/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/space_text/text_autocomplete.c
 *  \ingroup sptext
 */

#include <ctype.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_text_types.h"

#include "BLI_blenlib.h"
#include "BLI_ghash.h"

#include "BKE_context.h"
#include "BKE_text.h"
#include "BKE_screen.h"
#include "BKE_suggestions.h"

#include "WM_api.h"
#include "WM_types.h"

#include "ED_screen.h"
#include "UI_interface.h"

#include "text_format.h"
#include "text_intern.h"  /* own include */


/* -------------------------------------------------------------------- */
/* Public API */

int text_do_suggest_select(SpaceText *st, ARegion *ar)
{
	SuggItem *item, *first, *last /* , *sel */ /* UNUSED */;
	TextLine *tmp;
	int l, x, y, w, h, i;
	int tgti, *top;
	int mval[2] = {0, 0};

	if (!st || !st->text) return 0;
	if (!texttool_text_is_active(st->text)) return 0;

	first = texttool_suggest_first();
	last = texttool_suggest_last();
	/* sel = texttool_suggest_selected(); */ /* UNUSED */
	top = texttool_suggest_top();

	if (!last || !first)
		return 0;

	/* Count the visible lines to the cursor */
	for (tmp = st->text->curl, l = -st->top; tmp; tmp = tmp->prev, l++) ;
	if (l < 0) return 0;

	text_update_character_width(st);

	if (st->showlinenrs) {
		x = st->cwidth * (st->text->curc - st->left) + TXT_OFFSET + TEXTXLOC - 4;
	}
	else {
		x = st->cwidth * (st->text->curc - st->left) + TXT_OFFSET - 4;
	}
	y = ar->winy - st->lheight_dpi * l - 2;

	w = SUGG_LIST_WIDTH * st->cwidth + U.widget_unit;
	h = SUGG_LIST_SIZE * st->lheight_dpi + 0.4f * U.widget_unit;

	// XXX getmouseco_areawin(mval);

	if (mval[0] < x || x + w < mval[0] || mval[1] < y - h || y < mval[1])
		return 0;

	/* Work out which of the items is at the top of the visible list */
	for (i = 0, item = first; i < *top && item->next; i++, item = item->next) ;

	/* Work out the target item index in the visible list */
	tgti = (y - mval[1] - 4) / st->lheight_dpi;
	if (tgti < 0 || tgti > SUGG_LIST_SIZE)
		return 1;

	for (i = tgti; i > 0 && item->next; i--, item = item->next) ;
	if (item)
		texttool_suggest_select(item);
	return 1;
}

void text_pop_suggest_list(void)
{
	SuggItem *item, *sel;
	int *top, i;

	item = texttool_suggest_first();
	sel = texttool_suggest_selected();
	top = texttool_suggest_top();

	i = 0;
	while (item && item != sel) {
		item = item->next;
		i++;
	}
	if (i > *top + SUGG_LIST_SIZE - 1)
		*top = i - SUGG_LIST_SIZE + 1;
	else if (i < *top)
		*top = i;
}

/* -------------------------------------------------------------------- */
/* Private API */

static void text_autocomplete_free(bContext *C, wmOperator *op);

static GHash *text_autocomplete_build(Text *text)
{
	GHash *gh;
	int seek_len = 0;
	const char *seek;
	texttool_text_clear();

	texttool_text_set_active(text);

	/* first get the word we're at */
	{
		const int i = text_find_identifier_start(text->curl->line, text->curc);
		seek_len = text->curc - i;
		seek = text->curl->line + i;

