import type { ConsumerOptions, StopOptions, UpdatableOptions } from "./types.js";
import { TypedEventEmitter } from "./emitter.js";
/**
 * [Usage](https://bbc.github.io/sqs-consumer/index.html#usage)
 */
export declare class Consumer extends TypedEventEmitter {
    private pollingTimeoutId;
    private stopped;
    protected queueUrl: string;
    private isFifoQueue;
    private suppressFifoWarning;
    private handleMessage;
    private handleMessageBatch;
    private preReceiveMessageCallback?;
    private postReceiveMessageCallback?;
    private sqs;
    private handleMessageTimeout;
    private attributeNames;
    private messageAttributeNames;
    private messageSystemAttributeNames;
    private shouldDeleteMessages;
    private alwaysAcknowledge;
    private batchSize;
    private visibilityTimeout;
    private terminateVisibilityTimeout;
    private waitTimeSeconds;
    private authenticationErrorTimeout;
    private pollingWaitTimeMs;
    private pollingCompleteWaitTimeMs;
    private heartbeatInterval;
    private isPolling;
    private stopRequestedAtTimestamp;
    abortController: AbortController;
    private extendedAWSErrors;
    private strictReturn;
    constructor(options: ConsumerOptions);
    /**
     * Creates a new SQS consumer.
     */
    static create(options: ConsumerOptions): Consumer;
    /**
     * Start polling the queue for messages.
     */
    start(): void;
    /**
     * A reusable options object for sqs.send that's used to avoid duplication.
     */
    private get sqsSendOptions();
    /**
     * Stop polling the queue for messages (pre existing requests will still be made until concluded).
     */
    stop(options?: StopOptions): void;
    /**
     * Wait for final poll and in flight messages to complete.
     * @private
     */
    private waitForPollingToComplete;
    /**
     * Returns the current status of the consumer.
     * This includes whether it is running or currently polling.
     */
    get status(): {
        isRunning: boolean;
        isPolling: boolean;
    };
    /**
     * Validates and then updates the provided option to the provided value.
     * @param option The option to validate and then update
     * @param value The value to set the provided option to
     */
    updateOption(option: UpdatableOptions, value: ConsumerOptions[UpdatableOptions]): void;
    /**
     * Emit one of the consumer's error events depending on the error received.
     * @param err The error object to forward on
     * @param message The message that the error occurred on
     */
    private emitError;
    /**
     * Poll for new messages from SQS
     */
    private poll;
    /**
     * Send a request to SQS to retrieve messages
     * @param params The required params to receive messages from SQS
     */
    private receiveMessage;
    /**
     * Handles the response from AWS SQS, determining if we should proceed to
     * the message handler.
     * @param response The output from AWS SQS
     */
    private handleSqsResponse;
    /**
     * Process a message that has been received from SQS. This will execute the message
     * handler and delete the message once complete.
     * @param message The message that was delivered from SQS
     */
    private processMessage;
    /**
     * Process a batch of messages from the SQS queue.
     * @param messages The messages that were delivered from SQS
     */
    private processMessageBatch;
    /**
     * Trigger a function on a set interval
     * @param heartbeatFn The function that should be triggered
     */
    private startHeartbeat;
    /**
     * Change the visibility timeout on a message
     * @param message The message to change the value of
     * @param timeout The new timeout that should be set
     */
    private changeVisibilityTimeout;
    /**
     * Change the visibility timeout on a batch of messages
     * @param messages The messages to change the value of
     * @param timeout The new timeout that should be set
     */
    private changeVisibilityTimeoutBatch;
    /**
     * Trigger the applications handleMessage function
     * @param message The message that was received from SQS
     */
    private executeHandler;
    /**
     * Execute the application's message batch handler
     * @param messages The messages that should be forwarded from the SQS queue
     */
    private executeBatchHandler;
    /**
     * Delete a single message from SQS
     * @param message The message to delete from the SQS queue
     */
    private deleteMessage;
    /**
     * Delete a batch of messages from the SQS queue.
     * @param messages The messages that should be deleted from SQS
     */
    private deleteMessageBatch;
}