/**
 * @module EnvAccessor
 */
import { type StandardSchemaV1 } from "@standard-schema/spec";
import { type BaseEnvConfig, type IEnvAccessor, type RawEnvConfig } from "../../env-accessor/contracts/_module.js";
import { type UndefinedToNull, type OneOrMore, type AsyncLazyable } from "../../utilities/_module.js";
/**
 * Settings for configuring an {@link  EnvAccessor | `EnvAccessor`} instance.
 *
 * @template TEnvConfig The environment config type.
 */
export type EnvAccessorSettings<TEnvConfig extends BaseEnvConfig = BaseEnvConfig> = {
    /**
     * The schema used to validate and type the environment config.
     */
    schema: StandardSchemaV1<Partial<Record<string, string>>, TEnvConfig>;
    /**
     * One or more sources (sync/async/lazy) providing raw environment config values.
     */
    sources: OneOrMore<AsyncLazyable<RawEnvConfig>>;
};
/**
 * `EnvAccessor` provides type-safe access to environment variables, with optional schema validation.
 *
 * It supports multiple sources (sync/async/lazy), schema validation, and convenient access patterns.
 *
 * @template TEnvConfig The environment config type.
 * @group Implementations
 */
export declare class EnvAccessor<TEnvConfig extends BaseEnvConfig> implements IEnvAccessor<TEnvConfig> {
    private envConfig;
    private readonly schema;
    private readonly sources;
    /**
     * @example
     * ```ts
     * import { EnvAccessor } from "@daiso-tech/core/env-accessor";
     * import { z } from "zod";
     * import { SecretsManagerClient, GetSecretValueCommand } from "@aws-sdk/client-secrets-manager";
     *
     *
     * // Combine AWS Secrets Manager and process.env as sources
     * // Note: The order matters—later sources override previous ones for overlapping keys.
     * const secretsManager = new SecretsManagerClient({ region: "us-east-1" });
     * const sources = [
     *   process.env,
     *   async () => {
     *     const secret = await secretsManager.send(
     *       new GetSecretValueCommand({ SecretId: "my-app/env" })
     *     );
     *     return JSON.parse(secret.SecretString ?? "{}");
     *   },
     * ];
     *
     * // Define a schema for your environment variables
     * const schema = z.object({
     *   NODE_ENV: z.string(),
     *   PORT: z.string().default("3000").pipe(z.coerce.number()),
     * });
     *
     * // Initialize the accessor
     * const accessor = new EnvAccessor({ schema, sources });
     * await accessor.init();
     *
     * // Retrieve a value
     * const port = accessor.get("PORT");
     * ```
     */
    constructor(settings: EnvAccessorSettings<TEnvConfig>);
    /**
     * Initialize the EnvAccessor by resolving all sources and validating the merged config.
     *
     * @returns Promise that resolves when initialization is complete.
     */
    init(): Promise<void>;
    get<TField extends keyof TEnvConfig, TValue extends TEnvConfig[TField]>(field: TField): UndefinedToNull<TValue>;
    getOr<TField extends keyof TEnvConfig, TValue extends TEnvConfig[TField]>(field: TField, defaultValue: NonNullable<TValue>): NonNullable<TValue>;
}