// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.1 OR LicenseRef-Slint-commercial

import { ScrollView } from "scrollview.slint";
import { ListItem } from "components.slint";

export component ListView inherits ScrollView {
    @children
}

component StandardListViewBase inherits ListView {
    private property <length> item-height: self.viewport-height / self.model.length;
    private property <length> current-item-y: self.viewport-y + current-item * item-height;

    callback current-item-changed(int /* current-item */);
    callback item-pointer-event(int /* item-index */, PointerEvent /* event */, Point /* absolute mouse position */);

    in property<[StandardListViewItem]> model;
    in-out property<int> current-item: -1;

    for item[index] in root.model : ListItem {
        height: self.min-height;
        text: item.text;
        selected: index == root.current-item;

        clicked => {
            root.set-current-item(index);
        }

        pointer-event(pe) => {
            root.item-pointer-event(index, pe, {
                x: self.absolute-position.x + self.mouse-x - root.absolute-position.x,
                y: self.absolute-position.y + self.mouse-y - root.absolute-position.y,
            });
        }
    }

    public function set-current-item(index: int) {
        if(index < 0 || index >= model.length) {
            return;
        }

        current-item = index;
        current-item-changed(current-item);

        if(current-item-y < 0) {
            self.viewport-y += 0 - current-item-y;
        }

        if(current-item-y + item-height > self.visible-height) {
            self.viewport-y -= current-item-y + item-height - self.visible-height;
        }
    }
}

export component StandardListView inherits StandardListViewBase {
    FocusScope {
        x: 0;
        width: 0;  // Do not react on clicks
        key-pressed(event) => {
            if (event.text == Key.UpArrow) {
                root.set-current-item(root.current-item - 1);
                return accept;
            } else if (event.text == Key.DownArrow) {
                root.set-current-item(root.current-item + 1);
                return accept;
            }
            reject
        }
    }
}