/**
 * KWin Scratchpad — i3-like hide/show/cycle behavior.
 *
 * Two shortcuts:
 *   Meta+Shift+-  : Move active window to scratchpad (hide it).
 *   Meta+-        : Show/hide/cycle through scratchpad windows.
 *
 * Cycle behavior (Meta+-):
 *   - If a scratchpad window is visible: hide it.
 *   - If no scratchpad window is visible: show the next one.
 *   - Wraps around the list.
 *
 * A window leaves the scratchpad ONLY when:
 *   - It is closed.
 *   - It is explicitly moved to a desktop.
 */

(function () {
    "use strict";

    // --- State ---
    var scratchpad = [];    // ordered list of windows in the scratchpad
    var visibleWindow = null; // the currently-visible scratchpad window, or null
    var nextIndex = 0;      // which window to show on the next "show" press

    // --- Helpers ---

    function indexInScratchpad(win) {
        for (var i = 0; i < scratchpad.length; i++) {
            if (scratchpad[i] === win) return i;
        }
        return -1;
    }

    function isScratchpadWindow(win) {
        return indexInScratchpad(win) >= 0;
    }

    function removeScratchpadWindow(win) {
        var i = indexInScratchpad(win);
        if (i < 0) return false;

        scratchpad.splice(i, 1);

        if (win === visibleWindow) {
            visibleWindow = null;
        }

        // Keep nextIndex in bounds
        if (scratchpad.length === 0) {
            nextIndex = 0;
        } else if (nextIndex >= scratchpad.length) {
            nextIndex = 0;
        }
        return true;
    }

    function hideWindow(win) {
        win.minimized = true;
        win.skipTaskbar = true;
        win.skipPager = true;
        win.skipSwitcher = true;
    }

    function showWindow(win) {
        win.desktops = [workspace.currentDesktop];
        win.minimized = false;
        win.skipTaskbar = true;
        win.skipPager = true;
        win.skipSwitcher = true;
        workspace.activeWindow = win;
    }

    function restoreWindow(win) {
        win.minimized = false;
        win.skipTaskbar = false;
        win.skipPager = false;
        win.skipSwitcher = false;
    }

    // --- Shortcut 1: Add to scratchpad (Meta+Shift+-) ---

    function scratchpadAdd() {
        var active = workspace.activeWindow;
        if (!active) return;
        if (active.desktopWindow || active.dock || active.specialWindow) return;
        if (isScratchpadWindow(active)) return;

        scratchpad.push(active);
        hideWindow(active);
        print("Scratchpad: added — " + active.caption + " (" + scratchpad.length + " total)");
    }

    // --- Shortcut 2: Show/hide/cycle (Meta+-) ---

    function scratchpadCycle() {
        if (scratchpad.length === 0) return;

        // If a scratchpad window is currently visible — hide it. Full stop.
        if (visibleWindow !== null) {
            hideWindow(visibleWindow);
            // Advance nextIndex past the one we just hid
            var idx = indexInScratchpad(visibleWindow);
            if (idx >= 0) {
                nextIndex = (idx + 1) % scratchpad.length;
            }
            visibleWindow = null;
            return;
        }

        // No scratchpad window is visible — show the next one.
        if (nextIndex >= scratchpad.length) {
            nextIndex = 0;
        }
        visibleWindow = scratchpad[nextIndex];
        showWindow(visibleWindow);
    }

    // --- Track window closure ---

    workspace.windowRemoved.connect(function (win) {
        removeScratchpadWindow(win);
    });

    // --- Track desktop changes (window explicitly moved to a desktop) ---

    function watchDesktopChange(win) {
        win.desktopsChanged.connect(function () {
            if (!isScratchpadWindow(win)) return;

            // If it's the visible one and not minimized, this is likely our
            // own showWindow() call — ignore.
            if (win === visibleWindow && !win.minimized) {
                return;
            }

            // User moved it to a desktop — release from scratchpad.
            removeScratchpadWindow(win);
            restoreWindow(win);
            print("Scratchpad: window released to desktop — " + win.caption);
        });
    }

    var clients = workspace.stackingOrder;
    for (var i = 0; i < clients.length; i++) {
        watchDesktopChange(clients[i]);
    }

    workspace.windowAdded.connect(function (win) {
        watchDesktopChange(win);
    });

    // --- Register shortcuts ---

    registerShortcut(
        "ScratchpadAdd",
        "Move Window to Scratchpad",
        "Meta+Shift+-",
        scratchpadAdd
    );

    registerShortcut(
        "ScratchpadCycle",
        "Scratchpad Show/Hide/Cycle",
        "Meta+-",
        scratchpadCycle
    );

    print("KWin Scratchpad loaded");
})();