end) {
                        tr.tr_begin.tp_row = t->t_scrollreg.ts_begin;
                        tr.tr_begin.tp_col = 0;
                        tr.tr_end.tp_row = t->t_scrollreg.ts_end - amount;
                        tr.tr_end.tp_col = t->t_winsize.tp_col;
                        tp.tp_row = t->t_scrollreg.ts_begin + amount;
                        tp.tp_col = 0;
                        teken_funcs_copy(t, &tr, &tp);

                        tr.tr_end.tp_row = t->t_scrollreg.ts_begin + amount;
                } else {
                        tr.tr_end.tp_row = t->t_scrollreg.ts_end;
                }

                /* Clear the first lines. */
                tr.tr_begin.tp_row = t->t_scrollreg.ts_begin;
                tr.tr_begin.tp_col = 0;
                tr.tr_end.tp_col = t->t_winsize.tp_col;
                teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
        }
}

static ssize_t
teken_subr_do_cpr(const teken_t *t, unsigned int cmd, char response[16])
{

        switch (cmd) {
        case 5: /* Operating status. */
                strcpy(response, "0n");
                return (2);
        case 6: { /* Cursor position. */
                int len;

                len = snprintf(response, 16, "%u;%uR",
                    (t->t_cursor.tp_row - t->t_originreg.ts_begin) + 1,
                    t->t_cursor.tp_col + 1);

                if (len >= 16)
                        return (-1);
                return (len);
        }
        case 15: /* Printer status. */
                strcpy(response, "13n");
                return (3);
        case 25: /* UDK status. */
                strcpy(response, "20n");
                return (3);
        case 26: /* Keyboard status. */
                strcpy(response, "27;1n");
                return (5);
        default:
                teken_printf("Unknown DSR\n");
                return (-1);
        }
}

static void
teken_subr_alignment_test(teken_t *t)
{
        teken_rect_t tr;

        t->t_cursor.tp_row = t->t_cursor.tp_col = 0;
        t->t_scrollreg.ts_begin = 0;
        t->t_scrollreg.ts_end = t->t_winsize.tp_row;
        t->t_originreg = t->t_scrollreg;
        t->t_stateflags &= ~(TS_WRAPPED|TS_ORIGIN);
        teken_funcs_cursor(t);

        tr.tr_begin.tp_row = 0;
        tr.tr_begin.tp_col = 0;
        tr.tr_end = t->t_winsize;
        teken_funcs_fill(t, &tr, 'E', &t->t_defattr);
}

static void
teken_subr_backspace(teken_t *t)
{

        if (t->t_stateflags & TS_CONS25) {
                if (t->t_cursor.tp_col == 0) {
                        if (t->t_cursor.tp_row == t->t_originreg.ts_begin)
                                return;
                        t->t_cursor.tp_row--;
                        t->t_cursor.tp_col = t->t_winsize.tp_col - 1;
                } else {
                        t->t_cursor.tp_col--;
                }
        } else {
                if (t->t_cursor.tp_col == 0)
                        return;

                t->t_cursor.tp_col--;
                t->t_stateflags &= ~TS_WRAPPED;
        }

        teken_funcs_cursor(t);
}

static void
teken_subr_bell(const teken_t *t)
{

        teken_funcs_bell(t);
}

static void
teken_subr_carriage_return(teken_t *t)
{

        t->t_cursor.tp_col = 0;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_backward(teken_t *t, unsigned int ncols)
{

        if (ncols > t->t_cursor.tp_col)
                t->t_cursor.tp_col = 0;
        else
                t->t_cursor.tp_col -= ncols;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_backward_tabulation(teken_t *t, unsigned int ntabs)
{

        do {
                /* Stop when we've reached the beginning of the line. */
                if (t->t_cursor.tp_col == 0)
                        break;

                t->t_cursor.tp_col--;

                /* Tab marker set. */
                if (teken_tab_isset(t, t->t_cursor.tp_col))
                        ntabs--;
        } while (ntabs > 0);

        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_down(teken_t *t, unsigned int nrows)
{

        if (t->t_cursor.tp_row + nrows >= t->t_scrollreg.ts_end)
                t->t_cursor.tp_row = t->t_scrollreg.ts_end - 1;
        else
                t->t_cursor.tp_row += nrows;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_forward(teken_t *t, unsigned int ncols)
{

        if (t->t_cursor.tp_col + ncols >= t->t_winsize.tp_col)
                t->t_cursor.tp_col = t->t_winsize.tp_col - 1;
        else
                t->t_cursor.tp_col += ncols;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_forward_tabulation(teken_t *t, unsigned int ntabs)
{

        do {
                /* Stop when we've reached the end of the line. */
                if (t->t_cursor.tp_col == t->t_winsize.tp_col - 1)
                        break;

                t->t_cursor.tp_col++;