		// BLI_strncpy(seek, seek_ptr, seek_len);
	}

	/* now walk over entire doc and suggest words */
	{
		TextLine *linep;

		gh = BLI_ghash_str_new(__func__);

		for (linep = text->lines.first; linep; linep = linep->next) {
			size_t i_start = 0;
			size_t i_end = 0;
			size_t i_pos = 0;

			while (i_start < linep->len) {
				/* seek identifier beginning */
				i_pos = i_start;
				while ((i_start < linep->len) &&
				       (!text_check_identifier_nodigit_unicode(BLI_str_utf8_as_unicode_and_size_safe(&linep->line[i_start], &i_pos))))
				{
					i_start = i_pos;
				}
				i_pos = i_end = i_start;
				while ((i_end < linep->len) &&
				       (text_check_identifier_unicode(BLI_str_utf8_as_unicode_and_size_safe(&linep->line[i_end], &i_pos))))
				{
					i_end = i_pos;
				}

				if ((i_start != i_end) &&
				    /* check we're at the beginning of a line or that the previous char is not an identifier
				     * this prevents digits from being added */
				    ((i_start < 1) || !text_check_identifier_unicode(BLI_str_utf8_as_unicode(&linep->line[i_start - 1]))))
				{
					char *str_sub = &linep->line[i_start];
					const int choice_len = i_end - i_start;

					if ((choice_len > seek_len) &&
					    (seek_len == 0 || STREQLEN(seek, str_sub, seek_len)) &&
					    (seek != str_sub))
					{
						// printf("Adding: %s\n", s);
						char str_sub_last = str_sub[choice_len];
						str_sub[choice_len] = '\0';
						if (!BLI_ghash_lookup(gh, str_sub)) {
							char *str_dup = BLI_strdupn(str_sub, choice_len);
							BLI_ghash_insert(gh, str_dup, str_dup);  /* A 'set' would make more sense here */
						}
						str_sub[choice_len] = str_sub_last;
					}
				}
				if (i_end != i_start) {
					i_start = i_end;
				}
				else {
					/* highly unlikely, but prevent eternal loop */
					i_start++;
				}
			}
		}

		{
			GHashIterator gh_iter;

			/* get the formatter for highlighting */
			TextFormatType *tft;
			tft = ED_text_format_get(text);

			GHASH_ITER (gh_iter, gh) {
				const char *s = BLI_ghashIterator_getValue(&gh_iter);
				texttool_suggest_add(s, tft->format_identifier(s));
			}
		}
	}

	texttool_suggest_prefix(seek, seek_len);

	return gh;
}

/* -- */

static void get_suggest_prefix(Text *text, int offset)
{
	int i, len;
	const char *line;

	if (!text) return;
	if (!texttool_text_is_active(text)) return;

	line = text->curl->line;
	i = text_find_identifier_start(line, text->curc + offset);
	len = text->curc - i + offset;
	texttool_suggest_prefix(line + i, len);
}

static void confirm_suggestion(Text *text)
{
	SuggItem *sel;
	int i, over = 0;
	const char *line;

	if (!text) return;
	if (!texttool_text_is_active(text)) return;

	sel = texttool_suggest_selected();
	if (!sel) return;

	line = text->curl->line;
	i = text_find_identifier_start(line, text->curc /* - skipleft */);
	over = text->curc - i;

//	for (i = 0; i < skipleft; i++)
//		txt_move_left(text, 0);
	BLI_assert(memcmp(sel->name, &line[i], over) == 0);
	txt_insert_buf(text, sel->name + over);

//	for (i = 0; i < skipleft; i++)
//		txt_move_right(text, 0);

	texttool_text_clear();
}

/* -- */


static int text_autocomplete_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
{
	SpaceText *st = CTX_wm_space_text(C);
	Text *text = CTX_data_edit_text(C);

	st->doplugins = true;
	op->customdata = text_autocomplete_build(text);

	if (texttool_suggest_first()) {

		ED_area_tag_redraw(CTX_wm_area(C));

		if (texttool_suggest_first() == texttool_suggest_last()) {
			confirm_suggestion(st->text);
			text_update_line_edited(st->text->curl);
			text_autocomplete_free(C, op);
			return OPERATOR_FINISHED;
		}
		else {
			WM_event_add_modal_handler(C, op);
			return OPERATOR_RUNNING_MODAL;
		}
	}
	else {
		text_autocomplete_free(C, op);
		return OPERATOR_CANCELLED;
	}
}

static int doc_scroll = 0;

static int text_autocomplete_modal(bContext *C, wmOperator *op, const wmEvent *event)
{
	SpaceText *st = CTX_wm_space_text(C);
	ScrArea *sa = CTX_wm_area(C);
	ARegion *ar = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);

	int draw = 0, tools = 0, swallow = 0, scroll = 1;
	Text *text = CTX_data_edit_text(C);
	int retval = OPERATOR_RUNNING_MODAL;

