import { before } from 'mocha';
import * as db from '../lib/db.js';
import * as assert from 'assert/strict';

const rng = Math.random();

describe('lib/db', function () {
  let myDb;
  let dbFuncs;
  
  describe('#init()', function () {
    it('should fail to connect given invalid connection string', function () {
      return db.init('not a connection string').then(() => Promise.reject()).catch(() => Promise.resolve());
    });
    it('should successfully connect to mongodb', function () {
      return myDb = db.init(process.env.MONGO_TEST_CONN_STR);
    });
  });
  describe('#close()', function () {
    it('should close the connection', function () {
      return myDb.then(db => db.close());
    });
  });

  describe('with a established connection ->', function () {
    before(function () {
      myDb = db.init(process.env.MONGO_TEST_CONN_STR)
        .then(funcs => dbFuncs = funcs);
    });

    after(function () {
      dbFuncs.purge(['readWriteTest'])
        .then(() => myDb.then(db => db.close()));
    });

    describe('#persist()', function () {
      it('should be able to write to mongodb', function () {
        return dbFuncs.persist('readWriteTest', {}, 'rng', rng);
      });
      it('should be able to write a second entry into the same collection based on a filter', function () {
        return dbFuncs.persist('readWriteTest', { 'rng.transientValue': 2*rng }, 'rng', 2*rng);
      });
    });

    describe('#subscribe()', function () {
      it('should be able to read from mongodb', function () {
        return dbFuncs
          .subscribe('readWriteTest', {})
          .then(v => {
            assert.equal(v.length, 2);
          });
      });
      it('should be able to query for specific values from mongodb', function () {
        return dbFuncs
          .subscribe('readWriteTest', { 'rng.transientValue': rng })
          .then(v => {
            assert.equal(v.length, 1);
            assert.equal(v[0].rng.transientValue, rng);
          });
      });
      it('should be able to query for specific values from mongodb based on _id', function () {
        return dbFuncs
          .subscribe('readWriteTest', { 'rng.transientValue': rng })
          .then(v => {
            return dbFuncs.subscribe('readWriteTest', { '_id': v[0]._id });
          })
          .then(v => {
            assert.equal(v.length, 1);
            assert.equal(v[0].rng.transientValue, rng);
          });
      });
    });
  });
});