import { renderHook, RenderHookResult } from '@testing-library/react';
import { getOrCreateSharedImpl } from '../get-shared';
import { init, RumService, type ServiceConfig } from '../init';
import { useRumService } from '../use-rum-service';

jest.mock('../init');
jest.mock('../get-shared');

describe(`[datadog-rum] ${useRumService.name}`, () => {
    const cleanup = jest.fn();
    const setServiceContext = jest.fn();
    const initSetServiceContext = jest.fn();
    let config: ServiceConfig;

    beforeEach(() => {
        jest.clearAllMocks();
        jest.mocked(init).mockReturnValue({ cleanup, setServiceContext: initSetServiceContext });
        jest.mocked(getOrCreateSharedImpl).mockReturnValue({
            setServiceContext,
        } as unknown as ReturnType<typeof getOrCreateSharedImpl>);

        config = { name: 'foo' };
    });

    const subject = () =>
        renderHook((cfg: ServiceConfig) => useRumService(cfg), { initialProps: config });

    describe('on mount', () => {
        beforeEach(() => {
            subject();
        });

        test('registers the service', () => {
            expect(init).toHaveBeenCalledWith({ service: config });
        });
    });

    describe('on unmount', () => {
        beforeEach(() => {
            const { unmount } = subject();
            unmount();
        });

        test('runs cleanup', () => {
            expect(cleanup).toHaveBeenCalled();
        });
    });

    test('setServiceContext delegates to the shared implementation', () => {
        const context = { foo: 'bar' };

        subject().result.current.setServiceContext(context);

        expect(setServiceContext).toHaveBeenCalledWith(config.name, context);
    });

    describe('when already rendered', () => {
        let rerender: RenderHookResult<RumService, ServiceConfig>['rerender'];
        let result: RenderHookResult<RumService, ServiceConfig>['result'];

        beforeEach(() => {
            const renderHookResult = subject();
            rerender = renderHookResult.rerender;
            result = renderHookResult.result;
            jest.clearAllMocks();
        });

        test('does not register the service again', () => {
            rerender({ name: 'changed' });

            expect(init).not.toHaveBeenCalled();
        });

        test('returns same result', () => {
            const initial = result.current;

            rerender({ name: 'changed' });

            expect(result.current).toBe(initial);
        });
    });
});