/*
   *  textbox.c -- implements the text box
   *
   *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
   *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
   *
   *  This program 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 2
   *  of the License, or (at your option) any later version.
   *
   *  This program 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, write to the Free Software
   *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include "dialog.h"
  
  static void back_lines(int n);
  static void print_page(WINDOW *win, int height, int width, update_text_fn
  		       update_text, void *data);
  static void print_line(WINDOW *win, int row, int width);
  static char *get_line(void);
  static void print_position(WINDOW * win);
  
  static int hscroll;
  static int begin_reached, end_reached, page_length;
  static char *buf;
  static char *page;
  
  /*
   * refresh window content
   */
  static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
  			     int cur_y, int cur_x, update_text_fn update_text,
  			     void *data)
  {
  	print_page(box, boxh, boxw, update_text, data);
  	print_position(dialog);
  	wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
  	wrefresh(dialog);
  }
  
  
  /*
   * Display text from a file in a dialog box.
   *
   * keys is a null-terminated array
   * update_text() may not add or remove any '
  ' or '\0' in tbuf
   */
  int dialog_textbox(const char *title, char *tbuf, int initial_height,
  		   int initial_width, int *keys, int *_vscroll, int *_hscroll,
  		   update_text_fn update_text, void *data)
  {
  	int i, x, y, cur_x, cur_y, key = 0;
  	int height, width, boxh, boxw;
  	WINDOW *dialog, *box;
  	bool done = false;
  
  	begin_reached = 1;
  	end_reached = 0;
  	page_length = 0;
  	hscroll = 0;
  	buf = tbuf;
  	page = buf;	/* page is pointer to start of page to be displayed */
  
  	if (_vscroll && *_vscroll) {
  		begin_reached = 0;
  
  		for (i = 0; i < *_vscroll; i++)
  			get_line();
  	}
  	if (_hscroll)
  		hscroll = *_hscroll;
  
  do_resize:
  	getmaxyx(stdscr, height, width);
  	if (height < TEXTBOX_HEIGTH_MIN || width < TEXTBOX_WIDTH_MIN)
  		return -ERRDISPLAYTOOSMALL;
  	if (initial_height != 0)
  		height = initial_height;
  	else
  		if (height > 4)
  			height -= 4;
  		else
  			height = 0;
  	if (initial_width != 0)
  		width = initial_width;
  	else
  		if (width > 5)
  			width -= 5;
  		else
  			width = 0;
  
  	/* center dialog box on screen */
  	x = (getmaxx(stdscr) - width) / 2;
  	y = (getmaxy(stdscr) - height) / 2;
  
  	draw_shadow(stdscr, y, x, height, width);
  
  	dialog = newwin(height, width, y, x);
  	keypad(dialog, TRUE);
  
  	/* Create window for box region, used for scrolling text */
  	boxh = height - 4;
  	boxw = width - 2;
  	box = subwin(dialog, boxh, boxw, y + 1, x + 1);
  	wattrset(box, dlg.dialog.atr);
  	wbkgdset(box, dlg.dialog.atr & A_COLOR);
  
  	keypad(box, TRUE);
  
  	/* register the new window, along with its borders */
  	draw_box(dialog, 0, 0, height, width,
  		 dlg.dialog.atr, dlg.border.atr);
  
  	wattrset(dialog, dlg.border.atr);
  	mvwaddch(dialog, height - 3, 0, ACS_LTEE);
  	for (i = 0; i < width - 2; i++)
  		waddch(dialog, ACS_HLINE);
  	wattrset(dialog, dlg.dialog.atr);
  	wbkgdset(dialog, dlg.dialog.atr & A_COLOR);
  	waddch(dialog, ACS_RTEE);
  
  	print_title(dialog, title, width);
  
  	print_button(dialog, gettext(" Exit "), height - 2, width / 2 - 4, TRUE);
  	wnoutrefresh(dialog);
  	getyx(dialog, cur_y, cur_x);	/* Save cursor position */
  
  	/* Print first page of text */
  	attr_clear(box, boxh, boxw, dlg.dialog.atr);
  	refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x, update_text,
  			 data);
  
  	while (!done) {
  		key = wgetch(dialog);
  		switch (key) {
  		case 'E':	/* Exit */
  		case 'e':
  		case 'X':
  		case 'x':
  		case 'q':
  		case '
  ':
  			done = true;
  			break;
  		case 'g':	/* First page */
  		case KEY_HOME:
  			if (!begin_reached) {
  				begin_reached = 1;
  				page = buf;
  				refresh_text_box(dialog, box, boxh, boxw,
  						 cur_y, cur_x, update_text,
  						 data);
  			}
  			break;
  		case 'G':	/* Last page */
  		case KEY_END:
  
  			end_reached = 1;
  			/* point to last char in buf */
  			page = buf + strlen(buf);
  			back_lines(boxh);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case 'K':	/* Previous line */
  		case 'k':
  		case KEY_UP:
  			if (begin_reached)
  				break;
  
  			back_lines(page_length + 1);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case 'B':	/* Previous page */
  		case 'b':
  		case 'u':
  		case KEY_PPAGE:
  			if (begin_reached)
  				break;
  			back_lines(page_length + boxh);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case 'J':	/* Next line */
  		case 'j':
  		case KEY_DOWN:
  			if (end_reached)
  				break;
  
