/*
   Interface to the terminal controlling library.
   Slang wrapper.

   Copyright (C) 2005-2022
   Free Software Foundation, Inc.

   Written by:
   Andrew Borodin <aborodin@vmail.ru>, 2009
   Egmont Koblinger <egmont@gmail.com>, 2010

   This file is part of the Midnight Commander.

   The Midnight Commander 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 3 of the License,
   or (at your option) any later version.

   The Midnight Commander 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, see <http://www.gnu.org/licenses/>.
 */

/** \file
 *  \brief Source: S-Lang-based tty layer of Midnight Commander
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>          /* size_t */
#include <unistd.h>
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#include <termios.h>

#include "lib/global.h"
#include "lib/strutil.h"        /* str_term_form */
#include "lib/util.h"           /* is_printable() */

#include "tty-internal.h"       /* mc_tty_normalize_from_utf8() */
#include "tty.h"
#include "color.h"
#include "color-slang.h"
#include "color-internal.h"
#include "mouse.h"              /* Gpm_Event is required in key.h */
#include "key.h"                /* define_sequence */
#include "win.h"


/*** global variables ****************************************************************************/

/* If true program softkeys (HP terminals only) on startup and after every
   command ran in the subshell to the description found in the termcap/terminfo
   database */
int reset_hp_softkeys = 0;

/*** file scope macro definitions ****************************************************************/

#ifndef SLTT_MAX_SCREEN_COLS
#define SLTT_MAX_SCREEN_COLS 512
#endif

#ifndef SLTT_MAX_SCREEN_ROWS
#define SLTT_MAX_SCREEN_ROWS 512
#endif

/*** file scope type declarations ****************************************************************/

/*** file scope variables ************************************************************************/

/* Various saved termios settings that we control here */
static struct termios boot_mode;
static struct termios new_mode;

/* Controls whether we should wait for input in tty_lowlevel_getch */
static gboolean no_slang_delay;

static gboolean slsmg_active = FALSE;

/* This table describes which capabilities we want and which values we
 * assign to them.
 */
static const struct
{
    int key_code;
    const char *key_name;
} key_table[] =
{
    /* *INDENT-OFF* */
    { KEY_F (0), "k0" },
    { KEY_F (1), "k1" },
    { KEY_F (2), "k2" },
    { KEY_F (3), "k3" },
    { KEY_F (4), "k4" },
    { KEY_F (5), "k5" },
    { KEY_F (6), "k6" },
    { KEY_F (7), "k7" },
    { KEY_F (8), "k8" },
    { KEY_F (9), "k9" },
    { KEY_F (10), "k;" },
    { KEY_F (11), "F1" },
    { KEY_F (12), "F2" },
    { KEY_F (13), "F3" },
    { KEY_F (14), "F4" },
    { KEY_F (15), "F5" },
    { KEY_F (16), "F6" },
    { KEY_F (17), "F7" },
    { KEY_F (18), "F8" },
    { KEY_F (19), "F9" },
    { KEY_F (20), "FA" },
    { KEY_IC, "kI" },
    { KEY_NPAGE, "kN" },
    { KEY_PPAGE, "kP" },
    { KEY_LEFT, "kl" },
    { KEY_RIGHT, "kr" },
    { KEY_UP, "ku" },
    { KEY_DOWN, "kd" },
    { KEY_DC, "kD" },
    { KEY_BACKSPACE, "kb" },
    { KEY_HOME, "kh" },
    { KEY_END, "@7" },
    { 0, NULL }
    /* *INDENT-ON* */
};

/* --------------------------------------------------------------------------------------------- */
/*** file scope functions ************************************************************************/
/* --------------------------------------------------------------------------------------------- */

static void
tty_setup_sigwinch (void (*handler) (int))
{
    (void) SLsignal (SIGWINCH, handler);
    tty_create_winch_pipe ();
}

/* --------------------------------------------------------------------------------------------- */

static void
sigwinch_handler (int dummy)
{
    ssize_t n = 0;

    (void) dummy;

    n = write (sigwinch_pipe[1], "", 1);
    (void) n;

