#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#if !defined( _WIN32) && !defined( DOS)
#define USE_TERMIOS
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>

static struct termios orig_term;
#endif
#include <assert.h>
#include "curspriv.h"
#include "pdcvt.h"

#ifdef DOS
bool PDC_is_ansi = TRUE;
#else
bool PDC_is_ansi = FALSE;
#endif

#ifdef _WIN32
#include <windows.h>

#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
#define ENABLE_VIRTUAL_TERMINAL_PROCESSING 0x0004
#endif
#ifndef ENABLE_VIRTUAL_TERMINAL_INPUT
#define ENABLE_VIRTUAL_TERMINAL_INPUT      0x0200
#endif
#ifndef DISABLE_NEWLINE_AUTO_RETURN
#define DISABLE_NEWLINE_AUTO_RETURN        0x0008
#endif

/* In DOS/Windows,  we have two possible modes of operation.  If we can
successfully use SetConsoleMode to ENABLE_VIRTUAL_TERMINAL_INPUT,
we have access to most of what we'd use on xterm.  If not,  we can only
use what ANSI.SYS or ANSI.COM (or their NANSI or NNANSI variants) support.
We'll get sixteen colors,  no mouse events,  no resizable windows,  etc.

   So we check the return value from SetConsoleMode and set PDC_is_ansi
accordingly.  (In DOS,  PDC_is_ansi is always true -- there's no xterm-like
support there.  On non-MS platforms,  PDC_is_ansi is always false...
though that should be revisited for the Linux console,  and probably
elsewhere.)  */

static int set_win10_for_vt_codes( const bool setting_mode)
{
    const HANDLE hIn = GetStdHandle( STD_INPUT_HANDLE);
    HANDLE hOut;
    DWORD dwMode = 0;
    static DWORD old_input_mode;
    const DWORD out_mask = ENABLE_VIRTUAL_TERMINAL_PROCESSING
                               | DISABLE_NEWLINE_AUTO_RETURN;

    if( hIn == INVALID_HANDLE_VALUE)
        return GetLastError( );
    PDC_is_ansi = TRUE;
    if( setting_mode)
        {
        GetConsoleMode( hIn, &old_input_mode);
        dwMode = ENABLE_VIRTUAL_TERMINAL_INPUT;
        }
    else       /* restoring initial mode */
        dwMode = old_input_mode;
    if( !SetConsoleMode( hIn, dwMode))
        return GetLastError( );
        /* Set output mode to handle virtual terminal sequences */
    hOut = GetStdHandle( STD_OUTPUT_HANDLE);
    if( hOut == INVALID_HANDLE_VALUE)
        return GetLastError( );

    if( !GetConsoleMode( hOut, &dwMode))
        return GetLastError( );
    if( setting_mode)
        dwMode |= out_mask;
    else                    /* clearing VT mode,  not setting it */
        dwMode &= ~out_mask;
    if( !SetConsoleMode( hOut, dwMode))
        return GetLastError( );
              /* If we've gotten this far,  the terminal has been  */
              /* set up to process xterm-like sequences : */
    PDC_is_ansi = FALSE;
    return( 0);
}
#endif

int PDC_rows = -1, PDC_cols = -1;
bool PDC_resize_occurred = FALSE;
const int STDIN = 0;
chtype PDC_capabilities = 0;

/* COLOR_PAIR to attribute encoding table. */

static short *color_pair_indices = (short *)NULL;
PACKED_RGB *pdc_rgbs = (PACKED_RGB *)NULL;

unsigned long pdc_key_modifiers = 0L;

void PDC_reset_prog_mode( void)
{
}

void PDC_reset_shell_mode( void)
{
}

static int initial_PDC_rows, initial_PDC_cols;

int PDC_resize_screen(int nlines, int ncols)
{
   if( PDC_rows == -1)     /* initscr( ) hasn't been called;  we're just */
      {                    /* setting desired size at startup */
      initial_PDC_rows = nlines;
      initial_PDC_cols = ncols;
      }
   else if( nlines > 1 && ncols > 1 && !PDC_is_ansi)
      {
      printf( "\033[8;%d;%dt", nlines, ncols);
      PDC_rows = nlines;
      PDC_cols = ncols;
      }
   return( 0);
}

void PDC_restore_screen_mode(int i)
{
}

void PDC_save_screen_mode(int i)
{
}

void PDC_scr_close( void)
{
   printf( "\0338");         /* restore cursor & attribs (VT100) */
   printf( "\033[m");         /* set default screen attributes */
   printf( "\033[?47l");      /* restore screen */
   PDC_gotoyx( PDC_cols - 1, 0);
   printf( "\033[?1000l");        /* turn off mouse events */
#ifdef _WIN32
   set_win10_for_vt_codes( FALSE);
#else
   #if !defined( DOS)
      tcsetattr( STDIN, TCSANOW, &orig_term);
   #endif
#endif
   return;
}

void PDC_scr_free( void)
{
    if (SP)
        free(SP);
    SP = (SCREEN *)NULL;

    if (color_pair_indices)
        free(color_pair_indices);
    color_pair_indices = (short *)NULL;

    if (pdc_rgbs)
        free(pdc_rgbs);
    pdc_rgbs = (PACKED_RGB *)NULL;
}

#ifdef USE_TERMIOS
static void sigwinchHandler( int sig)
{
   struct winsize ws;

   if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) != -1)
      if( PDC_rows != ws.ws_row || PDC_cols != ws.ws_col)
         {
         PDC_rows = ws.ws_row;
         PDC_cols = ws.ws_col;
         PDC_resize_occurred = TRUE;
         }
}
#endif

