import type { RumResourceEvent } from '@datadog/browser-rum';
import { type Mutable } from '../__mocks__';
import { handleResource } from '../handle-resource';

describe(`[datadog-rum] ${handleResource.name}`, () => {
    const cfRay = 'ray-1';
    const headers = new Map([['cf-ray', cfRay]]);

    let event: Mutable<RumResourceEvent>;
    let context: any;

    function makeResourceEvent(type: 'fetch' | 'xhr', url: string) {
        return {
            type: 'resource',
            resource: { type, url },
        } as unknown as Mutable<RumResourceEvent>;
    }

    const subject = () => handleResource(event, context);

    function itAddsCfRayToContext() {
        test('adds the cf-ray value to event context', () => {
            subject();

            expect(event.context?.cfRay).toBe(cfRay);
        });
    }

    function itDoesNotAddCfRay() {
        test('does not add a cf-ray value', () => {
            subject();

            expect(event.context?.cfRay).toBeUndefined();
        });
    }

    describe('with a "fetch" resource', () => {
        beforeEach(() => {
            event = makeResourceEvent('fetch', window.location.toString());
            context = { response: { headers } };
        });

        itAddsCfRayToContext();

        describe('when the request targets a different domain', () => {
            beforeEach(() => (event = makeResourceEvent('fetch', 'https://example.com/')));

            itDoesNotAddCfRay();
        });

        describe('without a cf-ray response header', () => {
            beforeEach(() => (context = { response: { headers: new Map() } }));

            itDoesNotAddCfRay();
        });

        describe('with pre-existing event context', () => {
            beforeEach(() => (event.context = { existing: 'keep' }));

            test('merges the cf-ray value without dropping existing keys', () => {
                subject();

                expect(event.context).toEqual({ existing: 'keep', cfRay });
            });
        });
    });

    describe('with an "xhr" resource', () => {
        beforeEach(() => {
            event = makeResourceEvent('xhr', window.location.toString());
            context = { xhr: { getResponseHeader: (key: string) => headers.get(key) } };
        });

        itAddsCfRayToContext();
    });
});