    (void) SLsignal (SIGWINCH, sigwinch_handler);
}

/* --------------------------------------------------------------------------------------------- */

/* HP Terminals have capabilities (pfkey, pfloc, pfx) to program function keys.
   elm 2.4pl15 invoked with the -K option utilizes these softkeys and the
   consequence is that function keys don't work in MC sometimes...
   Unfortunately I don't now the one and only escape sequence to turn off.
   softkeys (elm uses three different capabilities to turn on softkeys and two.
   capabilities to turn them off)..
   Among other things elm uses the pair we already use in slang_keypad. That's.
   the reason why I call slang_reset_softkeys from slang_keypad. In lack of
   something better the softkeys are programmed to their defaults from the
   termcap/terminfo database.
   The escape sequence to program the softkeys is taken from elm and it is.
   hardcoded because neither slang nor ncurses 4.1 know how to 'printf' this.
   sequence. -- Norbert
 */

static void
slang_reset_softkeys (void)
{
    int key;
    static const char display[] = "                ";
    char tmp[BUF_SMALL];

    for (key = 1; key < 9; key++)
    {
        char *send;

        g_snprintf (tmp, sizeof (tmp), "k%d", key);
        send = SLtt_tgetstr (tmp);
        if (send != NULL)
        {
            g_snprintf (tmp, sizeof (tmp), ESC_STR "&f%dk%dd%dL%s%s", key,
                        (int) (sizeof (display) - 1), (int) strlen (send), display, send);
            SLtt_write_string (tmp);
        }
    }
}

/* --------------------------------------------------------------------------------------------- */

static void
do_define_key (int code, const char *strcap)
{
    char *seq;

    seq = SLtt_tgetstr ((SLFUTURE_CONST char *) strcap);
    if (seq != NULL)
        define_sequence (code, seq, MCKEY_NOACTION);
}

/* --------------------------------------------------------------------------------------------- */

static void
load_terminfo_keys (void)
{
    int i;

    for (i = 0; key_table[i].key_code; i++)
        do_define_key (key_table[i].key_code, key_table[i].key_name);
}

/* --------------------------------------------------------------------------------------------- */
/*** public functions ****************************************************************************/
/* --------------------------------------------------------------------------------------------- */

int
mc_tty_normalize_lines_char (const char *str)
{
    char *str2;
    int res;

    struct mc_tty_lines_struct
    {
        const char *line;
        int line_code;
    } const lines_codes[] = {
        {"\342\224\214", SLSMG_ULCORN_CHAR},
        {"\342\224\220", SLSMG_URCORN_CHAR},
        {"\342\224\224", SLSMG_LLCORN_CHAR},
        {"\342\224\230", SLSMG_LRCORN_CHAR},
        {"\342\224\234", SLSMG_LTEE_CHAR},
        {"\342\224\244", SLSMG_RTEE_CHAR},
        {"\342\224\254", SLSMG_UTEE_CHAR},
        {"\342\224\264", SLSMG_DTEE_CHAR},
        {"\342\224\200", SLSMG_HLINE_CHAR},
        {"\342\224\202", SLSMG_VLINE_CHAR},
        {"\342\224\274", SLSMG_PLUS_CHAR},

        {NULL, 0}
    };

    if (!str)
        return (int) ' ';

    for (res = 0; lines_codes[res].line; res++)
    {
        if (strcmp (str, lines_codes[res].line) == 0)
            return lines_codes[res].line_code;
    }

    str2 = mc_tty_normalize_from_utf8 (str);
    res = g_utf8_get_char_validated (str2, -1);

    if (res < 0)
        res = (unsigned char) str2[0];
    g_free (str2);

    return res;
}

/* --------------------------------------------------------------------------------------------- */

void
tty_init (gboolean mouse_enable, gboolean is_xterm)
{
    SLtt_Ignore_Beep = 1;

