import type { IsNever, Simplify } from "type-fest";
import { JustOneOf, StringKeys, ValueOf } from "./utils";
export type TypeMismatchError<TError extends {
    error: string;
    actual: any;
    expected: any;
} = any> = {
    error: TError["error"];
    actual: Simplify<TError["actual"]>;
    expected: Simplify<TError["expected"]>;
};
/**
 * Extracts all TypeMismatchError's from the projection result,
 * making it easy to report these errors.
 * Returns a string of error messages,
 * or `never` if there are no errors.
 */
export type ExtractTypeMismatchErrors<TProjectionResult> = ValueOf<{
    [TKey in StringKeys<keyof TProjectionResult>]: TypeMismatchError extends TProjectionResult[TKey] ? Extract<TProjectionResult[TKey], TypeMismatchError>["error"] : never;
}>;
/**
 * When we map projection results, we return TypeMismatchError's
 * for any fields that have an invalid mapping configuration.
 * However, this does not cause TypeScript to throw any errors.
 *
 * In order to get TypeScript to complain about these invalid mappings,
 * we will "require" an extra parameter, which will reveal the error messages.
 */
export type RequireAFakeParameterIfThereAreTypeMismatchErrors<TProjectionResult, _Errors extends string = ExtractTypeMismatchErrors<TProjectionResult>> = IsNever<_Errors> extends true ? [] : ["⛔️ Error: this projection has an invalid property ⛔️"] | [JustOneOf<_Errors>];