/*
 * Schism Tracker - a cross-platform Impulse Tracker clone
 * copyright (c) 2003-2005 Storlek <storlek@rigelseven.com>
 * copyright (c) 2005-2008 Mrs. Brisby <mrs.brisby@nimh.org>
 * copyright (c) 2009 Storlek & Mrs. Brisby
 * copyright (c) 2010-2012 Storlek
 * URL: http://schismtracker.org/
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* --->> WARNING <<---
 *
 * This is an excellent example of how NOT to write a text editor.
 * IMHO, the best way to add a song message is by writing it in some
 * other program and attaching it to the song with something like
 * ZaStaR's ITTXT utility (hmm, maybe I should rewrite that, too ^_^) so
 * I'm not *really* concerned about the fact that this code completely
 * sucks. Just remember, this ain't Xcode. */

#include "headers.h"

#include "song.h"
#include "clippy.h"

#include <ctype.h>
#include <assert.h>

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

static struct widget widgets_message[1];

static int top_line = 0;
static int cursor_line = 0;
static int cursor_char = 0;
/* this is the absolute cursor position from top of message.
 * (should be updated whenever cursor_line/cursor_char change) */
static int cursor_pos = 0;

static int edit_mode = 0;

/* nonzero => message should use the alternate font */
static int message_extfont = 1;

/* This is a bit weird... Impulse Tracker usually wraps at 74, but if
 * the line doesn't have any spaces in it (like in a solid line of
 * dashes or something) it gets wrapped at 75. I'm using 75 for
 * everything because it's always nice to have a bit extra space :) */
#define LINE_WRAP 75

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

static int message_handle_key_editmode(struct key_event * k);
static int message_handle_key_viewmode(struct key_event * k);

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

/* returns the number of characters on the nth line of text, setting ptr
 * to the first character on the line. if it there are fewer than n
 * lines, ptr is set to the \0 at the end of the string, and the
 * function returns -1. note: if *ptr == text, weird things will
 * probably happen, so don't do that. */
static int get_nth_line(char *text, int n, char **ptr)
{
	char *tmp;

	assert(text != NULL);

	*ptr = text;
	while (n > 0) {
		n--;
		*ptr = strpbrk(*ptr, "\xd\xa");
		if (!(*ptr)) {
			*ptr = text + strlen(text);
			return -1;
		}
		if ((*ptr)[0] == 13 && (*ptr)[1] == 10)
			*ptr += 2;
		else
			(*ptr)++;
	}

	tmp = strpbrk(*ptr, "\xd\xa");
	return (tmp ? (unsigned) (tmp - *ptr) : strlen(*ptr));
}
static void set_absolute_position(char *text, int pos, int *line, int *ch)
{
	int len;
	char *ptr;

	*line = *ch = 0;
	ptr = NULL;
	while (pos > 0) {
		len = get_nth_line(text, *line, &ptr);
		if (len < 0) {
			/* end of file */
			(*line) = (*line) - 1;
			if (*line < 0) *line = 0;
			len = get_nth_line(text, *line, &ptr);
			if (len < 0) {
				*ch = 0;
			} else {
				*ch = len;
			}
			pos = 0;

		} else if (len >= pos) {
			*ch = pos;
			pos = 0;
		} else {
			pos -= (len+1); /* EOC */
			(*line) = (*line) + 1;
		}
	}
}
static int get_absolute_position(char *text, int line, int character)
{
	int len;
	char *ptr;

	ptr = NULL;
	len = get_nth_line(text, line, &ptr);
	if (len < 0) {
		return 0;
	}
	/* hrm... what if cursor_char > len? */
	return (ptr - text) + character;
}

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

static void message_reposition(void)
{
	if (cursor_line < top_line) {
		top_line = cursor_line;
	} else if (cursor_line > top_line + 34) {
		top_line = cursor_line - 34;
	}
}

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

/* returns 1 if a character was actually added */
static int message_add_char(int newchar, int position)
{
	int len = strlen(current_song->message);

	if (len == MAX_MESSAGE) {
		dialog_create(DIALOG_OK, "  Song message too long!  ", NULL, NULL, 0, NULL);
		return 0;
	}
	if (position < 0 || position > len) {
		log_appendf(4, "message_add_char: position=%d, len=%d - shouldn't happen!", position, len);
		return 0;
	}

	memmove(current_song->message + position + 1, current_song->message + position, len - position);
	current_song->message[len + 1] = 0;
	current_song->message[position] = (unsigned char)newchar;
	return 1;
}