	(void)text;

	if (st->doplugins && texttool_text_is_active(st->text)) {
		if (texttool_suggest_first()) tools |= TOOL_SUGG_LIST;
		if (texttool_docs_get()) tools |= TOOL_DOCUMENT;
	}

	switch (event->type) {
		case LEFTMOUSE:
			if (event->val == KM_PRESS) {
				if (text_do_suggest_select(st, ar))
					swallow = 1;
				else {
					if (tools & TOOL_SUGG_LIST) {
						texttool_suggest_clear();
					}
					if (tools & TOOL_DOCUMENT)  {
						texttool_docs_clear();
						doc_scroll = 0;
					}
					retval = OPERATOR_FINISHED;
				}
				draw = 1;
			}
			break;
		case MIDDLEMOUSE:
			if (event->val == KM_PRESS) {
				if (text_do_suggest_select(st, ar)) {
					confirm_suggestion(st->text);
					text_update_line_edited(st->text->curl);
					swallow = 1;
				}
				else {
					if (tools & TOOL_SUGG_LIST) {
						texttool_suggest_clear();
					}
					if (tools & TOOL_DOCUMENT) {
						texttool_docs_clear();
						doc_scroll = 0;
					}
					retval = OPERATOR_FINISHED;
				}
				draw = 1;
			}
			break;
		case ESCKEY:
			if (event->val == KM_PRESS) {
				draw = swallow = 1;
				if (tools & TOOL_SUGG_LIST) {
					texttool_suggest_clear();
				}
				else if (tools & TOOL_DOCUMENT) {
					texttool_docs_clear();
					doc_scroll = 0;
				}
				else draw = swallow = 0;
				retval = OPERATOR_CANCELLED;
			}
			break;
		case RETKEY:
		case PADENTER:
			if (event->val == KM_PRESS) {
				if (tools & TOOL_SUGG_LIST) {
					confirm_suggestion(st->text);
					text_update_line_edited(st->text->curl);
					swallow = 1;
					draw = 1;
				}
				if (tools & TOOL_DOCUMENT) {
					texttool_docs_clear();
					doc_scroll = 0;
					draw = 1;
				}
				retval = OPERATOR_FINISHED;
			}
			break;
		case LEFTARROWKEY:
		case BACKSPACEKEY:
			if (event->val == KM_PRESS) {
				if (tools & TOOL_SUGG_LIST) {
					if (event->ctrl) {
						texttool_suggest_clear();
						retval = OPERATOR_CANCELLED;
					}
					else {
						/* Work out which char we are about to delete/pass */
						if (st->text->curl && st->text->curc > 0) {
							char ch = st->text->curl->line[st->text->curc - 1];
							if ((ch == '_' || !ispunct(ch)) && !text_check_whitespace(ch)) {
								get_suggest_prefix(st->text, -1);
								text_pop_suggest_list();
							}
							else {
								texttool_suggest_clear();
								retval = OPERATOR_CANCELLED;
							}
						}
						else {
							texttool_suggest_clear();
							retval = OPERATOR_CANCELLED;
						}
					}
				}
				if (tools & TOOL_DOCUMENT) {
					texttool_docs_clear();
					doc_scroll = 0;
				}
			}
			break;
		case RIGHTARROWKEY:
			if (event->val == KM_PRESS) {
				if (tools & TOOL_SUGG_LIST) {
					if (event->ctrl) {
						texttool_suggest_clear();
						retval = OPERATOR_CANCELLED;
					}
					else {
						/* Work out which char we are about to pass */
						if (st->text->curl && st->text->curc < st->text->curl->len) {
							char ch = st->text->curl->line[st->text->curc + 1];
							if ((ch == '_' || !ispunct(ch)) && !text_check_whitespace(ch)) {
								get_suggest_prefix(st->text, 1);
								text_pop_suggest_list();
							}
							else {
								texttool_suggest_clear();
								retval = OPERATOR_CANCELLED;
							}
						}
						else {
							texttool_suggest_clear();
							retval = OPERATOR_CANCELLED;
						}
					}
				}
				if (tools & TOOL_DOCUMENT) {
					texttool_docs_clear();
					doc_scroll = 0;
				}
			}
			break;
		case PAGEDOWNKEY:
			scroll = SUGG_LIST_SIZE - 1;
			ATTR_FALLTHROUGH;
		case WHEELDOWNMOUSE:
		case DOWNARROWKEY:
			if (event->val == KM_PRESS) {
				if (tools & TOOL_DOCUMENT) {
					doc_scroll++;
					swallow = 1;
					draw = 1;
				}
				else if (tools & TOOL_SUGG_LIST) {
					SuggItem *sel = texttool_suggest_selected();
					if (!sel) {
						texttool_suggest_select(texttool_suggest_first());
					}
					else {
						while (sel && scroll--) {
							if (sel != texttool_suggest_last() && sel->next) {
								texttool_suggest_select(sel->next);
								sel = sel->next;
							}
							else {
								texttool_suggest_select(texttool_suggest_first());
								sel = texttool_suggest_first();
							}
						}
					}
					text_pop_suggest_list();
					swallow = 1;
					draw = 1;
				}
			}
			break;
		case PAGEUPKEY:
			scroll = SUGG_LIST_SIZE - 1;
			ATTR_FALLTHROUGH;
		case WHEELUPMOUSE:
		case UPARROWKEY:
			if (event->val == KM_PRESS) {
				if (tools & TOOL_DOCUMENT) {
					if (doc_scroll > 0) doc_scroll--;
					swallow = 1;
					draw = 1;
				}
				else if (tools & TOOL_SUGG_LIST) {
					SuggItem *sel = texttool_suggest_selected();
					while (sel && scroll--) {
						if (sel != texttool_suggest_first() && sel->prev) {
							texttool_suggest_select(sel->prev);
							sel = sel->prev;
						}
						else {
							texttool_suggest_select(texttool_suggest_last());
							sel = texttool_suggest_last();
						}
					}
					text_pop_suggest_list();
					swallow = 1;
					draw = 1;
				}
			}
			break;
		case RIGHTSHIFTKEY:
		case LEFTSHIFTKEY:
			break;
#if 0
		default:
			if (tools & TOOL_SUGG_LIST) {
				texttool_suggest_clear();
				draw = 1;
			}
			if (tools & TOOL_DOCUMENT) {
				texttool_docs_clear();
				doc_scroll = 0;
				draw = 1;
			}
#endif
	}

