/**
 * Copyright 2018, OpenCensus Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { StatsEventListener } from '../exporters/types';
import { Metric } from '../metrics/export/types';
import { TagMap } from '../tags/tag-map';
import { TagKey, TagValue } from '../tags/types';
/** Default type for functions */
declare type Func<T> = (...args: any[]) => T;
/** Main interface for stats. */
export interface Stats {
    /**
     * Creates a view.
     * @param name The view name
     * @param measure The view measure
     * @param aggregation The view aggregation type
     * @param tagKeys The view columns (tag keys)
     * @param description The view description
     * @param bucketBoundaries The view bucket boundaries for a distribution
     *     aggregation type
     */
    createView(name: string, measure: Measure, aggregation: AggregationType, tagKeys: TagKey[], description: string, bucketBoundaries?: number[]): View;
    /**
     * Registers a view to listen to new measurements in its measure.
     * @param view The view to be registered
     */
    registerView(view: View): void;
    /**
     * Creates a measure of type Double.
     * @param name The measure name
     * @param unit The measure unit
     * @param description The measure description
     */
    createMeasureDouble(name: string, unit: MeasureUnit, description?: string): Measure;
    /**
     * Creates a measure of type Int64. Values must be integers up to
     * Number.MAX_SAFE_INTERGER.
     * @param name The measure name
     * @param unit The measure unit
     * @param description The measure description
     */
    createMeasureInt64(name: string, unit: MeasureUnit, description?: string): Measure;
    /**
     * Updates all views with the new measurements.
     * @param measurements A list of measurements to record
     * @param tags optional The tags to which the value is applied.
     *     tags could either be explicitly passed to the method, or implicitly
     *     read from current execution context.
     * @param attachments optional The contextual information associated with an
     *     example value. The contextual information is represented as key - value
     *     string pairs.
     */
    record(measurements: Measurement[], tags?: TagMap, attachments?: {
        [key: string]: string;
    }): void;
    /**
     * Remove all registered Views and exporters from the stats.
     */
    clear(): void;
    /**
     * Gets a collection of produced Metric`s to be exported.
     * @returns The List of metrics.
     */
    getMetrics(): Metric[];
    /**
     * Registers an exporter to send stats data to a service.
     * @param exporter An stats exporter
     */
    registerExporter(exporter: StatsEventListener): void;
    /**
     * Unregisters an exporter. It should be called whenever the exporter is not
     * needed anymore.
     * @param exporter An stats exporter
     */
    unregisterExporter(exporter: StatsEventListener): void;
    /**
     * Enters the scope of code where the given `TagMap` is in the current context
     * (replacing the previous `TagMap`).
     * @param tags The TagMap to be set to the current context.
     * @param fn Callback function.
     * @returns The callback return.
     */
    withTagContext<T>(tags: TagMap, fn: Func<T>): T;
    /** Gets the current tag context. */
    getCurrentTagContext(): TagMap;
}
/**
 * Describes the type of the individual values/measurements recorded by an
 * application. It includes information such as the type of measurement, the
 * units of measurement and descriptive names for the data. This provides the
 * fundamental type used for recording data.
 */
export interface Measure {
    /**
     * A string by which the measure will be referred to, e.g.
     * "rpc_server_latency". Names MUST be unique within the library.
     */
    readonly name: string;
    /** Describes the measure, e.g. "RPC latency in seconds". */
    readonly description?: string;
    /**
     * Describes the unit used for the Measure. Follows the format described by
     * http://unitsofmeasure.org/ucum.html.
     */
    readonly unit: MeasureUnit;
    /** The type used for this Measure. */
    readonly type: MeasureType;
}
/**
 * Describes the unit used for the Measure. Should follows the format described
 * by http://unitsofmeasure.org/ucum.html.
 */
export declare enum MeasureUnit {
    UNIT = "1",
    BYTE = "by",
    KBYTE = "kb",
    SEC = "s",
    MS = "ms",
    NS = "ns"
}
/** Describes the types of a Measure. It can be Int64 or a Double type. */
export declare enum MeasureType {
    INT64 = "INT64",
    DOUBLE = "DOUBLE"
}
/** Describes a data point to be collected for a Measure. */
export interface Measurement {
    /** The measure to which the value is applied */
    readonly measure: Measure;
    /**
     * The recorded value. If the measure has type INT64, value must be an integer
     * up to Number.MAX_SAFE_INTERGER.