/* this returns the new length of the line */
static int message_wrap_line(char *bol_ptr)
{
	char *eol_ptr;
	char *last_space = NULL;
	char *tmp = bol_ptr;

	if (!bol_ptr)
		/* shouldn't happen, but... */
		return 0;

	eol_ptr = strpbrk(bol_ptr, "\xd\xa");
	if (!eol_ptr)
		eol_ptr = bol_ptr + strlen(bol_ptr);

	for (;;) {
		tmp = strpbrk((tmp + 1), " \t");
		if (tmp == NULL || tmp > eol_ptr
		    || tmp - bol_ptr > LINE_WRAP)
			break;
		last_space = tmp;
	}

	if (last_space) {
		*last_space = 13;
		return last_space - bol_ptr;
	} else {
		/* what, no spaces to cut at? chop it mercilessly. */
		if (message_add_char(13, bol_ptr + LINE_WRAP - current_song->message)
		    == 0)
			/* ack, the message is too long to wrap the line!
			 * gonna have to resort to something ugly. */
			bol_ptr[LINE_WRAP] = 13;
		return LINE_WRAP;
	}
}

/* --------------------------------------------------------------------- */
static void text(char *line, int len, int n)
{
	unsigned char ch;
	int fg = (message_extfont ? 12 : 6);
	int  i;

	for (i = 0; line[i] && i < len; i++) {
		ch = line[i];

		if (ch == ' ') {
			draw_char(' ', 2+i, 13+n, 3,0);
		} else {
			(message_extfont ? draw_char_bios : draw_char)(ch, 2+i, 13+n, fg, 0);
		}
	}
}

static void message_draw(void)
{
	char *line, *prevline = current_song->message;
	int len = get_nth_line(current_song->message, top_line, &line);
	int n, cp, clipl, clipr;
	int skipc, cutc;

	draw_fill_chars(2, 13, 77, 47, 0);

	if (clippy_owner(CLIPPY_SELECT) == widgets_message) {
		clipl = widgets_message[0].clip_start;
		clipr = widgets_message[0].clip_end;
		if (clipl > clipr) {
			cp = clipl;
			clipl = clipr;
			clipr = cp;
		}
	} else {
		clipl = clipr = -1;
	}

	for (n = 0; n < 35; n++) {
		if (len < 0) {
			break;
		} else if (len > 0) {
			/* FIXME | shouldn't need this check here,
			 * FIXME | because the line should already be
			 * FIXME | short enough to fit */
			if (len > LINE_WRAP)
				len = LINE_WRAP;
			text(line, len, n);

			if (clipl > -1) {
				cp = line - current_song->message;
				skipc = clipl - cp;
				cutc = clipr - clipl;
				if (skipc < 0) {
					cutc += skipc; /* ... -skipc */
					skipc = 0;
				}
				if (cutc < 0) cutc = 0;
				if (cutc > (len-skipc)) cutc = (len-skipc);
				if (cutc > 0 && skipc < len) {
					if (message_extfont)
						draw_text_bios_len(line+skipc, cutc, 2+skipc, 13 + n, 6, 8);
					else
						draw_text_len(line+skipc, cutc, 2+skipc, 13 + n, 6, 8);
				}
			}
		}
		if (edit_mode) {
			draw_char(20, 2 + len, 13 + n, 1, 0);
		}
		prevline = line;
		len = get_nth_line(prevline, 1, &line);
	}

	if (edit_mode && len < 0) {
		/* end of the message */
		len = get_nth_line(prevline, 0, &line);
		/* FIXME: see above */
		if (len > LINE_WRAP)
			len = LINE_WRAP;
		draw_char(20, 2 + len, 13 + n - 1, 2, 0);
	}

	if (edit_mode) {
		/* draw the cursor */
		len = get_nth_line(current_song->message, cursor_line, &line);

		/* FIXME: ... ugh */
		if (len > LINE_WRAP)
			len = LINE_WRAP;
		if (cursor_char > LINE_WRAP + 1)
			cursor_char = LINE_WRAP + 1;

		if (cursor_char >= len) {
			(message_extfont ? draw_char_bios : draw_char)
				(20, 2 + cursor_char, 13 + (cursor_line - top_line), 0, 3);
		} else {
			(message_extfont ? draw_char_bios : draw_char)
				(line[cursor_char], 2 + cursor_char, 13 + (cursor_line - top_line), 8, 3);
		}
	}
}

