pragma Singleton

// ─────────────────────────────────────────────────────────────────────────────
// The freedesktop notification server, plus the two lists the UI renders:
//
//   popups  — what Toasts.qml is currently showing (transient, timed)
//   history — GNOME's message tray, what NotificationList.qml shows
//
// A notification lives exactly as long as `tracked` is true, so history holds
// the *live* objects rather than copies: that keeps actions and inline replies
// working from the tray, which is what GNOME does. The cost is that a
// notification an app closes itself (progress bars, "download finished"
// replacing "downloading") disappears from history too — correct behavior,
// but the reason history is not append-only.
// ─────────────────────────────────────────────────────────────────────────────

import Quickshell
import Quickshell.Io
import Quickshell.Services.Notifications
import QtQuick
import qs.config

Singleton {
    id: root

    readonly property alias server: server

    // Live tracked set, straight from the server. Mostly useful for counting;
    // the UI wants `popups` / `history`, which are ordered newest-first.
    readonly property alias active: server.trackedNotifications

    property var history: []
    property var popups: []

    // Suppresses toasts entirely. Notifications still reach history.
    property bool doNotDisturb: false

    // Cleared when the notification center is opened. The bar binds to this.
    property int unreadCount: 0

    // Kept separate from the persisted map so this version can safely run
    // before the matching schema entry lands. A later accepted write folds the
    // complete map into DesktopPreferences and clears this fallback.
    property var fallbackAppRules: ({})

    // Display metadata is intentionally session-only. The durable shape stays
    // just the per-application rule map, while a fresh notification gives the
    // settings page a human-readable name straight away.
    property var rememberedApplications: ({})

    readonly property var persistedAppRules: {
        const stored = DesktopPreferences.get("notificationAppRules");
        return stored && typeof stored === "object" && !Array.isArray(stored) ? stored : {};
    }

    // The schema change is the persistence boundary. This branch keeps a
    // session fallback only so it remains usable while that companion change
    // is being integrated; it intentionally makes no restart guarantee then.
    readonly property bool appRulesSchemaAvailable: PreferenceSchema.has("notificationAppRules")

    readonly property var appRules: Object.assign({}, root.persistedAppRules, root.fallbackAppRules)

    // Every application that has a rule, with everything the settings list
    // needs to draw a row: the live-resolved name, the cached icon, when it
    // last said something, and the rule itself. Sorted by name, because the
    // page decides its own sections (recent / customized / all) from the
    // fields rather than from this order.
    readonly property var applications: {
        // byId()/heuristicLookup() do not make a binding by themselves. This
        // read updates persisted app labels once DesktopEntries finishes scan.
        const entries = DesktopEntries.applications.values;
        const remembered = root.rememberedApplications;
        return Object.keys(root.appRules).map(appId => {
            const rule = root.appRule(appId);
            return {
                id: appId,
                name: root.applicationLabel(appId, entries, remembered),
                icon: root.applicationIcon(appId, rule.icon),
                lastSeenMs: rule.lastSeenMs,
                rule: rule
            };
        }).sort((a, b) => a.name.localeCompare(b.name));
    }

    // Arrival times, keyed by notification id — the protocol carries no
    // timestamp. Deliberately formatted once at arrival rather than shown as
    // "5 minutes ago", which would need a clock ticking behind every card.
    readonly property var arrivals: ({})

    function timeText(id: int): string {
        const at = root.arrivals[id];
        return at ? Qt.formatDateTime(at, Settings.use24Hour ? "HH:mm" : "h:mm AP") : "";
    }

    // Freedesktop timeout resolution, shared by the toast countdown (Toast.qml)
    // and the no-display expiry a transient notification gets while Do Not
    // Disturb is on (below). Critical urgency and an explicit expireTimeout
    // override policy; -1 ("server decides") falls back to it. 0 means "never
    // auto-expire" per spec.
    // Reads the effective urgency, so an application told to be treated as
    // critical also gets the critical banner duration rather than only the
    // critical look.
    function notificationTimeoutMs(notification: var): int {
        if (root.effectiveUrgency(notification) === NotificationUrgency.Critical)
            return Settings.notificationTimeoutCriticalMs;
        if (notification.expireTimeout === 0)
            return 0;
        if (notification.expireTimeout > 0)
            return Math.round(notification.expireTimeout * 1000);
        return Settings.notificationTimeoutMs;
    }

    readonly property bool hasNotifications: root.history.length > 0

    function notificationAppId(notification: var): string {
        const desktopEntry = String(notification.desktopEntry ?? "").trim();
        return desktopEntry || String(notification.appName ?? "").trim() || "Notifications";
    }

