Handle renames (#14)

* [sync] move thunks to s3client to bottom of class

Also, use the thunk methods from within run rather than accessing the
s3client object directly.

* Layout tweaks to put each parameter on own line

* [syncsuite] value renames and move sync.run outside it() call

Future tests will be evaluating the result of that call, so this
avoids repeatedly calling it.

* Add first pass at copy methods and some delete stubs

* [Bucket] Convert from type alias for String to a case class

* [SyncSuite] mark new tests as pending

* [RemoteKey] Convert from type alias for String to a case class

* [MD5Hash] Convert from type alias for String to a case class

* [LastModified] Convert from type alias for String to a case class

* [LocalFile] Revert to using a normal File

* [Sync] Use a for-comprehension and restructure S3MetaData

The for-comprehension will make it easier to generate multiple actions
out of the stream of enriched metadata. The restructured S3MetaData
avoids the need to wrap it in an Either in some cases.

* [ToUpload] Add an wrapper to indicate action required on File

* [S3Action] Stub actions for IO events

* [S3Action] Use UploadS3Action

* [Sync] Fix formating when echoing parameters

* [logging] Change log level down to 4 for listing every file considered

* [Sync] Use a case class to hold counters

* [HashModified] Add case class to replace MD5Hash, LastModified tuples

* [logging] Move file considered logging to source of files

Rather than logging this where adding meta data, move to where the
files are being initially identified.

* [logging] Log all final counters

* Pass Config and HashLookup as implicit parameters

* [LocalFileStream] rename method as findFiles

* [S3MetaDataEnricher] rename method as getMetadata

* Rename selection filter and uploader trait and methods

* [MD5HashGenerator] Extract as trait

* [Action] Convert ToUpload into an Action sealed trait

* [ActionGenerator] refactored and removed logging

* fix up tests

* [LocalFileStream] adjust logging

* [RemoteMetaData] Added

* [ActionGenerator] remove redundant braces

* [LocalFile] Added as wrapper for File

* [Sync] run: remove redundant braces

* [Sync] run: rename HashLookup as S3ObjectsData

* WIP - toward copy action

* Extract S3ObjectsByHash for grouping

* extract internal wrapper for S3CatsIOClient

Remove some boiler plate from the middle of a test

* Explicitly name the Map parameters in extected result

* All lastModified are the same to avoid confusion

We aren't testing this field, just that the keys and hash values are correct.

* Rename variable

* space out object cxreation

* Fix test - error in expected result

Code has been working for ages!

* [readme] condense and simplify behaviour table, adding option delete

Reduce the complexity by only noting the distinct attributes leading
to each action.

Add the action of delete when a local file is missing.

* [S3MetaDataEnricherSuite] rename tests and note missing tests

* [ActionGeneratorSuite] rename tests and note missing tests

* Note unwritten tests as such

* [ActionGenerator]  #2 local exists, remote is missing, other matches

* [S3ClientSuite] fix tests

* [S3MetaDataEnricherSuite] #2a local exists, remote is missing, remote matches, other matches - copy

* [S3MetaDataEnricherSuite] drop 'remote is missing, remote matches'

Impossible to represent this combination

* [S3MetaDataEnricherSuite] #3 local exists, remote is missing, remote no match, other no matches - upload

* [S3MetaDataEnricherSuite] Tests #1-3 rename variables consistantly

* [S3MetadataEnricherSuite] #4 local exists, remote exists, remote no match, other matches - copy

* [S3MetadataEnricherSuite] #5 local exists, remote exists, remote no match, other no matches - upload

* [S3MetadataEnricherSuite] drop test #6 - no way to make request

* [ActionGeneratorSuite] standardise tests 2-4

* [ActionGeneratorSuite] #1 local exists, remote exists, remote matches - do nothing

* [ActionGeneratorSuite] Comment expected outcome

* [ActionGeneratorSuite] #5 local exists, remote exists, remote no match, other no matches - upload

* [Action] Add ToDelete case class

* Use ToDelete and fix up return types for DeleteS3Action

* [ActionGenerator] Add explicit case for #1

* [ActionGenerator] Add explicit check for local exists in #2

* [ActionGenerator] match case against #3

* [ActionGenerator] simplify case and match against #5

* [ActionGenerator] Add case for #4

* [ActionGenerator] Remote explicit checks for file existing

If we are called with a LocalFile parameter then we assume the file exists.

* [ActionGenerator] Avoid #1 matching condition #5

* [ActionGeneratorSuite] enable tests

* [test] remove stray println

* [SyncSuite] Add test helper RecordingSync

* [SyncSuite] Use RecordingSync

* [SyncSuite] enable rename test - excluding delete test

* [Sync] log and increment counters for copy and delete

* [Sync] Use case matched RemoteKey in log message

* [Sync] Reorder actioins to do copy then upload then delete

* [S3Action] Drop Move as a distinct action

Can be implemented as a Copy followed by a Delete.

* [S3Action] Actions are ordered Copy, Upload then Delete

This allows sequencing of actions so that all the quick to accomplish
copies take place before bandwidth/time costly updates or destructive
deletes. Deletes come last after they have had the opportunity to b
used as the source for any copies.

* [Sync] Use S3Action's default sorting

* [Sync] extract logging of activity

* [SyncLogging] Extract logging out of Sync

Single Responsibility principle - Sync knows nothing about how it
logs, it just delegates to SyncLogging.

* [Sync] Rename variables and extract sort into private def

* [SyncLogging] Use IO context

* [SyncLogging] Remove moved counter

* [SyncLogging] Clean up an log start of run config info

* Verify that IO actions are evaluated before the program terminates

* [Sync] ensure logging runs

* [ActionGenerator] Don't upload files every time

* [ActionGenerator] fix remote hash for #5

* [SyncSuite] Add tests for delete and delete after rename

* [RemoteKey] Add asFile and isMissingLocally helpers

* [Sync] Generate delete actions

* Remove old extensions upon MD5HashGenerator

* [MD5Hash] prevent confusion by never allowing quotes

This means we need to filter quotes from md5hash values at source

* [Sync] ensure start log message is run

* [ThorpS3Client] Fix passing parameters for source key

* [ThorpS3Client] reformat byKey for clarity

* [S3Client] Add level 5 logging around s3 sdk calls

* fix up tests

README.org

@@ -20,6 +20,21 @@ hash of the file contents.
       -v, --verbose <value>  Verbosity level (1-5)
   #+end_example
 
+* Behaviour
+
+When considering a local file, the following table governs what should happen:
+
+|---+------------+------------+------------------+--------------------+---------------------|
+| # | local file | remote key | hash of same key | hash of other keys | action              |
+|---+------------+------------+------------------+--------------------+---------------------|
+| 1 | exists     | exists     | matches          | -                  | do nothing          |
+| 2 | exists     | is missing | -                | matches            | copy from other key |
+| 3 | exists     | is missing | -                | no matches         | upload              |
+| 4 | exists     | exists     | no match         | matches            | copy from other key |
+| 5 | exists     | exists     | no match         | no matches         | upload              |
+| 6 | is missing | exists     | -                | -                  | delete              |
+|---+------------+------------+------------------+--------------------+---------------------|
+
 * Creating Native Images
 
   - Download and install GraalVM

src/main/scala/net/kemitix/s3thorp/Action.scala

@@ -0,0 +1,8 @@
+package net.kemitix.s3thorp
+
+sealed trait Action
+case class ToUpload(localFile: LocalFile) extends Action
+case class ToCopy(sourceKey: RemoteKey,
+                  hash: MD5Hash,
+                  targetKey: RemoteKey) extends Action
+case class ToDelete(remoteKey: RemoteKey) extends Action

src/main/scala/net/kemitix/s3thorp/ActionGenerator.scala

@@ -0,0 +1,48 @@
+package net.kemitix.s3thorp
+
+trait ActionGenerator
+  extends Logging {
+
+  def createActions(s3MetaData: S3MetaData)
+                   (implicit c: Config): Stream[Action] =
+    s3MetaData match {
+
+      // #1 local exists, remote exists, remote matches - do nothing
+      case S3MetaData(localFile, _, Some(RemoteMetaData(_, remoteHash, _)))
+        if localFile.hash == remoteHash
+      => Stream.empty
+
+      // #2 local exists, remote is missing, other matches - copy
+      case S3MetaData(localFile, otherMatches, None)
+        if otherMatches.nonEmpty
+      => copyFile(localFile, otherMatches)
+
+      // #3 local exists, remote is missing, other no matches - upload
+      case S3MetaData(localFile, otherMatches, None)
+        if otherMatches.isEmpty
+      => uploadFile(localFile)
+
+      // #4 local exists, remote exists, remote no match, other matches - copy
+      case S3MetaData(localFile, otherMatches, Some(RemoteMetaData(_, remoteHash, _)))
+        if localFile.hash != remoteHash &&
+          otherMatches.nonEmpty
+      => copyFile(localFile, otherMatches)
+
+      // #5 local exists, remote exists, remote no match, other no matches - upload
+      case S3MetaData(localFile, hashMatches, Some(_))
+        if hashMatches.isEmpty
+      => uploadFile(localFile)
+
+      case _ => Stream.empty
+    }
+
+  private def uploadFile(localFile: LocalFile) = Stream(ToUpload(localFile))
+
+  private def copyFile(localFile: LocalFile, matchByHash: Set[RemoteMetaData]): Stream[Action] =
+    Stream(ToCopy(
+      sourceKey = matchByHash.head.remoteKey,
+      hash = localFile.hash,
+      targetKey = localFile.remoteKey
+    ))
+
+}

