import { PrometheusDatasource } from './datasource';
import { DataSourceInstanceSettings } from '@grafana/ui';
import { PromContext, PromOptions } from './types';
import { dateTime, LoadingState } from '@grafana/data';

const defaultInstanceSettings: DataSourceInstanceSettings<PromOptions> = {
  url: 'test_prom',
  jsonData: {},
} as any;

const backendSrvMock: any = {
  datasourceRequest: jest.fn(),
};

const templateSrvMock: any = {
  replace(): null {
    return null;
  },
  getAdhocFilters(): any[] {
    return [];
  },
};

const timeSrvMock: any = {
  timeRange(): any {
    return {
      from: dateTime(),
      to: dateTime(),
    };
  },
};

describe('datasource', () => {
  describe('query', () => {
    const ds = new PrometheusDatasource(
      defaultInstanceSettings,
      {} as any,
      backendSrvMock,
      templateSrvMock,
      timeSrvMock
    );

    it('returns empty array when no queries', done => {
      expect.assertions(2);
      ds.query(makeQuery([])).subscribe({
        next(next) {
          expect(next.data).toEqual([]);
          expect(next.state).toBe(LoadingState.Done);
        },
        complete() {
          done();
        },
      });
    });

    it('performs time series queries', done => {
      expect.assertions(2);
      backendSrvMock.datasourceRequest.mockReturnValueOnce(Promise.resolve(makePromResponse()));
      ds.query(makeQuery([{}])).subscribe({
        next(next) {
          expect(next.data.length).not.toBe(0);
          expect(next.state).toBe(LoadingState.Done);
        },
        complete() {
          done();
        },
      });
    });

    it('with 2 queries and used from Explore, sends results as they arrive', done => {
      expect.assertions(4);
      backendSrvMock.datasourceRequest.mockReturnValue(Promise.resolve(makePromResponse()));
      const responseStatus = [LoadingState.Loading, LoadingState.Done];
      ds.query(makeQuery([{ context: PromContext.Explore }, { context: PromContext.Explore }])).subscribe({
        next(next) {
          expect(next.data.length).not.toBe(0);
          expect(next.state).toBe(responseStatus.shift());
        },
        complete() {
          done();
        },
      });
    });

    it('with 2 queries and used from Panel, waits for all to finish until sending Done status', done => {
      expect.assertions(2);
      backendSrvMock.datasourceRequest.mockReturnValue(Promise.resolve(makePromResponse()));
      ds.query(makeQuery([{ context: PromContext.Panel }, { context: PromContext.Panel }])).subscribe({
        next(next) {
          expect(next.data.length).not.toBe(0);
          expect(next.state).toBe(LoadingState.Done);
        },
        complete() {
          done();
        },
      });
    });
  });
});

function makeQuery(targets: any[]): any {
  return {
    targets: targets.map(t => {
      return {
        instant: false,
        start: dateTime().subtract(5, 'minutes'),
        end: dateTime(),
        expr: 'test',
        showingGraph: true,
        ...t,
      };
    }),
    range: {
      from: dateTime(),
      to: dateTime(),
    },
    interval: '15s',
  };
}

/**
 * Creates a pretty bogus prom response. Definitelly needs more work but right now we do not test the contents of the
 * messages anyway.
 */
function makePromResponse() {
  return {
    data: {
      data: {
        result: [
          {
            metric: {
              __name__: 'test_metric',
            },
            values: [[1568369640, 1]],
          },
        ],
        resultType: 'matrix',
      },
    },
  };
}