    SLutf8_enable (-1);         /* has to be called first before any of the other functions. */
    SLtt_get_terminfo ();
    /*
     * If the terminal in not in terminfo but begins with a well-known
     * string such as "linux" or "xterm" S-Lang will go on, but the
     * terminal size and several other variables won't be initialized
     * (as of S-Lang 1.4.4). Detect it and abort. Also detect extremely
     * small screen dimensions.
     */
    if ((COLS < 10) || (LINES < 5)
#if SLANG_VERSION < 20303
        /* Beginning from pre2.3.3-8 (55f58798c267d76a1b93d0d916027b71a10ac1ee),
           these limitations were eliminated. */
        || (COLS > SLTT_MAX_SCREEN_COLS) || (LINES > SLTT_MAX_SCREEN_ROWS)
#endif
        )
    {
        fprintf (stderr,
                 _("Screen size %dx%d is not supported.\n"
                   "Check the TERM environment variable.\n"), COLS, LINES);
        exit (EXIT_FAILURE);
    }

    tcgetattr (fileno (stdin), &boot_mode);
    /* 255 = ignore abort char; XCTRL('g') for abort char = ^g */
    SLang_init_tty (XCTRL ('g'), 1, 0);

    if (mc_global.tty.ugly_line_drawing)
        SLtt_Has_Alt_Charset = 0;

    tcgetattr (SLang_TT_Read_FD, &new_mode);

    tty_reset_prog_mode ();
    load_terminfo_keys ();

    SLtt_Blink_Mode = (tty_use_256colors (NULL) || tty_use_truecolors (NULL)) ? 1 : 0;

    tty_start_interrupt_key ();

    /* It's the small part from the previous init_key() */
    init_key_input_fd ();

    /* For 8-bit locales, NCurses handles 154 (0x9A) symbol properly, while S-Lang
     * requires SLsmg_Display_Eight_Bit >= 154 (OR manual filtering if xterm display
     * detected - but checking TERM would fail under screen, OR running xterm
     * with allowC1Printable).
     */
    tty_display_8bit (FALSE);

    SLsmg_init_smg ();
    slsmg_active = TRUE;
    if (!mouse_enable)
        use_mouse_p = MOUSE_DISABLED;
    tty_init_xterm_support (is_xterm);  /* do it before tty_enter_ca_mode() call */
    tty_enter_ca_mode ();
    tty_keypad (TRUE);
    tty_nodelay (FALSE);

    tty_setup_sigwinch (sigwinch_handler);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_shutdown (void)
{
    char *op_cap;

    tty_destroy_winch_pipe ();
    tty_reset_shell_mode ();
    tty_noraw_mode ();
    tty_keypad (FALSE);
    tty_reset_screen ();
    tty_exit_ca_mode ();
    SLang_reset_tty ();
    slsmg_active = FALSE;

    /* Load the op capability to reset the colors to those that were 
     * active when the program was started up 
     */
    op_cap = SLtt_tgetstr ((SLFUTURE_CONST char *) "op");
    if (op_cap != NULL)
    {
        fputs (op_cap, stdout);
        fflush (stdout);
    }
}

/* --------------------------------------------------------------------------------------------- */

void
tty_enter_ca_mode (void)
{
    /* S-Lang handles alternate screen switching and cursor position saving */
}

/* --------------------------------------------------------------------------------------------- */

void
tty_exit_ca_mode (void)
{
    /* S-Lang handles alternate screen switching and cursor position restoring */
}

/* --------------------------------------------------------------------------------------------- */

void
tty_change_screen_size (void)
{
    SLtt_get_screen_size ();
    if (slsmg_active)
        SLsmg_reinit_smg ();

#ifdef ENABLE_SUBSHELL
    if (mc_global.tty.use_subshell)
        tty_resize (mc_global.tty.subshell_pty);
#endif
}

/* --------------------------------------------------------------------------------------------- */
/* Done each time we come back from done mode */

void
tty_reset_prog_mode (void)
{
    tcsetattr (SLang_TT_Read_FD, TCSANOW, &new_mode);
    SLsmg_init_smg ();
    slsmg_active = TRUE;
    SLsmg_touch_lines (0, LINES);
}