src/main/scala/net/kemitix/s3thorp/ActionSubmitter.scala

@@ -0,0 +1,24 @@
+package net.kemitix.s3thorp
+
+import cats.effect.IO
+import net.kemitix.s3thorp.awssdk.S3Client
+
+trait ActionSubmitter
+  extends S3Client
+    with Logging {
+
+  def submitAction(action: Action)
+                  (implicit c: Config): IO[S3Action] = {
+    action match {
+      case ToUpload(file) =>
+        log4(s"    Upload: ${file.relative}")
+        upload(file, c.bucket)
+      case ToCopy(sourceKey, hash, targetKey) =>
+        log4(s"      Copy: $sourceKey => $targetKey")
+        copy(c.bucket, sourceKey, hash, targetKey)
+      case ToDelete(remoteKey) =>
+        log4(s"    Delete: $remoteKey")
+        delete(c.bucket, remoteKey)
+    }
+  }
+}

src/main/scala/net/kemitix/s3thorp/Bucket.scala

@@ -0,0 +1,5 @@
+package net.kemitix.s3thorp
+
+final case class Bucket(name: String) {
+
+}

src/main/scala/net/kemitix/s3thorp/Config.scala

@@ -1,16 +1,11 @@
 package net.kemitix.s3thorp
 
 import java.io.File
-import java.nio.file.Path
 
-import net.kemitix.s3thorp.Sync.{Bucket, LocalFile}
-
-case class Config(bucket: Bucket = "",
-                  prefix: String = "",
+case class Config(bucket: Bucket = Bucket(""),
+                  prefix: RemoteKey = RemoteKey(""),
                   verbose: Int = 1,
-                  source: LocalFile
+                  source: File
                ) {
-
-  def relativePath(file: File): Path = source.toPath.relativize(file.toPath)
-
+  require(source.isDirectory, s"Source must be a directory: $source")
 }

src/main/scala/net/kemitix/s3thorp/HashModified.scala

@@ -0,0 +1,6 @@
+package net.kemitix.s3thorp
+
+final case class HashModified(hash: MD5Hash,
+                              modified: LastModified) {
+
+}

src/main/scala/net/kemitix/s3thorp/KeyGenerator.scala

@@ -4,11 +4,12 @@ import java.io.File
 
 trait KeyGenerator {
 
-  def generateKey(c: Config)(file: File): String = {
+  def generateKey(source: File, prefix: RemoteKey)
+                 (file: File): RemoteKey = {
     val otherPath = file.toPath.toAbsolutePath
-    val sourcePath = c.source.toPath
+    val sourcePath = source.toPath
     val relativePath = sourcePath.relativize(otherPath)
-    s"${c.prefix}/$relativePath"
+    RemoteKey(s"${prefix.key}/$relativePath")
   }
 
 }

src/main/scala/net/kemitix/s3thorp/KeyModified.scala

@@ -0,0 +1,6 @@
+package net.kemitix.s3thorp
+
+final case class KeyModified(key: RemoteKey,
+                             modified: LastModified) {
+
+}

src/main/scala/net/kemitix/s3thorp/LastModified.scala

@@ -0,0 +1,7 @@
+package net.kemitix.s3thorp
+
+import java.time.Instant
+
+final case class LastModified(when: Instant) {
+
+}

src/main/scala/net/kemitix/s3thorp/LocalFile.scala

@@ -0,0 +1,25 @@
+package net.kemitix.s3thorp
+
+import java.io.File
+import java.nio.file.Path
+
+case class LocalFile(file: File,
+                     source: File,
+                     keyGenerator: File => RemoteKey)
+  extends MD5HashGenerator {
+
+  require(!file.isDirectory, s"LocalFile must not be a directory: $file")
+
+  private lazy val myhash = md5File(file)
+
+  def hash: MD5Hash = myhash
+
+  // the equivalent location of the file on S3
+  def remoteKey: RemoteKey = keyGenerator(file)
+
+  def isDirectory: Boolean = file.isDirectory
+
+  // the path of the file within the source
+  def relative: Path = source.toPath.relativize(file.toPath)
+
+}

src/main/scala/net/kemitix/s3thorp/LocalFileStream.scala

@@ -2,18 +2,28 @@ package net.kemitix.s3thorp
 
 import java.io.File
 
-trait LocalFileStream {
+trait LocalFileStream
+  extends KeyGenerator
+    with Logging {
 
-  def streamDirectoryPaths(file: File): Stream[File] =
-    dirPaths(file)
-        .flatMap(f => recurseIntoSubDirectories(f))
+  def findFiles(file: File)
+               (implicit c: Config): Stream[LocalFile] = {
+    log5(s"- Entering: $file")
+    val files = for {
+      f <- dirPaths(file)
+      fs <- recurseIntoSubDirectories(f)
+      } yield fs
+    log5(s"-  Leaving: $file")
+    files
+  }
 
-  private def dirPaths(file: File): Stream[File] = Option(file.listFiles)
-    .getOrElse(throw new IllegalArgumentException(s"Directory not found $file")).toStream
+  private def dirPaths(file: File): Stream[File] = {
+    Option(file.listFiles)
+      .getOrElse(throw new IllegalArgumentException(s"Directory not found $file")).toStream
+  }
 
-  private def recurseIntoSubDirectories: File => Stream[File] =
-    file =>
-      if (file.isDirectory) streamDirectoryPaths(file)
-      else Stream(file)
+  private def recurseIntoSubDirectories(file: File)(implicit c: Config): Stream[LocalFile] =
+    if (file.isDirectory) findFiles(file)(c)
+    else Stream(LocalFile(file, c.source, generateKey(c.source, c.prefix)))
 
 }

src/main/scala/net/kemitix/s3thorp/MD5Hash.scala

@@ -0,0 +1,7 @@
+package net.kemitix.s3thorp
+
+final case class MD5Hash(hash: String) {
+
+  require(!hash.contains("\""))
+
+}

src/main/scala/net/kemitix/s3thorp/MD5HashGenerator.scala

@@ -0,0 +1,18 @@
+package net.kemitix.s3thorp
+
+import java.io.{File, FileInputStream}
+import java.security.{DigestInputStream, MessageDigest}
+
+trait MD5HashGenerator
+  extends Logging {
+
+  def md5File(file: File): MD5Hash =  {
+    val buffer = new Array[Byte](8192)
+    val md5 = MessageDigest.getInstance("MD5")
+    val dis = new DigestInputStream(new FileInputStream(file), md5)
+    try { while (dis.read(buffer) != -1) { } } finally { dis.close() }
+    val hash = md5.digest.map("%02x".format(_)).mkString
+    MD5Hash(hash)
+  }
+
+}

src/main/scala/net/kemitix/s3thorp/ParseArgs.scala

@@ -19,11 +19,11 @@ object ParseArgs {
         .required()
         .text("Source directory to sync to S3"),
       opt[String]('b', "bucket")
-        .action((str, c) => c.copy(bucket = str))
+        .action((str, c) => c.copy(bucket = Bucket(str)))
         .required()
         .text("S3 bucket name"),
       opt[String]('p', "prefix")
-        .action((str, c) => c.copy(prefix = str))
+        .action((str, c) => c.copy(prefix = RemoteKey(str)))
         .text("Prefix within the S3 Bucket"),
       opt[Int]('v', "verbose")
         .validate(i =>

src/main/scala/net/kemitix/s3thorp/RemoteKey.scala

@@ -0,0 +1,11 @@
+package net.kemitix.s3thorp
+
+import java.io.File
+import java.nio.file.Paths
+
+final case class RemoteKey(key: String) {
+  def asFile(implicit c: Config): File =
+    c.source.toPath.resolve(Paths.get(c.prefix.key).relativize(Paths.get(key))).toFile
+  def isMissingLocally(implicit c: Config): Boolean =
+    ! asFile.exists
+}

src/main/scala/net/kemitix/s3thorp/RemoteMetaData.scala

@@ -0,0 +1,7 @@
+package net.kemitix.s3thorp
+
+final case class RemoteMetaData(remoteKey: RemoteKey,
+                                hash: MD5Hash,
+                                lastModified: LastModified) {
+
+}

src/main/scala/net/kemitix/s3thorp/S3Action.scala

@@ -0,0 +1,25 @@
+package net.kemitix.s3thorp
+
+sealed trait S3Action {
+
+  // the remote key that was uploaded, deleted or otherwise updated by the action
+  def remoteKey: RemoteKey
+
+  val order: Int
+
+}
+
+case class CopyS3Action(remoteKey: RemoteKey) extends S3Action {
+  override val order: Int = 1
+}
+case class UploadS3Action(remoteKey: RemoteKey,
+                          md5Hash: MD5Hash) extends S3Action {
+  override val order: Int = 2
+}
+case class DeleteS3Action(remoteKey: RemoteKey) extends S3Action {
+  override val order: Int = 3
+}
+
+object S3Action {
+  implicit def ord[A <: S3Action]: Ordering[A] = Ordering.by(_.order)
+}

src/main/scala/net/kemitix/s3thorp/S3MetaData.scala

@@ -1,8 +1,6 @@
 package net.kemitix.s3thorp
 
-import net.kemitix.s3thorp.Sync.{MD5Hash, LastModified, LocalFile, RemoteKey}
-
+// For the LocalFile, the set of matching S3 objects with the same MD5Hash, and any S3 object with the same remote key
 case class S3MetaData(localFile: LocalFile,
-                      remotePath: RemoteKey,
-                      remoteHash: MD5Hash,
-                      remoteLastModified: LastModified)
+                      matchByHash: Set[RemoteMetaData],
+                      matchByKey: Option[RemoteMetaData])

src/main/scala/net/kemitix/s3thorp/S3MetaDataEnricher.scala

@@ -1,25 +1,21 @@
 package net.kemitix.s3thorp
 
-import java.io.File
-
-import net.kemitix.s3thorp.Sync.{LastModified, MD5Hash}
-import net.kemitix.s3thorp.awssdk.{HashLookup, S3Client}
+import net.kemitix.s3thorp.awssdk.{S3ObjectsData, S3Client}
 
 trait S3MetaDataEnricher
   extends S3Client
-    with KeyGenerator
     with Logging {
 