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

static inline void message_set_editmode(void)
{
	edit_mode = 1;
	widgets_message[0].accept_text = 1;
	top_line = cursor_line = cursor_char = cursor_pos = 0;
	widgets_message[0].d.other.handle_key = message_handle_key_editmode;

	status.flags |= NEED_UPDATE;
}

static inline void message_set_viewmode(void)
{
	edit_mode = 0;
	widgets_message[0].accept_text = 0;
	widgets_message[0].d.other.handle_key = message_handle_key_viewmode;

	status.flags |= NEED_UPDATE;
}

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

static void message_insert_char(int c)
{
	char *ptr;
	int n;

	if (!edit_mode)
		return;

	memused_songchanged();
	if (c == '\t') {
		/* Find the number of characters until the next tab stop.
		 * (This is new behaviour; Impulse Tracker just inserts
		 * eight characters regardless of the cursor position.) */
		n = 8 - cursor_char % 8;
		if (cursor_char + n > LINE_WRAP) {
			message_insert_char('\r');
		} else {
			do {
				if (!message_add_char(' ', cursor_pos))
					break;
				cursor_char++;
				cursor_pos++;
				n--;
			} while (n);
		}
	} else if (c < 32 && c != '\r') {
		return;
	} else {
		if (!message_add_char(c, cursor_pos))
			return;
		cursor_pos++;
		if (c == '\r') {
			cursor_char = 0;
			cursor_line++;
		} else {
			cursor_char++;
		}
	}
	if (get_nth_line(current_song->message, cursor_line, &ptr) >= LINE_WRAP) {
		message_wrap_line(ptr);
	}
	if (cursor_char >= LINE_WRAP) {
		cursor_char = get_nth_line(current_song->message, ++cursor_line, &ptr);
		cursor_pos = get_absolute_position(current_song->message, cursor_line, cursor_char);
	}

	message_reposition();
	status.flags |= NEED_UPDATE | SONG_NEEDS_SAVE;
}

static void message_delete_char(void)
{
	int len = strlen(current_song->message);
	char *ptr;

	if (cursor_pos == 0)
		return;
	memmove(current_song->message + cursor_pos - 1, current_song->message + cursor_pos,
		len - cursor_pos + 1);
	current_song->message[MAX_MESSAGE] = 0;
	cursor_pos--;
	if (cursor_char == 0) {
		cursor_line--;
		cursor_char = get_nth_line(current_song->message, cursor_line, &ptr);
	} else {
		cursor_char--;
	}

	message_reposition();
	status.flags |= NEED_UPDATE | SONG_NEEDS_SAVE;
}

static void message_delete_next_char(void)
{
	int len = strlen(current_song->message);

	if (cursor_pos == len)
		return;
	memmove(current_song->message + cursor_pos, current_song->message + cursor_pos + 1,
		len - cursor_pos);
	current_song->message[MAX_MESSAGE] = 0;

	status.flags |= NEED_UPDATE | SONG_NEEDS_SAVE;
}

static void message_delete_line(void)
{
	int len;
	int movelen;
	char *ptr;

	len = get_nth_line(current_song->message, cursor_line, &ptr);
	if (len < 0)
		return;
	if (ptr[len] == 13 && ptr[len + 1] == 10)
		len++;
	movelen = (current_song->message + strlen(current_song->message) - ptr);
	if (movelen == 0)
		return;
	memmove(ptr, ptr + len + 1, movelen);
	len = get_nth_line(current_song->message, cursor_line, &ptr);
	if (cursor_char > len) {
		cursor_char = len;
		cursor_pos = get_absolute_position(current_song->message, cursor_line, cursor_char);
	}
	message_reposition();
	status.flags |= NEED_UPDATE | SONG_NEEDS_SAVE;
}

static void message_clear(UNUSED void *data)
{
	current_song->message[0] = 0;
	memused_songchanged();
	message_set_viewmode();
	status.flags |= SONG_NEEDS_SAVE;
}

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

static void prompt_message_clear(void)
{
	dialog_create(DIALOG_OK_CANCEL, "Clear song message?", message_clear, NULL, 1, NULL);
}

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

static int message_handle_key_viewmode(struct key_event * k)
{
	if (k->state == KEY_PRESS) {
		if (k->mouse == MOUSE_SCROLL_UP) {
			top_line -= MOUSE_SCROLL_LINES;
		} else if (k->mouse == MOUSE_SCROLL_DOWN) {
			top_line += MOUSE_SCROLL_LINES;
		} else if (k->mouse == MOUSE_CLICK) {
			message_set_editmode();
			return message_handle_key_editmode(k);
		}
	}

