// S3Adapter
//
// Stores Parse files in AWS S3.

import * as AWS from 'aws-sdk';
import { FilesAdapter } from './FilesAdapter';

const DEFAULT_S3_REGION = "us-east-1";
const DEFAULT_S3_BUCKET = "parse-files";

export class S3Adapter extends FilesAdapter {
  // Creates an S3 session.
  // Providing AWS access and secret keys is mandatory
  // Region and bucket will use sane defaults if omitted
  constructor(
    accessKey,
    secretKey,
    { region = DEFAULT_S3_REGION,
      bucket = DEFAULT_S3_BUCKET,
      bucketPrefix = '',
      directAccess = false } = {}
  ) {
    super();

    this._region = region;
    this._bucket = bucket;
    this._bucketPrefix = bucketPrefix;
    this._directAccess = directAccess;

    let s3Options = {
      accessKeyId: accessKey,
      secretAccessKey: secretKey,
      params: { Bucket: this._bucket }
    };
    AWS.config._region = this._region;
    this._s3Client = new AWS.S3(s3Options);
  }

  // For a given config object, filename, and data, store a file in S3
  // Returns a promise containing the S3 object creation response
  createFile(config, filename, data) {
    let params = {
      Key: this._bucketPrefix + filename,
      Body: data
    };
    if (this._directAccess) {
      params.ACL = "public-read"
    }
    return new Promise((resolve, reject) => {
      this._s3Client.upload(params, (err, data) => {
        if (err !== null) {
          return reject(err);
        }
        resolve(data);
      });
    });
  }

  deleteFile(config, filename) {
    return new Promise((resolve, reject) => {
      let params = {
        Key: this._bucketPrefix + filename
      };
      this._s3Client.deleteObject(params, (err, data) =>{
        if(err !== null) {
          return reject(err);
        }
        resolve(data);
      });
    });
  }

  // Search for and return a file if found by filename
  // Returns a promise that succeeds with the buffer result from S3
  getFileData(config, filename) {
    let params = {Key: this._bucketPrefix + filename};
    return new Promise((resolve, reject) => {
      this._s3Client.getObject(params, (err, data) => {
        if (err !== null) {
          return reject(err);
        }
        resolve(data.Body);
      });
    });
  }

  // Generates and returns the location of a file stored in S3 for the given request and filename
  // The location is the direct S3 link if the option is set, otherwise we serve the file through parse-server
  getFileLocation(config, filename) {
    if (this._directAccess) {
      return ('https://' + this.bucket + '._s3Client.amazonaws.com' + '/' + this._bucketPrefix + filename);
    }
    return (config.mount + '/files/' + config.applicationId + '/' + encodeURIComponent(filename));
  }
}

export default S3Adapter;