/*************************************************************************/
/*  tabs.cpp                                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

#include "tabs.h"

#include "core/message_queue.h"
#include "scene/gui/box_container.h"
#include "scene/gui/label.h"
#include "scene/gui/texture_rect.h"

Size2 Tabs::get_minimum_size() const {
	Ref<StyleBox> tab_bg = get_stylebox("tab_bg");
	Ref<StyleBox> tab_fg = get_stylebox("tab_fg");
	Ref<StyleBox> tab_disabled = get_stylebox("tab_disabled");
	Ref<Font> font = get_font("font");

	Size2 ms(0, MAX(MAX(tab_bg->get_minimum_size().height, tab_fg->get_minimum_size().height), tab_disabled->get_minimum_size().height) + font->get_height());

	for (int i = 0; i < tabs.size(); i++) {
		Ref<Texture> tex = tabs[i].icon;
		if (tex.is_valid()) {
			ms.height = MAX(ms.height, tex->get_size().height);
			if (tabs[i].text != "") {
				ms.width += get_constant("hseparation");
			}
		}

		ms.width += Math::ceil(font->get_string_size(tabs[i].xl_text).width);

		if (tabs[i].disabled) {
			ms.width += tab_disabled->get_minimum_size().width;
		} else if (current == i) {
			ms.width += tab_fg->get_minimum_size().width;
		} else {
			ms.width += tab_bg->get_minimum_size().width;
		}

		if (tabs[i].right_button.is_valid()) {
			Ref<Texture> rb = tabs[i].right_button;
			Size2 bms = rb->get_size();
			bms.width += get_constant("hseparation");
			ms.width += bms.width;
			ms.height = MAX(bms.height + tab_bg->get_minimum_size().height, ms.height);
		}

		if (cb_displaypolicy == CLOSE_BUTTON_SHOW_ALWAYS || (cb_displaypolicy == CLOSE_BUTTON_SHOW_ACTIVE_ONLY && i == current)) {
			Ref<Texture> cb = get_icon("close");
			Size2 bms = cb->get_size();
			bms.width += get_constant("hseparation");
			ms.width += bms.width;
			ms.height = MAX(bms.height + tab_bg->get_minimum_size().height, ms.height);
		}
	}

	ms.width = 0; // TODO: should make this optional.
	return ms;
}

void Tabs::_gui_input(const Ref<InputEvent> &p_event) {
	Ref<InputEventMouseMotion> mm = p_event;

	if (mm.is_valid()) {
		Point2 pos = mm->get_position();

		if (buttons_visible) {
			Ref<Texture> incr = get_icon("increment");
			Ref<Texture> decr = get_icon("decrement");

			int limit = get_size().width - incr->get_width() - decr->get_width();

			if (pos.x > limit + decr->get_width()) {
				if (highlight_arrow != 1) {
					highlight_arrow = 1;
					update();
				}
			} else if (pos.x > limit) {
				if (highlight_arrow != 0) {
					highlight_arrow = 0;
					update();
				}
			} else if (highlight_arrow != -1) {
				highlight_arrow = -1;
				update();
			}
		}

		_update_hover();
		return;
	}

	Ref<InputEventMouseButton> mb = p_event;

	if (mb.is_valid()) {
		if (mb->is_pressed() && mb->get_button_index() == BUTTON_WHEEL_UP && !mb->get_command()) {
			if (scrolling_enabled && buttons_visible) {
				if (offset > 0) {
					offset--;
					update();
				}
			}
		}

		if (mb->is_pressed() && mb->get_button_index() == BUTTON_WHEEL_DOWN && !mb->get_command()) {
			if (scrolling_enabled && buttons_visible) {
				if (missing_right) {
					offset++;
					_ensure_no_over_offset(); // Avoid overreaching when scrolling fast.
					update();
				}
			}
		}

		if (rb_pressing && !mb->is_pressed() && mb->get_button_index() == BUTTON_LEFT) {
			if (rb_hover != -1) {
				// Right tab button pressed.
				emit_signal("right_button_pressed", rb_hover);
			}

			rb_pressing = false;
			update();
		}

		if (cb_pressing && !mb->is_pressed() && mb->get_button_index() == BUTTON_LEFT) {
			if (cb_hover != -1) {
				// Close button pressed.
				emit_signal("tab_close", cb_hover);
			}

			cb_pressing = false;
			update();
		}

		if (mb->is_pressed() && (mb->get_button_index() == BUTTON_LEFT || (select_with_rmb && mb->get_button_index() == BUTTON_RIGHT))) {
			// Clicks.
			Point2 pos(mb->get_position().x, mb->get_position().y);

