/**
 * @license Copyright 2022 The Lighthouse Authors. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
 */

declare module Util {
  /** Make properties K in T optional. */
  type MakeOptional<T, K extends keyof T> = {
    [P in Exclude<keyof T, K>]: T[P]
  } & {
    [P in K]+?: T[P]
  }

  /** An object with the keys in the union K mapped to themselves as values. */
  type SelfMap<K extends string> = {
    [P in K]: P;
  };

  /** Make optional all properties on T and any properties on object properties of T. */
  type RecursivePartial<T> =
    // Recurse into arrays and tuples: elements aren't (newly) optional, but any properties they have are.
    T extends (infer U)[] ? RecursivePartial<U>[] :
    // Recurse into objects: properties and any of their properties are optional.
    T extends object ? {[P in keyof T]?: RecursivePartial<T[P]>} :
    // Strings, numbers, etc. (terminal types) end here.
    T;

  /** Recursively makes all properties of T read-only. */
  type Immutable<T> =
    T extends Function ? T :
    T extends Array<infer R> ? ImmutableArray<R> :
    T extends Map<infer K, infer V> ? ImmutableMap<K, V> :
    T extends Set<infer M> ? ImmutableSet<M> :
    T extends object ? ImmutableObject<T> :
    T

  // Intermediate immutable types. Prefer e.g. Immutable<Set<T>> over direct use.
  type ImmutableArray<T> = ReadonlyArray<Immutable<T>>;
  type ImmutableMap<K, V> = ReadonlyMap<Immutable<K>, Immutable<V>>;
  type ImmutableSet<T> = ReadonlySet<Immutable<T>>;
  type ImmutableObject<T> = {
    readonly [K in keyof T]: Immutable<T[K]>;
  };

  /**
   * Exclude void from T
   */
  type NonVoid<T> = T extends void ? never : T;

  /** Remove properties K from T. */
  type StrictOmit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;

  /** Obtain the type of the first parameter of a function. */
  type FirstParamType<T extends (arg1: any, ...args: any[]) => any> =
    T extends (arg1: infer P, ...args: any[]) => any ? P : never;

  /**
   * If `S` is a kebab-style string `S`, convert to camelCase.
   */
  type KebabToCamelCase<S> =
    S extends `${infer T}-${infer U}` ?
    `${T}${Capitalize<KebabToCamelCase<U>>}` :
    S

  /** Returns T with any kebab-style property names rewritten as camelCase. */
  type CamelCasify<T> = {
    [K in keyof T as KebabToCamelCase<K>]: T[K];
  }
}

export default Util;