/*
 * ***** 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.
 *
 * The Original Code is Copyright (C) 2008 Blender Foundation.
 * All rights reserved.
 *
 * 
 * Contributor(s): Blender Foundation
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/space_sequencer/space_sequencer.c
 *  \ingroup spseq
 */


#include <string.h>
#include <stdio.h>

#include "DNA_scene_types.h"
#include "DNA_mask_types.h"

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_utildefines.h"

#include "BKE_context.h"
#include "BKE_screen.h"
#include "BKE_sequencer.h"
#include "BKE_global.h"

#include "ED_space_api.h"
#include "ED_screen.h"
#include "ED_view3d.h" /* only for sequencer view3d drawing callback */

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

#include "UI_interface.h"
#include "UI_resources.h"
#include "UI_view2d.h"

#include "IMB_imbuf.h"

#include "sequencer_intern.h"   // own include

/**************************** common state *****************************/

static void sequencer_scopes_tag_refresh(ScrArea *sa)
{
	SpaceSeq *sseq = (SpaceSeq *)sa->spacedata.first;

	sseq->scopes.reference_ibuf = NULL;
}

/* ******************** manage regions ********************* */

ARegion *sequencer_has_buttons_region(ScrArea *sa)
{
	ARegion *ar, *arnew;

	ar = BKE_area_find_region_type(sa, RGN_TYPE_UI);
	if (ar) return ar;
	
	/* add subdiv level; after header */
	ar = BKE_area_find_region_type(sa, RGN_TYPE_HEADER);

	/* is error! */
	if (ar == NULL) return NULL;
	
	arnew = MEM_callocN(sizeof(ARegion), "buttons for sequencer");
	
	BLI_insertlinkafter(&sa->regionbase, ar, arnew);
	arnew->regiontype = RGN_TYPE_UI;
	arnew->alignment = RGN_ALIGN_RIGHT;
	
	arnew->flag = RGN_FLAG_HIDDEN;
	
	return arnew;
}

static ARegion *sequencer_find_region(ScrArea *sa, short type)
{
	ARegion *ar = NULL;
	
	for (ar = sa->regionbase.first; ar; ar = ar->next)
		if (ar->regiontype == type)
			return ar;

	return ar;
}

/* ******************** default callbacks for sequencer space ***************** */

static SpaceLink *sequencer_new(const bContext *C)
{
	Scene *scene = CTX_data_scene(C);
	ARegion *ar;
	SpaceSeq *sseq;
	
	sseq = MEM_callocN(sizeof(SpaceSeq), "initsequencer");
	sseq->spacetype = SPACE_SEQ;
	sseq->chanshown = 0;
	sseq->view = SEQ_VIEW_SEQUENCE;
	sseq->mainb = SEQ_DRAW_IMG_IMBUF;
	sseq->flag = SEQ_SHOW_GPENCIL | SEQ_USE_ALPHA;

	/* header */
	ar = MEM_callocN(sizeof(ARegion), "header for sequencer");
	
	BLI_addtail(&sseq->regionbase, ar);
	ar->regiontype = RGN_TYPE_HEADER;
	ar->alignment = RGN_ALIGN_BOTTOM;
	
	/* buttons/list view */
	ar = MEM_callocN(sizeof(ARegion), "buttons for sequencer");
	
	BLI_addtail(&sseq->regionbase, ar);
	ar->regiontype = RGN_TYPE_UI;
	ar->alignment = RGN_ALIGN_RIGHT;
	ar->flag = RGN_FLAG_HIDDEN;
	
	/* preview area */
	/* NOTE: if you change values here, also change them in sequencer_init_preview_region */
	ar = MEM_callocN(sizeof(ARegion), "preview area for sequencer");
	BLI_addtail(&sseq->regionbase, ar);
	ar->regiontype = RGN_TYPE_PREVIEW;
	ar->alignment = RGN_ALIGN_TOP;
	ar->flag |= RGN_FLAG_HIDDEN;
	/* for now, aspect ratio should be maintained, and zoom is clamped within sane default limits */
	ar->v2d.keepzoom = V2D_KEEPASPECT | V2D_KEEPZOOM | V2D_LIMITZOOM;
	ar->v2d.minzoom = 0.001f;
	ar->v2d.maxzoom = 1000.0f;
	ar->v2d.tot.xmin = -960.0f; /* 1920 width centered */
	ar->v2d.tot.ymin = -540.0f; /* 1080 height centered */
	ar->v2d.tot.xmax = 960.0f;
	ar->v2d.tot.ymax = 540.0f;
	ar->v2d.min[0] = 0.0f;
	ar->v2d.min[1] = 0.0f;
	ar->v2d.max[0] = 12000.0f;
	ar->v2d.max[1] = 12000.0f;
	ar->v2d.cur = ar->v2d.tot;
	ar->v2d.align = V2D_ALIGN_FREE;
	ar->v2d.keeptot = V2D_KEEPTOT_FREE;