			if (buttons_visible) {
				Ref<Texture> incr = get_icon("increment");
				Ref<Texture> decr = get_icon("decrement");

				int limit = get_size().width - incr->get_width() - decr->get_width();

				if (pos.x > limit + decr->get_width()) {
					if (missing_right) {
						offset++;
						update();
					}
					return;
				} else if (pos.x > limit) {
					if (offset > 0) {
						offset--;
						update();
					}
					return;
				}
			}

			if (tabs.empty()) {
				// Return early if there are no actual tabs to handle input for.
				return;
			}

			int found = -1;
			for (int i = offset; i <= max_drawn_tab; i++) {
				if (tabs[i].rb_rect.has_point(pos)) {
					rb_pressing = true;
					update();
					return;
				}

				if (tabs[i].cb_rect.has_point(pos) && (cb_displaypolicy == CLOSE_BUTTON_SHOW_ALWAYS || (cb_displaypolicy == CLOSE_BUTTON_SHOW_ACTIVE_ONLY && i == current))) {
					cb_pressing = true;
					update();
					return;
				}

				if (pos.x >= tabs[i].ofs_cache && pos.x < tabs[i].ofs_cache + tabs[i].size_cache) {
					if (!tabs[i].disabled) {
						found = i;
					}
					break;
				}
			}

			if (found != -1) {
				set_current_tab(found);
				emit_signal("tab_clicked", found);
			}
		}
	}
}

void Tabs::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_TRANSLATION_CHANGED: {
			for (int i = 0; i < tabs.size(); ++i) {
				tabs.write[i].xl_text = tr(tabs[i].text);
			}
			minimum_size_changed();
			update();
		} break;
		case NOTIFICATION_RESIZED: {
			_update_cache();
			_ensure_no_over_offset();
			ensure_tab_visible(current);
		} break;
		case NOTIFICATION_DRAW: {
			_update_cache();
			RID ci = get_canvas_item();

			Ref<StyleBox> tab_bg = get_stylebox("tab_bg");
			Ref<StyleBox> tab_fg = get_stylebox("tab_fg");
			Ref<StyleBox> tab_disabled = get_stylebox("tab_disabled");
			Ref<Font> font = get_font("font");
			Color color_fg = get_color("font_color_fg");
			Color color_bg = get_color("font_color_bg");
			Color color_disabled = get_color("font_color_disabled");
			Ref<Texture> close = get_icon("close");

			int h = get_size().height;
			int w = 0;
			int mw = 0;

			for (int i = 0; i < tabs.size(); i++) {
				tabs.write[i].ofs_cache = mw;
				mw += get_tab_width(i);
			}

			if (tab_align == ALIGN_CENTER) {
				w = (get_size().width - mw) / 2;
			} else if (tab_align == ALIGN_RIGHT) {
				w = get_size().width - mw;
			}

			if (w < 0) {
				w = 0;
			}

			Ref<Texture> incr = get_icon("increment");
			Ref<Texture> decr = get_icon("decrement");
			Ref<Texture> incr_hl = get_icon("increment_highlight");
			Ref<Texture> decr_hl = get_icon("decrement_highlight");

			int limit = get_size().width - incr->get_size().width - decr->get_size().width;

			missing_right = false;

			for (int i = 0; i < tabs.size(); i++) {
				if (i < offset) {
					continue;
				}

				tabs.write[i].ofs_cache = w;

				int lsize = tabs[i].size_cache;

				Ref<StyleBox> sb;
				Color col;

				if (tabs[i].disabled) {
					sb = tab_disabled;
					col = color_disabled;
				} else if (i == current) {
					sb = tab_fg;
					col = color_fg;
				} else {
					sb = tab_bg;
					col = color_bg;
				}

				if (w + lsize > limit) {
					max_drawn_tab = i - 1;
					missing_right = true;
					break;
				} else {
					max_drawn_tab = i;
				}

				Rect2 sb_rect = Rect2(w, 0, tabs[i].size_cache, h);
				sb->draw(ci, sb_rect);

				w += sb->get_margin(MARGIN_LEFT);