	switch (k->sym) {
	case SDLK_UP:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line--;
		break;
	case SDLK_DOWN:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line++;
		break;
	case SDLK_PAGEUP:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line -= 35;
		break;
	case SDLK_PAGEDOWN:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line += 35;
		break;
	case SDLK_HOME:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line = 0;
		break;
	case SDLK_END:
		if (k->state == KEY_RELEASE)
			return 0;
		top_line = get_num_lines(current_song->message) - 34;
		break;
	case SDLK_t:
		if (k->state == KEY_RELEASE)
			return 0;
		if (k->mod & KMOD_CTRL) {
			message_extfont = !message_extfont;
			break;
		}
		return 1;
	case SDLK_RETURN:
		if (k->state == KEY_PRESS)
			return 0;
		message_set_editmode();
		return 1;
	default:
		return 0;
	}

	if (top_line < 0)
		top_line = 0;

	status.flags |= NEED_UPDATE;

	return 1;
}
static void _delete_selection(void)
{
	int len = strlen(current_song->message);
	int eat;

	cursor_pos = widgets_message[0].clip_start;
	if (cursor_pos > widgets_message[0].clip_end) {
		cursor_pos = widgets_message[0].clip_end;
		eat = widgets_message[0].clip_start - cursor_pos;
	} else {
		eat = widgets_message[0].clip_end - cursor_pos;
	}
	clippy_select(NULL, NULL, 0);
	if (cursor_pos == len)
		return;
	memmove(current_song->message + cursor_pos, current_song->message + cursor_pos + eat + 1,
		((len - cursor_pos) - eat)+1);
	current_song->message[MAX_MESSAGE] = 0;
	set_absolute_position(current_song->message, cursor_pos, &cursor_line, &cursor_char);
	message_reposition();

	status.flags |= NEED_UPDATE | SONG_NEEDS_SAVE;
}

static int message_handle_key_editmode(struct key_event * k)
{
	int line_len, num_lines = -1;
	int new_cursor_line = cursor_line;
	int new_cursor_char = cursor_char;
	char *ptr;
	int doing_drag = 0;
	int clipl, clipr, cp;

	if (k->mouse == MOUSE_SCROLL_UP) {
		if (k->state == KEY_RELEASE)
			return 0;
		new_cursor_line -= MOUSE_SCROLL_LINES;
	} else if (k->mouse == MOUSE_SCROLL_DOWN) {
		if (k->state == KEY_RELEASE)
			return 0;
		new_cursor_line += MOUSE_SCROLL_LINES;
	} else if (k->mouse == MOUSE_CLICK && k->mouse_button == 2) {
		if (k->state == KEY_RELEASE)
			status.flags |= CLIPPY_PASTE_SELECTION;
		return 1;
	} else if (k->mouse == MOUSE_CLICK) {
		if (k->x >= 2 && k->x <= 77 && k->y >= 13 && k->y <= 47) {
			new_cursor_line = (k->y - 13) + top_line;
			new_cursor_char = (k->x - 2);
			if (k->sx != k->x || k->sy != k->y) {
				/* yay drag operation */
				cp = get_absolute_position(current_song->message, (k->sy-13)+top_line,
							(k->sx-2));
				widgets_message[0].clip_start = cp;
				doing_drag = 1;
			}
		}
	}

	line_len = get_nth_line(current_song->message, cursor_line, &ptr);


	switch (k->sym) {
	case SDLK_UP:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_line--;
		break;
	case SDLK_DOWN:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_line++;
		break;
	case SDLK_LEFT:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_char--;
		break;
	case SDLK_RIGHT:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_char++;
		break;
	case SDLK_PAGEUP:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_line -= 35;
		break;
	case SDLK_PAGEDOWN:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		new_cursor_line += 35;
		break;
	case SDLK_HOME:
		if (k->state == KEY_RELEASE)
			return 1;
		if (k->mod & KMOD_CTRL)
			new_cursor_line = 0;
		else
			new_cursor_char = 0;
		break;
	case SDLK_END:
		if (k->state == KEY_RELEASE)
			return 1;
		if (k->mod & KMOD_CTRL) {
			num_lines = get_num_lines(current_song->message);
			new_cursor_line = num_lines;
		} else {
			new_cursor_char = line_len;
		}
		break;
	case SDLK_ESCAPE:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		message_set_viewmode();
		memused_songchanged();
		return 1;
	case SDLK_BACKSPACE:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		if (k->sym && clippy_owner(CLIPPY_SELECT) == widgets_message) {
			_delete_selection();
		} else {
			message_delete_char();
		}
		return 1;
	case SDLK_DELETE:
		if (!NO_MODIFIER(k->mod))
			return 0;
		if (k->state == KEY_RELEASE)
			return 1;
		if (k->sym && clippy_owner(CLIPPY_SELECT) == widgets_message) {
			_delete_selection();
		} else {
			message_delete_next_char();
		}
		return 1;
	default:
		if (k->mod & KMOD_CTRL) {
			if (k->state == KEY_RELEASE)
				return 1;
			if (k->sym == SDLK_t) {
				message_extfont = !message_extfont;
				break;
			} else if (k->sym == SDLK_y) {
				clippy_select(NULL, NULL, 0);
				message_delete_line();
				break;
			}
		} else if (k->mod & KMOD_ALT) {
			if (k->state == KEY_RELEASE)
				return 1;
			if (k->sym == SDLK_c) {
				prompt_message_clear();
				return 1;
			}
		} else if (k->mouse == MOUSE_NONE) {
			if (k->unicode == '\r' || k->unicode == '\t'
			|| k->unicode >= 32) {
				if (k->state == KEY_RELEASE)
					return 1;
				if (k->sym && clippy_owner(CLIPPY_SELECT) == widgets_message) {
					_delete_selection();
				}
				if (k->mod & (KMOD_SHIFT|KMOD_CAPS)) {
					message_insert_char(toupper((unsigned int)k->unicode));
				} else {
					message_insert_char(k->unicode);
				}
				return 1;
			}
			return 0;
		}