	/* main area */
	ar = MEM_callocN(sizeof(ARegion), "main area for sequencer");
	
	BLI_addtail(&sseq->regionbase, ar);
	ar->regiontype = RGN_TYPE_WINDOW;
	
	
	/* seq space goes from (0,8) to (0, efra) */
	
	ar->v2d.tot.xmin = 0.0f;
	ar->v2d.tot.ymin = 0.0f;
	ar->v2d.tot.xmax = scene->r.efra;
	ar->v2d.tot.ymax = 8.0f;
	
	ar->v2d.cur = ar->v2d.tot;
	
	ar->v2d.min[0] = 10.0f;
	ar->v2d.min[1] = 0.5f;
	
	ar->v2d.max[0] = MAXFRAMEF;
	ar->v2d.max[1] = MAXSEQ;
	
	ar->v2d.minzoom = 0.01f;
	ar->v2d.maxzoom = 100.0f;

	ar->v2d.scroll |= (V2D_SCROLL_BOTTOM | V2D_SCROLL_SCALE_HORIZONTAL);
	ar->v2d.scroll |= (V2D_SCROLL_LEFT | V2D_SCROLL_SCALE_VERTICAL);
	ar->v2d.keepzoom = 0;
	ar->v2d.keeptot = 0;
	ar->v2d.align = V2D_ALIGN_NO_NEG_Y;

	return (SpaceLink *)sseq;
}

/* not spacelink itself */
static void sequencer_free(SpaceLink *sl)
{	
	SpaceSeq *sseq = (SpaceSeq *) sl;
	SequencerScopes *scopes = &sseq->scopes;

// XXX	if (sseq->gpd) BKE_gpencil_free(sseq->gpd);

	if (scopes->zebra_ibuf)
		IMB_freeImBuf(scopes->zebra_ibuf);

	if (scopes->waveform_ibuf)
		IMB_freeImBuf(scopes->waveform_ibuf);

	if (scopes->sep_waveform_ibuf)
		IMB_freeImBuf(scopes->sep_waveform_ibuf);

	if (scopes->vector_ibuf)
		IMB_freeImBuf(scopes->vector_ibuf);

	if (scopes->histogram_ibuf)
		IMB_freeImBuf(scopes->histogram_ibuf);
}


/* spacetype; init callback */
static void sequencer_init(struct wmWindowManager *UNUSED(wm), ScrArea *UNUSED(sa))
{
	
}

static void sequencer_refresh(const bContext *C, ScrArea *sa)
{
	wmWindowManager *wm = CTX_wm_manager(C);
	wmWindow *window = CTX_wm_window(C);
	SpaceSeq *sseq = (SpaceSeq *)sa->spacedata.first;
	ARegion *ar_main = sequencer_find_region(sa, RGN_TYPE_WINDOW);
	ARegion *ar_preview = sequencer_find_region(sa, RGN_TYPE_PREVIEW);
	bool view_changed = false;

