import importedFetch from 'node-fetch';

import { put } from './request/put';
import { post } from './request/post';
import { get } from './request/get';
import { head } from './request/head';
import { requestDelete } from './request/delete';
import { Configuration } from './configuration';

import { InstrumentationOverrides } from './types/internal';
import { TracingHeaders } from './types/tracing';
import { HttpRequest } from './types/request';

export class Base {
	public config: Configuration;
	public requestPost: Function;
	public requestPut: Function;
	public requestGet: Function;
	public requestHead: Function;
	public requestDelete: Function;
	public fetch: Function;
	public tracingHeaders: TracingHeaders;

	constructor(config: Configuration, { xRequestId, fetchOverride = importedFetch }: InstrumentationOverrides = {}) {
		this.config = config;
		// Tracing headers.
		this.tracingHeaders = {
			...(xRequestId && { 'X-Request-Id': xRequestId }),
			'X-Origin-System-Id': this.config.get('originSystemId'),
		};
		this.requestPost = this.tracedRequest(post);
		this.requestPut = this.tracedRequest(put);
		this.requestGet = this.tracedRequest(get);
		this.requestHead = this.tracedRequest(head);
		this.requestDelete = this.tracedRequest(requestDelete);
		this.fetch = fetchOverride;
	}

	private tracedRequest(requestFunction: Function) {
		return async (originalArguments: HttpRequest) => {
			const tracedRequest = originalArguments;
			// Adding tracing headers
			tracedRequest.additionalHeaders = Object.assign({},
				this.tracingHeaders,
				// Let additional headers override trace if needed.
				originalArguments.additionalHeaders
			);

			return await requestFunction(tracedRequest, this.fetch);
		};
	}

	public setOriginUser(userId: string) {
		this.tracingHeaders['X-Origin-User'] = userId;
	}
}