// Copyright © SixtyFPS GmbH <info@slint-ui.com>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-commercial


import { md } from "md.slint";

ScrollBar := Rectangle {
    property <bool> horizontal;
    property<length> maximum;
    property<length> page-size;
    // this is always negative and bigger than  -maximum
    property<length> value;
    property<bool> enabled <=> touch.enabled;

    state_layer := Rectangle {
        width: 100%;
        height: 100%;
        background: md.sys.color.primary;
        border-radius: 4px;
        opacity: 0;
        visible: handle.width > 0 && handle.height > 0;
        animate opacity { duration: 250ms; easing: ease; }
    }

    handle := Rectangle {
        x: !horizontal ? 0phx : (root.width - handle.width) * (-value / maximum);
        y: horizontal ? 0phx : (root.height - handle.height) * (-value / maximum);
        width: !horizontal ? parent.width : maximum <= 0phx ? 0phx : parent.width * (page-size / (maximum + page-size));
        height: horizontal ? parent.height : maximum <= 0phx ? 0phx : parent.height * (page-size / (maximum + page-size));
     
        container := Rectangle {
            width: 100%;
            height: 100%;
            border-radius: 4px;
            border-color: md.sys.color.outline;
            border-width: 1px;
        }
    }

    touch := TouchArea {
        property <length> pressed-value;

        width: parent.width;
        height: parent.height;
      
        pointer-event(event) => {
            if (event.button == PointerEventButton.left && event.kind == PointerEventKind.down) {
                pressed-value = -root.value;
            }
        }
        moved => {
            if (enabled && pressed) {
                value = -max(0px, min(root.maximum, pressed-value + (
                    horizontal ? (touch.mouse-x - touch.pressed-x) * (maximum / (root.width - handle.width))
                               : (touch.mouse-y - touch.pressed-y) * (maximum / (root.height - handle.height))
                )));
            }
        }
    }

    states [
        disabled when !touch.enabled : {
            container.border-color: md.sys.color.on-surface;
            handle.opacity: 0.12;
        }
        hover when touch.has-hover : {
            state-layer.opacity: 0.08;    
        }
        pressed when touch.has-hover : {
            state-layer.opacity: 0.12;    
        }
    ]
}

// Scrollview contains a viewport that is bigger than the view and can be scrolled.
export ScrollView := Rectangle {
    property <length> viewport-width <=> fli.viewport-width;
    property <length> viewport-height <=> fli.viewport-height;
    property <length> viewport-x <=> fli.viewport-x;
    property <length> viewport-y <=> fli.viewport-y;
    property <length> visible-width <=> fli.width;
    property <length> visible-height <=> fli.height;
    property <bool> enabled: true;
    property <bool> has-focus;
 
    background: md.sys.color.surface;

    fli := Flickable {
        interactive: false;
        viewport-y <=> vbar.value;
        viewport-x <=> hbar.value;
        width: parent.width - vbar.width - 4px;
        height: parent.height - hbar.height - 4px;

        @children
    }

    vbar := ScrollBar {
        width: 8px;
        x: fli.width + fli.x;
        y: fli.y;
        height: fli.height;
        horizontal: false;
        maximum: fli.viewport-height - fli.height;
        page-size: fli.height;
        enabled: root.enabled;
    }

    hbar := ScrollBar {
        height: 8px;
        y: fli.height + fli.y;
        x: fli.x;
        width: fli.width;
        horizontal: true;
        maximum: fli.viewport-width - fli.width;
        page-size: fli.width;
        enabled: root.enabled;
    }
}