	switch (sseq->view) {
		case SEQ_VIEW_SEQUENCE:
			if (ar_main && (ar_main->flag & RGN_FLAG_HIDDEN)) {
				ar_main->flag &= ~RGN_FLAG_HIDDEN;
				ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
				view_changed = true;
			}
			if (ar_preview && !(ar_preview->flag & RGN_FLAG_HIDDEN)) {
				ar_preview->flag |= RGN_FLAG_HIDDEN;
				ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
				WM_event_remove_handlers((bContext *)C, &ar_preview->handlers);
				view_changed = true;
			}
			if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
				ar_main->alignment = RGN_ALIGN_NONE;
				view_changed = true;
			}
			if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
				ar_preview->alignment = RGN_ALIGN_NONE;
				view_changed = true;
			}
			break;
		case SEQ_VIEW_PREVIEW:
			if (ar_main && !(ar_main->flag & RGN_FLAG_HIDDEN)) {
				ar_main->flag |= RGN_FLAG_HIDDEN;
				ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
				WM_event_remove_handlers((bContext *)C, &ar_main->handlers);
				view_changed = true;
			}
			if (ar_preview && (ar_preview->flag & RGN_FLAG_HIDDEN)) {
				ar_preview->flag &= ~RGN_FLAG_HIDDEN;
				ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
				ar_preview->v2d.cur = ar_preview->v2d.tot;
				view_changed = true;
			}
			if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
				ar_main->alignment = RGN_ALIGN_NONE;
				view_changed = true;
			}
			if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
				ar_preview->alignment = RGN_ALIGN_NONE;
				view_changed = true;
			}
			break;
		case SEQ_VIEW_SEQUENCE_PREVIEW:
			if (ar_main && ar_preview) {
				/* Get available height (without DPI correction). */
				const float height = (sa->winy - ED_area_headersize()) / UI_DPI_FAC;

				/* We reuse hidden area's size, allows to find same layout as before if we just switch
				 * between one 'full window' view and the combined one. This gets lost if we switch to both
				 * 'full window' views before, though... Better than nothing. */
				if (ar_main->flag & RGN_FLAG_HIDDEN) {
					ar_main->flag &= ~RGN_FLAG_HIDDEN;
					ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
					ar_preview->sizey = (int)(height - ar_main->sizey);
					view_changed = true;
				}
				if (ar_preview->flag & RGN_FLAG_HIDDEN) {
					ar_preview->flag &= ~RGN_FLAG_HIDDEN;
					ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
					ar_preview->v2d.cur = ar_preview->v2d.tot;
					ar_main->sizey = (int)(height - ar_preview->sizey);
					view_changed = true;
				}
				if (ar_main->alignment != RGN_ALIGN_NONE) {
					ar_main->alignment = RGN_ALIGN_NONE;
					view_changed = true;
				}
				if (ar_preview->alignment != RGN_ALIGN_TOP) {
					ar_preview->alignment = RGN_ALIGN_TOP;
					view_changed = true;
				}
				/* Final check that both preview and main height are reasonable! */
				if (ar_preview->sizey < 10 || ar_main->sizey < 10 || ar_preview->sizey + ar_main->sizey > height) {
					ar_preview->sizey = (int)(height * 0.4f + 0.5f);
					ar_main->sizey = (int)(height - ar_preview->sizey);
					view_changed = true;
				}
			}
			break;
	}

	if (view_changed) {
		ED_area_initialize(wm, window, sa);
		ED_area_tag_redraw(sa);
	}
}

static SpaceLink *sequencer_duplicate(SpaceLink *sl)
{
	SpaceSeq *sseqn = MEM_dupallocN(sl);
	
	/* clear or remove stuff from old */
// XXX	sseq->gpd = gpencil_data_duplicate(sseq->gpd, false);

	memset(&sseqn->scopes, 0, sizeof(sseqn->scopes));

	return (SpaceLink *)sseqn;
}

static void sequencer_listener(bScreen *UNUSED(sc), ScrArea *sa, wmNotifier *wmn)
{
	/* context changes */
	switch (wmn->category) {
		case NC_SCENE:
			switch (wmn->data) {
				case ND_FRAME:
				case ND_SEQUENCER:
					sequencer_scopes_tag_refresh(sa);
					break;
			}
			break;
		case NC_WINDOW:
		case NC_SPACE:
			if (wmn->data == ND_SPACE_SEQUENCER)
				sequencer_scopes_tag_refresh(sa);
			break;
		case NC_GPENCIL:
			if (wmn->data & ND_GPENCIL_EDITMODE)
				ED_area_tag_redraw(sa);
			break;
	}
}

/* ************* dropboxes ************* */

static int image_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
{
	ARegion *ar = CTX_wm_region(C);
	Scene *scene = CTX_data_scene(C);
	int hand;

	if (drag->type == WM_DRAG_PATH)
		if (ELEM(drag->icon, ICON_FILE_IMAGE, ICON_FILE_BLANK)) /* rule might not work? */
			if (find_nearest_seq(scene, &ar->v2d, &hand, event->mval) == NULL)
				return 1;

	return 0;
}

static int movie_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
{
	ARegion *ar = CTX_wm_region(C);
	Scene *scene = CTX_data_scene(C);
	int hand;