                /* Tab marker set. */
                if (teken_tab_isset(t, t->t_cursor.tp_col))
                        ntabs--;
        } while (ntabs > 0);

        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_next_line(teken_t *t, unsigned int ncols)
{

        t->t_cursor.tp_col = 0;
        teken_subr_cursor_down(t, ncols);
}

static void
teken_subr_cursor_position(teken_t *t, unsigned int row, unsigned int col)
{

        row = (row - 1) + t->t_originreg.ts_begin;
        t->t_cursor.tp_row = row < t->t_originreg.ts_end ?
            row : t->t_originreg.ts_end - 1;

        col--;
        t->t_cursor.tp_col = col < t->t_winsize.tp_col ?
            col : t->t_winsize.tp_col - 1;

        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_cursor_position_report(const teken_t *t, unsigned int cmd)
{
        char response[18] = "\x1B[";
        ssize_t len;

        len = teken_subr_do_cpr(t, cmd, response + 2);
        if (len < 0)
                return;

        teken_funcs_respond(t, response, len + 2);
}

static void
teken_subr_cursor_previous_line(teken_t *t, unsigned int ncols)
{

        t->t_cursor.tp_col = 0;
        teken_subr_cursor_up(t, ncols);
}

static void
teken_subr_cursor_up(teken_t *t, unsigned int nrows)
{

        if (t->t_scrollreg.ts_begin + nrows >= t->t_cursor.tp_row)
                t->t_cursor.tp_row = t->t_scrollreg.ts_begin;
        else
                t->t_cursor.tp_row -= nrows;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_set_cursor_style(teken_t *t __unused, unsigned int style __unused)
{

        /* TODO */

        /*
         * CSI Ps SP q
         *   Set cursor style (DECSCUSR), VT520.
         *     Ps = 0  -> blinking block.
         *     Ps = 1  -> blinking block (default).
         *     Ps = 2  -> steady block.
         *     Ps = 3  -> blinking underline.
         *     Ps = 4  -> steady underline.
         *     Ps = 5  -> blinking bar (xterm).
         *     Ps = 6  -> steady bar (xterm).
         */
}

static void
teken_subr_delete_character(const teken_t *t, unsigned int ncols)
{
        teken_rect_t tr;

        tr.tr_begin.tp_row = t->t_cursor.tp_row;
        tr.tr_end.tp_row = t->t_cursor.tp_row + 1;
        tr.tr_end.tp_col = t->t_winsize.tp_col;

        if (t->t_cursor.tp_col + ncols >= t->t_winsize.tp_col) {
                tr.tr_begin.tp_col = t->t_cursor.tp_col;
        } else {
                /* Copy characters to the left. */
                tr.tr_begin.tp_col = t->t_cursor.tp_col + ncols;
                teken_funcs_copy(t, &tr, &t->t_cursor);

                tr.tr_begin.tp_col = t->t_winsize.tp_col - ncols;
        }

        /* Blank trailing columns. */
        teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
}

static void
teken_subr_delete_line(const teken_t *t, unsigned int nrows)
{
        teken_rect_t tr;

        /* Ignore if outside scrolling region. */
        if (t->t_cursor.tp_row < t->t_scrollreg.ts_begin ||
            t->t_cursor.tp_row >= t->t_scrollreg.ts_end)
                return;

        tr.tr_begin.tp_col = 0;
        tr.tr_end.tp_row = t->t_scrollreg.ts_end;
        tr.tr_end.tp_col = t->t_winsize.tp_col;

        if (t->t_cursor.tp_row + nrows >= t->t_scrollreg.ts_end) {
                tr.tr_begin.tp_row = t->t_cursor.tp_row;
        } else {
                teken_pos_t tp;

                /* Copy rows up. */
                tr.tr_begin.tp_row = t->t_cursor.tp_row + nrows;
                tp.tp_row = t->t_cursor.tp_row;
                tp.tp_col = 0;
                teken_funcs_copy(t, &tr, &tp);

                tr.tr_begin.tp_row = t->t_scrollreg.ts_end - nrows;
        }

        /* Blank trailing rows. */
        teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
}

static void
teken_subr_device_control_string(teken_t *t)
{

        teken_printf("Unsupported device control string\n");
        t->t_stateflags |= TS_INSTRING;
}

static void
teken_subr_device_status_report(const teken_t *t, unsigned int cmd)
{
        char response[19] = "\x1B[?";
        ssize_t len;

        len = teken_subr_do_cpr(t, cmd, response + 3);
        if (len < 0)
                return;

        teken_funcs_respond(t, response, len + 3);
}

static void
teken_subr_double_height_double_width_line_top(const teken_t *t)
{

        (void)t;
        teken_printf("double height double width top\n");
}

static void
teken_subr_double_height_double_width_line_bottom(const teken_t *t)
{

