/**
 * Self-update service — polls the npm registry for the version published on the
 * update channel and triggers a graceful update. Update rules:
 *   - SAME channel: forward-only — update only when the published version is a
 *     strictly newer semver (an equal/older version is ignored, never a
 *     downgrade).
 *   - Channel CHANGED (operator edited install.config.json):
 *       · legacy/self-spawn mode — force-switch to the new channel's published
 *         version even if it is an OLDER semver (the self-spawn respawn pins that
 *         exact version, so the switch lands).
 *       · broker mode — the switch is DEFERRED, not applied: the supervisor
 *         respawns its own frozen launch channel and ignores install.config, so
 *         a force-switch + /restart would restart-loop. The poller keeps the
 *         launch channel forward-only until a full-stack restart (or the pending
 *         supervisor-side change that passes targetVersion to /restart / re-reads
 *         install.config) makes the switch honourable.
 *     See decideUpdate.
 *
 * Single lifecycle owner (plan §4.5, Phase 4): this service no longer spawns
 * its own replacement. It quiesces the agents, then asks the supervisor
 * (POST /restart) to run the shared teardown/respawn choreography — the spawn
 * command re-resolves the channel version by itself (npx). The pre-Phase-4
 * self-spawn path survives only as the legacy fallback for dev mode without a
 * supervisor, gated by the same SENSORIUM_BROKER_SPAWN cutover flag the spawn
 * services use (see brokerSpawnMode in spawn-common.ts).
 *
 * Entry point: startSelfUpdatePoller({ pkgVersion, httpPort })
 * Call once after the HTTP server is listening (HTTP mode only).
 *
 * Environment variables:
 *   SELF_UPDATE_ENABLED        "false" to disable (default: enabled)
 *   SELF_UPDATE_POLL_INTERVAL_MS  Registry check interval (default: 60000)
 *   SELF_UPDATE_MIN_UPTIME_MS  Min uptime before first update (default: 600000)
 *   SELF_UPDATE_GRACE_MS       Grace period for agents to observe flag (default: 30000)
 *   SENSORIUM_BROKER_SPAWN     Two-state spawn switch (see brokerSpawnMode):
 *                              1/required = supervisor-only, 0/off = legacy
 *                              self-spawn; unset → win32 required, else off
 *   MCP_START_COMMAND          Launch-time command; its "@<tag>" is the baseline
 *                              (currently-running) channel and the fallback when
 *                              install.config.json cannot be read.
 *
 * Update channel:
 *   Resolved LIVE from ~/.remote-copilot-mcp/install.config.json (MCPStartCommand
 *   → the npm spec tag in "sensorium-mcp@<tag>", e.g. @latest or @board) on every
 *   poll cycle. In legacy/self-spawn mode, editing that file re-points the poller
 *   with NO restart or Install-Sensorium.ps1 re-run. In broker/production mode a
 *   file-only edit does NOT complete the switch (see above) — the supervisor is
 *   frozen on its launch channel, so switching production needs a full-stack
 *   restart / installer re-run (or the pending supervisor-side change). If the
 *   config is missing/garbled/tag-less the poller falls back to the launch-time
 *   MCP_START_COMMAND channel; the baseline it compares against is always what
 *   THIS process was launched on. No config / no env / no tag = "latest".
 */
/**
 * Resolve the DESIRED release channel LIVE from install.config.json on every
 * call, so editing that file re-points the poller without any process restart
 * or installer re-run (behaviour 1). The channel is the "@<tag>" in the config's
 * MCPStartCommand — the same field Install-Sensorium.ps1 reads.
 *
 * Defensive by construction: any problem — file missing, unreadable, garbled
 * JSON, MCPStartCommand absent/non-string, or no parseable @tag — falls back to
 * the launch-time env channel (getUpdateChannel). A broken config can therefore
 * never crash the poller nor strand it on a bad channel; worst case it keeps
 * following the channel it was launched with.
 */
export declare function resolveDesiredChannel(): string;
/**
 * True iff `a` is a strictly NEWER semver than `b`. Used to keep same-channel
 * updates forward-only. Defensive: if either version fails to parse, returns
 * false — an unparseable version must never justify a same-channel update, which
 * could otherwise be an accidental downgrade.
 */
export declare function isStrictlyNewer(a: string, b: string): boolean;
/** The verdict of one poll cycle — kept pure (no I/O) so the decision logic is
 *  unit-testable in isolation from the registry fetch and the restart path. */
export type UpdateDecision = {
    action: "none";
} | {
    action: "adopt-channel";
    channel: string;
} | {
    action: "defer-channel-switch";
    channel: string;
} | {
    action: "update";
    targetVersion: string;
    reason: "forward" | "channel-switch";
};
/**
 * Decide what a single poll cycle should do, given the running version/channel,
 * the freshly-resolved desired channel, and whether we are in broker mode.
 *
 * `remoteVersion` is the published version of the channel this cycle actually
 * TRACKS: the desired channel in legacy/self-spawn mode, but the LAUNCH channel
 * (currentChannel) in broker mode — because the supervisor can only respawn its
 * own frozen launch channel (see the caller).
 *
 *  - Legacy/self-spawn mode, channel CHANGED (behaviour 2): force-switch to the
 *    desired channel's published version even if it is an OLDER semver — the
 *    self-spawn path pins that exact version, so the switch lands. If that
 *    version is already running, just adopt the new channel label.
 *  - Broker mode, channel CHANGED: DO NOT force-switch. The supervisor respawns
 *    its frozen launch channel and ignores install.config, so a force-switch +
 *    /restart would loop forever (each child comes up on the launch channel and
 *    re-detects the mismatch). We defer the switch and keep tracking the launch
 *    channel forward-only, so a genuine forward move on the launch channel still
 *    applies while the switch waits for a full-stack restart.
 *  - SAME channel (either mode): forward-only — update only when the published
 *    version is strictly newer (an equal/older version is ignored, so a poll can
 *    never downgrade).
 */
export declare function decideUpdate(args: {
    currentVersion: string;
    currentChannel: string;
    desiredChannel: string;
    remoteVersion: string;
    brokerMode: boolean;
}): UpdateDecision;
/**
 * Fetch the published version of sensorium-mcp for the given update channel
 * (npm dist-tag) from the registry. Defaults to the live desired channel when no
 * channel is supplied, so external callers keep the previous behaviour.
 * Returns null on any error so the caller can silently skip this poll cycle.
 */
export declare function getRemoteVersion(channel?: string): Promise<string | null>;
/**
 * Run one check cycle. The desired channel is resolved LIVE from
 * install.config.json each cycle (behaviour 1). A change vs the running channel
 * force-switches to that channel's published version even if it is older
 * (behaviour 2); a same-channel poll updates only when the published version is
 * strictly newer. See decideUpdate for the full rule set.
 */
export declare function checkForUpdate(): Promise<void>;
/**
 * Start the self-update polling loop.
 * Call once after the HTTP server is listening (HTTP mode only).
 *
 * @param config.pkgVersion  Current package version string (e.g. "3.0.30").
 * @param config.httpPort    HTTP port the server is bound to (for health polling).
 */
export declare function startSelfUpdatePoller(config: {
    pkgVersion: string;
    httpPort: number;
    onBeforeSpawn?: () => Promise<void> | void;
}): void;
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