				Size2i sb_ms = sb->get_minimum_size();
				Ref<Texture> icon = tabs[i].icon;
				if (icon.is_valid()) {
					icon->draw(ci, Point2i(w, sb->get_margin(MARGIN_TOP) + ((sb_rect.size.y - sb_ms.y) - icon->get_height()) / 2));
					if (tabs[i].text != "") {
						w += icon->get_width() + get_constant("hseparation");
					}
				}

				font->draw(ci, Point2i(w, sb->get_margin(MARGIN_TOP) + ((sb_rect.size.y - sb_ms.y) - font->get_height()) / 2 + font->get_ascent()), tabs[i].xl_text, col, tabs[i].size_text);

				w += tabs[i].size_text;

				if (tabs[i].right_button.is_valid()) {
					Ref<StyleBox> style = get_stylebox("button");
					Ref<Texture> rb = tabs[i].right_button;

					w += get_constant("hseparation");

					Rect2 rb_rect;
					rb_rect.size = style->get_minimum_size() + rb->get_size();
					rb_rect.position.x = w;
					rb_rect.position.y = sb->get_margin(MARGIN_TOP) + ((sb_rect.size.y - sb_ms.y) - (rb_rect.size.y)) / 2;

					if (rb_hover == i) {
						if (rb_pressing) {
							get_stylebox("button_pressed")->draw(ci, rb_rect);
						} else {
							style->draw(ci, rb_rect);
						}
					}

					rb->draw(ci, Point2i(w + style->get_margin(MARGIN_LEFT), rb_rect.position.y + style->get_margin(MARGIN_TOP)));
					w += rb->get_width();
					tabs.write[i].rb_rect = rb_rect;
				}

				if (cb_displaypolicy == CLOSE_BUTTON_SHOW_ALWAYS || (cb_displaypolicy == CLOSE_BUTTON_SHOW_ACTIVE_ONLY && i == current)) {
					Ref<StyleBox> style = get_stylebox("button");
					Ref<Texture> cb = close;

					w += get_constant("hseparation");

					Rect2 cb_rect;
					cb_rect.size = style->get_minimum_size() + cb->get_size();
					cb_rect.position.x = w;
					cb_rect.position.y = sb->get_margin(MARGIN_TOP) + ((sb_rect.size.y - sb_ms.y) - (cb_rect.size.y)) / 2;

					if (!tabs[i].disabled && cb_hover == i) {
						if (cb_pressing) {
							get_stylebox("button_pressed")->draw(ci, cb_rect);
						} else {
							style->draw(ci, cb_rect);
						}
					}

					cb->draw(ci, Point2i(w + style->get_margin(MARGIN_LEFT), cb_rect.position.y + style->get_margin(MARGIN_TOP)));
					w += cb->get_width();
					tabs.write[i].cb_rect = cb_rect;
				}

				w += sb->get_margin(MARGIN_RIGHT);
			}

			if (offset > 0 || missing_right) {
				int vofs = (get_size().height - incr->get_size().height) / 2;

				if (offset > 0) {
					draw_texture(highlight_arrow == 0 ? decr_hl : decr, Point2(limit, vofs));
				} else {
					draw_texture(decr, Point2(limit, vofs), Color(1, 1, 1, 0.5));
				}

				if (missing_right) {
					draw_texture(highlight_arrow == 1 ? incr_hl : incr, Point2(limit + decr->get_size().width, vofs));
				} else {
					draw_texture(incr, Point2(limit + decr->get_size().width, vofs), Color(1, 1, 1, 0.5));
				}

				buttons_visible = true;
			} else {
				buttons_visible = false;
			}
		} break;
	}
}

int Tabs::get_tab_count() const {
	return tabs.size();
}

void Tabs::set_current_tab(int p_current) {
	if (current == p_current) {
		return;
	}
	ERR_FAIL_INDEX(p_current, get_tab_count());

	previous = current;
	current = p_current;

	_change_notify("current_tab");
	_update_cache();
	update();

	emit_signal("tab_changed", p_current);
}

int Tabs::get_current_tab() const {
	return current;
}

int Tabs::get_previous_tab() const {
	return previous;
}

int Tabs::get_hovered_tab() const {
	return hover;
}

int Tabs::get_tab_offset() const {
	return offset;
}

bool Tabs::get_offset_buttons_visible() const {
	return buttons_visible;
}

void Tabs::set_tab_title(int p_tab, const String &p_title) {
	ERR_FAIL_INDEX(p_tab, tabs.size());
	tabs.write[p_tab].text = p_title;
	tabs.write[p_tab].xl_text = tr(p_title);
	update();
	minimum_size_changed();
}