        (void)t;
        teken_printf("double height double width bottom\n");
}

static void
teken_subr_erase_character(const teken_t *t, unsigned int ncols)
{
        teken_rect_t tr;

        tr.tr_begin = t->t_cursor;
        tr.tr_end.tp_row = t->t_cursor.tp_row + 1;

        if (t->t_cursor.tp_col + ncols >= t->t_winsize.tp_col)
                tr.tr_end.tp_col = t->t_winsize.tp_col;
        else
                tr.tr_end.tp_col = t->t_cursor.tp_col + ncols;

        teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
}

static void
teken_subr_erase_display(const teken_t *t, unsigned int mode)
{
        teken_rect_t r;

        r.tr_begin.tp_col = 0;
        r.tr_end.tp_col = t->t_winsize.tp_col;

        switch (mode) {
        case 1: /* Erase from the top to the cursor. */
                teken_subr_erase_line(t, 1);

                /* Erase lines above. */
                if (t->t_cursor.tp_row == 0)
                        return;
                r.tr_begin.tp_row = 0;
                r.tr_end.tp_row = t->t_cursor.tp_row;
                break;
        case 2: /* Erase entire display. */
                r.tr_begin.tp_row = 0;
                r.tr_end.tp_row = t->t_winsize.tp_row;
                break;
        default: /* Erase from cursor to the bottom. */
                teken_subr_erase_line(t, 0);

                /* Erase lines below. */
                if (t->t_cursor.tp_row == t->t_winsize.tp_row - 1)
                        return;
                r.tr_begin.tp_row = t->t_cursor.tp_row + 1;
                r.tr_end.tp_row = t->t_winsize.tp_row;
                break;
        }

        teken_funcs_fill(t, &r, BLANK, &t->t_curattr);
}

static void
teken_subr_erase_line(const teken_t *t, unsigned int mode)
{
        teken_rect_t r;

        r.tr_begin.tp_row = t->t_cursor.tp_row;
        r.tr_end.tp_row = t->t_cursor.tp_row + 1;

        switch (mode) {
        case 1: /* Erase from the beginning of the line to the cursor. */
                r.tr_begin.tp_col = 0;
                r.tr_end.tp_col = t->t_cursor.tp_col + 1;
                break;
        case 2: /* Erase entire line. */
                r.tr_begin.tp_col = 0;
                r.tr_end.tp_col = t->t_winsize.tp_col;
                break;
        default: /* Erase from cursor to the end of the line. */
                r.tr_begin.tp_col = t->t_cursor.tp_col;
                r.tr_end.tp_col = t->t_winsize.tp_col;
                break;
        }

        teken_funcs_fill(t, &r, BLANK, &t->t_curattr);
}

static void
teken_subr_g0_scs_special_graphics(teken_t *t)
{

        t->t_scs[0] = teken_scs_special_graphics;
}

static void
teken_subr_g0_scs_uk_national(teken_t *t)
{

        t->t_scs[0] = teken_scs_uk_national;
}

static void
teken_subr_g0_scs_us_ascii(teken_t *t)
{

        t->t_scs[0] = teken_scs_us_ascii;
}

static void
teken_subr_g1_scs_special_graphics(teken_t *t)
{

        t->t_scs[1] = teken_scs_special_graphics;
}

static void
teken_subr_g1_scs_uk_national(teken_t *t)
{

        t->t_scs[1] = teken_scs_uk_national;
}

static void
teken_subr_g1_scs_us_ascii(teken_t *t)
{

        t->t_scs[1] = teken_scs_us_ascii;
}

static void
teken_subr_horizontal_position_absolute(teken_t *t, unsigned int col)
{

        col--;
        t->t_cursor.tp_col = col < t->t_winsize.tp_col ?
            col : t->t_winsize.tp_col - 1;