    // The installed application behind a rule key, or null. An appId is either
    // a desktop entry id or the raw name an application announced itself with,
    // so both spellings and the heuristic are tried.
    function desktopEntryFor(appId: string): var {
        const desktopId = appId.endsWith(".desktop") ? appId.slice(0, -8) : appId;
        return DesktopEntries.byId(appId)
            || DesktopEntries.byId(desktopId)
            || DesktopEntries.heuristicLookup(appId)
            || DesktopEntries.heuristicLookup(desktopId);
    }

    // Live first, cache second: an installed application is named by its
    // desktop entry every time, and the name stored on the rule only stands in
    // for one that is gone, sandboxed, or not scanned yet. The other way round
    // would freeze a name at the moment it was first heard from.
    function applicationLabel(appId: string, entries: var, remembered: var): string {
        return root.desktopEntryFor(appId)?.name || remembered[appId]?.name || appId;
    }

    // Same rule for the icon: the desktop entry wins, the cached icon (an
    // entry icon, or the appIcon the notification carried) is the fallback.
    function applicationIcon(appId: string, cached: string): string {
        return root.desktopEntryFor(appId)?.icon || String(cached ?? "");
    }

    // The durable per-application rule. Everything past `enabled` is optional
    // so rules written when this held only `enabled` still load, and anything
    // unrecognized -- including the lock-screen pair described below -- is
    // dropped rather than carried forward as if something read it.
    //
    //   enabled     off rejects the notification before anything else happens
    //   sound       false silences the bell for this application only
    //   display     "history" files it without a banner and without a bell
    //   urgency     "low"/"critical" override what the application claims
    //   lastSeenMs  when it last notified, stamped by rememberApplication
    //   name, icon  cached labels for the settings list (see above: fallback)
    function normalizedAppRule(rule: var): var {
        const source = rule && typeof rule === "object" && !Array.isArray(rule) ? rule : {};
        const display = String(source.display ?? "");
        const urgency = String(source.urgency ?? "");
        const lastSeen = Number(source.lastSeenMs);
        return {
            enabled: source.enabled !== false,
            sound: source.sound !== false,
            display: display === "history" ? "history" : "banners",
            urgency: urgency === "low" || urgency === "critical" ? urgency : "auto",
            lastSeenMs: isFinite(lastSeen) && lastSeen > 0 ? Math.round(lastSeen) : 0,
            name: String(source.name ?? ""),
            icon: String(source.icon ?? "")
        };
    }

    // A rule with no defaults touched. Everything the page calls "customized"
    // is a field that differs from this.
    readonly property var defaultAppRule: root.normalizedAppRule({})

    function appRule(appId: string): var {
        return root.normalizedAppRule(root.appRules[appId]);
    }

    // Has this application been given a rule that actually says something? The
    // bookkeeping fields do not count -- an application is "customized"
    // because of a decision somebody made about it, not because it notified.
    function isCustomized(appId: string): bool {
        const rule = root.appRule(appId);
        return rule.enabled !== true || rule.sound !== true
            || rule.display !== "banners" || rule.urgency !== "auto";
    }

    function setAppRule(appId: string, patch: var): bool {
        if (!appId)
            return false;

        const changes = patch && typeof patch === "object" ? patch : {};
        const merged = Object.assign({}, root.appRule(appId));
        // Field by field rather than a blind merge, so a patch cannot smuggle
        // a value of the wrong type (or an unknown key) into the stored rule.
        if (changes.enabled !== undefined)
            merged.enabled = changes.enabled === true;
        if (changes.sound !== undefined)
            merged.sound = changes.sound === true;
        if (changes.display !== undefined)
            merged.display = String(changes.display);
        if (changes.urgency !== undefined)
            merged.urgency = String(changes.urgency);
        if (changes.lastSeenMs !== undefined)
            merged.lastSeenMs = Number(changes.lastSeenMs);
        if (changes.name !== undefined)
            merged.name = String(changes.name);
        if (changes.icon !== undefined)
            merged.icon = String(changes.icon);

        const next = {};
        for (const knownAppId of Object.keys(root.appRules))
            next[knownAppId] = root.appRule(knownAppId);
        next[appId] = root.normalizedAppRule(merged);

        if (root.appRulesSchemaAvailable && DesktopPreferences.set("notificationAppRules", next))
            root.fallbackAppRules = {};
        else
            root.fallbackAppRules = next;
        return true;
    }