-  def enrichWithS3MetaData(c: Config)(implicit hashLookup: HashLookup): File => Either[File, S3MetaData] = {
-    val remoteKey = generateKey(c)_
-    file => {
-      log3(s"- Consider: ${c.relativePath(file)}")(c)
-      val key = remoteKey(file)
-      objectHead(key).map {
-        hlm: (MD5Hash, LastModified) => {
-          Right(S3MetaData(file, key, hlm._1.filter { c => c != '"' }, hlm._2))
-        }
-      }.getOrElse(Left(file))
-    }
+  def getMetadata(localFile: LocalFile)
+                 (implicit c: Config,
+                  s3ObjectsData: S3ObjectsData): S3MetaData = {
+    val (keyMatches: Option[HashModified], hashMatches: Set[KeyModified]) = getS3Status(localFile)
+
+    S3MetaData(localFile,
+      matchByKey = keyMatches.map{kmAsRemoteMetaData(localFile.remoteKey)},
+      matchByHash = hashMatches.map(km => RemoteMetaData(km.key, localFile.hash, km.modified)))
   }
+
+  private def kmAsRemoteMetaData(key: RemoteKey): HashModified => RemoteMetaData = hm => RemoteMetaData(key, hm.hash, hm.modified)
+
 }

src/main/scala/net/kemitix/s3thorp/S3Uploader.scala

@@ -1,23 +0,0 @@
-package net.kemitix.s3thorp
-
-import java.io.File
-
-import cats.effect.IO
-import net.kemitix.s3thorp.Sync.MD5Hash
-import net.kemitix.s3thorp.awssdk.S3Client
-
-trait S3Uploader
-  extends S3Client
-    with KeyGenerator
-    with Logging {
-
-  def performUpload(c: Config): File => (File, IO[Either[Throwable, MD5Hash]]) = {
-    val remoteKey = generateKey(c) _
-    file => {
-      val key = remoteKey(file)
-      val shortFile = c.relativePath(file)
-      log4(s"    Upload: $shortFile")(c)
-      (file, upload(file, c.bucket, key))
-    }
-  }
-}

src/main/scala/net/kemitix/s3thorp/Sync.scala

@@ -1,48 +1,59 @@
 package net.kemitix.s3thorp
 
-import java.io.File
-import java.time.Instant
+import java.nio.file.Paths
 
-import cats.effect._
-import net.kemitix.s3thorp.Sync.{Bucket, LocalFile, MD5Hash, RemoteKey}
-import net.kemitix.s3thorp.awssdk.{HashLookup, S3Client}
+import cats.effect.IO
+import cats.implicits._
+import net.kemitix.s3thorp.awssdk.{S3Client, S3ObjectsData}
 
 class Sync(s3Client: S3Client)
   extends LocalFileStream
     with S3MetaDataEnricher
-    with UploadSelectionFilter
-    with S3Uploader
-    with Logging {
+    with ActionGenerator
+    with ActionSubmitter
+    with SyncLogging {
 
-  override def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey) =
-    s3Client.upload(localFile, bucket, remoteKey)
-
-  def run(c: Config): IO[Unit] = {
-    implicit val config: Config = c
-    log1(s"Bucket: ${c.bucket}, Prefix: ${c.prefix}, Source: ${c.source}")
-    s3Client.listObjects(c.bucket, c.prefix).map { hashLookup => {
-      val stream: Stream[(File, IO[Either[Throwable, MD5Hash]])] = streamDirectoryPaths(c.source).map(
-        enrichWithS3MetaData(c)(hashLookup)).flatMap(
-        uploadRequiredFilter(c)).map(
-        performUpload(c))
-      val count: Int = stream.foldLeft(0)((a: Int, io) => {
-        io._2.unsafeRunSync
-        log1(s"-     Done: ${io._1}")
-        a + 1
-      })
-      log1(s"Uploaded $count files")
-    }}
+  def run(implicit c: Config): IO[Unit] = {
+    logRunStart(c).unsafeRunSync
+    listObjects(c.bucket, c.prefix)
+      .map { implicit s3ObjectsData => {
+        val actions = (for {
+          file <- findFiles(c.source)
+          meta = getMetadata(file)
+          action <- createActions(meta)
+          ioS3Action = submitAction(action)
+        } yield ioS3Action).sequence
+        val sorted = sort(actions)
+        val list = sorted.unsafeRunSync.toList
+        val delActions = (for {
+          key <- s3ObjectsData.byKey.keys
+          if key.isMissingLocally
+          ioDelAction = submitAction(ToDelete(key))
+        } yield ioDelAction).toStream.sequence
+        val delList = delActions.unsafeRunSync.toList
+        logRunFinished(list ++ delList).unsafeRunSync
+      }}
   }
 
-  override def listObjects(bucket: Bucket, prefix: RemoteKey): IO[HashLookup] = ???
-}
-
-object Sync {
-
-  type Bucket = String // the S3 bucket name
-  type LocalFile = File // the file or directory
-  type RemoteKey = String // path within an S3 bucket
-  type MD5Hash = String // an MD5 hash
-  type LastModified = Instant // or scala equivalent
-
+  private def sort(ioActions: IO[Stream[S3Action]]) =
+    ioActions.flatMap { actions => IO { actions.sorted } }
+
+  override def upload(localFile: LocalFile,
+                      bucket: Bucket)(implicit c: Config): IO[UploadS3Action] =
+    s3Client.upload(localFile, bucket)
+
+  override def copy(bucket: Bucket,
+                    sourceKey: RemoteKey,
+                    hash: MD5Hash,
+                    targetKey: RemoteKey)(implicit c: Config): IO[CopyS3Action] =
+    s3Client.copy(bucket, sourceKey, hash, targetKey)
+
+  override def delete(bucket: Bucket,
+                      remoteKey: RemoteKey)(implicit c: Config): IO[DeleteS3Action] =
+    s3Client.delete(bucket, remoteKey)
+
+  override def listObjects(bucket: Bucket,
+                           prefix: RemoteKey
+                          )(implicit c: Config): IO[S3ObjectsData] =
+    s3Client.listObjects(bucket, prefix)
 }

src/main/scala/net/kemitix/s3thorp/SyncLogging.scala

@@ -0,0 +1,40 @@
+package net.kemitix.s3thorp
+
+import cats.effect.IO
+
+// Logging for the Sync class
+trait SyncLogging extends Logging {
+
+  def logRunStart(c: Config): IO[Unit] = IO {
+    log1(s"Bucket: ${c.bucket.name}, Prefix: ${c.prefix.key}, Source: ${c.source}")(c)
+  }
+
+  def logRunFinished(actions: List[S3Action])
+                    (implicit c: Config): IO[Unit] = IO {
+    val counters = actions.foldLeft(Counters())(logActivity)
+    log1(s"Uploaded ${counters.uploaded} files")
+    log1(s"Copied   ${counters.copied} files")
+    log1(s"Deleted  ${counters.deleted} files")
+  }
+
+  private def logActivity(implicit c: Config): (Counters, S3Action) => Counters =
+    (counters: Counters, s3Action: S3Action) => {
+      s3Action match {
+        case UploadS3Action(remoteKey, _) =>
+          log1(s"- Uploaded: ${remoteKey.key}")
+          counters.copy(uploaded = counters.uploaded + 1)
+        case CopyS3Action(remoteKey) =>
+          log1(s"-   Copied: ${remoteKey.key}")
+          counters.copy(copied = counters.copied + 1)
+        case DeleteS3Action(remoteKey) =>
+          log1(s"-  Deleted: ${remoteKey.key}")
+          counters.copy(deleted = counters.deleted + 1)
+        case _ => counters
+      }
+    }
+
+  case class Counters(uploaded: Int = 0,
+                      deleted: Int = 0,
+                      copied: Int = 0)
+
+}

src/main/scala/net/kemitix/s3thorp/UploadSelectionFilter.scala

@@ -1,35 +0,0 @@
-package net.kemitix.s3thorp
-
-import java.io.{File, FileInputStream}
-import java.security.{DigestInputStream, MessageDigest}
-
-import net.kemitix.s3thorp.Sync.{LocalFile, MD5Hash}
-
-trait UploadSelectionFilter
-  extends Logging {
-
-  private def md5File(localFile: LocalFile): MD5Hash =  {
-    val buffer = new Array[Byte](8192)
-    val md5 = MessageDigest.getInstance("MD5")
-
-    val dis = new DigestInputStream(new FileInputStream(localFile), md5)
-    try { while (dis.read(buffer) != -1) { } } finally { dis.close() }
-
-    md5.digest.map("%02x".format(_)).mkString
-  }
-
-  def uploadRequiredFilter(c: Config): Either[File, S3MetaData] => Stream[File] = {
-    case Left(file) => {
-      log5(s"   Created: ${c.relativePath(file)}")(c)
-      Stream(file)
-    }
-    case Right(s3Metadata) => {
-      val localHash: MD5Hash = md5File(s3Metadata.localFile)
-      if (localHash != s3Metadata.remoteHash) {
-        log5(s"   Updated: ${c.relativePath(s3Metadata.localFile)}")(c)
-        Stream(s3Metadata.localFile)
-      }
-      else Stream.empty
-    }
-  }
-}

src/main/scala/net/kemitix/s3thorp/awssdk/HashLookup.scala

@@ -1,11 +0,0 @@
-package net.kemitix.s3thorp.awssdk
-
-import net.kemitix.s3thorp.Sync.{LastModified, MD5Hash, RemoteKey}
-
-/**
-  * A list of objects and their MD5 hash values.
-  */
-case class HashLookup(byHash: Map[MD5Hash, (RemoteKey, LastModified)],
-                      byKey: Map[RemoteKey, (MD5Hash, LastModified)]) {
-
-}

src/main/scala/net/kemitix/s3thorp/awssdk/S3Client.scala

@@ -1,24 +1,46 @@
 package net.kemitix.s3thorp.awssdk
 
 import cats.effect.IO
+import com.github.j5ik2o.reactive.aws.s3.S3AsyncClient
 import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
-import net.kemitix.s3thorp.Sync.{Bucket, LastModified, LocalFile, MD5Hash, RemoteKey}
+import net.kemitix.s3thorp._
 
 trait S3Client {
 
-  final def objectHead(remoteKey: RemoteKey)(implicit hashLookup: HashLookup): Option[(MD5Hash, LastModified)] =
-    hashLookup.byKey.get(remoteKey)
+  final def getS3Status(localFile: LocalFile)
+                       (implicit s3ObjectsData: S3ObjectsData): (Option[HashModified], Set[KeyModified]) = {
+    val matchingByKey = s3ObjectsData.byKey.get(localFile.remoteKey)
+    val matchingByHash = s3ObjectsData.byHash.getOrElse(localFile.hash, Set())
+    (matchingByKey, matchingByHash)
+  }
 