        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_horizontal_tab(teken_t *t)
{

        teken_subr_cursor_forward_tabulation(t, 1);
}

static void
teken_subr_horizontal_tab_set(teken_t *t)
{

        teken_tab_set(t, t->t_cursor.tp_col);
}

static void
teken_subr_index(teken_t *t)
{

        if (t->t_cursor.tp_row < t->t_scrollreg.ts_end - 1) {
                t->t_cursor.tp_row++;
                t->t_stateflags &= ~TS_WRAPPED;
                teken_funcs_cursor(t);
        } else {
                teken_subr_do_scroll(t, 1);
        }
}

static void
teken_subr_insert_character(const teken_t *t, unsigned int ncols)
{
        teken_rect_t tr;

        tr.tr_begin = t->t_cursor;
        tr.tr_end.tp_row = t->t_cursor.tp_row + 1;

        if (t->t_cursor.tp_col + ncols >= t->t_winsize.tp_col) {
                tr.tr_end.tp_col = t->t_winsize.tp_col;
        } else {
                teken_pos_t tp;

                /* Copy characters to the right. */
                tr.tr_end.tp_col = t->t_winsize.tp_col - ncols;
                tp.tp_row = t->t_cursor.tp_row;
                tp.tp_col = t->t_cursor.tp_col + ncols;
                teken_funcs_copy(t, &tr, &tp);

                tr.tr_end.tp_col = t->t_cursor.tp_col + ncols;
        }

        /* Blank current location. */
        teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
}

static void
teken_subr_insert_line(const teken_t *t, unsigned int nrows)
{
        teken_rect_t tr;

        /* Ignore if outside scrolling region. */
        if (t->t_cursor.tp_row < t->t_scrollreg.ts_begin ||
            t->t_cursor.tp_row >= t->t_scrollreg.ts_end)
                return;

        tr.tr_begin.tp_row = t->t_cursor.tp_row;
        tr.tr_begin.tp_col = 0;
        tr.tr_end.tp_col = t->t_winsize.tp_col;

        if (t->t_cursor.tp_row + nrows >= t->t_scrollreg.ts_end) {
                tr.tr_end.tp_row = t->t_scrollreg.ts_end;
        } else {
                teken_pos_t tp;

                /* Copy lines down. */
                tr.tr_end.tp_row = t->t_scrollreg.ts_end - nrows;
                tp.tp_row = t->t_cursor.tp_row + nrows;
                tp.tp_col = 0;
                teken_funcs_copy(t, &tr, &tp);

                tr.tr_end.tp_row = t->t_cursor.tp_row + nrows;
        }

        /* Blank current location. */
        teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
}

static void
teken_subr_keypad_application_mode(const teken_t *t)
{

        teken_funcs_param(t, TP_KEYPADAPP, 1);
}

static void
teken_subr_keypad_numeric_mode(const teken_t *t)
{

        teken_funcs_param(t, TP_KEYPADAPP, 0);
}

static void
teken_subr_newline(teken_t *t)
{

        t->t_cursor.tp_row++;

        if (t->t_cursor.tp_row >= t->t_scrollreg.ts_end) {
                teken_subr_do_scroll(t, 1);
                t->t_cursor.tp_row = t->t_scrollreg.ts_end - 1;
        }

        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_newpage(teken_t *t)
{

        if (t->t_stateflags & TS_CONS25) {
                teken_rect_t tr;

                /* Clear screen. */
                tr.tr_begin.tp_row = t->t_originreg.ts_begin;
                tr.tr_begin.tp_col = 0;
                tr.tr_end.tp_row = t->t_originreg.ts_end;
                tr.tr_end.tp_col = t->t_winsize.tp_col;
                teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);

                /* Cursor at top left. */
                t->t_cursor.tp_row = t->t_originreg.ts_begin;
                t->t_cursor.tp_col = 0;
                t->t_stateflags &= ~TS_WRAPPED;
                teken_funcs_cursor(t);
        } else {
                teken_subr_newline(t);
        }
}

static void
teken_subr_next_line(teken_t *t)
{

        t->t_cursor.tp_col = 0;
        teken_subr_newline(t);
}

static void
teken_subr_operating_system_command(teken_t *t)
{

        teken_printf("Unsupported operating system command\n");
        t->t_stateflags |= TS_INSTRING;
}

static void
teken_subr_pan_down(const teken_t *t, unsigned int nrows)
{

        teken_subr_do_scroll(t, (int)nrows);
}

static void
teken_subr_pan_up(const teken_t *t, unsigned int nrows)
{

        teken_subr_do_scroll(t, -(int)nrows);
}

static void
teken_subr_primary_device_attributes(const teken_t *t, unsigned int request)
{

        if (request == 0) {
                const char response[] = "\x1B[?1;2c";

                teken_funcs_respond(t, response, sizeof response - 1);
        } else {
                teken_printf("Unknown DA1\n");
        }
}

static void
teken_subr_do_putchar(teken_t *t, const teken_pos_t *tp, teken_char_t c,
    int width)
{

        t->t_last = c;
        if (t->t_stateflags & TS_INSERT &&
            tp->tp_col < t->t_winsize.tp_col - width) {
                teken_rect_t ctr;
                teken_pos_t ctp;

