import { Str } from '@rimbu/typical';
import { ReplaceAllIf } from '../typescript/String.types';
/** */
export type Case = 'upper' | 'lower';
/**
 * Transforms a given string type `T` by replacing all occurrences of 'ae' with 'ä',
 * 'oe' with 'ö', and 'ue' with 'ü'.
 *
 * @template T - The string type to be transformed.
 * @returns A new string type with the specified replacements applied.
 */
export type ToUmlautReturn<T extends string> = ReplaceAllIf<Str.ReplaceAll<Str.ReplaceAll<T, 'ae', 'ä'>, 'oe', 'ö'>, 'ue', 'ü'>;
/**
 * Transforms a given string type `T` by replacing certain character sequences with their corresponding umlaut characters,
 * based on the specified case `C`.
 *
 * @template T - The string type to be transformed.
 * @template C - The case type which determines the transformation. Can be either 'lower' or 'upper'.
 *
 * @remarks
 * - If `C` is 'lower', the string `T` is converted to lowercase and umlaut replacements are applied.
 * - If `C` is 'upper', the string `T` is converted to uppercase and umlaut replacements are applied.
 *
 * @returns The transformed string type with umlaut replacements applied.
 */
export type SetUmlautsReturn<T extends string, C extends Case> = C extends 'lower' ? ToUmlautReturn<Lowercase<T>> : ReplaceAllIf<Str.ReplaceAll<Str.ReplaceAll<Uppercase<T>, 'AE', 'Ä'>, 'OE', 'Ö'>, 'UE', 'Ü'>;
/**
 * A utility type that removes umlauts from a given string and replaces them with their respective digraphs.
 * The replacement is based on the specified case ('lower' or 'upper').
 *
 * @template T - The input string type.
 * @template C - The case type, either 'lower' or 'upper'.
 *
 * @remarks
 * - If `C` is 'lower', it replaces 'ä' with 'ae', 'ö' with 'oe', and 'ü' with 'ue'.
 * - If `C` is 'upper', it replaces 'Ä' with 'AE', 'Ö' with 'OE', and 'Ü' with 'UE'.
 *
 * @example
 * ```typescript
 * type Result1 = RemoveUmlautsReturn<'München', 'lower'>; // 'Muenchen'
 * type Result2 = RemoveUmlautsReturn<'MÜNCHEN', 'upper'>; // 'MUENCHEN'
 * ```
 */
export type RemoveUmlautsReturn<T extends string, C extends Case> = C extends 'lower' ? ReplaceAllIf<Str.ReplaceAll<Str.ReplaceAll<Lowercase<T>, 'ä', 'ae'>, 'ö', 'oe'>, 'ü', 'ue'> : ReplaceAllIf<Str.ReplaceAll<Str.ReplaceAll<Uppercase<T>, 'Ä', 'AE'>, 'Ö', 'OE'>, 'Ü', 'UE'>;