	if (drag->type == WM_DRAG_PATH)
		if (ELEM(drag->icon, 0, ICON_FILE_MOVIE, ICON_FILE_BLANK)) /* rule might not work? */
			if (find_nearest_seq(scene, &ar->v2d, &hand, event->mval) == NULL)
				return 1;
	return 0;
}

static int sound_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
{
	ARegion *ar = CTX_wm_region(C);
	Scene *scene = CTX_data_scene(C);
	int hand;

	if (drag->type == WM_DRAG_PATH)
		if (ELEM(drag->icon, ICON_FILE_SOUND, ICON_FILE_BLANK)) /* rule might not work? */
			if (find_nearest_seq(scene, &ar->v2d, &hand, event->mval) == NULL)
				return 1;
	return 0;
}

static void sequencer_drop_copy(wmDrag *drag, wmDropBox *drop)
{
	/* copy drag path to properties */
	if (RNA_struct_find_property(drop->ptr, "filepath"))
		RNA_string_set(drop->ptr, "filepath", drag->path);

	if (RNA_struct_find_property(drop->ptr, "directory")) {
		PointerRNA itemptr;
		char dir[FILE_MAX], file[FILE_MAX];

		BLI_split_dirfile(drag->path, dir, file, sizeof(dir), sizeof(file));
		
		RNA_string_set(drop->ptr, "directory", dir);

		RNA_collection_clear(drop->ptr, "files");
		RNA_collection_add(drop->ptr, "files", &itemptr);
		RNA_string_set(&itemptr, "name", file);
	}
}

/* this region dropbox definition */
static void sequencer_dropboxes(void)
{
	ListBase *lb = WM_dropboxmap_find("Sequencer", SPACE_SEQ, RGN_TYPE_WINDOW);

	WM_dropbox_add(lb, "SEQUENCER_OT_image_strip_add", image_drop_poll, sequencer_drop_copy);
	WM_dropbox_add(lb, "SEQUENCER_OT_movie_strip_add", movie_drop_poll, sequencer_drop_copy);
	WM_dropbox_add(lb, "SEQUENCER_OT_sound_strip_add", sound_drop_poll, sequencer_drop_copy);
}

/* ************* end drop *********** */

const char *sequencer_context_dir[] = {"edit_mask", NULL};

static int sequencer_context(const bContext *C, const char *member, bContextDataResult *result)
{
	Scene *scene = CTX_data_scene(C);

	if (CTX_data_dir(member)) {
		CTX_data_dir_set(result, sequencer_context_dir);

		return true;
	}
	else if (CTX_data_equals(member, "edit_mask")) {
		Mask *mask = BKE_sequencer_mask_get(scene);
		if (mask) {
			CTX_data_id_pointer_set(result, &mask->id);
		}
		return true;
	}

	return false;
}

/* *********************** sequencer (main) region ************************ */
/* add handlers, stuff you only do once or on area/region changes */
static void sequencer_main_area_init(wmWindowManager *wm, ARegion *ar)
{
	wmKeyMap *keymap;
	ListBase *lb;

	UI_view2d_region_reinit(&ar->v2d, V2D_COMMONVIEW_CUSTOM, ar->winx, ar->winy);

#if 0
	keymap = WM_keymap_find(wm->defaultconf, "Mask Editing", 0, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);
#endif

	keymap = WM_keymap_find(wm->defaultconf, "SequencerCommon", SPACE_SEQ, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);

	/* own keymap */
	keymap = WM_keymap_find(wm->defaultconf, "Sequencer", SPACE_SEQ, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);

	/* add drop boxes */
	lb = WM_dropboxmap_find("Sequencer", SPACE_SEQ, RGN_TYPE_WINDOW);

	WM_event_add_dropbox_handler(&ar->handlers, lb);
}

static void sequencer_main_area_draw(const bContext *C, ARegion *ar)
{
	/* NLE - strip editing timeline interface */
	draw_timeline_seq(C, ar);
}

static void sequencer_main_area_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar, wmNotifier *wmn)
{
	/* context changes */
	switch (wmn->category) {
		case NC_SCENE:
			switch (wmn->data) {
				case ND_FRAME:
				case ND_FRAME_RANGE:
				case ND_MARKERS:
				case ND_RENDER_OPTIONS: /* for FPS and FPS Base */
				case ND_SEQUENCER:
				case ND_RENDER_RESULT:
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_ANIMATION:
			switch (wmn->data) {
				case ND_KEYFRAME:
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_SPACE:
			if (wmn->data == ND_SPACE_SEQUENCER)
				ED_region_tag_redraw(ar);
			break;
		case NC_ID:
			if (wmn->action == NA_RENAME)
				ED_region_tag_redraw(ar);
			break;
		case NC_SCREEN:
			if (ELEM(wmn->data, ND_SCREENCAST, ND_ANIMPLAY))
				ED_region_tag_redraw(ar);
			break;
	}
}