                /* Insert mode. Move existing characters to the right. */
                ctr.tr_begin = *tp;
                ctr.tr_end.tp_row = tp->tp_row + 1;
                ctr.tr_end.tp_col = t->t_winsize.tp_col - width;
                ctp.tp_row = tp->tp_row;
                ctp.tp_col = tp->tp_col + width;
                teken_funcs_copy(t, &ctr, &ctp);
        }

        teken_funcs_putchar(t, tp, c, &t->t_curattr);

        if (width == 2 && tp->tp_col + 1 < t->t_winsize.tp_col) {
                teken_pos_t tp2;
                teken_attr_t attr;

                /* Print second half of CJK fullwidth character. */
                tp2.tp_row = tp->tp_row;
                tp2.tp_col = tp->tp_col + 1;
                attr = t->t_curattr;
                attr.ta_format |= TF_CJK_RIGHT;
                teken_funcs_putchar(t, &tp2, c, &attr);
        }
}

static void
teken_subr_regular_character(teken_t *t, teken_char_t c)
{
        int width;

        if (t->t_stateflags & TS_8BIT) {
                if (!(t->t_stateflags & TS_CONS25) && (c <= 0x1b || c == 0x7f))
                        return;
                c = teken_scs_process(t, c);
                width = 1;
        } else {
                c = teken_scs_process(t, c);
                width = teken_wcwidth(c);
                /* XXX: Don't process zero-width characters yet. */
                if (width <= 0)
                        return;
        }

        if (t->t_stateflags & TS_CONS25) {
                teken_subr_do_putchar(t, &t->t_cursor, c, width);
                t->t_cursor.tp_col += width;

                if (t->t_cursor.tp_col >= t->t_winsize.tp_col) {
                        if (t->t_cursor.tp_row == t->t_scrollreg.ts_end - 1) {
                                /* Perform scrolling. */
                                teken_subr_do_scroll(t, 1);
                        } else {
                                /* No scrolling needed. */
                                if (t->t_cursor.tp_row <
                                    t->t_winsize.tp_row - 1)
                                        t->t_cursor.tp_row++;
                        }
                        t->t_cursor.tp_col = 0;
                }
        } else if (t->t_stateflags & TS_AUTOWRAP &&
            ((t->t_stateflags & TS_WRAPPED &&
            t->t_cursor.tp_col + 1 == t->t_winsize.tp_col) ||
            t->t_cursor.tp_col + width > t->t_winsize.tp_col)) {
                teken_pos_t tp;

                /*
                 * Perform line wrapping, if:
                 * - Autowrapping is enabled, and
                 *   - We're in the wrapped state at the last column, or
                 *   - The character to be printed does not fit anymore.
                 */
                if (t->t_cursor.tp_row == t->t_scrollreg.ts_end - 1) {
                        /* Perform scrolling. */
                        teken_subr_do_scroll(t, 1);
                        tp.tp_row = t->t_scrollreg.ts_end - 1;
                } else {
                        /* No scrolling needed. */
                        tp.tp_row = t->t_cursor.tp_row + 1;
                        if (tp.tp_row == t->t_winsize.tp_row) {
                                /*
                                 * Corner case: regular character
                                 * outside scrolling region, but at the
                                 * bottom of the screen.
                                 */
                                teken_subr_do_putchar(t, &t->t_cursor,
                                    c, width);
                                return;
                        }
                }

                tp.tp_col = 0;
                teken_subr_do_putchar(t, &tp, c, width);

                t->t_cursor.tp_row = tp.tp_row;
                t->t_cursor.tp_col = width;
                t->t_stateflags &= ~TS_WRAPPED;
        } else {
                /* No line wrapping needed. */
                teken_subr_do_putchar(t, &t->t_cursor, c, width);
                t->t_cursor.tp_col += width;

                if (t->t_cursor.tp_col >= t->t_winsize.tp_col) {
                        t->t_stateflags |= TS_WRAPPED;
                        t->t_cursor.tp_col = t->t_winsize.tp_col - 1;
                } else {
                        t->t_stateflags &= ~TS_WRAPPED;
                }
        }

