/**
 * Applies a string-based index of an optionally specified type (defaults to any).
 */
export interface Indexed<T = any> {
	[index: string]: T;
}

/**
 * Construct a new type from an existing one, excluding specified keys. Opposite of TypeScript's built-in Pick type.
 * Learn more: http://ideasintosoftware.com/typescript-advanced-tricks/
 */
export type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;

/**
 * Convert an existing type into a projection specification, where 0 is omitted and 1 is included.
 * Learn more: http://ideasintosoftware.com/typescript-advanced-tricks/
 */
export type Projection<T> = Partial<Record<keyof T, 0 | 1>>;

/**
 * A simple configuration object, useful for a variety of different project types.
 */
export interface IConfig {
	/**
	 * The name of the library or application.
	 */
	NAME?: string;

	/**
	 * The current library or application version, either as a string (e.g. 1.0.0 or v1) or as a number (e.g. 1 or 2.3)
	 */
	VERSION?: string | number;

	/**
	 * The host environment for the library or application.
	 */
	ENV?: string;

	/**
	 * A key/value map of prefixes for outgoing data requests.
	 */
	PREFIX?: {
		API?: string;
		TEMPLATE?: string;
	};
}

/**
 * A list of IConfig objects, indexed by string.
 */
export interface IConfigList extends Indexed<IConfig> { }

/**
 * A list of items with separate display and data representations.
 * Useful for things like browser select lists or Array-based maps.
 */
export interface IListItem<T = string | number> extends Indexed<T | string> {
	/**
	 * The display representation of the item.
	 */
	Text: string;

	/**
	 * The data representation of the item.
	 */
	Value: T;
}

/**
 * Valid path separators for both UNIX- and Windows-based file systems.
 */
export type PathSeparator = '/' | '\\';

export type JSONLike = {
	[k: string]: string | number | (string | number)[] | JSONLike
}

/**
 * Extract Keys from T where T[Key] extends U
 */
export type KeyByType<T, U> =
	Exclude<
		{ [K in keyof T]: T[K] extends U ? K : never }[keyof T],
		undefined
	>;

/**
 * @see https://stackoverflow.com/questions/52443276/how-to-exclude-getter-only-properties-from-type-in-typescript/52473108#52473108
 * @see https://github.com/Microsoft/TypeScript/issues/27024#issuecomment-421529650
 */
export type IfEquals<X, Y, A, B> =
	(<T>() => T extends X ? 1 : 2) extends
	(<T>() => T extends Y ? 1 : 2) ? A : B;

/**
 * @see https://stackoverflow.com/questions/52443276/how-to-exclude-getter-only-properties-from-type-in-typescript/52473108#52473108
 * @see https://github.com/Microsoft/TypeScript/issues/27024#issuecomment-421529650
 */
export type WritableKeysOf<T> = {
	[P in keyof T]: IfEquals<{ [Q in P]: T[P] }, { -readonly [Q in P]: T[P] }, P, never>
}[keyof T];

/**
 * @see https://stackoverflow.com/questions/52443276/how-to-exclude-getter-only-properties-from-type-in-typescript/52473108#52473108
 * @see https://github.com/Microsoft/TypeScript/issues/27024#issuecomment-421529650
 */
export type WritablePart<T> = Pick<T, WritableKeysOf<T>>;