    // Delete the rule outright, rather than resetting its fields: an
    // application with no rule is treated as permissive, so forgetting one is
    // undone by its next notification, which writes a fresh default rule.
    // The session-only remembered name goes with it, otherwise the row would
    // linger under a name nothing is keeping.
    function forgetApp(appId: string): bool {
        if (!appId || root.appRules[appId] === undefined)
            return false;

        const next = {};
        for (const knownAppId of Object.keys(root.appRules)) {
            if (knownAppId !== appId)
                next[knownAppId] = root.appRule(knownAppId);
        }

        const remembered = Object.assign({}, root.rememberedApplications);
        delete remembered[appId];
        root.rememberedApplications = remembered;

        // The session fallback is a whole-map replacement, so a deletion only
        // truly lands once the preference write succeeds -- which it does
        // whenever the schema key exists, i.e. always outside the transitional
        // build this fallback was written for.
        if (root.appRulesSchemaAvailable && DesktopPreferences.set("notificationAppRules", next))
            root.fallbackAppRules = {};
        else
            root.fallbackAppRules = next;
        return true;
    }

    // What this notification counts as after the application's override: the
    // urgency the sender claimed unless a rule disagrees with it. Read by the
    // bell, the banner timeout, the Do Not Disturb breakthrough gate, and the
    // card's critical edge, so all four agree on one answer.
    function effectiveUrgency(notification: var): var {
        const rule = root.appRule(root.notificationAppId(notification));
        if (rule.urgency === "low")
            return NotificationUrgency.Low;
        if (rule.urgency === "critical")
            return NotificationUrgency.Critical;
        return notification.urgency;
    }

    function rememberApplication(notification: var): string {
        const appId = root.notificationAppId(notification);
        const next = Object.assign({}, root.rememberedApplications);
        next[appId] = {
            name: String(notification.appName ?? "").trim() || appId
        };
        root.rememberedApplications = next;

        // Stamped alongside the labels the settings list falls back to when
        // the application is not installed here. Coalesced to one write per
        // minute per app: every setAppRule bumps the preferences revision and
        // restarts the settings.json write debounce, so stamping a chat
        // burst's every message would churn the whole preference store for a
        // timestamp nobody reads at that resolution.
        const rule = root.appRule(appId);
        const name = root.applicationLabel(appId, DesktopEntries.applications.values, next);
        const icon = root.applicationIcon(appId, String(notification.appIcon ?? ""));
        if (Date.now() - rule.lastSeenMs >= 60000 || rule.name !== name || rule.icon !== icon) {
            root.setAppRule(appId, {
                lastSeenMs: Date.now(),
                name: name,
                icon: icon
            });
        }
        return appId;
    }

    // There are deliberately no lock-screen policy getters here, and no
    // lock-screen switches on the Notifications page. The lock screen is
    // hyprlock, which cannot render notifications, so two per-app privacy
    // toggles shipped for a while that controlled nothing -- on the page a
    // person checks precisely when they care. Stored rules may still carry
    // showOnLockScreen fields from that era; nothing reads them. If a lock
    // screen that can render notifications ever exists, the rule store and
    // appRule() are the right place to hang its policy back onto.

    // history grouped by app, in most-recent-app-first order — the shape
    // NotificationList.qml renders directly.
    readonly property var groups: {
        const out = [];
        const byApp = {};
        for (const n of root.history) {
            const key = n.appName || "Notifications";
            let group = byApp[key];
            if (!group) {
                group = {
                    app: key,
                    icon: n.appIcon,
                    desktopEntry: n.desktopEntry,
                    items: []
                };
                byApp[key] = group;
                out.push(group);
            }
            group.items.push(n);
        }
        return out;
    }

    NotificationServer {
        id: server

        keepOnReload: true
        persistenceSupported: true
        bodySupported: true
        bodyMarkupSupported: true
        bodyImagesSupported: true
        imageSupported: true
        actionsSupported: true
        actionIconsSupported: true
        inlineReplySupported: true

        onNotification: notification => root.handleNotification(notification)
    }

    function handleNotification(notification: var): void {
            // Replayed from before a shell reload. Letting these through would
            // re-toast and re-list everything on every edit, so they are left
            // untracked and allowed to die.
            if (notification.lastGeneration)
                return;

            const appId = root.rememberApplication(notification);
            // Read once: the same rule decides rejection, the bell, and
            // whether this is allowed to be a banner at all.
            const rule = root.appRule(appId);
            if (!rule.enabled)
                return;