-  def listObjects(bucket: Bucket, prefix: RemoteKey): IO[HashLookup]
+  def listObjects(bucket: Bucket,
+                  prefix: RemoteKey
+                 )(implicit c: Config): IO[S3ObjectsData]
 
-  def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey): IO[Either[Throwable, MD5Hash]]
+  def upload(localFile: LocalFile,
+             bucket: Bucket
+            )(implicit c: Config): IO[UploadS3Action]
+
+  def copy(bucket: Bucket,
+           sourceKey: RemoteKey,
+           hash: MD5Hash,
+           targetKey: RemoteKey
+          )(implicit c: Config): IO[CopyS3Action]
+
+  def delete(bucket: Bucket,
+             remoteKey: RemoteKey
+            )(implicit c: Config): IO[DeleteS3Action]
 
 }
 
 object S3Client {
 
+  def createClient(s3AsyncClient: S3AsyncClient): S3Client = {
+    new ThorpS3Client(S3CatsIOClient(s3AsyncClient))
+  }
+
   val defaultClient: S3Client =
-    new ThorpS3Client(
-      S3CatsIOClient(new JavaClientWrapper {}.underlying))
+    createClient(new JavaClientWrapper {}.underlying)
 
 }

src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientLogging.scala

@@ -0,0 +1,16 @@
+package net.kemitix.s3thorp.awssdk
+
+import net.kemitix.s3thorp.{Bucket, Config, LocalFile, Logging}
+
+trait S3ClientLogging
+  extends Logging {
+
+  def logUploadStart(localFile: LocalFile, bucket: Bucket)
+                    (implicit c: Config)=
+    log5(s"s3Client:upload:start: ${localFile.file}")
+
+  def logUploadDone(localFile: LocalFile, bucket: Bucket)
+                   (implicit c: Config) =
+    log5(s"s3Client:upload:done : ${localFile.file}")
+
+}

src/main/scala/net/kemitix/s3thorp/awssdk/S3ObjectsByHash.scala

@@ -0,0 +1,15 @@
+package net.kemitix.s3thorp.awssdk
+
+import net.kemitix.s3thorp.{KeyModified, LastModified, MD5Hash, RemoteKey}
+import software.amazon.awssdk.services.s3.model.S3Object
+
+trait S3ObjectsByHash {
+
+  def byHash(os: Stream[S3Object]): Map[MD5Hash, Set[KeyModified]] = {
+    val mD5HashToS3Objects: Map[MD5Hash, Stream[S3Object]] = os.groupBy(o => MD5Hash(o.eTag.filter{c => c != '"'}))
+    val hashToModifieds: Map[MD5Hash, Set[KeyModified]] =
+      mD5HashToS3Objects.mapValues { os => os.map { o => KeyModified(RemoteKey(o.key), LastModified(o.lastModified())) }.toSet }
+    hashToModifieds
+  }
+
+}

src/main/scala/net/kemitix/s3thorp/awssdk/S3ObjectsData.scala

@@ -0,0 +1,11 @@
+package net.kemitix.s3thorp.awssdk
+
+import net.kemitix.s3thorp.{HashModified, KeyModified, MD5Hash, RemoteKey}
+
+/**
+  * A list of objects and their MD5 hash values.
+  */
+case class S3ObjectsData(byHash: Map[MD5Hash, Set[KeyModified]],
+                         byKey: Map[RemoteKey, HashModified]) {
+
+}

src/main/scala/net/kemitix/s3thorp/awssdk/ThorpS3Client.scala

@@ -2,40 +2,83 @@ package net.kemitix.s3thorp.awssdk
 
 import cats.effect.IO
 import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
-import net.kemitix.s3thorp.Sync._
+import net.kemitix.s3thorp._
 import software.amazon.awssdk.core.async.AsyncRequestBody
-import software.amazon.awssdk.services.s3.model.{ListObjectsV2Request, PutObjectRequest, S3Object}
+import software.amazon.awssdk.services.s3.model.{Bucket => _, _}
 
 import scala.collection.JavaConverters._
 
-private class ThorpS3Client(s3Client: S3CatsIOClient) extends S3Client {
+private class ThorpS3Client(s3Client: S3CatsIOClient)
+  extends S3Client
+    with S3ObjectsByHash
+    with Logging {
 
-  def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey): IO[Either[Throwable, MD5Hash]] = {
+  override def upload(localFile: LocalFile,
+                      bucket: Bucket
+                     )(implicit c: Config): IO[UploadS3Action] = {
+    log5(s"upload:bucket = ${bucket.name}, localFile = ${localFile.remoteKey}")
     val request = PutObjectRequest.builder()
-      .bucket(bucket)
-      .key(remoteKey)
+      .bucket(bucket.name)
+      .key(localFile.remoteKey.key)
       .build()
-    val body = AsyncRequestBody.fromFile(localFile)
-    s3Client.putObject(request, body).map(r => Right(r.eTag()))
+    val body = AsyncRequestBody.fromFile(localFile.file)
+    s3Client.putObject(request, body)
+      .map(_.eTag)
+      .map(_.filter{c => c != '"'})
+      .map(MD5Hash)
+      .map(md5Hash => UploadS3Action(localFile.remoteKey, md5Hash))
   }
 
-  private def asHashLookup: Stream[S3Object] => HashLookup =
-    os => HashLookup(byHash(os), byKey(os))
+  override def copy(bucket: Bucket,
+                    sourceKey: RemoteKey,
+                    hash: MD5Hash,
+                    targetKey: RemoteKey
+                   )(implicit c: Config): IO[CopyS3Action] = {
+    log5(s"copy:bucket = ${bucket.name}, sourceKey = ${sourceKey.key}, targetKey = ${targetKey.key}")
+    val request = CopyObjectRequest.builder()
+      .bucket(bucket.name)
+      .copySource(s"${bucket.name}/${sourceKey.key}")
+      .copySourceIfMatch(hash.hash)
+      .key(targetKey.key)
+      .build()
+    s3Client.copyObject(request)
+      .map(_ => CopyS3Action(targetKey))
+  }
 
-  private def byHash(os: Stream[S3Object]) =
-    os.map{o => (o.eTag, (o.key, o.lastModified))}.toMap
+  override def delete(bucket: Bucket,
+                      remoteKey: RemoteKey
+                     )(implicit c: Config): IO[DeleteS3Action] = {
+    log5(s"delete:bucket = ${bucket.name}, remoteKey = ${remoteKey.key}")
+    val request = DeleteObjectRequest.builder()
+      .bucket(bucket.name)
+      .key(remoteKey.key)
+      .build()
+    s3Client.deleteObject(request)
+      .map(_ => DeleteS3Action(remoteKey))
+  }
+
+  private def asS3ObjectsData: Stream[S3Object] => S3ObjectsData =
+    os => S3ObjectsData(byHash(os), byKey(os))
 
   private def byKey(os: Stream[S3Object]) =
-    os.map{o => (o.key(), (o.eTag(), o.lastModified()))}.toMap
+    os.map { o => {
+      val remoteKey = RemoteKey(o.key)
+      val hash = MD5Hash(o.eTag().filter { c => c != '"' })
+      val lastModified = LastModified(o.lastModified())
+      (remoteKey, HashModified(hash, lastModified))
+    }}.toMap
 
-  def listObjects(bucket: Bucket, prefix: RemoteKey): IO[HashLookup] = {
+
+  def listObjects(bucket: Bucket, prefix: RemoteKey)
+                 (implicit c: Config): IO[S3ObjectsData] = {
+    log5(s"listObjects:bucket = ${bucket.name}, prefix: ${prefix.key}")
     val request = ListObjectsV2Request.builder()
-      .bucket(bucket)
-      .prefix(prefix)
+      .bucket(bucket.name)
+      .prefix(prefix.key)
       .build()
     s3Client.listObjectsV2(request)
       .map(r => r.contents.asScala.toStream)
-      .map(asHashLookup)
+      .map(asS3ObjectsData)
   }
 