/* *********************** header region ************************ */
/* add handlers, stuff you only do once or on area/region changes */
static void sequencer_header_area_init(wmWindowManager *UNUSED(wm), ARegion *ar)
{
	ED_region_header_init(ar);
}

static void sequencer_header_area_draw(const bContext *C, ARegion *ar)
{
	ED_region_header(C, ar);
}

/* *********************** preview region ************************ */
static void sequencer_preview_area_init(wmWindowManager *wm, ARegion *ar)
{
	wmKeyMap *keymap;

	UI_view2d_region_reinit(&ar->v2d, V2D_COMMONVIEW_CUSTOM, ar->winx, ar->winy);

#if 0
	keymap = WM_keymap_find(wm->defaultconf, "Mask Editing", 0, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);
#endif

	keymap = WM_keymap_find(wm->defaultconf, "SequencerCommon", SPACE_SEQ, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);

	/* own keymap */
	keymap = WM_keymap_find(wm->defaultconf, "SequencerPreview", SPACE_SEQ, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);
}

static void sequencer_preview_area_draw(const bContext *C, ARegion *ar)
{
	ScrArea *sa = CTX_wm_area(C);
	SpaceSeq *sseq = sa->spacedata.first;
	Scene *scene = CTX_data_scene(C);
	wmWindowManager *wm = CTX_wm_manager(C);
	int show_split = scene->ed && scene->ed->over_flag & SEQ_EDIT_OVERLAY_SHOW && sseq->mainb == SEQ_DRAW_IMG_IMBUF;

	/* XXX temp fix for wrong setting in sseq->mainb */
	if (sseq->mainb == SEQ_DRAW_SEQUENCE) sseq->mainb = SEQ_DRAW_IMG_IMBUF;

	if (!show_split || sseq->overlay_type != SEQ_DRAW_OVERLAY_REFERENCE)
		draw_image_seq(C, scene, ar, sseq, scene->r.cfra, 0, false, false);

	if (show_split && sseq->overlay_type != SEQ_DRAW_OVERLAY_CURRENT) {
		int over_cfra;

		if (scene->ed->over_flag & SEQ_EDIT_OVERLAY_ABS)
			over_cfra = scene->ed->over_cfra;
		else
			over_cfra = scene->r.cfra + scene->ed->over_ofs;

		if (over_cfra != scene->r.cfra || sseq->overlay_type != SEQ_DRAW_OVERLAY_RECT)
			draw_image_seq(C, scene, ar, sseq, scene->r.cfra, over_cfra - scene->r.cfra, true, false);
	}

	if ((U.uiflag & USER_SHOW_FPS) && ED_screen_animation_playing(wm)) {
		rcti rect;
		ED_region_visible_rect(ar, &rect);
		ED_scene_draw_fps(scene, &rect);
	}
}

static void sequencer_preview_area_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar, wmNotifier *wmn)
{
	/* context changes */
	switch (wmn->category) {
		case NC_GPENCIL:
			if (ELEM(wmn->action, NA_EDITED, NA_SELECTED)) {
				ED_region_tag_redraw(ar);
			}
			break;
		case NC_SCENE:
			switch (wmn->data) {
				case ND_FRAME:
				case ND_MARKERS:
				case ND_SEQUENCER:
				case ND_RENDER_OPTIONS:
				case ND_DRAW_RENDER_VIEWPORT:
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_ANIMATION:
			switch (wmn->data) {
				case ND_KEYFRAME:
					/* Otherwise, often prevents seing immediately effects of keyframe editing... */
					BKE_sequencer_cache_cleanup();
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_SPACE:
			if (wmn->data == ND_SPACE_SEQUENCER)
				ED_region_tag_redraw(ar);
			break;
		case NC_ID:
			switch (wmn->data) {
				case NA_RENAME:
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_MASK:
			if (wmn->action == NA_EDITED) {
				ED_region_tag_redraw(ar);
			}
			break;
	}
}