		if (k->mouse != MOUSE_CLICK)
			return 0;

		if (k->state == KEY_RELEASE)
			return 1;
		if (!doing_drag) {
			clippy_select(NULL, NULL, 0);
		}
	}

	if (new_cursor_line != cursor_line) {
		if (num_lines == -1)
			num_lines = get_num_lines(current_song->message);

		if (new_cursor_line < 0)
			new_cursor_line = 0;
		else if (new_cursor_line > num_lines)
			new_cursor_line = num_lines;

		/* make sure the cursor doesn't go past the new eol */
		line_len = get_nth_line(current_song->message, new_cursor_line, &ptr);
		if (new_cursor_char > line_len)
			new_cursor_char = line_len;

		cursor_char = new_cursor_char;
		cursor_line = new_cursor_line;
	} else if (new_cursor_char != cursor_char) {
	/* we say "else" here ESPECIALLY because the mouse can only come
	in the top section - not because it's some clever optimization */
		if (new_cursor_char < 0) {
			if (cursor_line == 0) {
				new_cursor_char = cursor_char;
			} else {
				cursor_line--;
				new_cursor_char =
					get_nth_line(current_song->message, cursor_line, &ptr);
			}

		} else if (new_cursor_char >
			   get_nth_line(current_song->message, cursor_line, &ptr)) {
			if (cursor_line == get_num_lines(current_song->message)) {
				new_cursor_char = cursor_char;
			} else {
				cursor_line++;
				new_cursor_char = 0;
			}
		}
		cursor_char = new_cursor_char;
	}

	message_reposition();
	cursor_pos = get_absolute_position(current_song->message, cursor_line, cursor_char);

	if (doing_drag) {
		widgets_message[0].clip_end = cursor_pos;

		clipl = widgets_message[0].clip_start;
		clipr = widgets_message[0].clip_end;
		if (clipl > clipr) {
			cp = clipl;
			clipl = clipr;
			clipr = cp;
		}
		clippy_select(widgets_message, (current_song->message+clipl), clipr-clipl);
	}

	status.flags |= NEED_UPDATE;

	return 1;
}

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

static void message_draw_const(void)
{
	draw_box(1, 12, 78, 48, BOX_THICK | BOX_INNER | BOX_INSET);
}

static void song_changed_cb(void)
{
	char *line, *prevline;
	int len;

	edit_mode = 0;
	widgets_message[0].accept_text = 0;
	widgets_message[0].d.other.handle_key = message_handle_key_viewmode;
	top_line = 0;

	len = get_nth_line(current_song->message, 0, &line);
	while (len >= 0) {
		if (len > LINE_WRAP)
			message_wrap_line(line);
		prevline = line;
		len = get_nth_line(prevline, 1, &line);
	}

	if (status.current_page == PAGE_MESSAGE)
		status.flags |= NEED_UPDATE;
}

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

void message_load_page(struct page *page)
{
	page->title = "Message Editor (Shift-F9)";
	page->draw_const = message_draw_const;
	page->song_changed_cb = song_changed_cb;
	page->total_widgets = 1;
	page->widgets = widgets_message;
	page->help_index = HELP_MESSAGE_EDITOR;

	create_other(widgets_message + 0, 0, message_handle_key_viewmode, message_draw);
	widgets_message[0].accept_text = edit_mode;
}

void message_reset_selection(void)
{
	widgets_message[0].clip_start = widgets_message[0].clip_end = 0;
}