     */
    readonly value: number;
}
/**
 * Defines how individual measurements are broken down by tags and aggregated.
 */
export interface View {
    /**
     * A string by which the View will be referred to, e.g. "rpc_latency". Names
     * MUST be unique within the library.
     */
    readonly name: string;
    /** Describes the view, e.g. "RPC latency distribution" */
    readonly description: string;
    /** The Measure to which this view is applied. */
    readonly measure: Measure;
    /**
     * An Aggregation describes how data collected is aggregated.
     * There are four aggregation types: count, sum, lastValue and distirbution.
     */
    readonly aggregation: AggregationType;
    /** The start time for this view */
    readonly startTime: number;
    /**
     * The end time for this view - represents the last time a value was recorded
     */
    endTime?: number;
    /** true if the view was registered */
    registered: boolean;
    /**
     * Records a measurement in the proper view's row. This method is used by
     * Stats. User should prefer using Stats.record() instead.
     *
     * Measurements with measurement type INT64 will have its value truncated.
     * @param measurement The measurement to record
     * @param tags The tags to which the value is applied
     * @param attachments optional The contextual information associated with an
     *     example value. THe contextual information is represented as key - value
     *     string pairs.
     */
    recordMeasurement(measurement: Measurement, tags: TagMap, attachments?: {
        [key: string]: string;
    }): void;
    /**
     * Returns a snapshot of an AggregationData for that tags/labels values.
     * @param tagValues The desired data's tag values.
     */
    getSnapshot(tagValues: Array<TagValue | null>): AggregationData;
    /** Gets the view's tag keys */
    getColumns(): TagKey[];
    /** Gets view`s metric */
    getMetric(start: number): Metric;
}
/**
 * Informs the type of the aggregation. It can be: count, sum, lastValue or
 * distribution.
 */
export declare enum AggregationType {
    COUNT = 0,
    SUM = 1,
    LAST_VALUE = 2,
    DISTRIBUTION = 3
}
/** Defines how data is collected and aggregated */
export interface AggregationMetadata {
    /** The aggregation type of the aggregation data */
    readonly type: AggregationType;
    /** The tagValues that this AggregationData collects and aggregates */
    readonly tagValues: Array<TagValue | null>;
    /** The latest timestamp a new data point was recorded */
    timestamp: number;
}
/**
 * Data collected and aggregated with this AggregationData will be summed
 * up.
 */
export interface SumData extends AggregationMetadata {
    type: AggregationType.SUM;
    /** The current accumulated value */
    value: number;
}
/**
 * This AggregationData counts the number of measurements recorded.
 */
export interface CountData extends AggregationMetadata {
    type: AggregationType.COUNT;
    /** The current counted value */
    value: number;
}
/**
 * This AggregationData represents the last recorded value. This is useful
 * when giving support to Gauges.
 */
export interface LastValueData extends AggregationMetadata {
    type: AggregationType.LAST_VALUE;
    /** The last recorded value */
    value: number;
}
/** This AggregationData contains a histogram of the collected values. */
export interface DistributionData extends AggregationMetadata {
    type: AggregationType.DISTRIBUTION;
    /** The first timestamp a datapoint was added */
    readonly startTime: number;
    /** Get the total count of all recorded values in the histogram */
    count: number;
    /** Sum of all recorded values in the histogram */
    sum: number;
    /** Get the computed mean value of all recorded values in the histogram */
    mean: number;
    /**
     * Get the computed standard deviation of all recorded values in the
     * histogram
     */
    stdDeviation: number;
    /**
     * Get the computed sum of squared deviations of all recorded values in the
     * histogram.
     */
    sumOfSquaredDeviation: number;
    /** Bucket distribution of the histogram */
    buckets: Bucket[];
    /** Buckets count */
    bucketCounts?: number[];
    /** If the distribution does not have a histogram, then omit this field. */
    exemplars?: StatsExemplar[];
}
/**
 * Exemplars are example points that may be used to annotate aggregated
 * Distribution values. They are metadata that gives information about a
 * particular value added to a Distribution bucket.
 */
export interface StatsExemplar {
    /**
     * Value of the exemplar point. It determines which bucket the exemplar
     * belongs to.
     */
    readonly value: number;
    /** The observation (sampling) time of the above value. */
    readonly timestamp: number;
    /** Contextual information about the example value. */
    readonly attachments: {
        [key: string]: string;
    };
}
export declare type Bucket = number;
export declare type AggregationData = SumData | CountData | LastValueData | DistributionData;
export {};