String Tabs::get_tab_title(int p_tab) const {
	ERR_FAIL_INDEX_V(p_tab, tabs.size(), "");
	return tabs[p_tab].text;
}

void Tabs::set_tab_icon(int p_tab, const Ref<Texture> &p_icon) {
	ERR_FAIL_INDEX(p_tab, tabs.size());
	tabs.write[p_tab].icon = p_icon;
	update();
	minimum_size_changed();
}

Ref<Texture> Tabs::get_tab_icon(int p_tab) const {
	ERR_FAIL_INDEX_V(p_tab, tabs.size(), Ref<Texture>());
	return tabs[p_tab].icon;
}

void Tabs::set_tab_disabled(int p_tab, bool p_disabled) {
	ERR_FAIL_INDEX(p_tab, tabs.size());
	tabs.write[p_tab].disabled = p_disabled;
	update();
}
bool Tabs::get_tab_disabled(int p_tab) const {
	ERR_FAIL_INDEX_V(p_tab, tabs.size(), false);
	return tabs[p_tab].disabled;
}

void Tabs::set_tab_right_button(int p_tab, const Ref<Texture> &p_right_button) {
	ERR_FAIL_INDEX(p_tab, tabs.size());
	tabs.write[p_tab].right_button = p_right_button;
	_update_cache();
	update();
	minimum_size_changed();
}
Ref<Texture> Tabs::get_tab_right_button(int p_tab) const {
	ERR_FAIL_INDEX_V(p_tab, tabs.size(), Ref<Texture>());
	return tabs[p_tab].right_button;
}

void Tabs::_update_hover() {
	if (!is_inside_tree()) {
		return;
	}

	const Point2 &pos = get_local_mouse_position();
	// Test hovering to display right or close button.
	int hover_now = -1;
	int hover_buttons = -1;
	for (int i = 0; i < tabs.size(); i++) {
		if (i < offset) {
			continue;
		}

		Rect2 rect = get_tab_rect(i);
		if (rect.has_point(pos)) {
			hover_now = i;
		}
		if (tabs[i].rb_rect.has_point(pos)) {
			rb_hover = i;
			cb_hover = -1;
			hover_buttons = i;
			break;
		} else if (!tabs[i].disabled && tabs[i].cb_rect.has_point(pos)) {
			cb_hover = i;
			rb_hover = -1;
			hover_buttons = i;
			break;
		}
	}
	if (hover != hover_now) {
		hover = hover_now;
		emit_signal("tab_hover", hover);
	}

	if (hover_buttons == -1) { // No hover.
		rb_hover = hover_buttons;
		cb_hover = hover_buttons;
	}
}

void Tabs::_update_cache() {
	Ref<StyleBox> tab_disabled = get_stylebox("tab_disabled");
	Ref<StyleBox> tab_bg = get_stylebox("tab_bg");
	Ref<StyleBox> tab_fg = get_stylebox("tab_fg");
	Ref<Font> font = get_font("font");
	Ref<Texture> incr = get_icon("increment");
	Ref<Texture> decr = get_icon("decrement");
	int limit = get_size().width - incr->get_width() - decr->get_width();

	int w = 0;
	int mw = 0;
	int size_fixed = 0;
	int count_resize = 0;
	for (int i = 0; i < tabs.size(); i++) {
		tabs.write[i].ofs_cache = mw;
		tabs.write[i].size_cache = get_tab_width(i);
		tabs.write[i].size_text = Math::ceil(font->get_string_size(tabs[i].xl_text).width);
		mw += tabs[i].size_cache;
		if (tabs[i].size_cache <= min_width || i == current) {
			size_fixed += tabs[i].size_cache;
		} else {
			count_resize++;
		}
	}
	int m_width = min_width;
	if (count_resize > 0) {
		m_width = MAX((limit - size_fixed) / count_resize, min_width);
	}
	for (int i = 0; i < tabs.size(); i++) {
		if (i < offset) {
			continue;
		}
		Ref<StyleBox> sb;
		if (tabs[i].disabled) {
			sb = tab_disabled;
		} else if (i == current) {
			sb = tab_fg;
		} else {
			sb = tab_bg;
		}
		int lsize = tabs[i].size_cache;
		int slen = tabs[i].size_text;
		if (min_width > 0 && mw > limit && i != current) {
			if (lsize > m_width) {
				slen = m_width - (sb->get_margin(MARGIN_LEFT) + sb->get_margin(MARGIN_RIGHT));
				if (tabs[i].icon.is_valid()) {
					slen -= tabs[i].icon->get_width();
					slen -= get_constant("hseparation");
				}
				if (cb_displaypolicy == CLOSE_BUTTON_SHOW_ALWAYS || (cb_displaypolicy == CLOSE_BUTTON_SHOW_ACTIVE_ONLY && i == current)) {
					Ref<Texture> cb = get_icon("close");
					slen -= cb->get_width();
					slen -= get_constant("hseparation");
				}
				slen = MAX(slen, 1);
				lsize = m_width;
			}
		}
		tabs.write[i].ofs_cache = w;
		tabs.write[i].size_cache = lsize;
		tabs.write[i].size_text = slen;
		w += lsize;
	}
}