 }

src/test/scala/net/kemitix/s3thorp/ActionGeneratorSuite.scala

@@ -0,0 +1,106 @@
+package net.kemitix.s3thorp
+
+import java.time.Instant
+
+import org.scalatest.FunSpec
+
+class ActionGeneratorSuite
+  extends UnitTest
+    with KeyGenerator {
+
+  private val source = Resource(this, "upload")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val fileToKey = generateKey(config.source, config.prefix) _
+  val lastModified = LastModified(Instant.now())
+
+  new ActionGenerator {
+
+    describe("create actions") {
+
+      def invoke(input: S3MetaData) = createActions(input).toList
+
+      describe("#1 local exists, remote exists, remote matches - do nothing") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteMetadata = RemoteMetaData(theFile.remoteKey, theHash, lastModified)
+        val input = S3MetaData(theFile, // local exists
+          matchByHash = Set(theRemoteMetadata), // remote matches
+          matchByKey = Some(theRemoteMetadata) // remote exists
+          )
+        it("do nothing") {
+          val expected = List.empty // do nothing
+          val result = invoke(input)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#2 local exists, remote is missing, other matches - copy") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey = theFile.remoteKey
+        val otherRemoteKey = aRemoteKey(prefix, "other-key")
+        val otherRemoteMetadata = RemoteMetaData(otherRemoteKey, theHash, lastModified)
+        val input = S3MetaData(theFile, // local exists
+          matchByHash = Set(otherRemoteMetadata), // other matches
+          matchByKey = None) // remote is missing
+        it("copy from other key") {
+          val expected = List(ToCopy(otherRemoteKey, theHash, theRemoteKey)) // copy
+          val result = invoke(input)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#3 local exists, remote is missing, other no matches - upload") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val input = S3MetaData(theFile, // local exists
+          matchByHash = Set.empty, // other no matches
+          matchByKey = None) // remote is missing
+        it("upload") {
+          val expected = List(ToUpload(theFile)) // upload
+          val result = invoke(input)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#4 local exists, remote exists, remote no match, other matches - copy") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey = theFile.remoteKey
+        val oldHash = MD5Hash("old-hash")
+        val otherRemoteKey = aRemoteKey(prefix, "other-key")
+        val otherRemoteMetadata = RemoteMetaData(otherRemoteKey, theHash, lastModified)
+        val oldRemoteMetadata = RemoteMetaData(theRemoteKey,
+          hash = oldHash, // remote no match
+          lastModified = lastModified)
+        val input = S3MetaData(theFile, // local exists
+          matchByHash = Set(otherRemoteMetadata), // other matches
+          matchByKey = Some(oldRemoteMetadata)) // remote exists
+        it("copy from other key") {
+          val expected = List(ToCopy(otherRemoteKey, theHash, theRemoteKey)) // copy
+          val result = invoke(input)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#5 local exists, remote exists, remote no match, other no matches - upload") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey = theFile.remoteKey
+        val oldHash = MD5Hash("old-hash")
+        val theRemoteMetadata = RemoteMetaData(theRemoteKey, oldHash, lastModified)
+        val input = S3MetaData(theFile, // local exists
+          matchByHash = Set.empty, // remote no match, other no match
+          matchByKey = Some(theRemoteMetadata) // remote exists
+        )
+        it("upload") {
+          val expected = List(ToUpload(theFile)) // upload
+          val result = invoke(input)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#6 local missing, remote exists - delete") {
+        it("TODO") {
+          pending
+        }
+      }
+    }
+  }
+}

src/test/scala/net/kemitix/s3thorp/DummyS3Client.scala

@@ -1,12 +1,26 @@
 package net.kemitix.s3thorp
 
 import cats.effect.IO
-import net.kemitix.s3thorp.Sync.{Bucket, LocalFile, MD5Hash, RemoteKey}
-import net.kemitix.s3thorp.awssdk.{HashLookup, S3Client}
+import net.kemitix.s3thorp.awssdk.{S3ObjectsData, S3Client}
 
 trait DummyS3Client extends S3Client {
 
-  override def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey): IO[Either[Throwable, MD5Hash]] = ???
+  override def upload(localFile: LocalFile,
+                      bucket: Bucket
+                     )(implicit c: Config): IO[UploadS3Action] = ???
+
+  override def copy(bucket: Bucket,
+                    sourceKey: RemoteKey,
+                    hash: MD5Hash,
+                    targetKey: RemoteKey
+                   )(implicit c: Config): IO[CopyS3Action] = ???
+
+  override def delete(bucket: Bucket,
+                      remoteKey: RemoteKey
+                     )(implicit c: Config): IO[DeleteS3Action] = ???
+
+  override def listObjects(bucket: Bucket,
+                           prefix: RemoteKey
+                          )(implicit c: Config): IO[S3ObjectsData] = ???
 
-  override def listObjects(bucket: Bucket, prefix: RemoteKey): IO[HashLookup] = ???
 }

src/test/scala/net/kemitix/s3thorp/KeyGeneratorSuite.scala

@@ -0,0 +1,35 @@
+package net.kemitix.s3thorp
+
+import java.io.File
+
+import org.scalatest.FunSpec
+
+class KeyGeneratorSuite extends FunSpec {
+
+  new KeyGenerator {
+    private val source: File = Resource(this, "upload")
+    private val prefix = RemoteKey("prefix")
+    implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+    private val fileToKey = generateKey(config.source, config.prefix) _
+
+    describe("key generator") {
+      def resolve(subdir: String): File = {
+        source.toPath.resolve(subdir).toFile
+      }
+
+      describe("when file is within source") {
+        it("has a valid key") {
+          val subdir = "subdir"
+          assertResult(RemoteKey(s"${prefix.key}/$subdir"))(fileToKey(resolve(subdir)))
+        }
+      }
+
+      describe("when file is deeper within source") {
+        it("has a valid key") {
+          val subdir = "subdir/deeper/still"
+          assertResult(RemoteKey(s"${prefix.key}/$subdir"))(fileToKey(resolve(subdir)))
+        }
+      }
+    }
+  }
+}

src/test/scala/net/kemitix/s3thorp/LocalFileStreamSuite.scala

@@ -1,16 +1,15 @@
 package net.kemitix.s3thorp
 
-import java.io.File
-
 import org.scalatest.FunSpec
 
 class LocalFileStreamSuite extends FunSpec with LocalFileStream {
 
-  describe("streamDirectoryPaths") {
-    var uploadResource = Resource(this, "upload")
+  describe("findFiles") {
+    val uploadResource = Resource(this, "upload")
+    val config: Config = Config(source = uploadResource)
     it("should find all files") {
-      val result: Set[String] = streamDirectoryPaths(uploadResource).toSet
-          .map { x: File => uploadResource.toPath.relativize(x.toPath).toString }
+      val result: Set[String] = findFiles(uploadResource)(config).toSet
+          .map { x: LocalFile => x.relative.toString }
       assertResult(Set("subdir/leaf-file", "root-file"))(result)
     }
   }

src/test/scala/net/kemitix/s3thorp/Resource.scala

@@ -7,7 +7,8 @@ import scala.util.Try
 object Resource {
 
   def apply(base: AnyRef,
-            name: String): File =
+            name: String): File = {
     Try(new File(base.getClass.getResource(name).getPath))
       .getOrElse(throw new FileNotFoundException(name))
+  }
 }

src/test/scala/net/kemitix/s3thorp/S3ActionSuite.scala

@@ -0,0 +1,19 @@
+package net.kemitix.s3thorp
+
+class S3ActionSuite extends UnitTest {
+
+  describe("Ordering of types") {
+    val remoteKey = RemoteKey("remote-key")
+    val md5Hash = MD5Hash("md5hash")
+    val copy = CopyS3Action(remoteKey)
+    val upload = UploadS3Action(remoteKey, md5Hash)
+    val delete = DeleteS3Action(remoteKey)
+    val unsorted = List(delete, copy, upload)
+    it("should sort as copy < upload < delete ") {
+      val result = unsorted.sorted
+      val expected = List(copy, upload, delete)
+      assertResult(expected)(result)
+    }
+  }
+
+}

src/test/scala/net/kemitix/s3thorp/S3MetaDataEnricherSuite.scala

@@ -1,69 +1,133 @@
 package net.kemitix.s3thorp
 
-import java.io.File
-import java.nio.file.Paths
 import java.time.Instant
 
-import net.kemitix.s3thorp.awssdk.HashLookup
-import org.scalatest.FunSpec
+import net.kemitix.s3thorp.awssdk.S3ObjectsData
 
-class S3MetaDataEnricherSuite extends FunSpec {
+class S3MetaDataEnricherSuite
+  extends UnitTest
+    with KeyGenerator {
 
-  private val sourcePath = "/root/from/here/"
-  private val source = Paths.get(sourcePath).toFile
-  private val prefix = "prefix"
-  private val config = Config("bucket", prefix, source = source)
-
-  new S3MetaDataEnricher with DummyS3Client {
-    describe("key generator") {
-      val subject = generateKey(config)_
-
-      def resolve(subdir: String): File = {
-        source.toPath.resolve(subdir).toFile
-      }
-
-      describe("when file is within source") {
-        it("has a valid key") {
-          val subdir = "subdir"
-          assertResult(s"$prefix/$subdir")(subject(resolve(subdir)))
-        }
-      }
-
-      describe("when file is deeper within source") {
-        it("has a valid key") {
-          val subdir = "subdir/deeper/still"
-          assertResult(s"$prefix/$subdir")(subject(resolve(subdir)))
-        }
-      }
-    }
-  }
+  private val source = Resource(this, "upload")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val fileToKey = generateKey(config.source, config.prefix) _
+  val lastModified = LastModified(Instant.now())
 
   describe("enrich with metadata") {
-    val local = "localFile"
-    val fileWithRemote = new File(sourcePath + local)
-    val fileWithNoRemote = new File(sourcePath + "noRemote")
-    val remoteKey = prefix + "/" + local
-    val hash = "hash"
-    val lastModified = Instant.now()
-    val hashLookup = HashLookup(
-      byHash = Map(hash -> (remoteKey, lastModified)),
-      byKey = Map(remoteKey -> (hash, lastModified))
-    )
-    describe("when remote exists") {
-      new S3MetaDataEnricher with DummyS3Client {
-        it("returns metadata") {
-          val expectedMetadata = S3MetaData(fileWithRemote, remoteKey, hash, lastModified)
+    new S3MetaDataEnricher with DummyS3Client {
 
