qbz/crates/qbz-slint/ui/discover/Carousel.slint

// Discover section carousel — a title, prev/next page controls, and a
// clipped, sliding track of album cards.
//
// Pagination by slice (no scrollbar), mirroring the Svelte
// DiscoverySection. Because there is no ScrollView the height is exactly
// the card height — nothing injects extra vertical space.

import { Theme } from "../foundation/semantic-colors.slint";
import { Typography } from "../foundation/typography.slint";
import { DiscoverSection } from "../state.slint";
import { AlbumCard } from "AlbumCard.slint";
import { QbzIcon } from "../primitives/QbzIcon.slint";

component NavButton inherits Rectangle {
    in property <image> icon;
    in property <bool> enabled: true;
    callback clicked();

    width: 28px;
    height: 28px;
    border-radius: 14px;
    opacity: root.enabled ? 1.0 : 0.4;
    background: ta.has-hover && root.enabled
        ? Theme.surface-hover
        : Theme.surface-elevated;

    QbzIcon {
        source: root.icon;
        width: 15px;
        height: 15px;
        x: (parent.width - self.width) / 2;
        y: (parent.height - self.height) / 2;
        tint: root.enabled ? Theme.text-primary : Theme.text-muted;
    }

    ta := TouchArea {
        enabled: root.enabled;
        mouse-cursor: root.enabled ? pointer : default;
        clicked => {
            root.clicked();
        }
    }
}

component ViewAllLink inherits Rectangle {
    callback clicked();
    width: link-text.preferred-width + 16px;
    height: 26px;
    border-radius: 4px;
    background: ta.has-hover ? Theme.surface-hover : transparent;
    link-text := Text {
        text: @tr("View all");
        color: Theme.accent;
        font-size: 14px;
        font-weight: Typography.medium;
        x: (parent.width - self.width) / 2;
        y: (parent.height - self.height) / 2;
    }
    ta := TouchArea {
        mouse-cursor: pointer;
        clicked => {
            root.clicked();
        }
    }
}

export component Carousel inherits VerticalLayout {
    in property <DiscoverSection> section;
    in property <bool> show-view-all: false;
    callback album-clicked(string);
    callback media-action(string, string, string);
    callback view-all-clicked();

    property <length> card-width: 220px;
    property <length> card-height: 266px;
    property <length> gap: 32px;

    property <int> count: root.section.albums.length;
    property <int> per-page: Math.max(
        1,
        Math.floor((flick.width + root.gap) / (root.card-width + root.gap)));
    property <length> step: root.per-page * (root.card-width + root.gap);
    property <length> content-width:
        root.count * root.card-width + Math.max(0, root.count - 1) * root.gap;
    // Max leftward scroll (viewport-x is 0 at start, negative when
    // scrolled right). Zero when everything fits.
    property <length> max-scroll: Math.max(0px, root.content-width - flick.width);

    spacing: 12px;

    // --- Header: title + page controls -----------------------------------
    HorizontalLayout {
        Text {
            text: root.section.title;
            color: Theme.text-primary;
            font-size: 18px;
            font-weight: Typography.semibold;
            vertical-alignment: center;
            horizontal-stretch: 1;
        }
        HorizontalLayout {
            spacing: 4px;
            VerticalLayout {
                alignment: center;
                NavButton {
                    icon: @image-url("../assets/icons/chevron-left.svg");
                    enabled: flick.viewport-x < -1px;
                    clicked => {
                        flick.viewport-x = Math.min(0px, flick.viewport-x + root.step);
                    }
                }
            }
            VerticalLayout {
                alignment: center;
                NavButton {
                    icon: @image-url("../assets/icons/chevron-right.svg");
                    enabled: flick.viewport-x > -root.max-scroll + 1px;
                    clicked => {
                        flick.viewport-x = Math.max(-root.max-scroll, flick.viewport-x - root.step);
                    }
                }
            }
            if root.show-view-all: VerticalLayout {
                alignment: center;
                ViewAllLink {
                    clicked => {
                        root.view-all-clicked();
                    }
                }
            }
        }
    }

    // --- Track: a horizontal Flickable so the row drags by touch /
    // pointer (kinetic), while card taps still register — Flickable
    // distinguishes a flick from a tap, unlike nested TouchAreas. The
    // prev/next buttons nudge viewport-x by a page. viewport-height ==
    // height pins it to horizontal-only so it never fights the home
    // page's vertical Flickable.
    viewport := Rectangle {
        height: root.card-height;
        clip: true;

        flick := Flickable {
            width: 100%;
            height: root.card-height;
            viewport-width: root.content-width;
            viewport-height: self.height;

            HorizontalLayout {
                spacing: root.gap;
                for album in root.section.albums: AlbumCard {
                    album: album;
                    clicked(id) => {
                        root.album-clicked(id);
                    }
                    media-action(kind, id, action) => {
                        root.media-action(kind, id, action);
                    }
                }
            }
        }

        // Cider-style edge fades — content dissolves into the page
        // background at the scrolled edges instead of a hard cut.
        Rectangle {
            x: 0px;
            width: 56px;
            background: @linear-gradient(90deg, Theme.surface-main 0%, transparent 100%);
            opacity: flick.viewport-x < -1px ? 1.0 : 0.0;
            animate opacity { duration: 150ms; }
        }
        Rectangle {
            x: parent.width - self.width;
            width: 56px;
            background: @linear-gradient(90deg, transparent 0%, Theme.surface-main 100%);
            opacity: flick.viewport-x > -root.max-scroll + 1px ? 1.0 : 0.0;
            animate opacity { duration: 150ms; }
        }
    }
}