export interface Spec<T> {
    /**
     * An Array that lists the admissable parsed values for the env var.
     */
    choices?: ReadonlyArray<T>;
    /**
     * A string that describes the env var.
     */
    desc?: string;
    /**
     * An example value for the env var.
     */
    example?: string;
    /**
     * A url that leads to more detailed documentation about the env var.
     */
    docs?: string;
    /**
     * A fallback value, which will be used if the env var wasn't specified. Providing a default effectively makes the env var optional.
     */
    default?: NonNullable<T> | undefined;
    /**
     * A fallback value to use only when NODE_ENV is not 'production'.
     * This is handy for env vars that are required for production environments, but optional for development and testing.
     */
    devDefault?: NonNullable<T> | undefined;
}
type OptionalAttrs<T> = {
    default: undefined;
} | {
    devDefault: undefined;
} | {
    default: undefined;
    devDefault: undefined;
} | {
    default: NonNullable<T>;
    devDefault: undefined;
} | {
    default: undefined;
    devDefault: NonNullable<T>;
};
type RequiredAttrs<T> = {
    default: NonNullable<T>;
} | {
    devDefault: NonNullable<T>;
} | {
    devDefault: NonNullable<T>;
    default: NonNullable<T>;
} | {};
type DefaultKeys = 'default' | 'devDefault';
type OptionalSpec<T> = Spec<T> & OptionalAttrs<T>;
type OptionalTypelessSpec = Omit<OptionalSpec<unknown>, 'choices'>;
type RequiredSpec<T> = Spec<T> & RequiredAttrs<T>;
type RequiredTypelessSpec = Omit<RequiredSpec<unknown>, 'choices' | DefaultKeys>;
type ChoicelessOptionalSpec<T> = Omit<Spec<T>, 'choices' | DefaultKeys> & OptionalAttrs<T>;
type ChoicelessRequiredSpec<T> = Omit<Spec<T>, 'choices' | DefaultKeys> & RequiredAttrs<T>;
type WithParser<T> = {
    _parse: (input: string) => T;
};
export type RequiredValidatorSpec<T> = RequiredSpec<T> & WithParser<T>;
export type OptionalValidatorSpec<T> = OptionalSpec<T> & WithParser<T>;
export type ValidatorSpec<T> = RequiredValidatorSpec<T> | OptionalValidatorSpec<T>;
export interface ExactValidator<T> {
    (spec: OptionalSpec<T>): OptionalValidatorSpec<T>;
    (spec?: RequiredSpec<T>): RequiredValidatorSpec<T>;
}
export interface BaseValidator<BaseT> {
    <T extends BaseT>(spec: OptionalSpec<T>): OptionalValidatorSpec<T>;
    (spec: ChoicelessRequiredSpec<BaseT>): RequiredValidatorSpec<BaseT>;
    <T extends BaseT>(spec?: RequiredSpec<T>): RequiredValidatorSpec<T>;
}
export interface StructuredValidator {
    (): RequiredValidatorSpec<any>;
    <T>(): RequiredValidatorSpec<T>;
    (spec: RequiredTypelessSpec): RequiredValidatorSpec<any>;
    (spec: OptionalTypelessSpec): OptionalValidatorSpec<any>;
    <T>(spec: ChoicelessOptionalSpec<T>): OptionalValidatorSpec<T>;
    <T>(spec: ChoicelessRequiredSpec<T>): RequiredValidatorSpec<T>;
}
export type SpecsOutput<S> = {
    [K in keyof S]: unknown;
};
export type CleanedEnv<S> = S extends Record<string, ValidatorSpec<unknown>> ? Readonly<{
    [K in keyof S]: S[K] extends OptionalValidatorSpec<infer U> ? U | undefined : S[K] extends RequiredValidatorSpec<infer U> ? U : never;
} & CleanedEnvAccessors> : never;
export interface CleanedEnvAccessors {
    /** true if NODE_ENV === 'development' */
    readonly isDevelopment: boolean;
    readonly isDev: boolean;
    /** true if NODE_ENV === 'test' */
    readonly isTest: boolean;
    /** true if NODE_ENV === 'production' */
    readonly isProduction: boolean;
    readonly isProd: boolean;
}
export interface ReporterOptions<T> {
    errors: Partial<Record<keyof T, Error>>;
    env: unknown;
}
export interface CleanOptions<T> {
    /**
     * Pass in a function to override the default error handling and console output.
     * See ./reporter.ts for the default implementation.
     */
    reporter?: ((opts: ReporterOptions<T>) => void) | null;
}
export interface StrictProxyMiddlewareOptions {
    /**
     * A list of extra inspectable properties to add to the middleware.
     *
     * This is useful if you want to add support for framework-specific values.
     */
    extraInspectables?: string[];
}
export {};