  			back_lines(page_length - 1);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case KEY_NPAGE:	/* Next page */
  		case ' ':
  		case 'd':
  			if (end_reached)
  				break;
  
  			begin_reached = 0;
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case '0':	/* Beginning of line */
  		case 'H':	/* Scroll left */
  		case 'h':
  		case KEY_LEFT:
  			if (hscroll <= 0)
  				break;
  
  			if (key == '0')
  				hscroll = 0;
  			else
  				hscroll--;
  			/* Reprint current page to scroll horizontally */
  			back_lines(page_length);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case 'L':	/* Scroll right */
  		case 'l':
  		case KEY_RIGHT:
  			if (hscroll >= MAX_LEN)
  				break;
  			hscroll++;
  			/* Reprint current page to scroll horizontally */
  			back_lines(page_length);
  			refresh_text_box(dialog, box, boxh, boxw, cur_y,
  					 cur_x, update_text, data);
  			break;
  		case KEY_ESC:
  			if (on_key_esc(dialog) == KEY_ESC)
  				done = true;
  			break;
  		case KEY_RESIZE:
  			back_lines(height);
  			delwin(box);
  			delwin(dialog);
  			on_key_resize();
  			goto do_resize;
  		default:
  			for (i = 0; keys[i]; i++) {
  				if (key == keys[i]) {
  					done = true;
  					break;
  				}
  			}
  		}
  	}
  	delwin(box);
  	delwin(dialog);
  	if (_vscroll) {
  		const char *s;
  
  		s = buf;
  		*_vscroll = 0;
  		back_lines(page_length);
  		while (s < page && (s = strchr(s, '
  '))) {
  			(*_vscroll)++;
  			s++;
  		}
  	}
  	if (_hscroll)
  		*_hscroll = hscroll;
  	return key;
  }
  
  /*
   * Go back 'n' lines in text. Called by dialog_textbox().
   * 'page' will be updated to point to the desired line in 'buf'.
   */
  static void back_lines(int n)
  {
  	int i;
  
  	begin_reached = 0;
  	/* Go back 'n' lines */
  	for (i = 0; i < n; i++) {
  		if (*page == '\0') {
  			if (end_reached) {
  				end_reached = 0;
  				continue;
  			}
  		}
  		if (page == buf) {
  			begin_reached = 1;
  			return;
  		}
  		page--;
  		do {
  			if (page == buf) {
  				begin_reached = 1;
  				return;
  			}
  			page--;
  		} while (*page != '
  ');
  		page++;
  	}
  }
  
  /*
   * Print a new page of text.
   */
  static void print_page(WINDOW *win, int height, int width, update_text_fn
  		       update_text, void *data)
  {
  	int i, passed_end = 0;
  
  	if (update_text) {
  		char *end;
  
  		for (i = 0; i < height; i++)
  			get_line();
  		end = page;
  		back_lines(height);
  		update_text(buf, page - buf, end - buf, data);
  	}
  
  	page_length = 0;
  	for (i = 0; i < height; i++) {
  		print_line(win, i, width);
  		if (!passed_end)
  			page_length++;
  		if (end_reached && !passed_end)
  			passed_end = 1;
  	}
  	wnoutrefresh(win);
  }
  
  /*
   * Print a new line of text.
   */
  static void print_line(WINDOW * win, int row, int width)
  {
  	char *line;
  
  	line = get_line();
  	line += MIN(strlen(line), hscroll);	/* Scroll horizontally */
  	wmove(win, row, 0);	/* move cursor to correct line */
  	waddch(win, ' ');
  	waddnstr(win, line, MIN(strlen(line), width - 2));
  
  	/* Clear 'residue' of previous line */
  #if OLD_NCURSES
  	{
  		int x = getcurx(win);
  		int i;
  		for (i = 0; i < width - x; i++)
  			waddch(win, ' ');
  	}
  #else
  	wclrtoeol(win);
  #endif
  }
  
  /*
   * Return current line of text. Called by dialog_textbox() and print_line().
   * 'page' should point to start of current line before calling, and will be
   * updated to point to start of next line.
   */
  static char *get_line(void)
  {
  	int i = 0;
  	static char line[MAX_LEN + 1];
  
  	end_reached = 0;
  	while (*page != '
  ') {
  		if (*page == '\0') {
  			end_reached = 1;
  			break;
  		} else if (i < MAX_LEN)
  			line[i++] = *(page++);
  		else {
  			/* Truncate lines longer than MAX_LEN characters */
  			if (i == MAX_LEN)
  				line[i++] = '\0';
  			page++;
  		}
  	}
  	if (i <= MAX_LEN)
  		line[i] = '\0';
  	if (!end_reached)
  		page++;		/* move past '
  ' */
  
  	return line;
  }
  
  /*
   * Print current position
   */
  static void print_position(WINDOW * win)
  {
  	int percent;
  
  	wattrset(win, dlg.position_indicator.atr);
  	wbkgdset(win, dlg.position_indicator.atr & A_COLOR);
  	percent = (page - buf) * 100 / strlen(buf);
  	wmove(win, getmaxy(win) - 3, getmaxx(win) - 9);
  	wprintw(win, "(%3d%%)", percent);
  }