var MongoClient = require("mongodb").MongoClient;
var GridStore = require("mongodb").GridStore;

var GridStoreAdapter = require("../src/Adapters/Files/GridStoreAdapter").GridStoreAdapter;
var Config = require("../src/Config");
var FilesController = require('../src/Controllers/FilesController').default;


// Small additional tests to improve overall coverage
describe_only_db('mongo')("GridStoreAdapter",() =>{
  it("should properly instanciate the GridStore when deleting a file", (done) => {

    var databaseURI = 'mongodb://localhost:27017/parse';
    var config = new Config(Parse.applicationId);
    var gridStoreAdapter = new GridStoreAdapter(databaseURI);
    var filesController = new FilesController(gridStoreAdapter);

    // save original unlink before redefinition
    var originalUnlink = GridStore.prototype.unlink;

    var gridStoreMode;

    // new unlink method that will capture the mode in which GridStore was opened
    GridStore.prototype.unlink = function() {

      // restore original unlink during first call
      GridStore.prototype.unlink = originalUnlink;

      gridStoreMode = this.mode;

      return originalUnlink.call(this);
    };


    filesController.createFile(config, 'myFilename.txt', 'my file content', 'text/plain')
      .then(myFile => {

        return MongoClient.connect(databaseURI)
          .then(database => {

            // Verify the existance of the fs.files document
            return database.collection('fs.files').count().then(count => {
              expect(count).toEqual(1);
              return database;
            });
          })
          .then(database => {

            // Verify the existance of the fs.files document
            return database.collection('fs.chunks').count().then(count => {
              expect(count).toEqual(1);
              return database.close();
            });
          })
          .then(() => {
            return filesController.deleteFile(config, myFile.name);
          });
      })
      .then(() => {
        return         MongoClient.connect(databaseURI)
          .then(database => {

            // Verify the existance of the fs.files document
            return database.collection('fs.files').count().then(count => {
              expect(count).toEqual(0);
              return database;
            });
          })
          .then(database => {

            // Verify the existance of the fs.files document
            return database.collection('fs.chunks').count().then(count => {
              expect(count).toEqual(0);
              return database.close();
            });
          });
      })
      .then(() => {
        // Verify that gridStore was opened in read only mode
        expect(gridStoreMode).toEqual('r');

        done();
      })
      .catch(fail);

  })
});