/*
 * Plasma Gnome Pager — ScreenCurrentDesktop.qml
 *
 * SPDX-FileCopyrightText: 2026 Kenan Salar
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * Resolves the current desktop FOR ONE SCREEN (Plasma 6.7 per-output; unit-tested by tst_screencurrentdesktop).
 * currentDesktopByScreenName is a METHOD + SIGNAL, not a notifying property, so currentDesktop is recomputed
 * imperatively (a plain binding evaluates once); the prefer-per-screen decision is Logic.resolveCurrentDesktop.
 */
pragma ComponentBehavior: Bound

import QtQuick

import "logic.js" as Logic

Item {
    id: resolver

    // Inputs (injected by WorkspaceIndicator).
    property var virtualDesktopInfo: null
    property string screenName: ""

    // Output: the current-desktop UUID for screenName (the global current when there is no per-screen info).
    property string currentDesktop: ""

    function updateCurrentDesktop() {
        const vdi = resolver.virtualDesktopInfo;
        const globalCurrent = vdi?.currentDesktop ?? "";
        let perScreen;   // stays undefined unless we have a screen AND the 6.7 API
        if (vdi && resolver.screenName && typeof vdi.currentDesktopByScreenName === "function")
            perScreen = vdi.currentDesktopByScreenName(resolver.screenName);
        resolver.currentDesktop = Logic.resolveCurrentDesktop(perScreen, globalCurrent);
    }

    // Recompute on every external change ("bind, don't cache"). The always-present signals keep their own
    // block (no ignoreUnknownSignals) so a typo here still warns.
    Connections {
        target: resolver.virtualDesktopInfo
        function onCurrentDesktopChanged() {
            resolver.updateCurrentDesktop();
        }
        function onDesktopIdsChanged() {
            resolver.updateCurrentDesktop();
        }
    }
    // The per-screen current signal is Plasma 6.7+ only; on 6.5/6.6 it is absent, so ignoreUnknownSignals
    // keeps the Connections quiet — the resolver already degrades to the global current (typeof guard above).
    Connections {
        target: resolver.virtualDesktopInfo
        ignoreUnknownSignals: true
        function onCurrentDesktopForScreenChanged(screenName) {
            if (screenName === resolver.screenName)
                resolver.updateCurrentDesktop();
        }
    }
    onScreenNameChanged: resolver.updateCurrentDesktop()
    onVirtualDesktopInfoChanged: resolver.updateCurrentDesktop()
    Component.onCompleted: resolver.updateCurrentDesktop()
}