-          val result = enrichWithS3MetaData(config)(hashLookup)(fileWithRemote)
-          assertResult(Right(expectedMetadata))(result)
+      describe("#1a local exists, remote exists, remote matches, other matches - do nothing") {
+        val theHash: MD5Hash = MD5Hash("the-file-hash")
+        val theFile: LocalFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey: RemoteKey = theFile.remoteKey
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(theHash -> Set(KeyModified(theRemoteKey, lastModified))),
+          byKey = Map(theRemoteKey -> HashModified(theHash, lastModified))
+        )
+        val theRemoteMetadata = RemoteMetaData(theRemoteKey, theHash, lastModified)
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set(theRemoteMetadata),
+            matchByKey = Some(theRemoteMetadata))
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
         }
       }
-    }
-    describe("when remote doesn't exist") {
-      new S3MetaDataEnricher with DummyS3Client {
-        it("returns file to upload") {
-          val result = enrichWithS3MetaData(config)(hashLookup)(fileWithNoRemote)
-          assertResult(Left(fileWithNoRemote))(result)
+      describe("#1b local exists, remote exists, remote matches, other no matches - do nothing") {
+        val theHash: MD5Hash = MD5Hash("the-file-hash")
+        val theFile: LocalFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey: RemoteKey = aRemoteKey(prefix, "the-file")
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(theHash -> Set(KeyModified(theRemoteKey, lastModified))),
+          byKey = Map(theRemoteKey -> HashModified(theHash, lastModified))
+        )
+        val theRemoteMetadata = RemoteMetaData(theRemoteKey, theHash, lastModified)
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set(theRemoteMetadata),
+            matchByKey = Some(theRemoteMetadata))
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#2 local exists, remote is missing, remote no match, other matches - copy") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val otherRemoteKey = RemoteKey("other-key")
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(theHash -> Set(KeyModified(otherRemoteKey, lastModified))),
+          byKey = Map(otherRemoteKey -> HashModified(theHash, lastModified))
+        )
+        val otherRemoteMetadata = RemoteMetaData(otherRemoteKey, theHash, lastModified)
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set(otherRemoteMetadata),
+            matchByKey = None)
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#3 local exists, remote is missing, remote no match, other no matches - upload") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(),
+          byKey = Map()
+        )
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set.empty,
+            matchByKey = None)
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#4 local exists, remote exists, remote no match, other matches - copy") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey = theFile.remoteKey
+        val oldHash = MD5Hash("old-hash")
+        val otherRemoteKey = aRemoteKey(prefix, "other-key")
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(
+            oldHash -> Set(KeyModified(theRemoteKey, lastModified)),
+            theHash -> Set(KeyModified(otherRemoteKey, lastModified))),
+          byKey = Map(
+            theRemoteKey -> HashModified(oldHash, lastModified),
+            otherRemoteKey -> HashModified(theHash, lastModified)
+          )
+        )
+        val theRemoteMetadata = RemoteMetaData(theRemoteKey, oldHash, lastModified)
+        val otherRemoteMetadata = RemoteMetaData(otherRemoteKey, theHash, lastModified)
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set(otherRemoteMetadata),
+            matchByKey = Some(theRemoteMetadata))
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
+        }
+      }
+      describe("#5 local exists, remote exists, remote no match, other no matches - upload") {
+        val theHash = MD5Hash("the-hash")
+        val theFile = aLocalFile("the-file", theHash, source, fileToKey)
+        val theRemoteKey = theFile.remoteKey
+        val oldHash = MD5Hash("old-hash")
+        implicit val s3: S3ObjectsData = S3ObjectsData(
+          byHash = Map(
+            oldHash -> Set(KeyModified(theRemoteKey, lastModified)),
+            theHash -> Set.empty),
+          byKey = Map(
+            theRemoteKey -> HashModified(oldHash, lastModified)
+          )
+        )
+        val theRemoteMetadata = RemoteMetaData(theRemoteKey, oldHash, lastModified)
+        it("generates valid metadata") {
+          val expected = S3MetaData(theFile,
+            matchByHash = Set.empty,
+            matchByKey = Some(theRemoteMetadata))
+          val result = getMetadata(theFile)
+          assertResult(expected)(result)
         }
       }
     }

src/test/scala/net/kemitix/s3thorp/SyncSuite.scala

@@ -2,83 +2,215 @@ package net.kemitix.s3thorp
 
 import java.io.File
 import java.time.Instant
+import java.util.concurrent.CompletableFuture
 
 import cats.effect.IO
-import net.kemitix.s3thorp.Sync.{Bucket, LocalFile, MD5Hash, RemoteKey}
-import net.kemitix.s3thorp.awssdk.{HashLookup, S3Client}
-import org.scalatest.FunSpec
+import net.kemitix.s3thorp.awssdk.{S3Client, S3ObjectsData}
+import com.github.j5ik2o.reactive.aws.s3.S3AsyncClient
+import software.amazon.awssdk.core.async.AsyncRequestBody
+import software.amazon.awssdk.services.s3.{S3AsyncClient => JavaS3AsyncClient}
+import software.amazon.awssdk.services.s3
+import software.amazon.awssdk.services.s3.model.{ListObjectsV2Request, ListObjectsV2Response, PutObjectRequest, PutObjectResponse}
 
-class SyncSuite extends FunSpec {
+class SyncSuite
+  extends UnitTest
+    with KeyGenerator {
+
+  private val source = Resource(this, "upload")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val lastModified = LastModified(Instant.now)
 