/* --------------------------------------------------------------------------------------------- */
/* Called each time we want to shutdown slang screen manager */

void
tty_reset_shell_mode (void)
{
    tcsetattr (SLang_TT_Read_FD, TCSANOW, &boot_mode);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_raw_mode (void)
{
    tcsetattr (SLang_TT_Read_FD, TCSANOW, &new_mode);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_noraw_mode (void)
{
}

/* --------------------------------------------------------------------------------------------- */

void
tty_noecho (void)
{
}

/* --------------------------------------------------------------------------------------------- */

int
tty_flush_input (void)
{
    return 0;                   /* OK */
}

/* --------------------------------------------------------------------------------------------- */

void
tty_keypad (gboolean set)
{
    char *keypad_string;

    keypad_string = SLtt_tgetstr ((SLFUTURE_CONST char *) (set ? "ks" : "ke"));
    if (keypad_string != NULL)
        SLtt_write_string (keypad_string);
    if (set && reset_hp_softkeys)
        slang_reset_softkeys ();
}

/* --------------------------------------------------------------------------------------------- */

void
tty_nodelay (gboolean set)
{
    no_slang_delay = set;
}

/* --------------------------------------------------------------------------------------------- */

int
tty_baudrate (void)
{
    return SLang_TT_Baud_Rate;
}

/* --------------------------------------------------------------------------------------------- */

int
tty_lowlevel_getch (void)
{
    int c;

    if (no_slang_delay && (SLang_input_pending (0) == 0))
        return -1;

    c = SLang_getkey ();
    if (c == SLANG_GETKEY_ERROR)
    {
        fprintf (stderr,
                 "SLang_getkey returned SLANG_GETKEY_ERROR\n"
                 "Assuming EOF on stdin and exiting\n");
        exit (EXIT_FAILURE);
    }

    return c;
}

/* --------------------------------------------------------------------------------------------- */

int
tty_reset_screen (void)
{
    SLsmg_reset_smg ();
    slsmg_active = FALSE;
    return 0;                   /* OK */
}

/* --------------------------------------------------------------------------------------------- */

void
tty_touch_screen (void)
{
    SLsmg_touch_lines (0, LINES);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_gotoyx (int y, int x)
{
    SLsmg_gotorc (y, x);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_getyx (int *py, int *px)
{
    *py = SLsmg_get_row ();
    *px = SLsmg_get_column ();
}

/* --------------------------------------------------------------------------------------------- */

void
tty_draw_hline (int y, int x, int ch, int len)
{
    int x1;

    if (y < 0 || y >= LINES || x >= COLS)
        return;

    x1 = x;

    if (x < 0)
    {
        len += x;
        if (len <= 0)
            return;
        x = 0;
    }

    if (ch == ACS_HLINE)
        ch = mc_tty_frm[MC_TTY_FRM_HORIZ];
    if (ch == 0)
        ch = ACS_HLINE;

    SLsmg_gotorc (y, x);

    if (ch == ACS_HLINE)
        SLsmg_draw_hline (len);
    else
        while (len-- != 0)
            tty_print_char (ch);

    SLsmg_gotorc (y, x1);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_draw_vline (int y, int x, int ch, int len)
{
    int y1;

    if (x < 0 || x >= COLS || y >= LINES)
        return;

    y1 = y;

    if (y < 0)
    {
        len += y;
        if (len <= 0)
            return;
        y = 0;
    }

    if (ch == ACS_VLINE)
        ch = mc_tty_frm[MC_TTY_FRM_VERT];
    if (ch == 0)
        ch = ACS_VLINE;

    SLsmg_gotorc (y, x);

    if (ch == ACS_VLINE)
        SLsmg_draw_vline (len);
    else
    {
        int pos = 0;

        while (len-- != 0)
        {
            SLsmg_gotorc (y + pos, x);
            tty_print_char (ch);
            pos++;
        }
    }