void Tabs::_on_mouse_exited() {
	rb_hover = -1;
	cb_hover = -1;
	hover = -1;
	highlight_arrow = -1;
	update();
}

void Tabs::add_tab(const String &p_str, const Ref<Texture> &p_icon) {
	Tab t;
	t.text = p_str;
	t.xl_text = tr(p_str);
	t.icon = p_icon;
	t.disabled = false;
	t.ofs_cache = 0;
	t.size_cache = 0;

	tabs.push_back(t);
	_update_cache();
	call_deferred("_update_hover");
	update();
	minimum_size_changed();
}

void Tabs::clear_tabs() {
	tabs.clear();
	current = 0;
	previous = 0;
	call_deferred("_update_hover");
	update();
}

void Tabs::remove_tab(int p_idx) {
	ERR_FAIL_INDEX(p_idx, tabs.size());
	tabs.remove(p_idx);
	if (current >= p_idx) {
		current--;
	}
	_update_cache();
	call_deferred("_update_hover");
	update();
	minimum_size_changed();

	if (current < 0) {
		current = 0;
		previous = 0;
	}
	if (current >= tabs.size()) {
		current = tabs.size() - 1;
	}

	_ensure_no_over_offset();
}

Variant Tabs::get_drag_data(const Point2 &p_point) {
	if (!drag_to_rearrange_enabled) {
		return Variant();
	}

	int tab_over = get_tab_idx_at_point(p_point);

	if (tab_over < 0) {
		return Variant();
	}

	HBoxContainer *drag_preview = memnew(HBoxContainer);

	if (!tabs[tab_over].icon.is_null()) {
		TextureRect *tf = memnew(TextureRect);
		tf->set_texture(tabs[tab_over].icon);
		drag_preview->add_child(tf);
	}
	Label *label = memnew(Label(tabs[tab_over].xl_text));
	drag_preview->add_child(label);
	if (!tabs[tab_over].right_button.is_null()) {
		TextureRect *tf = memnew(TextureRect);
		tf->set_texture(tabs[tab_over].right_button);
		drag_preview->add_child(tf);
	}
	set_drag_preview(drag_preview);

	Dictionary drag_data;
	drag_data["type"] = "tab_element";
	drag_data["tab_element"] = tab_over;
	drag_data["from_path"] = get_path();
	return drag_data;
}

bool Tabs::can_drop_data(const Point2 &p_point, const Variant &p_data) const {
	if (!drag_to_rearrange_enabled) {
		return false;
	}

	Dictionary d = p_data;
	if (!d.has("type")) {
		return false;
	}

	if (String(d["type"]) == "tab_element") {
		NodePath from_path = d["from_path"];
		NodePath to_path = get_path();
		if (from_path == to_path) {
			return true;
		} else if (get_tabs_rearrange_group() != -1) {
			// Drag and drop between other Tabs.
			Node *from_node = get_node(from_path);
			Tabs *from_tabs = Object::cast_to<Tabs>(from_node);
			if (from_tabs && from_tabs->get_tabs_rearrange_group() == get_tabs_rearrange_group()) {
				return true;
			}
		}
	}
	return false;
}

void Tabs::drop_data(const Point2 &p_point, const Variant &p_data) {
	if (!drag_to_rearrange_enabled) {
		return;
	}

	int hover_now = get_tab_idx_at_point(p_point);