            // Without this the object is destroyed the instant this returns.
            notification.tracked = true;
            root.arrivals[notification.id] = new Date();

            // The object may go away at any time (app-side close, dismiss()).
            // Drop our references synchronously when it does.
            notification.closed.connect(() => root.forget(notification));

            // `transient` is the volume-OSD case: show it, never file it.
            if (!notification.transient) {
                root.pushHistory(notification);
                root.unreadCount += 1;
            }

            // "History only" is the quiet filing cabinet: it was added to
            // history and counted as unread above, and that is all it gets --
            // no banner, and (never reaching playBell) no sound either.
            const historyOnly = rule.display === "history";

            // The one exception to Do Not Disturb that is not a focus mode's,
            // and it is off unless somebody turned it on. It reads the
            // effective urgency, so a per-application override decides who
            // gets to claim "critical" rather than the sender alone.
            const breaksThrough = Settings.criticalBreaksThrough
                && root.effectiveUrgency(notification) === NotificationUrgency.Critical;

            // An exception belongs to the focus mode that is in force. A Do Not
            // Disturb switched on by hand has no exceptions and stays absolute,
            // because FocusModes.allows is false whenever no mode is active.
            if (historyOnly) {
                // Transient notifications are filed nowhere, so a hidden one
                // still needs the release its popup timeout would have given.
                if (notification.transient)
                    root.scheduleTransientExpiry(notification);
            } else if (!root.doNotDisturb || FocusModes.allows(appId) || breaksThrough) {
                root.popups = [notification].concat(root.popups);
                root.playBell(notification);
            } else if (notification.transient) {
                // Never shown, and (being transient) never filed in history
                // either — nothing will otherwise dismiss() it, so schedule
                // the same release its popup timeout would have given it.
                root.scheduleTransientExpiry(notification);
            }
    }

    // ── The chime ───────────────────────────────────────────────────────────
    //
    // A notification you can hear. GTK applications get this from libcanberra
    // for free; Panama's own popups had no sound at all, so a notification that
    // arrived while you were looking elsewhere simply did not happen. Same
    // theme, same desktop preference: one switch covers the whole session
    // rather than leaving Panama as the one thing that stays quiet -- or the
    // one thing that will not shut up.
    //
    // Throttled to one bell a second. A burst -- a chat catching up after a
    // suspend, ten build jobs finishing together -- would otherwise stack a
    // dozen overlapping bells, which is a noise rather than a notification.
    property real lastBellAt: 0

    // Emitted for every notification that is bell-eligible, whether or not a
    // bell is actually audible. modules/notifications/VisualBell.qml listens.
    signal bellEligible(var notification)

    // Would this notification ring the bell, setting aside whether sound is
    // switched on at all?
    //
    // THE PINNED RULE, because it is the whole point of visual alerts: the
    // flash follows this predicate, and the bell follows this predicate AND
    // SoundFeedback.eventSounds. Every gate below is shared -- an application
    // you silenced stays silent both ways, a low-urgency notification stays
    // quiet both ways, and an application that says it played its own sound is
    // taken at its word both ways -- but the event-sounds switch is NOT.
    //
    // Gating the flash on event sounds would make Visual Alerts do nothing for
    // exactly the person it exists for: somebody who cannot hear the bell has
    // no reason to have event sounds on, and would turn on a switch that stays
    // dark. The flash is not a picture of the bell; it is the same alert in the
    // sense the person can receive.
    //
    // Sound RESOLUTION is deliberately not part of this. playBell gives up when
    // it cannot find a file to play, which is a fact about the sound theme on
    // disk; losing the flash because a theme is missing an ogg would be absurd.
    function bellWouldRing(notification: var): bool {
        // The per-application sound switch. Narrower than turning the
        // application off: its notifications still arrive and still show, they
        // just stop making noise.
        if (!root.appRule(root.notificationAppId(notification)).sound)
            return false;

        // Low urgency is the "you did not need to know this" tier -- battery
        // reaching full, a sync completing. It stays silent by design, and it
        // is the effective urgency, so "treat as low" is a way to keep an
        // application audible in principle but quiet in practice.
        if (root.effectiveUrgency(notification) === NotificationUrgency.Low)
            return false;

        // The freedesktop sound hint. This is the fix for the double chime: an
        // application that plays its own sound sets suppress-sound so the
        // notification server stays quiet, and Panama ignoring it meant one
        // notification made two noises a beat apart.
        const hints = notification.hints ?? {};
        if (hints["suppress-sound"] === true)
            return false;

        return true;
    }

    function playBell(notification: var): void {
        if (!root.bellWouldRing(notification))
            return;

