export type ProfileSwitchDecision = {
    allowed: true;
    backendChanged: boolean;
} | {
    allowed: false;
    reason: 'cross-backend-live-session';
};
/**
 * Pure switch policy shared by every surface (Slack / Feishu / Web).
 *
 * - No history (fresh session) → any switch is allowed, including across backends. `backendChanged`
 *   reports whether the backend moved (the caller may want it for messaging), but nothing is blocked.
 * - Has history (live conversation) → only a same-backend switch is allowed. A cross-backend switch
 *   is rejected because the running conversation cannot be resumed on a different backend; the user
 *   must start a new session to change backend.
 *
 * NOTE: `claudeBackend` (print vs tui) is deliberately NOT part of the identity — those share
 * `backend: 'claude'` and count as the same backend (product decision), so switching between a
 * print and a tui claude profile mid-conversation is allowed.
 */
export declare function decideProfileSwitch(opts: {
    currentBackend: string;
    targetBackend: string;
    hasHistory: boolean;
}): ProfileSwitchDecision;
export type SwitchProfileFailure = 'unknown-profile' | 'cross-backend-live-session';
export interface SwitchProfileResult {
    ok: boolean;
    /** The requested profile name (echoed back). */
    name: string;
    /** The channel's effective backend before the switch (empty when the profile was unknown). */
    currentBackend: string;
    /** The target profile's backend (empty when the profile was unknown). */
    targetBackend: string;
    /** True when the switch moved to a different backend (only possible on a fresh session). */
    backendChanged: boolean;
    /** Present only when `ok` is false. */
    reason?: SwitchProfileFailure;
}
/** Does the channel's session already carry conversation history? A fresh (just-created) session has
 *  a ledger entry with zero turns; a live conversation has ≥1 turn. */
export declare function channelHasHistory(channel: string): Promise<boolean>;
/**
 * Switch the active profile for a channel/session under the shared rule. Validates the profile,
 * applies {@link decideProfileSwitch}, and on success sets the channel's active profile AND syncs the
 * session-registry record's `profileName` (so `!resume` and the Web session list reflect it). Never
 * resets the session — a same-backend switch keeps the conversation, the model changes on the next
 * turn. Returns a structured result; the caller maps it to a reply / tRPC error.
 */
export declare function switchChannelProfile(opts: {
    channel: string;
    name: string;
}): Promise<SwitchProfileResult>;