	Dictionary d = p_data;
	if (!d.has("type")) {
		return;
	}

	if (String(d["type"]) == "tab_element") {
		int tab_from_id = d["tab_element"];
		NodePath from_path = d["from_path"];
		NodePath to_path = get_path();
		if (from_path == to_path) {
			if (hover_now < 0) {
				hover_now = get_tab_count() - 1;
			}
			move_tab(tab_from_id, hover_now);
			emit_signal("reposition_active_tab_request", hover_now);
			set_current_tab(hover_now);
		} else if (get_tabs_rearrange_group() != -1) {
			// Drag and drop between Tabs.
			Node *from_node = get_node(from_path);
			Tabs *from_tabs = Object::cast_to<Tabs>(from_node);
			if (from_tabs && from_tabs->get_tabs_rearrange_group() == get_tabs_rearrange_group()) {
				if (tab_from_id >= from_tabs->get_tab_count()) {
					return;
				}
				Tab moving_tab = from_tabs->tabs[tab_from_id];
				if (hover_now < 0) {
					hover_now = get_tab_count();
				}
				tabs.insert(hover_now, moving_tab);
				from_tabs->remove_tab(tab_from_id);
				set_current_tab(hover_now);
				emit_signal("tab_changed", hover_now);
				_update_cache();
			}
		}
	}
	update();
}

int Tabs::get_tab_idx_at_point(const Point2 &p_point) const {
	int hover_now = -1;
	for (int i = offset; i <= max_drawn_tab; i++) {
		Rect2 rect = get_tab_rect(i);
		if (rect.has_point(p_point)) {
			hover_now = i;
		}
	}

	return hover_now;
}

void Tabs::set_tab_align(TabAlign p_align) {
	ERR_FAIL_INDEX(p_align, ALIGN_MAX);
	tab_align = p_align;
	update();
}

Tabs::TabAlign Tabs::get_tab_align() const {
	return tab_align;
}

void Tabs::move_tab(int from, int to) {
	if (from == to) {
		return;
	}

	ERR_FAIL_INDEX(from, tabs.size());
	ERR_FAIL_INDEX(to, tabs.size());

	Tab tab_from = tabs[from];
	tabs.remove(from);
	tabs.insert(to, tab_from);

	_update_cache();
	update();
}

int Tabs::get_tab_width(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, tabs.size(), 0);

	Ref<StyleBox> tab_bg = get_stylebox("tab_bg");
	Ref<StyleBox> tab_fg = get_stylebox("tab_fg");
	Ref<StyleBox> tab_disabled = get_stylebox("tab_disabled");
	Ref<Font> font = get_font("font");

	int x = 0;

	Ref<Texture> tex = tabs[p_idx].icon;
	if (tex.is_valid()) {
		x += tex->get_width();
		if (tabs[p_idx].text != "") {
			x += get_constant("hseparation");
		}
	}

	x += Math::ceil(font->get_string_size(tabs[p_idx].xl_text).width);

	if (tabs[p_idx].disabled) {
		x += tab_disabled->get_minimum_size().width;
	} else if (current == p_idx) {
		x += tab_fg->get_minimum_size().width;
	} else {
		x += tab_bg->get_minimum_size().width;
	}

	if (tabs[p_idx].right_button.is_valid()) {
		Ref<Texture> rb = tabs[p_idx].right_button;
		x += rb->get_width();
		x += get_constant("hseparation");
	}

	if (cb_displaypolicy == CLOSE_BUTTON_SHOW_ALWAYS || (cb_displaypolicy == CLOSE_BUTTON_SHOW_ACTIVE_ONLY && p_idx == current)) {
		Ref<Texture> cb = get_icon("close");
		x += cb->get_width();
		x += get_constant("hseparation");
	}

	return x;
}

void Tabs::_ensure_no_over_offset() {
	if (!is_inside_tree()) {
		return;
	}

	Ref<Texture> incr = get_icon("increment");
	Ref<Texture> decr = get_icon("decrement");

	int limit = get_size().width - incr->get_width() - decr->get_width();

	while (offset > 0) {
		int total_w = 0;
		for (int i = 0; i < tabs.size(); i++) {
			if (i < offset - 1) {
				continue;
			}

			total_w += tabs[i].size_cache;
		}

		if (total_w < limit) {
			offset--;
			update();
		} else {
			break;
		}
	}
}

void Tabs::ensure_tab_visible(int p_idx) {
	if (!is_inside_tree()) {
		return;
	}

	if (tabs.size() == 0) {
		return;
	}
	ERR_FAIL_INDEX(p_idx, tabs.size());

	if (p_idx == offset) {
		return;
	}
	if (p_idx < offset) {
		offset = p_idx;
		update();
		return;
	}

	int prev_offset = offset;
	Ref<Texture> incr = get_icon("increment");
	Ref<Texture> decr = get_icon("decrement");
	int limit = get_size().width - incr->get_width() - decr->get_width();
	for (int i = offset; i <= p_idx; i++) {
		if (tabs[i].ofs_cache + tabs[i].size_cache > limit) {
			offset++;
		}
	}