    SLsmg_gotorc (y1, x);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_fill_region (int y, int x, int rows, int cols, unsigned char ch)
{
    SLsmg_fill_region (y, x, rows, cols, ch);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_colorize_area (int y, int x, int rows, int cols, int color)
{
    if (use_colors)
        SLsmg_set_color_in_region (color, y, x, rows, cols);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_set_alt_charset (gboolean alt_charset)
{
    SLsmg_set_char_set ((int) alt_charset);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_display_8bit (gboolean what)
{
    SLsmg_Display_Eight_Bit = what ? 128 : 160;
}

/* --------------------------------------------------------------------------------------------- */

void
tty_print_char (int c)
{
    SLsmg_write_char ((SLwchar_Type) ((unsigned int) c));
}

/* --------------------------------------------------------------------------------------------- */

void
tty_print_alt_char (int c, gboolean single)
{
#define DRAW(x, y) (x == y) \
       ? SLsmg_draw_object (SLsmg_get_row(), SLsmg_get_column(), x) \
       : SLsmg_write_char ((unsigned int) y)
    switch (c)
    {
    case ACS_VLINE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_VERT : MC_TTY_FRM_DVERT]);
        break;
    case ACS_HLINE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_HORIZ : MC_TTY_FRM_DHORIZ]);
        break;
    case ACS_LTEE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_LEFTMIDDLE : MC_TTY_FRM_DLEFTMIDDLE]);
        break;
    case ACS_RTEE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_RIGHTMIDDLE : MC_TTY_FRM_DRIGHTMIDDLE]);
        break;
    case ACS_TTEE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_TOPMIDDLE : MC_TTY_FRM_DTOPMIDDLE]);
        break;
    case ACS_BTEE:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_BOTTOMMIDDLE : MC_TTY_FRM_DBOTTOMMIDDLE]);
        break;
    case ACS_ULCORNER:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_LEFTTOP : MC_TTY_FRM_DLEFTTOP]);
        break;
    case ACS_LLCORNER:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_LEFTBOTTOM : MC_TTY_FRM_DLEFTBOTTOM]);
        break;
    case ACS_URCORNER:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_RIGHTTOP : MC_TTY_FRM_DRIGHTTOP]);
        break;
    case ACS_LRCORNER:
        DRAW (c, mc_tty_frm[single ? MC_TTY_FRM_RIGHTBOTTOM : MC_TTY_FRM_DRIGHTBOTTOM]);
        break;
    case ACS_PLUS:
        DRAW (c, mc_tty_frm[MC_TTY_FRM_CROSS]);
        break;
    default:
        SLsmg_write_char ((unsigned int) c);
    }
#undef DRAW
}

/* --------------------------------------------------------------------------------------------- */

void
tty_print_anychar (int c)
{
    if (c > 255)
    {
        char str[UTF8_CHAR_LEN + 1];
        int res;

        res = g_unichar_to_utf8 (c, str);
        if (res == 0)
        {
            str[0] = '.';
            str[1] = '\0';
        }
        else
        {
            str[res] = '\0';
        }
        SLsmg_write_string ((char *) str_term_form (str));
    }
    else
    {
        if (!is_printable (c))
            c = '.';
        SLsmg_write_char ((SLwchar_Type) ((unsigned int) c));
    }
}

/* --------------------------------------------------------------------------------------------- */

void
tty_print_string (const char *s)
{
    SLsmg_write_string ((char *) str_term_form (s));
}

/* --------------------------------------------------------------------------------------------- */

void
tty_printf (const char *fmt, ...)
{
    va_list args;

    va_start (args, fmt);
    SLsmg_vprintf ((char *) fmt, args);
    va_end (args);
}

/* --------------------------------------------------------------------------------------------- */

char *
tty_tgetstr (const char *cap)
{
    return SLtt_tgetstr ((SLFUTURE_CONST char *) cap);
}

/* --------------------------------------------------------------------------------------------- */

void
tty_refresh (void)
{
    SLsmg_refresh ();
}

/* --------------------------------------------------------------------------------------------- */

void
tty_beep (void)
{
    SLtt_beep ();
}

/* --------------------------------------------------------------------------------------------- */