import { At } from '../Any/At';
import { _OptionalKeys } from './OptionalKeys';
import { Key } from '../Any/Key';
import { List } from '../List/List';
import { Depth, Anyfy } from './_Internal';
import { BuiltIn } from '../Misc/BuiltIn';
import { Length } from '../List/Length';
import { RequiredKeys } from '../List/RequiredKeys';
import { Exclude } from '../Union/Exclude';
import { Has } from '../Union/Has';
/**
 * @hidden
 */
declare type Longer<L extends List, L1 extends List> = L extends unknown ? L1 extends unknown ? {
    0: 0;
    1: 1;
}[Has<RequiredKeys<L>, RequiredKeys<L1>>] : never : never;
/**
 * @hidden
 */
declare type MergeProp<OK, O1K, fill, OOKeys extends Key, K extends Key> = K extends OOKeys ? Exclude<OK, undefined> | O1K : [OK] extends [never] ? O1K : OK extends fill ? O1K : OK;
/**
 * @hidden
 */
declare type MergeFlatObject<O extends object, O1 extends object, fill, OOKeys extends Key = _OptionalKeys<O>> = {
    [K in keyof (Anyfy<O> & O1)]: MergeProp<At<O, K>, At<O1, K>, fill, OOKeys, K>;
} & {};
/**
 * @hidden
 */
declare type MergeFlatList<L extends List, L1 extends List, ignore extends object, fill, LOK extends Key = _OptionalKeys<L>> = number extends Length<L | L1> ? MergeFlatChoice<L[number], L1[number], ignore, fill>[] : Longer<L, L1> extends 1 ? {
    [K in keyof L]: MergeProp<L[K], At<L1, K>, fill, LOK, K>;
} : {
    [K in keyof L1]: MergeProp<At<L, K>, L1[K], fill, LOK, K>;
};
/**
 * @hidden
 */
export declare type MergeFlatChoice<O extends object, O1 extends object, ignore extends object, fill> = O extends ignore ? O : O1 extends ignore ? O : O extends List ? O1 extends List ? MergeFlatList<O, O1, ignore, fill> : MergeFlatObject<O, O1, fill> : MergeFlatObject<O, O1, fill>;
/**
 * @hidden
 */
export declare type MergeFlat<O extends object, O1 extends object, ignore extends object = BuiltIn, fill = undefined> = O extends unknown ? O1 extends unknown ? MergeFlatChoice<O, O1, ignore, fill> : never : never;
/**
 * @hidden
 */
declare type MergeDeepList<L extends List, L1 extends List, ignore extends object, fill> = number extends Length<L | L1> ? MergeDeepChoice<L[number], L1[number], ignore, fill, never, any>[] : Longer<L, L1> extends 1 ? {
    [K in keyof L]: MergeDeepChoice<L[K], At<L1, K>, ignore, fill, _OptionalKeys<L>, K>;
} : {
    [K in keyof L1]: MergeDeepChoice<At<L, K>, L1[K], ignore, fill, _OptionalKeys<L>, K>;
};
/**
 * @hidden
 */
declare type MergeDeepObject<O extends object, O1 extends object, ignore extends object, fill, OOKeys extends Key = _OptionalKeys<O>> = {
    [K in keyof (Anyfy<O> & O1)]: MergeDeepChoice<At<O, K>, At<O1, K>, ignore, fill, OOKeys, K>;
};
/**
 * @hidden
 */
declare type MergeDeepChoice<OK, O1K, ignore extends object, fill, OOKeys extends Key, K extends Key> = [
    OK
] extends [never] ? MergeProp<OK, O1K, fill, OOKeys, K> : [
    O1K
] extends [never] ? MergeProp<OK, O1K, fill, OOKeys, K> : OK extends ignore ? MergeProp<OK, O1K, fill, OOKeys, K> : O1K extends ignore ? MergeProp<OK, O1K, fill, OOKeys, K> : OK extends List ? O1K extends List ? MergeDeepList<OK, O1K, ignore, fill> : MergeProp<OK, O1K, fill, OOKeys, K> : OK extends object ? O1K extends object ? MergeDeepObject<OK, O1K, ignore, fill> : MergeProp<OK, O1K, fill, OOKeys, K> : MergeProp<OK, O1K, fill, OOKeys, K>;
/**
 * @hidden
 */
export declare type MergeDeep<O extends object, O1 extends object, ignore extends object, fill> = O extends unknown ? O1 extends unknown ? MergeDeepChoice<O, O1, ignore, fill, 'x', 'y'> : never : never;
/**
 * Accurately merge the fields of `O` with the ones of `O1`. It is
 * equivalent to the spread operator in JavaScript. [[Union]]s and [[Optional]]
 * fields will be handled gracefully.
 *
 * (⚠️ needs `--strictNullChecks` enabled)
 * @param O to complete
 * @param O1 to copy from
 * @param depth (?=`'flat'`) 'deep' to do it deeply
 * @param ignore (?=`BuiltIn`) types not to merge
 * @param fill (?=`undefined`) types of `O` to be replaced with ones of `O1`
 * @returns [[Object]]
 * @example
 * ```ts
 * import {O} from 'ts-toolbelt'
 *
 * type O = {
 *  name?: string
 *  age? : number
 *  zip? : string
 *  pay  : {
 *      cvv?: number
 *  }
 * }
 *
 * type O1 = {
 *  age : number
 *  zip?: number
 *  city: string
 *  pay : {
 *      cvv : number
 *      ccn?: string
 *  }
 * }
 *
 * type test = O.Merge<O, O1, 'deep'>
 * // {
 * //     name?: string;
 * //     age: number;
 * //     zip?: string | number;
 * //     pay: {
 * //         cvv: number;
 * //         ccn?: string;
 * //     };
 * //     city: string;
 * // }
 * ```
 */
export declare type Merge<O extends object, O1 extends object, depth extends Depth = 'flat', ignore extends object = BuiltIn, fill extends any = undefined> = {
    'flat': MergeFlat<O, O1, ignore, fill>;
    'deep': MergeDeep<O, O1, ignore, fill>;
}[depth];
export {};