#define MAX_LINES 1000
#define MAX_COLUMNS 1000

int PDC_scr_open(int argc, char **argv)
{
    int i, r, g, b, n_colors;
    char *capabilities = getenv( "PDC_VT");
    const char *colorterm = getenv( "COLORTERM");
#ifdef USE_TERMIOS
    struct sigaction sa;
    struct termios term;
#endif
#ifdef _WIN32
    set_win10_for_vt_codes( TRUE);
#endif

    PDC_LOG(("PDC_scr_open called\n"));
    if( colorterm && !strcmp( colorterm, "truecolor"))
       PDC_capabilities |= A_RGB_COLOR;
    if( capabilities)      /* these should really come from terminfo! */
       {
       if( strstr( capabilities, "RGB"))
          PDC_capabilities |= A_RGB_COLOR;
       if( strstr( capabilities, "UND"))
          PDC_capabilities |= A_UNDERLINE;
       if( strstr( capabilities, "BLI"))
          PDC_capabilities |= A_BLINK;
       if( strstr( capabilities, "DIM"))
          PDC_capabilities |= A_DIM;
       if( strstr( capabilities, "STA"))
          PDC_capabilities |= A_STANDOUT;
       }
    SP = calloc(1, sizeof(SCREEN));
    color_pair_indices = (short *)calloc( PDC_COLOR_PAIRS * 2, sizeof( short));
    n_colors = (PDC_is_ansi ? 16 : 256);
    pdc_rgbs = (PACKED_RGB *)calloc( n_colors, sizeof( PACKED_RGB));
    assert( SP && color_pair_indices && pdc_rgbs);
    if (!SP || !color_pair_indices || !pdc_rgbs)
        return ERR;

    COLORS = n_colors;  /* should give this a try and see if it works! */
    for( i = 0; i < 16 && i < n_colors; i++)
    {
        const int intensity = ((i & 8) ? 0xff : 0xc0);

        pdc_rgbs[i] = PACK_RGB( ((i & COLOR_RED) ? intensity : 0),
                           ((i & COLOR_GREEN) ? intensity : 0),
                           ((i & COLOR_BLUE) ? intensity : 0));
    }
           /* 256-color xterm extended palette:  216 colors in a
            6x6x6 color cube,  plus 24 (not 50) shades of gray */
    for( r = 0; r < 6; r++)
        for( g = 0; g < 6; g++)
            for( b = 0; b < 6; b++)
                if( i < n_colors)
                    pdc_rgbs[i++] = PACK_RGB( r ? r * 40 + 55 : 0,
                                   g ? g * 40 + 55 : 0,
                                   b ? b * 40 + 55 : 0);
    for( i = 0; i < 24; i++)
        if( i + 232 < n_colors)
            pdc_rgbs[i + 232] = PACK_RGB( i * 10 + 8, i * 10 + 8, i * 10 + 8);
    setbuf( stdin, NULL);
    setbuf( stdout, NULL);
#ifdef USE_TERMIOS
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sa.sa_handler = sigwinchHandler;
    if (sigaction(SIGWINCH, &sa, NULL) == -1)
    {
        fprintf( stderr, "Sigaction failed\n");
        return( -1);
    }
    sigwinchHandler( 0);
#else
    {
        const char *env = getenv("PDC_LINES");

        PDC_rows = (env ? atoi( env) : 25);
        env = getenv( "PDC_COLS");
        PDC_cols = (env ? atoi( env) : 80);
    }
#endif
    SP->mouse_wait = PDC_CLICK_PERIOD;
    SP->visibility = 0;                /* no cursor,  by default */
    SP->curscol = SP->cursrow = 0;
    SP->audible = TRUE;
    SP->mono = FALSE;

    while( PDC_get_rows( ) < 1 && PDC_get_columns( ) < 1)
      ;     /* wait for screen to be drawn and size determined */
    if( initial_PDC_rows > 1 && initial_PDC_cols > 1)
    {
        PDC_resize_screen( initial_PDC_rows, initial_PDC_cols);
        while( PDC_get_rows( ) != initial_PDC_rows
            && PDC_get_columns( ) != initial_PDC_rows)
           ;
    }

