import { Position } from '.';
import { Brand } from './brand';
/**
 * Object property names that are unsafe to use as keys when building or
 * walking a nested object tree from untrusted input: assigning through
 * them reaches Object.prototype and pollutes every object in the process.
 * None are valid Signal K context or path segments, so deltas containing
 * them are dropped rather than allowed to mutate the prototype chain.
 * @hidden
 */
export declare const FORBIDDEN_PATH_KEYS: Set<string>;
/** @hidden */
export interface WithContext {
    context: Context;
}
/** @inline - Not exported as part of the public API */
type NormalizedBaseDelta = {
    context: Context;
    $source: SourceRef;
    /** @deprecated Use $source instead */
    source?: Source;
    path: Path;
    timestamp: Timestamp;
};
/** @hidden */
export type NormalizedMetaDelta = NormalizedBaseDelta & {
    value: MetaValue;
    isMeta: true;
};
/** @hidden */
export type NormalizedValueDelta = NormalizedBaseDelta & {
    value: Value;
    /**
     * Optional staleness-state container preserved through the cache so
     * replayed deltas (and the HTTP API snapshot built from the cache)
     * surface the server's `state.timedOut` flag, matching what a live WS
     * client received in the original delta.
     */
    state?: PathValueState;
    isMeta: false;
};
/** @hidden */
export type NormalizedDelta = NormalizedValueDelta | NormalizedMetaDelta;
/** @category Server API */
export type SourceRef = Brand<string, 'sourceRef'>;
/** @category Server API */
export type Source = any;
/** @category Server API */
export type Path = Brand<string, 'path'>;
/** @category Server API */
export type Timestamp = Brand<string, 'timestamp'>;
/** @category Server API */
export type Context = Brand<string, 'context'>;
/** @category Server API */
export type NotificationId = Brand<string, 'notificationId'>;
/** @category Server API */
export type Value = object | number | string | null | Notification | boolean;
/** @category Server API */
export interface Delta {
    context?: Context;
    updates: Update[];
}
/**
 * @deprecated earlier mistake assumed ValuesDelta and MetaDelta were separate
 * @hidden
 */
export type ValuesDelta = Delta;
/**
 * @deprecated earlier mistake assumed ValuesDelta and MetaDelta were separate
 * @hidden
 */
export type MetaDelta = Delta;
/** @category Server API */
export type Update = {
    timestamp?: Timestamp;
    /** @deprecated Use $source (SourceRef) instead for more practical string-based referencing */
    source?: Source;
    $source?: SourceRef;
    notificationId?: NotificationId;
} & ({
    values: PathValue[];
} | {
    meta: Meta[];
});
/** @category Server API */
export declare function hasValues(u: Update): u is Update & {
    values: PathValue[];
};
/** @category Server API */
export declare function hasMeta(u: Update): u is Update & {
    meta: Meta[];
};
/** @category Server API */
export interface PathValue {
    path: Path;
    value: Value;
    state?: PathValueState;
}
/**
 * Out-of-band metadata about a particular delta value, set by the server when
 * a value is anything other than a fresh reading from its source. Distinct
 * from `Meta` (which describes the path itself) and from `value` (which is
 * what the source reported). Clients that don't recognise `state` ignore it.
 *
 * @category Server API
 */
export interface PathValueState {
    /**
     * Set to `true` on the synthetic delta the server emits when a source's
     * `meta.timeout` has elapsed since its last update. A sensor that
     * legitimately publishes `value: null` (e.g. an echosounder with no
     * bottom return) does not carry this flag.
     */
    readonly timedOut?: boolean;
    /**
     * The last good (non-null) value seen from the timed-out source and its
     * original timestamp. Absent if no good value was ever received.
     */
    readonly lastValue?: {
        readonly timestamp: Timestamp;
        readonly value: Value;
    };
}
/** @category Server API */
export interface Notification {
    state: ALARM_STATE;
    method: ALARM_METHOD[];
    message: string;
    status?: AlarmStatus;
    position?: Position;
    createdAt?: Timestamp;
    id?: string;
    data?: Record<string, Value>;
}
/** @category Server API */
export interface Meta {
    path: Path;
    value: MetaValue;
}
/**
 * Update contract for a path. Determines whether the server's staleness
 * enforcer treats silence as a failure (`periodic`) or as unchanged state
 * (`event`).
 *
 * @category Server API
 */
export type UpdateContract = 'periodic' | 'event';
/** @category Server API */
export interface MetaValue {
    description?: string;
    units?: string;
    example?: string;
    /**
     * Time in seconds after which a path+source's last value is considered
     * stale. `'auto'` lets the server derive the timeout from observed delta
     * arrival rate. `0` disables enforcement for the path.
     */
    timeout?: number | 'auto';
    /**
     * Declares the path's update contract for staleness enforcement.
     * Defaults to `'periodic'` when absent.
     */
    updateContract?: UpdateContract;
    displayName?: string;
    displayScale?: {
        lower: number;
        upper: number;
    };
    zones?: Zone[];
    supportsPut?: boolean;
    displayUnits?: {
        category: string;
        targetUnit: string;
        displayFormat?: string;
        formula: string;
        inverseFormula: string;
        symbol: string;
    };
}
/** @category Server API */
export declare enum ALARM_STATE {
    nominal = "nominal",
    normal = "normal",
    alert = "alert",
    warn = "warn",
    alarm = "alarm",
    emergency = "emergency"
}
/** @category Server API */
export declare enum ALARM_METHOD {
    visual = "visual",
    sound = "sound"
}
/** @category Server API */
export interface AlarmStatus {
    silenced: boolean;
    acknowledged: boolean;
    acknowledgedAt?: Timestamp;
    canSilence: boolean;
    canAcknowledge: boolean;
    canClear: boolean;
}
/** @category Server API */
export interface Zone {
    lower: number | undefined;
    upper: number | undefined;
    state: ALARM_STATE;
    message: string;
}
export {};
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