	if (draw) {
		ED_area_tag_redraw(sa);
	}

//	if (swallow) {
//		retval = OPERATOR_RUNNING_MODAL;
//	}

	if (texttool_suggest_first()) {
		if (retval != OPERATOR_RUNNING_MODAL) {
			text_autocomplete_free(C, op);
		}
		return retval;
	}
	else {
		text_autocomplete_free(C, op);
		return OPERATOR_FINISHED;
	}
}

static void text_autocomplete_free(bContext *C, wmOperator *op)
{
	GHash *gh = op->customdata;
	if (gh) {
		BLI_ghash_free(gh, NULL, MEM_freeN);
		op->customdata = NULL;
	}

	/* other stuff */
	{
		SpaceText *st = CTX_wm_space_text(C);
		st->doplugins = false;
		texttool_text_clear();
	}
}

static void text_autocomplete_cancel(bContext *C, wmOperator *op)
{
	text_autocomplete_free(C, op);
}

void TEXT_OT_autocomplete(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Text Auto Complete";
	ot->description = "Show a list of used text in the open document";
	ot->idname = "TEXT_OT_autocomplete";

	/* api callbacks */
	ot->invoke = text_autocomplete_invoke;
	ot->cancel = text_autocomplete_cancel;
	ot->modal = text_autocomplete_modal;
	ot->poll = text_space_edit_poll;

	/* flags */
	ot->flag = OPTYPE_BLOCKING;
}