    SP->lines = PDC_get_rows();
    SP->cols = PDC_get_columns();

    if (SP->lines < 2 || SP->lines > MAX_LINES
       || SP->cols < 2 || SP->cols > MAX_COLUMNS)
    {
        fprintf(stderr, "LINES value must be >= 2 and <= %d: got %d\n",
                MAX_LINES, SP->lines);
        fprintf(stderr, "COLS value must be >= 2 and <= %d: got %d\n",
                MAX_COLUMNS, SP->cols);

        return ERR;
    }

#ifdef USE_TERMIOS
    tcgetattr( STDIN, &orig_term);
    memcpy( &term, &orig_term, sizeof( term));
    term.c_lflag &= ~(ICANON | ECHO);
    tcsetattr( STDIN, TCSANOW, &term);
#endif
    printf( "\033[?47h");      /* Save screen */
    if( !PDC_is_ansi)
        printf( "\033[?1000h");  /* enable mouse events,  at least on xterm */
               /* NOTE: could send 1003h to get mouse motion events as well */
    printf( "\0337");         /* save cursor & attribs (VT100) */
    PDC_resize_occurred = FALSE;
    PDC_LOG(("PDC_scr_open exit\n"));
/*  PDC_reset_prog_mode();   doesn't do anything anyway */
    return( 0);
}

int PDC_set_function_key( const unsigned function, const int new_key)
{
   return( 0);
}

void PDC_set_resize_limits( const int new_min_lines,
                            const int new_max_lines,
                            const int new_min_cols,
                            const int new_max_cols)
{
   return;
}

/* PDC_init_color(), PDC_init_pair(),  and PDC_set_blink() all share a common
issue : after adjusting the display characteristic in question,  all relevant
text should be redrawn.  Call PDC_init_pair( 3, ...),  and all text using
color pair 3 should be redrawn;  call PDC_init_color( 5, ...) and all text
using color index 5 for either foreground or background should be redrawn;
turn "real blinking" on/off,  and all blinking text should be redrawn.
(On platforms where blinking text is controlled by a timer and redrawn every
half second or so,  such as X11,  SDLx,  and Win32a,  this function can be
used for that purpose as well.)

   PDC_show_changes( ) will look for relevant chains of text and redraw them.
For speed/simplicity,  the code looks for the first and last character in
each line that would be affected, then draws those in between.  Often --
perhaps usually -- this will be zero characters, i.e., no text on that
particular line happens to have an attribute requiring redrawing. */

static short get_pair( const chtype ch)

{
   return( (short)( (ch & A_COLOR) >> PDC_COLOR_SHIFT) & (COLOR_PAIRS - 1));
}

static int color_used_for_this_char( const chtype c, const int idx)
{
    const int color = get_pair( c);
    const int rval = (color_pair_indices[color] == idx ||
                     color_pair_indices[color + PDC_COLOR_PAIRS] == idx);

    return( rval);
}

void PDC_show_changes( const short pair, const short idx, const chtype attr)
{
    if( curscr && curscr->_y)
    {
        int i;

        for( i = 0; i < SP->lines - 1; i++)
            if( curscr->_y[i])
            {
                int j = 0, n_chars;
                chtype *line = curscr->_y[i];

         /* skip over starting text that isn't changed : */
                while( j < SP->cols && get_pair( *line) != pair
                       && !color_used_for_this_char( *line, idx)
                       && !(attr & *line))
                {
                    j++;
                    line++;
                }
                n_chars = SP->cols - j;
        /* then skip over text at the end that's not the right color: */
                while( n_chars && get_pair( line[n_chars - 1]) != pair
                       && !color_used_for_this_char( line[n_chars - 1], idx)
                       && !(attr & line[n_chars - 1]))
                    n_chars--;
                assert( n_chars >= 0);
                if( n_chars)
                    PDC_transform_line( i, j, n_chars, line);
            }
    }
}

void PDC_init_pair( short pair, short fg, short bg)
{
    if( color_pair_indices[pair] != fg ||
        color_pair_indices[pair + PDC_COLOR_PAIRS] != bg)
    {
        color_pair_indices[pair] = fg;
        color_pair_indices[pair + PDC_COLOR_PAIRS] = bg;
        PDC_show_changes( pair, -1, 0);
    }
}

int PDC_pair_content( short pair, short *fg, short *bg)
{
    *fg = color_pair_indices[pair];
    *bg = color_pair_indices[pair + PDC_COLOR_PAIRS];
    return OK;
}

bool PDC_can_change_color(void)
{
    return TRUE;
}

int PDC_color_content( short color, short *red, short *green, short *blue)
{
    PACKED_RGB col = pdc_rgbs[color];

    *red = DIVROUND( Get_RValue(col) * 1000, 255);
    *green = DIVROUND( Get_GValue(col) * 1000, 255);
    *blue = DIVROUND( Get_BValue(col) * 1000, 255);

    return OK;
}

int PDC_init_color( short color, short red, short green, short blue)
{
    const PACKED_RGB new_rgb = PACK_RGB(DIVROUND(red * 255, 1000),
                                 DIVROUND(green * 255, 1000),
                                 DIVROUND(blue * 255, 1000));

    if( pdc_rgbs[color] != new_rgb)
    {
        pdc_rgbs[color] = new_rgb;
        PDC_show_changes( -1, color, 0);
    }
    return OK;
}