        teken_funcs_cursor(t);
}

static void
teken_subr_reset_dec_mode(teken_t *t, unsigned int cmd)
{

        switch (cmd) {
        case 1: /* Cursor keys mode. */
                t->t_stateflags &= ~TS_CURSORKEYS;
                break;
        case 2: /* DECANM: ANSI/VT52 mode. */
                teken_printf("DECRST VT52\n");
                break;
        case 3: /* 132 column mode. */
                teken_funcs_param(t, TP_132COLS, 0);
                teken_subr_reset_to_initial_state(t);
                break;
        case 5: /* Inverse video. */
                teken_printf("DECRST inverse video\n");
                break;
        case 6: /* Origin mode. */
                t->t_stateflags &= ~TS_ORIGIN;
                t->t_originreg.ts_begin = 0;
                t->t_originreg.ts_end = t->t_winsize.tp_row;
                t->t_cursor.tp_row = t->t_cursor.tp_col = 0;
                t->t_stateflags &= ~TS_WRAPPED;
                teken_funcs_cursor(t);
                break;
        case 7: /* Autowrap mode. */
                t->t_stateflags &= ~TS_AUTOWRAP;
                break;
        case 8: /* Autorepeat mode. */
                teken_funcs_param(t, TP_AUTOREPEAT, 0);
                break;
        case 25: /* Hide cursor. */
                teken_funcs_param(t, TP_SHOWCURSOR, 0);
                break;
        case 40: /* Disallow 132 columns. */
                teken_printf("DECRST allow 132\n");
                break;
        case 45: /* Disable reverse wraparound. */
                teken_printf("DECRST reverse wraparound\n");
                break;
        case 47: /* Switch to alternate buffer. */
                teken_printf("Switch to alternate buffer\n");
                break;
        case 1000: /* Mouse input. */
                teken_funcs_param(t, TP_MOUSE, 0);
                break;
        default:
                teken_printf("Unknown DECRST: %u\n", cmd);
        }
}

static void
teken_subr_reset_mode(teken_t *t, unsigned int cmd)
{

        switch (cmd) {
        case 4:
                t->t_stateflags &= ~TS_INSERT;
                break;
        default:
                teken_printf("Unknown reset mode: %u\n", cmd);
        }
}

static void
teken_subr_do_resize(teken_t *t)
{

        t->t_scrollreg.ts_begin = 0;
        t->t_scrollreg.ts_end = t->t_winsize.tp_row;
        t->t_originreg = t->t_scrollreg;
}

static void
teken_subr_do_reset(teken_t *t)
{

        t->t_curattr = t->t_defattr;
        t->t_cursor.tp_row = t->t_cursor.tp_col = 0;
        t->t_scrollreg.ts_begin = 0;
        t->t_scrollreg.ts_end = t->t_winsize.tp_row;
        t->t_originreg = t->t_scrollreg;
        t->t_stateflags &= TS_8BIT | TS_CONS25 | TS_CONS25KEYS;
        t->t_stateflags |= TS_AUTOWRAP;

        t->t_scs[0] = teken_scs_us_ascii;
        t->t_scs[1] = teken_scs_us_ascii;
        t->t_curscs = 0;

        teken_subr_save_cursor(t);
        teken_tab_default(t);
}

static void
teken_subr_reset_to_initial_state(teken_t *t)
{

        teken_subr_do_reset(t);
        teken_subr_erase_display(t, 2);
        teken_funcs_param(t, TP_SHOWCURSOR, 1);
        teken_funcs_cursor(t);
}

static void
teken_subr_restore_cursor(teken_t *t)
{

        t->t_cursor = t->t_saved_cursor;
        t->t_curattr = t->t_saved_curattr;
        t->t_scs[t->t_curscs] = t->t_saved_curscs;
        t->t_stateflags &= ~TS_WRAPPED;

        /* Get out of origin mode when the cursor is moved outside. */
        if (t->t_cursor.tp_row < t->t_originreg.ts_begin ||
            t->t_cursor.tp_row >= t->t_originreg.ts_end) {
                t->t_stateflags &= ~TS_ORIGIN;
                t->t_originreg.ts_begin = 0;
                t->t_originreg.ts_end = t->t_winsize.tp_row;
        }

        teken_funcs_cursor(t);
}

static void
teken_subr_reverse_index(teken_t *t)
{

        if (t->t_cursor.tp_row > t->t_scrollreg.ts_begin) {
                t->t_cursor.tp_row--;
                t->t_stateflags &= ~TS_WRAPPED;
                teken_funcs_cursor(t);
        } else {
                teken_subr_do_scroll(t, -1);
        }
}