	if (prev_offset != offset) {
		update();
	}
}

Rect2 Tabs::get_tab_rect(int p_tab) const {
	ERR_FAIL_INDEX_V(p_tab, tabs.size(), Rect2());
	return Rect2(tabs[p_tab].ofs_cache, 0, tabs[p_tab].size_cache, get_size().height);
}

void Tabs::set_tab_close_display_policy(CloseButtonDisplayPolicy p_policy) {
	ERR_FAIL_INDEX(p_policy, CLOSE_BUTTON_MAX);
	cb_displaypolicy = p_policy;
	update();
}

Tabs::CloseButtonDisplayPolicy Tabs::get_tab_close_display_policy() const {
	return cb_displaypolicy;
}

void Tabs::set_min_width(int p_width) {
	min_width = p_width;
}

void Tabs::set_scrolling_enabled(bool p_enabled) {
	scrolling_enabled = p_enabled;
}

bool Tabs::get_scrolling_enabled() const {
	return scrolling_enabled;
}

void Tabs::set_drag_to_rearrange_enabled(bool p_enabled) {
	drag_to_rearrange_enabled = p_enabled;
}

bool Tabs::get_drag_to_rearrange_enabled() const {
	return drag_to_rearrange_enabled;
}
void Tabs::set_tabs_rearrange_group(int p_group_id) {
	tabs_rearrange_group = p_group_id;
}

int Tabs::get_tabs_rearrange_group() const {
	return tabs_rearrange_group;
}

void Tabs::set_select_with_rmb(bool p_enabled) {
	select_with_rmb = p_enabled;
}

bool Tabs::get_select_with_rmb() const {
	return select_with_rmb;
}

void Tabs::_bind_methods() {
	ClassDB::bind_method(D_METHOD("_gui_input"), &Tabs::_gui_input);
	ClassDB::bind_method(D_METHOD("_update_hover"), &Tabs::_update_hover);
	ClassDB::bind_method(D_METHOD("_on_mouse_exited"), &Tabs::_on_mouse_exited);
	ClassDB::bind_method(D_METHOD("get_tab_count"), &Tabs::get_tab_count);
	ClassDB::bind_method(D_METHOD("set_current_tab", "tab_idx"), &Tabs::set_current_tab);
	ClassDB::bind_method(D_METHOD("get_current_tab"), &Tabs::get_current_tab);
	ClassDB::bind_method(D_METHOD("get_previous_tab"), &Tabs::get_previous_tab);
	ClassDB::bind_method(D_METHOD("set_tab_title", "tab_idx", "title"), &Tabs::set_tab_title);
	ClassDB::bind_method(D_METHOD("get_tab_title", "tab_idx"), &Tabs::get_tab_title);
	ClassDB::bind_method(D_METHOD("set_tab_icon", "tab_idx", "icon"), &Tabs::set_tab_icon);
	ClassDB::bind_method(D_METHOD("get_tab_icon", "tab_idx"), &Tabs::get_tab_icon);
	ClassDB::bind_method(D_METHOD("set_tab_button_icon", "tab_idx", "icon"), &Tabs::set_tab_right_button);
	ClassDB::bind_method(D_METHOD("get_tab_button_icon", "tab_idx"), &Tabs::get_tab_right_button);
	ClassDB::bind_method(D_METHOD("set_tab_disabled", "tab_idx", "disabled"), &Tabs::set_tab_disabled);
	ClassDB::bind_method(D_METHOD("get_tab_disabled", "tab_idx"), &Tabs::get_tab_disabled);
	ClassDB::bind_method(D_METHOD("remove_tab", "tab_idx"), &Tabs::remove_tab);
	ClassDB::bind_method(D_METHOD("add_tab", "title", "icon"), &Tabs::add_tab, DEFVAL(""), DEFVAL(Ref<Texture>()));
	ClassDB::bind_method(D_METHOD("set_tab_align", "align"), &Tabs::set_tab_align);
	ClassDB::bind_method(D_METHOD("get_tab_align"), &Tabs::get_tab_align);
	ClassDB::bind_method(D_METHOD("get_tab_offset"), &Tabs::get_tab_offset);
	ClassDB::bind_method(D_METHOD("get_offset_buttons_visible"), &Tabs::get_offset_buttons_visible);
	ClassDB::bind_method(D_METHOD("ensure_tab_visible", "idx"), &Tabs::ensure_tab_visible);
	ClassDB::bind_method(D_METHOD("get_tab_rect", "tab_idx"), &Tabs::get_tab_rect);
	ClassDB::bind_method(D_METHOD("move_tab", "from", "to"), &Tabs::move_tab);
	ClassDB::bind_method(D_METHOD("set_tab_close_display_policy", "policy"), &Tabs::set_tab_close_display_policy);
	ClassDB::bind_method(D_METHOD("get_tab_close_display_policy"), &Tabs::get_tab_close_display_policy);
	ClassDB::bind_method(D_METHOD("set_scrolling_enabled", "enabled"), &Tabs::set_scrolling_enabled);
	ClassDB::bind_method(D_METHOD("get_scrolling_enabled"), &Tabs::get_scrolling_enabled);
	ClassDB::bind_method(D_METHOD("set_drag_to_rearrange_enabled", "enabled"), &Tabs::set_drag_to_rearrange_enabled);
	ClassDB::bind_method(D_METHOD("get_drag_to_rearrange_enabled"), &Tabs::get_drag_to_rearrange_enabled);
	ClassDB::bind_method(D_METHOD("set_tabs_rearrange_group", "group_id"), &Tabs::set_tabs_rearrange_group);
	ClassDB::bind_method(D_METHOD("get_tabs_rearrange_group"), &Tabs::get_tabs_rearrange_group);

