Source: shellfish-ui/ui/ListHeader.shui

/*******************************************************************************
This file is part of the Shellfish UI toolkit.
Copyright (c) 2023 Martin Grimme <martin.grimme@gmail.com>

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.
*******************************************************************************/

require "shellfish/ui";

/**
 * Element representing a list header with multiple columns. It is intended to
 * be placed directly above a {@link html.ListView} element.
 *
 * The model of columns supports several attributes:
 * - `title` (string): The title text
 * - `width` (number): The initial width
 * - `resizable` (bool): Whether the columns is resizable
 *
 * @memberof ui
 * @name ListHeader
 * @class
 * @extends html.Box
 *
 * @property {core.ListModel} model - The model of columns.
 * @property {number[]} columnWidths - [readonly] The widths of the particular columns.
 */
Box {
    id: header

    property model: ListModel { }
    property columnWidths: []

    /**
     * Is triggered when the user clicks on a column header.
     *
     * @memberof ui.ListHeader.prototype
     * @name columnClick
     * @event
     * @param {number} idx - The index number of the clicked column.
     */
    event columnClick

    /**
     * Resets the column widths.
     *
     * @memberof ui.ListHeader.prototype
     * @name resetColumns
     * @method
     */
    function resetColumns()
    {
        if (colRepeater.count === 0)
        {
            return;
        }

        let sizes = colRepeater.items.map((item, idx) =>
        {
            const modelItem = model.at(idx);
            const prefered = modelItem.width || -1;

            return prefered === -1 ? 0 : prefered;
        });

        const sum = sizes.reduce((a, b) => a + b, 0);
        const remainder = bboxWidth - sum;
        const flexAmount = sizes.filter(s => s === 0).length;
        
        if (flexAmount > 0)
        {
            const size = Math.max(theme.itemWidthSmall, remainder / sizes.filter(s => s === 0).length);
            sizes = sizes.map(s => s === 0 ? size : s);
        }

        columnWidths = sizes;

        columnWidths.forEach((w, idx) =>
        {
            colRepeater.items[idx].width = w;
        });
    }

    /**
     * Resizes the given column width by a delta amount.
     *
     * @memberof ui.ListHeader.prototype
     * @name resizeColumn
     * @method
     *
     * @param {number} idx - The index number of the column to resize.
     * @param {number} n - The amount to add to the column's width.
     */
    function resizeColumn(idx, n)
    {
        const ws = colRepeater.items.map(item =>
        {
            return item.width;
        });
        const totalWidth = ws.reduce((a, b) => a + b);

        colRepeater.items[idx].width += n;

        columnWidths = colRepeater.items.map(item =>
        {
            return item.width;
        });
    }

    fillWidth: true
    height: theme.itemHeightSmall
    layout: "row"

    onBboxWidthChanged: () => { resetColumns(); }

    Repeater {
        id: colRepeater

        model: header.model

        delegate: template MouseBox {
            width: 100
            fillHeight: true
            color: containsMouse ? theme.highlightBackgroundColor : "transparent"

            layout: "center-row"

            onInitialization: () =>
            {
                if (modelData.index === 0)
                {
                    wait(0).then(() =>
                    {
                        header.resetColumns();
                    });
                }
            }

            onClick: ev =>
            {
                ev.accepted = true;
                header.columnClick(modelData.index);
            }

            Label {
                fillWidth: true
                marginLeft: theme.paddingSmall
                marginRight: theme.paddingSmall
                overflowBehavior: "ellipsis"
                color: parent.containsMouse ? theme.highlightColor : theme.primaryColor
                text: parent.modelData.value.title
            }

            MouseBox {
                width: 6
                fillHeight: true
                cursor: "col-resize"

                onDrag: ev =>
                {
                    ev.accepted = true;

                    const resizable = parent.modelData.value.resizable ?? true;
                    if (resizable)
                    {
                        header.resizeColumn(parent.modelData.index, ev.deltaX);
                    }
                }

                onDoubleClick: ev =>
                {
                    ev.accepted = true;
                    header.resetColumns();
                }

                Box {
                    position: "free"
                    origin: "top-right"
                    width: 1
                    fillHeight: true
                    color: theme.borderColor
                }
            }
        }
    }
}