static void
teken_subr_save_cursor(teken_t *t)
{

        t->t_saved_cursor = t->t_cursor;
        t->t_saved_curattr = t->t_curattr;
        t->t_saved_curscs = t->t_scs[t->t_curscs];
}

static void
teken_subr_secondary_device_attributes(const teken_t *t, unsigned int request)
{

        if (request == 0) {
                const char response[] = "\x1B[>0;10;0c";
                teken_funcs_respond(t, response, sizeof response - 1);
        } else {
                teken_printf("Unknown DA2\n");
        }
}

static void
teken_subr_set_dec_mode(teken_t *t, unsigned int cmd)
{

        switch (cmd) {
        case 1: /* Cursor keys mode. */
                t->t_stateflags |= TS_CURSORKEYS;
                break;
        case 2: /* DECANM: ANSI/VT52 mode. */
                teken_printf("DECSET VT52\n");
                break;
        case 3: /* 132 column mode. */
                teken_funcs_param(t, TP_132COLS, 1);
                teken_subr_reset_to_initial_state(t);
                break;
        case 5: /* Inverse video. */
                teken_printf("DECSET inverse video\n");
                break;
        case 6: /* Origin mode. */
                t->t_stateflags |= TS_ORIGIN;
                t->t_originreg = t->t_scrollreg;
                t->t_cursor.tp_row = t->t_scrollreg.ts_begin;
                t->t_cursor.tp_col = 0;
                t->t_stateflags &= ~TS_WRAPPED;
                teken_funcs_cursor(t);
                break;
        case 7: /* Autowrap mode. */
                t->t_stateflags |= TS_AUTOWRAP;
                break;
        case 8: /* Autorepeat mode. */
                teken_funcs_param(t, TP_AUTOREPEAT, 1);
                break;
        case 25: /* Display cursor. */
                teken_funcs_param(t, TP_SHOWCURSOR, 1);
                break;
        case 40: /* Allow 132 columns. */
                teken_printf("DECSET allow 132\n");
                break;
        case 45: /* Enable reverse wraparound. */
                teken_printf("DECSET reverse wraparound\n");
                break;
        case 47: /* Switch to alternate buffer. */
                teken_printf("Switch away from alternate buffer\n");
                break;
        case 1000: /* Mouse input. */
                teken_funcs_param(t, TP_MOUSE, 1);
                break;
        default:
                teken_printf("Unknown DECSET: %u\n", cmd);
        }
}

static void
teken_subr_set_mode(teken_t *t, unsigned int cmd)
{

        switch (cmd) {
        case 4:
                teken_printf("Insert mode\n");
                t->t_stateflags |= TS_INSERT;
                break;
        default:
                teken_printf("Unknown set mode: %u\n", cmd);
        }
}

static void
teken_subr_set_graphic_rendition(teken_t *t, unsigned int ncmds,
    const unsigned int cmds[])
{
        unsigned int i, n;

        /* No attributes means reset. */
        if (ncmds == 0) {
                t->t_curattr = t->t_defattr;
                return;
        }

        for (i = 0; i < ncmds; i++) {
                n = cmds[i];

