/**
 * Base API client with shared functionality for both browser and standalone environments.
 */
export interface ApiResponse<T> {
    data?: T;
    success: boolean;
    status: number;
    headers: Headers;
    error?: Error | string;
    connectionError?: boolean;
}
export interface ApiClientConfig {
    baseUrl: string;
    apiKey: string;
    onConnectionChange?: (isConnected: boolean) => void;
}
/** Query parameters that can be passed to GET requests */
export type QueryParams = Record<string, string | number | boolean | undefined | null>;
/**
 * Abstract base class for API clients.
 * Provides shared functionality for making HTTP requests.
 */
export declare abstract class BaseApiClient {
    /**
     * Error messages that indicate a connection failure rather than a server error.
     * Grouped by source/environment.
     */
    protected static readonly CONNECTION_ERROR_MESSAGES: string[];
    protected onConnectionChange?: (isConnected: boolean) => void;
    baseUrl: string;
    api_key: string;
    constructor(config: ApiClientConfig);
    protected isConnectionError(error: unknown): boolean;
    protected setConnectionStatus(isConnected: boolean): void;
    protected baseHeaders(): Headers;
    /** Override in subclasses to provide the active UI locale for the Accept-Language header. */
    protected getLocale(): string | undefined;
    protected mergeHeaders(base: Headers, extra?: HeadersInit): Headers;
    /**
     * Builds a query string from params, filtering out undefined/null values.
     */
    protected buildQueryString(params?: QueryParams): string;
    /**
     * Override this in subclasses to add environment-specific request options.
     */
    protected abstract getRequestOptions(): RequestInit;
    /**
     * Override this in subclasses to handle connection errors (e.g., Sentry reporting).
     */
    protected abstract handleConnectionError(error: unknown, endpoint: string, method: string): void;
    protected request<T>(method: string, endpoint: string, body?: object, headers?: HeadersInit): Promise<ApiResponse<T>>;
    get<T>(endpoint: string, headers?: HeadersInit, params?: QueryParams): Promise<ApiResponse<T>>;
    post<T>(endpoint: string, body: object, headers?: HeadersInit): Promise<ApiResponse<T>>;
    patch<T>(endpoint: string, body: object, headers?: HeadersInit): Promise<ApiResponse<T>>;
    delete<T>(endpoint: string, headers?: HeadersInit): Promise<ApiResponse<T>>;
}