import type { Maybe, Nullable } from "./Maybe";
export type StrEnumType<T extends string> = {
    [K in T]: K;
};
/**
 * Helper methods and properties for string enum types created with {@link strEnum}.
 *
 * Provides type-safe utilities for working with predefined string literal types,
 * including validation, comparison, and transformation operations.
 *
 * @template T - The union of string literals that make up this enum
 */
export type StrEnumHelpers<T extends string> = {
    /** Array of all valid enum values in declaration order */
    values: T[];
    /** Number of enum values */
    length: number;
    /**
     * Synonym for {@link includes}. Checks if a string is a valid enum value.
     * @param s - String to check (can be null/undefined)
     * @returns Type predicate indicating if s is a valid enum value
     */
    has(s: Nullable<string>): s is T;
    /**
     * Type-safe check if a string is a valid enum value (case-sensitive).
     * @param s - String to check (can be null/undefined)
     * @returns Type predicate indicating if s is a valid enum value
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.includes("red") // true
     * Colors.includes("RED") // false
     */
    includes(s: Nullable<string>): s is T;
    /**
     * Get enum value with case-insensitive matching.
     * @param s - String to match (can be null/undefined)
     * @returns Matching enum value or undefined if no match
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.getCI("RED") // "red"
     * Colors.getCI("purple") // undefined
     */
    getCI(s: Nullable<string>): Maybe<T>;
    /**
     * Create a new array containing only the specified enum values.
     * @param t - Enum values to include
     * @returns Array of specified enum values
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.pick("red", "blue") // ["red", "blue"]
     */
    pick<O extends T>(...t: O[]): Extract<T, O>[];
    /**
     * Create a new array containing all enum values except the specified ones.
     * @param t - Enum values to exclude
     * @returns Array of remaining enum values
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.omit("green") // ["red", "blue"]
     */
    omit<O extends T>(...t: O[]): Exclude<T, O>[];
    /**
     * Get the zero-based index of an enum value.
     * @param s - Enum value to find (can be null/undefined)
     * @returns Index of the value or undefined if not found
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.indexOf("green") // 1
     * Colors.indexOf("purple") // undefined
     */
    indexOf(s: Nullable<string>): Maybe<number>;
    /**
     * Get the ordinal position of an enum value, or length if not found.
     * Useful for sorting where invalid values should sort last.
     * @param s - Enum value to find (can be null/undefined)
     * @returns Index of the value, or enum length if not found
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.ordinal("green") // 1
     * Colors.ordinal("purple") // 3 (length)
     */
    ordinal(s: Nullable<string>): number;
    /**
     * Synonym for {@link getCI}. Get enum value with case-insensitive matching.
     * @param s - String to validate (can be null/undefined)
     * @returns Valid enum value or undefined if no match
     */
    toValid(s: Nullable<string>): Maybe<T>;
    /**
     * Find the first valid enum value from a list of candidates.
     * @param arr - Array of potential enum values to check
     * @returns First valid enum value found, or undefined if none match
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.firstValid("purple", "GREEN", "red") // "green" (case-insensitive match)
     */
    firstValid(...arr: Nullable<string>[]): Maybe<T>;
    /**
     * Apply a function to a string if it's a valid enum value.
     * @param s - String to check and potentially transform
     * @param f - Function to apply if s is a valid enum value
     * @returns Result of function application, or undefined if s is invalid
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.mapValid("red", color => color.toUpperCase()) // "RED"
     * Colors.mapValid("purple", color => color.toUpperCase()) // undefined
     */
    mapValid<R>(s: Nullable<string>, f: (t: T) => R): Maybe<R>;
    /**
     * Compare two strings based on their enum order.
     * @param a - First string to compare
     * @param b - Second string to compare
     * @returns -1 if a < b, 0 if a === b, 1 if a > b, undefined if either is invalid
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.cmp("red", "green") // -1 (red comes before green)
     * Colors.cmp("blue", "red") // 1 (blue comes after red)
     */
    cmp(a: Nullable<string>, b: Nullable<string>): Maybe<number>;
    /**
     * Check if first enum value comes before second in declaration order.
     * @param a - First enum value
     * @param b - Second enum value
     * @returns True if a comes before b in the enum declaration
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.lt("red", "green") // true
     * Colors.lt("green", "red") // false
     */
    lt(a: T, b: T): boolean;
    /**
     * Get the next enum value in declaration order.
     * @param s - Current enum value
     * @returns Next enum value, or undefined if s is the last value or invalid
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Colors.next("red") // "green"
     * Colors.next("blue") // undefined (no next value)
     */
    next(s: Nullable<string>): Maybe<T>;
    /**
     * Create a new StrEnum with the values in reverse order.
     *
     * (This follows the new "toReversed" ES2023 naming convention for methods that return a new object)
     * @returns New StrEnum with values in reverse declaration order
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * const Reversed = Colors.toReversed();
     * Reversed.values // ["blue", "green", "red"]
     */
    toReversed(): StrEnum<T>;
    /**
     * Makes the StrEnum iterable, allowing use in for...of loops and array destructuring.
     * @returns Iterator that yields enum values in declaration order
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * for (const color of Colors) {
     *   console.log(color); // "red", "green", "blue"
     * }
     * const [first, second] = Colors; // first="red", second="green"
     */
    [Symbol.iterator](): IterableIterator<T>;
    /**
     * String tag used by Object.prototype.toString() for better debugging.
     * @example
     * const Colors = strEnum("red", "green", "blue");
     * Object.prototype.toString.call(Colors) // "[object StrEnum]"
     */
    [Symbol.toStringTag]: "StrEnum";
};
export type StrEnum<T extends string> = StrEnumType<T> & StrEnumHelpers<T>;
export type StrEnumKeys<Type> = Type extends StrEnum<infer X> ? X : never;
export declare function strEnum<T extends string>(...o: T[]): StrEnum<T>;