/*************************************************************************/
/*  grid_container.cpp                                                   */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "grid_container.h"

void GridContainer::_notification(int p_what) {

	switch (p_what) {

		case NOTIFICATION_SORT_CHILDREN: {

			Map<int, int> col_minw; // Max of min_width  of all controls in each col (indexed by col).
			Map<int, int> row_minh; // Max of min_height of all controls in each row (indexed by row).
			Set<int> col_expanded; // Columns which have the SIZE_EXPAND flag set.
			Set<int> row_expanded; // Rows which have the SIZE_EXPAND flag set.

			int hsep = get_constant("hseparation");
			int vsep = get_constant("vseparation");
			int max_col = MIN(get_child_count(), columns);
			int max_row = ceil((float)get_child_count() / (float)columns);

			// Compute the per-column/per-row data.
			int valid_controls_index = 0;
			for (int i = 0; i < get_child_count(); i++) {
				Control *c = Object::cast_to<Control>(get_child(i));
				if (!c || !c->is_visible_in_tree())
					continue;

				int row = valid_controls_index / columns;
				int col = valid_controls_index % columns;
				valid_controls_index++;

				Size2i ms = c->get_combined_minimum_size();
				if (col_minw.has(col))
					col_minw[col] = MAX(col_minw[col], ms.width);
				else
					col_minw[col] = ms.width;
				if (row_minh.has(row))
					row_minh[row] = MAX(row_minh[row], ms.height);
				else
					row_minh[row] = ms.height;

				if (c->get_h_size_flags() & SIZE_EXPAND) {
					col_expanded.insert(col);
				}
				if (c->get_v_size_flags() & SIZE_EXPAND) {
					row_expanded.insert(row);
				}
			}

			// Consider all empty columns expanded.
			for (int i = valid_controls_index; i < columns; i++) {
				col_expanded.insert(i);
			}

			// Evaluate the remaining space for expanded columns/rows.
			Size2 remaining_space = get_size();
			for (Map<int, int>::Element *E = col_minw.front(); E; E = E->next()) {
				if (!col_expanded.has(E->key()))
					remaining_space.width -= E->get();
			}

			for (Map<int, int>::Element *E = row_minh.front(); E; E = E->next()) {
				if (!row_expanded.has(E->key()))
					remaining_space.height -= E->get();
			}
			remaining_space.height -= vsep * MAX(max_row - 1, 0);
			remaining_space.width -= hsep * MAX(max_col - 1, 0);

			bool can_fit = false;
			while (!can_fit && col_expanded.size() > 0) {
				// Check if all minwidth constraints are OK if we use the remaining space.
				can_fit = true;
				int max_index = col_expanded.front()->get();
				for (Set<int>::Element *E = col_expanded.front(); E; E = E->next()) {
					if (col_minw[E->get()] > col_minw[max_index]) {
						max_index = E->get();
					}
					if (can_fit && (remaining_space.width / col_expanded.size()) < col_minw[E->get()]) {
						can_fit = false;
					}
				}

				// If not, the column with maximum minwidth is not expanded.
				if (!can_fit) {
					col_expanded.erase(max_index);
					remaining_space.width -= col_minw[max_index];
				}
			}

			can_fit = false;
			while (!can_fit && row_expanded.size() > 0) {
				// Check if all minheight constraints are OK if we use the remaining space.
				can_fit = true;
				int max_index = row_expanded.front()->get();
				for (Set<int>::Element *E = row_expanded.front(); E; E = E->next()) {
					if (row_minh[E->get()] > row_minh[max_index]) {
						max_index = E->get();
					}
					if (can_fit && (remaining_space.height / row_expanded.size()) < row_minh[E->get()]) {
						can_fit = false;
					}
				}

				// If not, the row with maximum minheight is not expanded.
				if (!can_fit) {
					row_expanded.erase(max_index);
					remaining_space.height -= row_minh[max_index];
				}
			}

			// Finally, fit the nodes.
			int col_expand = col_expanded.size() > 0 ? remaining_space.width / col_expanded.size() : 0;
			int row_expand = row_expanded.size() > 0 ? remaining_space.height / row_expanded.size() : 0;

			int col_ofs = 0;
			int row_ofs = 0;

			valid_controls_index = 0;
			for (int i = 0; i < get_child_count(); i++) {
				Control *c = Object::cast_to<Control>(get_child(i));
				if (!c || !c->is_visible_in_tree())
					continue;
				int row = valid_controls_index / columns;
				int col = valid_controls_index % columns;
				valid_controls_index++;

				if (col == 0) {
					col_ofs = 0;
					if (row > 0)
						row_ofs += (row_expanded.has(row - 1) ? row_expand : row_minh[row - 1]) + vsep;
				}

				Point2 p(col_ofs, row_ofs);
				Size2 s(col_expanded.has(col) ? col_expand : col_minw[col], row_expanded.has(row) ? row_expand : row_minh[row]);

				fit_child_in_rect(c, Rect2(p, s));

				col_ofs += s.width + hsep;
			}

		} break;
		case NOTIFICATION_THEME_CHANGED: {

			minimum_size_changed();
		} break;
	}
}

void GridContainer::set_columns(int p_columns) {

	ERR_FAIL_COND(p_columns < 1);
	columns = p_columns;
	queue_sort();
	minimum_size_changed();
}

int GridContainer::get_columns() const {

	return columns;
}

void GridContainer::_bind_methods() {

	ClassDB::bind_method(D_METHOD("set_columns", "columns"), &GridContainer::set_columns);
	ClassDB::bind_method(D_METHOD("get_columns"), &GridContainer::get_columns);

	ADD_PROPERTY(PropertyInfo(Variant::INT, "columns", PROPERTY_HINT_RANGE, "1,1024,1"), "set_columns", "get_columns");
}

Size2 GridContainer::get_minimum_size() const {

	Map<int, int> col_minw;
	Map<int, int> row_minh;

	int hsep = get_constant("hseparation");
	int vsep = get_constant("vseparation");

	int max_row = 0;
	int max_col = 0;

	int valid_controls_index = 0;
	for (int i = 0; i < get_child_count(); i++) {

		Control *c = Object::cast_to<Control>(get_child(i));
		if (!c || !c->is_visible())
			continue;
		int row = valid_controls_index / columns;
		int col = valid_controls_index % columns;
		valid_controls_index++;

		Size2i ms = c->get_combined_minimum_size();
		if (col_minw.has(col))
			col_minw[col] = MAX(col_minw[col], ms.width);
		else
			col_minw[col] = ms.width;

		if (row_minh.has(row))
			row_minh[row] = MAX(row_minh[row], ms.height);
		else
			row_minh[row] = ms.height;
		max_col = MAX(col, max_col);
		max_row = MAX(row, max_row);
	}

	Size2 ms;

	for (Map<int, int>::Element *E = col_minw.front(); E; E = E->next()) {
		ms.width += E->get();
	}

	for (Map<int, int>::Element *E = row_minh.front(); E; E = E->next()) {
		ms.height += E->get();
	}

	ms.height += vsep * max_row;
	ms.width += hsep * max_col;

	return ms;
}

GridContainer::GridContainer() {

	set_mouse_filter(MOUSE_FILTER_PASS);
	columns = 1;
}