                switch (n) {
                case 0: /* Reset. */
                        t->t_curattr = t->t_defattr;
                        break;
                case 1: /* Bold. */
                        t->t_curattr.ta_format |= TF_BOLD;
                        break;
                case 4: /* Underline. */
                        t->t_curattr.ta_format |= TF_UNDERLINE;
                        break;
                case 5: /* Blink. */
                        t->t_curattr.ta_format |= TF_BLINK;
                        break;
                case 7: /* Reverse. */
                        t->t_curattr.ta_format |= TF_REVERSE;
                        break;
                case 22: /* Remove bold. */
                        t->t_curattr.ta_format &= ~TF_BOLD;
                        break;
                case 24: /* Remove underline. */
                        t->t_curattr.ta_format &= ~TF_UNDERLINE;
                        break;
                case 25: /* Remove blink. */
                        t->t_curattr.ta_format &= ~TF_BLINK;
                        break;
                case 27: /* Remove reverse. */
                        t->t_curattr.ta_format &= ~TF_REVERSE;
                        break;
                case 30: /* Set foreground color: black */
                case 31: /* Set foreground color: red */
                case 32: /* Set foreground color: green */
                case 33: /* Set foreground color: brown */
                case 34: /* Set foreground color: blue */
                case 35: /* Set foreground color: magenta */
                case 36: /* Set foreground color: cyan */
                case 37: /* Set foreground color: white */
                        t->t_curattr.ta_fgcolor = n - 30;
                        break;
                case 38: /* Set foreground color: 256 color mode */
                        if (i + 2 >= ncmds || cmds[i + 1] != 5)
                                continue;
                        t->t_curattr.ta_fgcolor = cmds[i + 2];
                        i += 2;
                        break;
                case 39: /* Set default foreground color. */
                        t->t_curattr.ta_fgcolor = t->t_defattr.ta_fgcolor;
                        break;
                case 40: /* Set background color: black */
                case 41: /* Set background color: red */
                case 42: /* Set background color: green */
                case 43: /* Set background color: brown */
                case 44: /* Set background color: blue */
                case 45: /* Set background color: magenta */
                case 46: /* Set background color: cyan */
                case 47: /* Set background color: white */
                        t->t_curattr.ta_bgcolor = n - 40;
                        break;
                case 48: /* Set background color: 256 color mode */
                        if (i + 2 >= ncmds || cmds[i + 1] != 5)
                                continue;
                        t->t_curattr.ta_bgcolor = cmds[i + 2];
                        i += 2;
                        break;
                case 49: /* Set default background color. */
                        t->t_curattr.ta_bgcolor = t->t_defattr.ta_bgcolor;
                        break;
                case 90: /* Set bright foreground color: black */
                case 91: /* Set bright foreground color: red */
                case 92: /* Set bright foreground color: green */
                case 93: /* Set bright foreground color: brown */
                case 94: /* Set bright foreground color: blue */
                case 95: /* Set bright foreground color: magenta */
                case 96: /* Set bright foreground color: cyan */
                case 97: /* Set bright foreground color: white */
                        t->t_curattr.ta_fgcolor = (n - 90) + 8;
                        break;
                case 100: /* Set bright background color: black */
                case 101: /* Set bright background color: red */
                case 102: /* Set bright background color: green */
                case 103: /* Set bright background color: brown */
                case 104: /* Set bright background color: blue */
                case 105: /* Set bright background color: magenta */
                case 106: /* Set bright background color: cyan */
                case 107: /* Set bright background color: white */
                        t->t_curattr.ta_bgcolor = (n - 100) + 8;
                        break;
                default:
                        teken_printf("unsupported attribute %u\n", n);
                }
        }
}

static void
teken_subr_set_top_and_bottom_margins(teken_t *t, unsigned int top,
    unsigned int bottom)
{

        /* Adjust top row number. */
        if (top > 0)
                top--;
        /* Adjust bottom row number. */
        if (bottom == 0 || bottom > t->t_winsize.tp_row)
                bottom = t->t_winsize.tp_row;

        /* Invalid arguments. */
        if (top >= bottom - 1) {
                top = 0;
                bottom = t->t_winsize.tp_row;
        }

        /* Apply scrolling region. */
        t->t_scrollreg.ts_begin = top;
        t->t_scrollreg.ts_end = bottom;
        if (t->t_stateflags & TS_ORIGIN)
                t->t_originreg = t->t_scrollreg;

        /* Home cursor to the top left of the scrolling region. */
        t->t_cursor.tp_row = t->t_originreg.ts_begin;
        t->t_cursor.tp_col = 0;
        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_single_height_double_width_line(const teken_t *t)
{

        (void)t;
        teken_printf("single height double width???\n");
}

static void
teken_subr_single_height_single_width_line(const teken_t *t)
{

        (void)t;
        teken_printf("single height single width???\n");
}

static void
teken_subr_string_terminator(const teken_t *t)
{

        (void)t;
        /*
         * Strings are already terminated in teken_input_char() when ^[
         * is inserted.
         */
}

static void
teken_subr_tab_clear(teken_t *t, unsigned int cmd)
{

        switch (cmd) {
        case 0:
                teken_tab_clear(t, t->t_cursor.tp_col);
                break;
        case 3:
                memset(t->t_tabstops, 0, T_NUMCOL / 8);
                break;
        default:
                break;
        }
}

static void
teken_subr_vertical_position_absolute(teken_t *t, unsigned int row)
{

        row = (row - 1) + t->t_originreg.ts_begin;
        t->t_cursor.tp_row = row < t->t_originreg.ts_end ?
            row : t->t_originreg.ts_end - 1;

        t->t_stateflags &= ~TS_WRAPPED;
        teken_funcs_cursor(t);
}

static void
teken_subr_repeat_last_graphic_char(teken_t *t, unsigned int rpts)
{
        unsigned int max_repetitions;

        max_repetitions = t->t_winsize.tp_row * t->t_winsize.tp_col;
        if (rpts > max_repetitions)
                rpts = max_repetitions;
        for (; t->t_last != 0 && rpts > 0; rpts--)
                teken_subr_regular_character(t, t->t_last);
}