   describe("s3client thunk") {
-    val testBucket = "bucket"
-    val testRemoteKey = "prefix/file"
+    val testBucket = Bucket("bucket")
+    val prefix = RemoteKey("prefix")
+    val source = new File("/")
     describe("upload") {
-      val md5Hash = "the-hash"
-      val testLocalFile = new File("file")
+      val md5Hash = MD5Hash("the-hash")
+      val testLocalFile = aLocalFile("file", md5Hash, source, generateKey(source, prefix))
       val sync = new Sync(new S3Client with DummyS3Client {
-        override def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey): IO[Either[Throwable, MD5Hash]] = {
-          assert(localFile == testLocalFile)
+        override def upload(localFile: LocalFile, bucket: Bucket)(implicit c: Config) = IO {
           assert(bucket == testBucket)
-          assert(remoteKey == testRemoteKey)
-          IO(Right(md5Hash))
+          UploadS3Action(localFile.remoteKey, md5Hash)
         }
       })
       it("delegates unmodified to the S3Client") {
-        assertResult(Right(md5Hash))(
-          sync.upload(testLocalFile, testBucket, testRemoteKey).
+        assertResult(UploadS3Action(RemoteKey(prefix.key + "/file"), md5Hash))(
+          sync.upload(testLocalFile, testBucket).
             unsafeRunSync())
       }
     }
   }
   describe("run") {
-    val testBucket = "bucket"
+    val testBucket = Bucket("bucket")
     val source = Resource(this, "upload")
     // source contains the files root-file and subdir/leaf-file
-    val config = Config("bucket", "prefix", source = source)
+    val config = Config(Bucket("bucket"), RemoteKey("prefix"), source = source)
+    val rootRemoteKey = RemoteKey("prefix/root-file")
+    val leafRemoteKey = RemoteKey("prefix/subdir/leaf-file")
     describe("when all files should be uploaded") {
-      var uploadsRecord: Map[String, RemoteKey] = Map()
-      val sync = new Sync(new DummyS3Client{
-        override def listObjects(bucket: Bucket, prefix: RemoteKey) = IO(
-          HashLookup(
-            byHash = Map(),
-            byKey = Map()))
-        override def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey) = {
-          if (bucket == testBucket)
-            uploadsRecord += (source.toPath.relativize(localFile.toPath).toString -> remoteKey)
-          IO(Right("some hash value"))
-        }
-      })
+      val sync = new RecordingSync(testBucket, new DummyS3Client {}, S3ObjectsData(
+        byHash = Map(),
+        byKey = Map()))
+      sync.run(config).unsafeRunSync
       it("uploads all files") {
-        sync.run(config).unsafeRunSync
-        val expected = Map(
-          "subdir/leaf-file" -> "prefix/subdir/leaf-file",
-          "root-file" -> "prefix/root-file"
+        val expectedUploads = Map(
+          "subdir/leaf-file" -> leafRemoteKey,
+          "root-file" -> rootRemoteKey
         )
-        assertResult(expected)(uploadsRecord)
+        assertResult(expectedUploads)(sync.uploadsRecord)
+      }
+      it("copies nothing") {
+        val expectedCopies = Map()
+        assertResult(expectedCopies)(sync.copiesRecord)
+      }
+      it("deletes nothing") {
+        val expectedDeletions = Set()
+        assertResult(expectedDeletions)(sync.deletionsRecord)
       }
     }
     describe("when no files should be uploaded") {
-      val rootHash = "a3a6ac11a0eb577b81b3bb5c95cc8a6e"
-      val leafHash = "208386a650bdec61cfcd7bd8dcb6b542"
-      val lastModified = Instant.now
-      var uploadsRecord: Map[String, RemoteKey] = Map()
-      val sync = new Sync(new S3Client with DummyS3Client {
-        override def listObjects(bucket: Bucket, prefix: RemoteKey) = IO(
-          HashLookup(
-            byHash = Map(rootHash -> ("prefix/root-file", lastModified), leafHash -> ("prefix/subdir/leaf-file", lastModified)),
-            byKey = Map("prefix/root-file" -> (rootHash, lastModified), "prefix/subdir/leaf-file" -> (leafHash, lastModified))))
-        override def upload(localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey) = {
-          if (bucket == testBucket)
-            uploadsRecord += (source.toPath.relativize(localFile.toPath).toString -> remoteKey)
-          IO(Right("some hash value"))
-        }
-      })
+      val rootHash = MD5Hash("a3a6ac11a0eb577b81b3bb5c95cc8a6e")
+      val leafHash = MD5Hash("208386a650bdec61cfcd7bd8dcb6b542")
+      val s3ObjectsData = S3ObjectsData(
+        byHash = Map(
+          rootHash -> Set(KeyModified(RemoteKey("prefix/root-file"), lastModified)),
+          leafHash -> Set(KeyModified(RemoteKey("prefix/subdir/leaf-file"), lastModified))),
+        byKey = Map(
+          RemoteKey("prefix/root-file") -> HashModified(rootHash, lastModified),
+          RemoteKey("prefix/subdir/leaf-file") -> HashModified(leafHash, lastModified)))
+      val sync = new RecordingSync(testBucket, new DummyS3Client {}, s3ObjectsData)
+      sync.run(config).unsafeRunSync
       it("uploads nothing") {
-        sync.run(config).unsafeRunSync
-        val expected = Map()
-        assertResult(expected)(uploadsRecord)
+        val expectedUploads = Map()
+        assertResult(expectedUploads)(sync.uploadsRecord)
+      }
+      it("copies nothing") {
+        val expectedCopies = Map()
+        assertResult(expectedCopies)(sync.copiesRecord)
+      }
+      it("deletes nothing") {
+        val expectedDeletions = Set()
+        assertResult(expectedDeletions)(sync.deletionsRecord)
+      }
+    }
+    describe("when a file is renamed it is moved on S3 with no upload") {
+      // 'root-file-old' should be renamed as 'root-file'
+      val rootHash = MD5Hash("a3a6ac11a0eb577b81b3bb5c95cc8a6e")
+      val leafHash = MD5Hash("208386a650bdec61cfcd7bd8dcb6b542")
+      val s3ObjectsData = S3ObjectsData(
+        byHash = Map(
+          rootHash -> Set(KeyModified(RemoteKey("prefix/root-file-old"), lastModified)),
+          leafHash -> Set(KeyModified(RemoteKey("prefix/subdir/leaf-file"), lastModified))),
+        byKey = Map(
+          RemoteKey("prefix/root-file-old") -> HashModified(rootHash, lastModified),
+          RemoteKey("prefix/subdir/leaf-file") -> HashModified(leafHash, lastModified)))
+      val sync = new RecordingSync(testBucket, new DummyS3Client {}, s3ObjectsData)
+      sync.run(config).unsafeRunSync
+      it("uploads nothing") {
+        val expectedUploads = Map()
+        assertResult(expectedUploads)(sync.uploadsRecord)
+      }
+      it("copies the file") {
+        val expectedCopies = Map(RemoteKey("prefix/root-file-old") -> RemoteKey("prefix/root-file"))
+        assertResult(expectedCopies)(sync.copiesRecord)
+      }
+      it("deletes the original") {
+        val expectedDeletions = Set(RemoteKey("prefix/root-file-old"))
+        assertResult(expectedDeletions)(sync.deletionsRecord)
+      }
+    }
+    describe("when a file is copied it is copied on S3 with no upload") {
+      it("TODO") {
+        pending
+      }
+    }
+    describe("when a file is deleted locally it is deleted from S3") {
+      val deletedHash = MD5Hash("deleted-hash")
+      val deletedKey = RemoteKey("prefix/deleted-file")
+      val s3ObjectsData = S3ObjectsData(
+        byHash = Map(
+          deletedHash -> Set(KeyModified(RemoteKey("prefix/deleted-file"), lastModified))),
+        byKey = Map(
+          deletedKey -> HashModified(deletedHash, lastModified)))
+      val sync = new RecordingSync(testBucket, new DummyS3Client {}, s3ObjectsData)
+      sync.run(config).unsafeRunSync
+      it("deleted key") {
+        val expectedDeletions = Set(deletedKey)
+        assertResult(expectedDeletions)(sync.deletionsRecord)
+      }
+    }
+    describe("io actions execute") {
+      val recordingS3Client = new RecordingS3Client
+      val client = S3Client.createClient(recordingS3Client)
+      val sync = new Sync(client)
+      sync.run(config).unsafeRunSync
+      it("invokes the underlying Java s3client") {
+        val expected = Set(
+          PutObjectRequest.builder().bucket(testBucket.name).key(rootRemoteKey.key).build(),
+          PutObjectRequest.builder().bucket(testBucket.name).key(leafRemoteKey.key).build()
+        )
+        val result = recordingS3Client.puts
+        assertResult(expected)(result)
       }
     }
   }
+
+  class RecordingSync(testBucket: Bucket, s3Client: S3Client, s3ObjectsData: S3ObjectsData)
+    extends Sync(s3Client) {
+
+    var uploadsRecord: Map[String, RemoteKey] = Map()
+    var copiesRecord: Map[RemoteKey, RemoteKey] = Map()
+    var deletionsRecord: Set[RemoteKey] = Set()
+
+    override def listObjects(bucket: Bucket, prefix: RemoteKey)(implicit c: Config) = IO {s3ObjectsData}
+
+    override def upload(localFile: LocalFile,
+                        bucket: Bucket
+                       )(implicit c: Config) = IO {
+      if (bucket == testBucket)
+        uploadsRecord += (localFile.relative.toString -> localFile.remoteKey)
+      UploadS3Action(localFile.remoteKey, MD5Hash("some hash value"))
+    }
+
+    override def copy(bucket: Bucket,
+                      sourceKey: RemoteKey,
+                      hash: MD5Hash,
+                      targetKey: RemoteKey
+                     )(implicit c: Config) = IO {
+      if (bucket == testBucket)
+        copiesRecord += (sourceKey -> targetKey)
+      CopyS3Action(targetKey)
+    }
+
+    override def delete(bucket: Bucket,
+                        remoteKey: RemoteKey
+                       )(implicit c: Config) = IO {
+      if (bucket == testBucket)
+        deletionsRecord += remoteKey
+      DeleteS3Action(remoteKey)
+    }
+  }
+
+  class RecordingS3Client extends S3AsyncClient {
+    var lists: Set[ListObjectsV2Request] = Set()
+    var puts: Set[PutObjectRequest] = Set()
+    override val underlying: s3.S3AsyncClient = new JavaS3AsyncClient {
+      override def serviceName(): String = "s3Recorder"
+
+      override def close(): Unit = ()
+
+      override def listObjectsV2(listObjectsV2Request: ListObjectsV2Request): CompletableFuture[ListObjectsV2Response] = {
+        lists += listObjectsV2Request
+        CompletableFuture.completedFuture(ListObjectsV2Response.builder().build())
+      }
+
+      override def putObject(putObjectRequest: PutObjectRequest,
+                             requestBody: AsyncRequestBody): CompletableFuture[PutObjectResponse] = {
+        puts += putObjectRequest
+        CompletableFuture.completedFuture(PutObjectResponse.builder().eTag("not-null").build())
+      }
+
+    }
+  }
 }

src/test/scala/net/kemitix/s3thorp/UnitTest.scala

@@ -0,0 +1,17 @@
+package net.kemitix.s3thorp
+
+import java.io.File
+
+import org.scalatest.FunSpec
+
+abstract class UnitTest extends FunSpec {
+
+  def aLocalFile(path: String, myHash: MD5Hash, source: File, fileToKey: File => RemoteKey): LocalFile =
+    new LocalFile(source.toPath.resolve(path).toFile, source, fileToKey) {
+      override def hash: MD5Hash = myHash
+    }
+
+  def aRemoteKey(prefix: RemoteKey, path: String): RemoteKey =
+    RemoteKey(prefix.key + "/" + path)
+
+}

src/test/scala/net/kemitix/s3thorp/UploadSelectionFilterSuite.scala

@@ -1,39 +0,0 @@
-package net.kemitix.s3thorp
-
-import java.io.File
-import java.time.Instant
-
-import org.scalatest.FunSpec
-
-class UploadSelectionFilterSuite extends FunSpec {
-
-  new UploadSelectionFilter {
-    describe("uploadRequiredFilter") {
-      val localFile = Resource(this, "test-file-for-hash.txt")
-      val localHash = "0cbfe978783bd7950d5da4ff85e4af37"
-      val config = Config("bucket", "prefix", source = localFile.getParentFile)
-      def invokeSubject(input: Either[File, S3MetaData]) =
-        uploadRequiredFilter(config)(input).toList
-      describe("when supplied a file") {
-        val input = Left(localFile)
-        it("should be marked for upload") {
-          assertResult(List(localFile))(invokeSubject(input))
-        }
-      }
-      describe("when supplied S3MetaData") {
-        describe("when hash is different") {
-          val input = Right(S3MetaData(localFile, "", "doesn't match any hash", Instant.now))
-          it("should be marked for upload") {
-            assertResult(List(localFile))(invokeSubject(input))
-          }
-        }
-        describe("when hash is the same") {
-          val input = Right(S3MetaData(localFile, "", localHash, Instant.now))
-          it("should not be marked for upload") {
-            assertResult(List())(invokeSubject(input))
-          }
-        }
-      }
-    }
-  }
-}

src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientSuite.scala

@@ -5,55 +5,92 @@ import java.time.Instant
 
 import cats.effect.IO
 import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
-import net.kemitix.s3thorp.Sync.{Bucket, LocalFile, RemoteKey}
-import org.scalatest.FunSpec
-import software.amazon.awssdk.services.s3.model._
+import net.kemitix.s3thorp._
+import software.amazon.awssdk.services.s3.model.{PutObjectRequest, PutObjectResponse}
 
-class S3ClientSuite extends FunSpec {
+class S3ClientSuite
+  extends UnitTest
+    with KeyGenerator {
 
-  describe("objectHead") {
-    val key = "key"
-    val hash = "hash"
-    val lastModified = Instant.now
-    val hashLookup: HashLookup = HashLookup(
-      byHash = Map(hash -> (key, lastModified)),
-      byKey = Map(key -> (hash, lastModified)))
+  val source = Resource(this, "../upload")
 
