// SPDX-License-Identifier: MIT
.pragma library

// Task Manager fills unused panel space. Only delegates are task buttons.
function hasTaskAt(item, x, y, vertical) {
    if (!item.visible) return false;
    const point = item.mapFromItem(null, x, y);
    if (vertical === undefined) {
        if (!item.contains(point)) return false;
    } else if (item.width <= 0 || item.height <= 0
        || (vertical ? point.y < 0 || point.y > item.height : point.x < 0 || point.x > item.width)) {
        return false;
    }
    if (item.tasksRoot !== undefined && item.isWindow !== undefined && item.index !== undefined) return true;
    for (const child of item.children) {
        if (hasTaskAt(child, x, y, vertical)) return true;
    }
    return false;
}

function appletArea(child, x, y, vertical) {
    const applet = child.applet;
    const name = applet?.plasmoid?.pluginName;
    if (!name) return "other";
    if (name === "org.kde.plasma.taskmanager" || name === "org.kde.plasma.icontasks") {
        return hasTaskAt(applet, x, y, vertical) ? "tasks" : "empty";
    }
    if (name === "se.ajpanton.panelactions" || name === "org.kde.plasma.panelspacer"
        || name === "org.kde.plasma.marginsseparator") return "empty";
    if (name === "org.kde.plasma.systemtray") return "tray";
    if (name === "org.kde.plasma.digitalclock" || name === "org.kde.plasma.analogclock") return "clock";
    if (name === "org.kde.plasma.kickoff" || name === "org.kde.plasma.kicker"
        || name === "org.kde.plasma.kickerdash") return "launcher";
    return "other";
}

function areaAt(panelLayout, x, y) {
    if (!panelLayout) return "";
    for (const child of panelLayout.children) {
        if (child.visible && child.contains(child.mapFromItem(null, x, y))) {
            return appletArea(child, x, y);
        }
    }
    return "empty";
}

// Scrolling owns the full panel thickness and its outer end padding. Interior
// gaps and explicit spacers remain empty; clicks keep their exact hit testing.
function scrollAreaAt(panelLayout, x, y, vertical) {
    if (!panelLayout) return "";
    const point = panelLayout.mapFromItem(null, x, y);
    const along = vertical ? point.y : point.x;
    let first = null;
    let last = null;
    for (const child of panelLayout.children) {
        if (!child.visible || child.width <= 0 || child.height <= 0) continue;
        const a = child.mapToItem(panelLayout, 0, 0);
        const b = child.mapToItem(panelLayout, child.width, child.height);
        const start = vertical ? Math.min(a.y, b.y) : Math.min(a.x, b.x);
        const end = vertical ? Math.max(a.y, b.y) : Math.max(a.x, b.x);
        if (end <= start) continue;
        if (along >= start && along < end) return appletArea(child, x, y, vertical);
        if (!first || start < first.start) first = {child, start};
        if (!last || end > last.end) last = {child, end};
    }
    const edge = first && along < first.start ? first : last && along >= last.end ? last : null;
    if (!edge) return "empty";
    const boundary = edge === first ? first.start : last.end;
    const projected = panelLayout.mapToItem(null, vertical ? point.x : boundary, vertical ? boundary : point.y);
    return appletArea(edge.child, projected.x, projected.y, vertical);
}