logger = require "logger-sharelatex"
aws = require "aws-sdk"
_ = require "underscore"
fs = require "fs"

s3 = new aws.S3()

module.exports =
  sendFile: (bucketName, key, fsPath, callback)->
    logger.log bucketName:bucketName, key:key, "send file data to s3"
    stream = fs.createReadStream fsPath
    s3.upload Bucket: bucketName, Key: key, Body: stream, (err, data) ->
      if err?
        logger.err err: err, Bucket: bucketName, Key: key, "error sending file data to s3"
      callback err

  sendStream: (bucketName, key, stream, callback)->
    logger.log bucketName:bucketName, key:key, "send file stream to s3"
    s3.upload Bucket: bucketName, Key: key, Body: stream, (err, data) ->
      if err?
        logger.err err: err, Bucket: bucketName, Key: key, "error sending file stream to s3"
      callback err

  getFileStream: (bucketName, key, opts, callback = (err, res)->)->
    logger.log bucketName:bucketName, key:key, "get file stream from s3"
    callback = _.once callback
    params =
      Bucket:bucketName
      Key: key
    if opts.start? and opts.end?
      params['Range'] = "bytes=#{opts.start}-#{opts.end}"
    request = s3.getObject params
    stream = request.createReadStream()
    stream.on 'readable', () ->
      callback null, stream
    stream.on 'error', (err) ->
      logger.err err:err, bucketName:bucketName, key:key, "error getting file stream from s3"
      callback err

  copyFile: (bucketName, sourceKey, destKey, callback)->
    logger.log bucketName:bucketName, sourceKey:sourceKey, destKey: destKey, "copying file in s3"
    source = bucketName + '/' + sourceKey
    s3.copyObject {Bucket: bucketName, Key: destKey, CopySource: source}, (err) ->
      if err?
        logger.err err:err, bucketName:bucketName, sourceKey:sourceKey, destKey:destKey, "something went wrong copying file in s3"
      callback err

  deleteFile: (bucketName, key, callback)->
    logger.log bucketName:bucketName, key:key, "delete file in s3"
    s3.deleteObject {Bucket: bucketName, Key: key}, (err) ->
      if err?
        logger.err err:err, bucketName:bucketName, key:key, "something went wrong deleting file in s3"
      callback err

  deleteDirectory: (bucketName, key, callback)->
    logger.log bucketName:bucketName, key:key, "delete directory in s3"
    s3.listObjects {Bucket: bucketName, Prefix: key}, (err, data) ->
      if err?
        logger.err err:err, bucketName:bucketName, key:key, "something went wrong listing prefix in s3"
        return callback err
      if data.Contents.length == 0
        logger.log bucketName:bucketName, key:key, "the directory is empty"
        return callback()
      keys = _.map data.Contents, (entry)->
        Key: entry.Key
      s3.deleteObjects
        Bucket: bucketName
        Delete:
          Objects: keys
          Quiet: true
      , (err) ->
          if err?
            logger.err err:err, bucketName:bucketName, key:keys, "something went wrong deleting directory in s3"
          callback err

  checkIfFileExists:(bucketName, key, callback)->
    logger.log bucketName:bucketName, key:key, "check file existence in s3"
    s3.headObject {Bucket: bucketName, Key: key}, (err, data) ->
      if err?
        logger.err err:err, bucketName:bucketName, key:key, "something went wrong checking head in s3"
        return callback err
      callback null, data.ETag?