-    def invoke(self: S3Client, remoteKey: RemoteKey) = {
-      self.objectHead(remoteKey)(hashLookup)
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val fileToKey = generateKey(config.source, config.prefix) _
+
+  describe("getS3Status") {
+    val hash = MD5Hash("hash")
+    val localFile = aLocalFile("the-file", hash, source, fileToKey)
+    val key = localFile.remoteKey
+    val keyotherkey = aLocalFile("other-key-same-hash", hash, source, fileToKey)
+    val diffhash = MD5Hash("diff")
+    val keydiffhash = aLocalFile("other-key-diff-hash", diffhash, source, fileToKey)
+    val lastModified = LastModified(Instant.now)
+    val s3ObjectsData: S3ObjectsData = S3ObjectsData(
+      byHash = Map(
+        hash -> Set(KeyModified(key, lastModified), KeyModified(keyotherkey.remoteKey, lastModified)),
+        diffhash -> Set(KeyModified(keydiffhash.remoteKey, lastModified))),
+      byKey = Map(
+        key -> HashModified(hash, lastModified),
+        keyotherkey.remoteKey -> HashModified(hash, lastModified),
+        keydiffhash.remoteKey -> HashModified(diffhash, lastModified)))
+
+    def invoke(self: S3Client, localFile: LocalFile) = {
+      self.getS3Status(localFile)(s3ObjectsData)
     }
 
     describe("when remote key exists") {
       val s3Client = S3Client.defaultClient
-      it("should return Some(expected values)") {
-        assertResult(Some((hash, lastModified)))(invoke(s3Client, key))
+      it("should return (Some, Set.nonEmpty)") {
+        assertResult(
+          (Some(HashModified(hash, lastModified)),
+            Set(
+              KeyModified(key, lastModified),
+              KeyModified(keyotherkey.remoteKey, lastModified)))
+        )(invoke(s3Client, localFile))
       }
     }
 
-    describe("when remote key does not exist") {
+    describe("when remote key does not exist and no others matches hash") {
       val s3Client = S3Client.defaultClient
-      it("should return None") {
-        assertResult(None)(invoke(s3Client, "missing-key"))
+      it("should return (None, Set.empty)") {
+        val localFile = aLocalFile("missing-file", MD5Hash("unique"), source, fileToKey)
+        assertResult(
+          (None,
+            Set.empty)
+        )(invoke(s3Client, localFile))
+      }
+    }
+
+    describe("when remote key exists and no others match hash") {
+      val s3Client = S3Client.defaultClient
+      it("should return (None, Set.nonEmpty)") {
+        assertResult(
+          (Some(HashModified(diffhash, lastModified)),
+            Set(KeyModified(keydiffhash.remoteKey, lastModified)))
+        )(invoke(s3Client, keydiffhash))
       }
     }
 
   }
 
   describe("upload") {
-    def invoke(s3Client: ThorpS3Client, localFile: LocalFile, bucket: Bucket, remoteKey: RemoteKey) =
-      s3Client.upload(localFile, bucket, remoteKey).unsafeRunSync
+    def invoke(s3Client: ThorpS3Client, localFile: LocalFile, bucket: Bucket) =
+      s3Client.upload(localFile, bucket).unsafeRunSync
     describe("when uploading a file") {
-      val md5Hash = "the-md5hash"
+      val md5Hash = MD5Hash("the-md5hash")
       val s3Client = new ThorpS3Client(
         new S3CatsIOClient with JavaClientWrapper {
           override def putObject(putObjectRequest: PutObjectRequest, requestBody: RB) =
-            IO(PutObjectResponse.builder().eTag(md5Hash).build())
+            IO(PutObjectResponse.builder().eTag(md5Hash.hash).build())
         })
-      val localFile: LocalFile = new File("/some/file")
-      val bucket: Bucket = "a-bucket"
-      val remoteKey: RemoteKey = "prefix/file"
+      val source = new File("/")
+      val prefix = RemoteKey("prefix")
+      val localFile: LocalFile = aLocalFile("/some/file", md5Hash, source, generateKey(source, prefix))
+      val bucket: Bucket = Bucket("a-bucket")
+      val remoteKey: RemoteKey = RemoteKey("prefix/some/file")
       it("should return hash of uploaded file") {
-        assertResult(Right(md5Hash))(invoke(s3Client, localFile, bucket, remoteKey))
+        assertResult(UploadS3Action(remoteKey, md5Hash))(invoke(s3Client, localFile, bucket))
       }
     }
   }

src/test/scala/net/kemitix/s3thorp/awssdk/S3ObjectsByHashSuite.scala

@@ -0,0 +1,36 @@
+package net.kemitix.s3thorp.awssdk
+
+import java.time.Instant
+
+import net.kemitix.s3thorp.{KeyModified, LastModified, MD5Hash, RemoteKey, UnitTest}
+import software.amazon.awssdk.services.s3.model.S3Object
+
+class S3ObjectsByHashSuite extends UnitTest {
+
+  new S3ObjectsByHash {
+    describe("grouping s3 object together by their hash values") {
+      val hash = MD5Hash("hash")
+      val key1 = RemoteKey("key-1")
+      val key2 = RemoteKey("key-2")
+      val lastModified = LastModified(Instant.now)
+      val o1 = s3object(hash, key1, lastModified)
+      val o2 = s3object(hash, key2, lastModified)
+      val os = Stream(o1, o2)
+      it("should group by the hash value") {
+        val expected: Map[MD5Hash, Set[KeyModified]] = Map(
+          hash -> Set(KeyModified(key1, lastModified), KeyModified(key2, lastModified))
+        )
+        val result = byHash(os)
+        assertResult(expected)(result)
+      }
+    }
+  }
+
+  private def s3object(md5Hash: MD5Hash, remoteKey: RemoteKey, lastModified: LastModified): S3Object =
+    S3Object.builder
+      .eTag(md5Hash.hash)
+      .key(remoteKey.key)
+      .lastModified(lastModified.when)
+      .build
+
+}

src/test/scala/net/kemitix/s3thorp/awssdk/ThorpS3ClientSuite.scala

@@ -1,11 +1,13 @@
 package net.kemitix.s3thorp.awssdk
 
 import java.time.Instant
-import scala.collection.JavaConverters._
+import java.time.temporal.ChronoUnit
 
+import scala.collection.JavaConverters._
 import cats.effect.IO
 import com.github.j5ik2o.reactive.aws.s3.S3AsyncClient
 import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import net.kemitix.s3thorp.{Bucket, Config, HashModified, KeyModified, LastModified, MD5Hash, Main, RemoteKey, Resource}
 import org.scalatest.FunSpec
 import software.amazon.awssdk.services.s3
 import software.amazon.awssdk.services.s3.model.{ListObjectsV2Request, ListObjectsV2Response, S3Object}
@@ -13,37 +15,55 @@ import software.amazon.awssdk.services.s3.model.{ListObjectsV2Request, ListObjec
 class ThorpS3ClientSuite extends FunSpec {
 
   describe("listObjectsInPrefix") {
-    val h1 = "hash1"
-    val k1 = "key1"
-    val lm1 = Instant.now
-    val o1 = S3Object.builder.eTag(h1).key(k1).lastModified(lm1).build
-    val h2 = "hash2"
-    val k2 = "key2"
-    val lm2 = Instant.now.minusSeconds(200)
-    val o2 = S3Object.builder.eTag(h2).key(k2).lastModified(lm2).build
-    val myFakeResponse: IO[ListObjectsV2Response] = IO{
+    val source = Resource(Main, "upload")
+    val prefix = RemoteKey("prefix")
+    implicit val config: Config = Config(Bucket("bucket"), prefix, source = source)
+
+    val lm = LastModified(Instant.now)
+
+    val h1 = MD5Hash("hash1")
+
+    val k1a = RemoteKey("key1a")
+    val o1a = S3Object.builder.eTag(h1.hash).key(k1a.key).lastModified(lm.when).build
+
+    val k1b = RemoteKey("key1b")
+    val o1b = S3Object.builder.eTag(h1.hash).key(k1b.key).lastModified(lm.when).build
+
+    val h2 = MD5Hash("hash2")
+    val k2 = RemoteKey("key2")
+    val o2 = S3Object.builder.eTag(h2.hash).key(k2.key).lastModified(lm.when).build
+
+    val myFakeResponse: IO[ListObjectsV2Response] = IO {
       ListObjectsV2Response.builder()
-        .contents(List(o1, o2).asJava)
+        .contents(List(o1a, o1b, o2).asJava)
         .build()
     }
-    val subject = new ThorpS3Client(new S3CatsIOClient {
-      override val underlying: S3AsyncClient = new S3AsyncClient {
-        override val underlying: s3.S3AsyncClient = new s3.S3AsyncClient {
-          override def serviceName(): String = "fake-s3-client"
-
-          override def close(): Unit = ()
-        }
-      }
-      override def listObjectsV2(listObjectsV2Request: ListObjectsV2Request) =
+    val s3client = new ThorpS3Client(new MyS3CatsIOClient {
+      override def listObjectsV2(listObjectsV2Request: ListObjectsV2Request): IO[ListObjectsV2Response] =
         myFakeResponse
     })
-    it("should build list of hash lookups") {
-      val result: HashLookup = subject.listObjects("bucket", "prefix").unsafeRunSync()
-      val expected = HashLookup(
-        Map(h1 -> (k1, lm1), h2 -> (k2, lm2)),
-        Map(k1 -> (h1, lm1), k2 -> (h2, lm2)))
+    it("should build list of hash lookups, with duplicate objects grouped by hash") {
+      val expected = S3ObjectsData(
+        byHash = Map(
+          h1 -> Set(KeyModified(k1a, lm), KeyModified(k1b, lm)),
+          h2 -> Set(KeyModified(k2, lm))),
+        byKey = Map(
+          k1a -> HashModified(h1, lm),
+          k1b -> HashModified(h1, lm),
+          k2 -> HashModified(h2, lm)))
+      val result: S3ObjectsData = s3client.listObjects(Bucket("bucket"), RemoteKey("prefix")).unsafeRunSync()
+      assertResult(expected.byHash.keys)(result.byHash.keys)
+      assertResult(expected.byKey.keys)(result.byKey.keys)
       assertResult(expected)(result)
     }
   }
+  trait MyS3CatsIOClient extends S3CatsIOClient {
+    override val underlying: S3AsyncClient = new S3AsyncClient {
+      override val underlying: s3.S3AsyncClient = new s3.S3AsyncClient {
+        override def serviceName(): String = "fake-s3-client"
 
+        override def close(): Unit = ()
+      }
+    }
+  }
 }