import {URLSearchParams} from 'url';

export enum Method {
	HEAD = 'HEAD',
	GET = 'GET',
	POST = 'POST',
	PUT = 'PUT',
	PATCH = 'PATCH',
	DELETE = 'DELETE',
}

type Fetch = (input: RequestInfo, init?: RequestInit) => Promise<Response>

type CreateFetchClientOptions = {
	baseUrl: string,
	headers?: HeadersInit,
	fetch?: Fetch,
}

export type FetchClientParams = {
	url: string,
	method: Method,
	body?: BodyInit,
	query?: URLSearchParams | string | NodeJS.Dict<string | ReadonlyArray<string>> | Iterable<[string, string]> | ReadonlyArray<[string, string]>,
	headers?: HeadersInit,
	fetch?: Fetch,
}

export type FetchClient = (params: FetchClientParams) => Promise<Response>

type CreateFetchClient = (options: CreateFetchClientOptions) => FetchClient

export const createFetchClient: CreateFetchClient = ({
	baseUrl,
	headers: defaultHeaders = {},
	fetch: f = fetch,
}) => {
	return ({
		url,
		method,
		body,
		query,
		headers = {},
		fetch: ff = f,
	}) => {
		const theUrl = new URL(url, baseUrl)
		if (Boolean(query as unknown)) {
			theUrl.search = new URLSearchParams(query).toString()
		}
		return ff(theUrl.toString(), {
			method,
			body,
			// TODO handle any kind of headers init
			headers: {
				...defaultHeaders,
				...headers,
			},
		})
	}
}

export const createMockFetch = (body: BodyInit, response: ResponseInit): Fetch => async () => new Response(body, response)