/* *********************** buttons region ************************ */

/* add handlers, stuff you only do once or on area/region changes */
static void sequencer_buttons_area_init(wmWindowManager *wm, ARegion *ar)
{
	wmKeyMap *keymap;

	keymap = WM_keymap_find(wm->defaultconf, "SequencerCommon", SPACE_SEQ, 0);
	WM_event_add_keymap_handler_bb(&ar->handlers, keymap, &ar->v2d.mask, &ar->winrct);

	ED_region_panels_init(wm, ar);
}

static void sequencer_buttons_area_draw(const bContext *C, ARegion *ar)
{
	ED_region_panels(C, ar, 1, NULL, -1);
}

static void sequencer_buttons_area_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar, wmNotifier *wmn)
{
	/* context changes */
	switch (wmn->category) {
		case NC_GPENCIL:
			if (ELEM(wmn->action, NA_EDITED, NA_SELECTED)) {
				ED_region_tag_redraw(ar);
			}
			break;
		case NC_SCENE:
			switch (wmn->data) {
				case ND_FRAME:
				case ND_SEQUENCER:
					ED_region_tag_redraw(ar);
					break;
			}
			break;
		case NC_SPACE:
			if (wmn->data == ND_SPACE_SEQUENCER)
				ED_region_tag_redraw(ar);
			break;
		case NC_ID:
			if (wmn->action == NA_RENAME)
				ED_region_tag_redraw(ar);
			break;
	}
}
/* ************************************* */

/* only called once, from space/spacetypes.c */
void ED_spacetype_sequencer(void)
{
	SpaceType *st = MEM_callocN(sizeof(SpaceType), "spacetype sequencer");
	ARegionType *art;

	st->spaceid = SPACE_SEQ;
	strncpy(st->name, "Sequencer", BKE_ST_MAXNAME);

	st->new = sequencer_new;
	st->free = sequencer_free;
	st->init = sequencer_init;
	st->duplicate = sequencer_duplicate;
	st->operatortypes = sequencer_operatortypes;
	st->keymap = sequencer_keymap;
	st->context = sequencer_context;
	st->dropboxes = sequencer_dropboxes;
	st->refresh = sequencer_refresh;
	st->listener = sequencer_listener;

	/* regions: main window */
	art = MEM_callocN(sizeof(ARegionType), "spacetype sequencer region");
	art->regionid = RGN_TYPE_WINDOW;
	art->init = sequencer_main_area_init;
	art->draw = sequencer_main_area_draw;
	art->listener = sequencer_main_area_listener;
	art->keymapflag = ED_KEYMAP_VIEW2D | ED_KEYMAP_MARKERS | ED_KEYMAP_FRAMES | ED_KEYMAP_ANIMATION;

	BLI_addhead(&st->regiontypes, art);

	/* preview */
	art = MEM_callocN(sizeof(ARegionType), "spacetype sequencer region");
	art->regionid = RGN_TYPE_PREVIEW;
	art->init = sequencer_preview_area_init;
	art->draw = sequencer_preview_area_draw;
	art->listener = sequencer_preview_area_listener;
	art->keymapflag = ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES | ED_KEYMAP_GPENCIL;
	BLI_addhead(&st->regiontypes, art);

	/* regions: listview/buttons */
	art = MEM_callocN(sizeof(ARegionType), "spacetype sequencer region");
	art->regionid = RGN_TYPE_UI;
	art->prefsizex = 220; // XXX
	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_FRAMES;
	art->listener = sequencer_buttons_area_listener;
	art->init = sequencer_buttons_area_init;
	art->draw = sequencer_buttons_area_draw;
	BLI_addhead(&st->regiontypes, art);

	sequencer_buttons_register(art);

	/* regions: header */
	art = MEM_callocN(sizeof(ARegionType), "spacetype sequencer region");
	art->regionid = RGN_TYPE_HEADER;
	art->prefsizey = HEADERY;
	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES | ED_KEYMAP_HEADER;

	art->init = sequencer_header_area_init;
	art->draw = sequencer_header_area_draw;
	art->listener = sequencer_main_area_listener;

	BLI_addhead(&st->regiontypes, art);

	BKE_spacetype_register(st);

	/* set the sequencer callback when not in background mode */
	if (G.background == 0) {
		sequencer_view3d_cb = ED_view3d_draw_offscreen_imbuf_simple;
	}
}