        // Announced BEFORE the event-sounds gate, on purpose. See the rule
        // pinned above bellWouldRing.
        root.bellEligible(notification);

        if (!SoundFeedback.eventSounds)
            return;

        // The remaining two sound hints say what to play instead of the theme
        // bell -- sound-file is an absolute path the application supplies,
        // sound-name is a theme sound resolved through the same chain the bell
        // uses. Neither can make a notification ineligible, so neither is part
        // of the predicate above.
        const hints = notification.hints ?? {};
        const soundFile = String(hints["sound-file"] ?? "");
        const soundName = String(hints["sound-name"] ?? "");
        const candidates = soundFile.startsWith("/")
            ? [soundFile]
            : (soundName !== ""
                ? SoundFeedback.soundCandidates(soundName)
                : SoundFeedback.bellCandidates);
        // A hint naming something unresolvable is a request for that sound, not
        // a request for the bell -- substituting would be a lie about which
        // notification arrived.
        if (candidates.length === 0)
            return;

        const now = Date.now();
        if (bell.running || now - root.lastBellAt < 1000)
            return;
        root.lastBellAt = now;
        bell.command = SoundFeedback.playCommand(candidates);
        bell.running = true;
    }

    Process { id: bell }

    // Runs a DND-hidden transient notification through the same lifetime it
    // would have gotten as a visible popup (Toast.qml's countdown), just
    // without ever showing it, so it still gets released instead of staying
    // tracked forever.
    function scheduleTransientExpiry(notification: var): void {
        const ms = root.notificationTimeoutMs(notification);
        if (ms <= 0)
            return;

        const timer = Qt.createQmlObject("import QtQuick; Timer { repeat: false }", root);
        timer.interval = ms;
        timer.triggered.connect(() => {
            timer.destroy();
            root.releaseTransient(notification);
        });

        // Closed some other way first (app-side close, dismissAll()) — cancel
        // the pending timer instead of firing a stale dismiss() later.
        notification.closed.connect(() => timer.destroy());
        timer.running = true;
    }

    // Transient notifications are never filed in history, so nothing else
    // holds a reference once their lifetime ends — release tracked state
    // directly. Shared by the DND-hidden expiry above and dismissAll() below.
    function releaseTransient(n: var): void {
        if (n.transient)
            n.dismiss();
    }

    // ── Mutation ────────────────────────────────────────────────────────────

    function pushHistory(n: var): void {
        const next = [n].concat(root.history);

        // Anything past the cap is released, otherwise it stays tracked
        // forever and the server's set grows without bound.
        const evicted = next.splice(Settings.notificationHistoryLimit);
        root.history = next;
        for (const old of evicted)
            old.dismiss();
    }

    // Hide a toast without filing the notification away as read. Mirrors
    // GNOME: closing a banner leaves it in the tray.
    function dropPopup(n: Notification): void {
        const next = root.popups.filter(x => x !== n);
        if (next.length === root.popups.length)
            return;
        root.popups = next;
        root.releaseTransient(n);
    }

    function dismiss(n: Notification): void {
        n.dismiss();
    }

    function dismissAll(): void {
        // Copy first: dismiss() re-enters through forget() and rewrites both
        // lists while we iterate.
        const all = root.history.slice();

        // Transient notifications are never filed in history — whether
        // currently shown as a popup or hidden by Do Not Disturb with a
        // pending scheduleTransientExpiry() timer — so releasing them needs
        // its own pass over the server's full tracked set.
        const transients = root.active.values.filter(n => n.transient);

        root.history = [];
        root.popups = [];
        for (const n of all)
            n.dismiss();
        for (const n of transients)
            root.releaseTransient(n);
        root.unreadCount = 0;
    }

    function dismissApp(appName: string): void {
        const doomed = root.history.filter(n => (n.appName || "Notifications") === appName);
        root.history = root.history.filter(n => doomed.indexOf(n) === -1);
        root.popups = root.popups.filter(n => doomed.indexOf(n) === -1);
        for (const n of doomed)
            n.dismiss();
    }

    function markAllRead(): void {
        root.unreadCount = 0;
    }

    // Called from the `closed` signal — the object is on its way out, so this
    // only ever removes references, never touches the notification.
    function forget(n: var): void {
        delete root.arrivals[n.id];
        if (root.history.indexOf(n) !== -1)
            root.history = root.history.filter(x => x !== n);
        if (root.popups.indexOf(n) !== -1)
            root.popups = root.popups.filter(x => x !== n);
    }
}