	ClassDB::bind_method(D_METHOD("set_select_with_rmb", "enabled"), &Tabs::set_select_with_rmb);
	ClassDB::bind_method(D_METHOD("get_select_with_rmb"), &Tabs::get_select_with_rmb);

	ADD_SIGNAL(MethodInfo("tab_changed", PropertyInfo(Variant::INT, "tab")));
	ADD_SIGNAL(MethodInfo("right_button_pressed", PropertyInfo(Variant::INT, "tab")));
	ADD_SIGNAL(MethodInfo("tab_close", PropertyInfo(Variant::INT, "tab")));
	ADD_SIGNAL(MethodInfo("tab_hover", PropertyInfo(Variant::INT, "tab")));
	ADD_SIGNAL(MethodInfo("reposition_active_tab_request", PropertyInfo(Variant::INT, "idx_to")));
	ADD_SIGNAL(MethodInfo("tab_clicked", PropertyInfo(Variant::INT, "tab")));

	ADD_PROPERTY(PropertyInfo(Variant::INT, "current_tab", PROPERTY_HINT_RANGE, "-1,4096,1", PROPERTY_USAGE_EDITOR), "set_current_tab", "get_current_tab");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "tab_align", PROPERTY_HINT_ENUM, "Left,Center,Right"), "set_tab_align", "get_tab_align");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "tab_close_display_policy", PROPERTY_HINT_ENUM, "Show Never,Show Active Only,Show Always"), "set_tab_close_display_policy", "get_tab_close_display_policy");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "scrolling_enabled"), "set_scrolling_enabled", "get_scrolling_enabled");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "drag_to_rearrange_enabled"), "set_drag_to_rearrange_enabled", "get_drag_to_rearrange_enabled");

	BIND_ENUM_CONSTANT(ALIGN_LEFT);
	BIND_ENUM_CONSTANT(ALIGN_CENTER);
	BIND_ENUM_CONSTANT(ALIGN_RIGHT);
	BIND_ENUM_CONSTANT(ALIGN_MAX);

	BIND_ENUM_CONSTANT(CLOSE_BUTTON_SHOW_NEVER);
	BIND_ENUM_CONSTANT(CLOSE_BUTTON_SHOW_ACTIVE_ONLY);
	BIND_ENUM_CONSTANT(CLOSE_BUTTON_SHOW_ALWAYS);
	BIND_ENUM_CONSTANT(CLOSE_BUTTON_MAX);
}

Tabs::Tabs() {
	current = 0;
	previous = 0;
	tab_align = ALIGN_CENTER;
	rb_hover = -1;
	rb_pressing = false;
	highlight_arrow = -1;

	cb_hover = -1;
	cb_pressing = false;
	cb_displaypolicy = CLOSE_BUTTON_SHOW_NEVER;
	offset = 0;
	max_drawn_tab = 0;

	select_with_rmb = false;

	min_width = 0;
	scrolling_enabled = true;
	buttons_visible = false;
	hover = -1;
	drag_to_rearrange_enabled = false;
	tabs_rearrange_group = -1;

	connect("mouse_exited", this, "_on_mouse_exited");
}