Complete and validate (#13)

* isComplete implementation

* IntelliJ formatting

* isValid implementation

* fix compiler warning

* make docs more clear

* bullit list in scaladoc

* virtually valid type definition + documentation

* clarify documentation on isComplete and isValid

* formatting + imports

* isVirtuallyValid is no longer part of this issue

* formatting

* extra tests for isComplete and isValid

* formatting

src/main/scala/nl/knaw/dans/bag/DansBag.scala

@@ -539,6 +539,41 @@ trait DansBag {
    *         `scala.util.Failure` otherwise
    */
   def save(): Try[Unit]
+
+  /**
+   * Verifies if a bag is complete.
+   * According to the BagIt version 16 specs, a bag is complete when:
+   *   - bagit.txt is present
+   *   - data/ directory is present
+   *   - at least one payload manifest exists
+   *   - all fetch items are present in the bag
+   *   - all files in every payload manifest must be present
+   *   - all files in every tag manifest must be present
+   *   - (>= V1.0 bag) all files in the payload directory are listed in all payload manifests
+   *   - (< V1.0 bag) all files in the payload directory are listed in at least one payload manifest
+   *
+   * @return either `Unit` (if the bag is complete) or `String` (containing the error message if
+   *         the bag is not complete)
+   */
+  def isComplete: Either[String, Unit]
+
+  /**
+   * Verifies if a bag is valid.
+   * According to the BagIt v16 specs, a bag is valid when:
+   *   - the bag is complete
+   *   - every checksum in every payload manifest has been successfully verified against the
+   * contents of the corresponding file
+   *   - every checksum in every tag manifest has been successfully verified against the
+   * contents of the corresponding file
+   *
+   * Due to calculating the checksums for all files, this method may take some time to complete and
+   * return. It is therefore strongly advised to wrap a call to this method in a `Promise`/`Future`,
+   * `Observable` or any other desired data structure that deals with latency in a proper way.
+   *
+   * @return either `Unit` (if the bag is valid) or `String` (containing the error message if
+   *         the bag is not valid)
+   */
+  def isValid: Either[String, Unit]
 }
 
 object DansBag {

src/main/scala/nl/knaw/dans/bag/v0/DansV0Bag.scala

@@ -23,9 +23,10 @@ import java.util.{ UUID, Set => jSet }
 
 import better.files.{ CloseableOps, Disposable, File, Files, ManagedResource }
 import gov.loc.repository.bagit.creator.BagCreator
-import gov.loc.repository.bagit.domain.{ Version, Bag => LocBag, Manifest => LocManifest, Metadata => LocMetadata, FetchItem => LocFetchItem }
+import gov.loc.repository.bagit.domain.{ Version, Bag => LocBag, FetchItem => LocFetchItem, Manifest => LocManifest, Metadata => LocMetadata }
 import gov.loc.repository.bagit.reader.BagReader
 import gov.loc.repository.bagit.util.PathUtils
+import gov.loc.repository.bagit.verify.BagVerifier
 import gov.loc.repository.bagit.writer.{ BagitFileWriter, FetchWriter, ManifestWriter, MetadataWriter }
 import nl.knaw.dans.bag.ChecksumAlgorithm.{ ChecksumAlgorithm, locDeconverter }
 import nl.knaw.dans.bag.{ ChecksumAlgorithm, DansBag, FetchItem, RelativePath, betterFileToPath }
@@ -185,7 +186,7 @@ class DansV0Bag private(private[v0] val locBag: LocBag) extends DansBag {
       .map(_.asScala)
       .collect {
         case Seq(userId) => userId
-        case userIds if userIds.size > 1 => throw new IllegalStateException(s"Only one EASY-User-Account allowed; found ${userIds.size}")
+        case userIds if userIds.size > 1 => throw new IllegalStateException(s"Only one EASY-User-Account allowed; found ${ userIds.size }")
       }
   }
 
@@ -209,7 +210,9 @@ class DansV0Bag private(private[v0] val locBag: LocBag) extends DansBag {
   /**
    * @inheritdoc
    */
-  override def fetchFiles: Seq[FetchItem] = locBag.getItemsToFetch.asScala.map(fetch => fetch: FetchItem)
+  override def fetchFiles: Seq[FetchItem] = {
+    locBag.getItemsToFetch.asScala.map(fetch => fetch: FetchItem)
+  }
 
   /**
    * @inheritdoc
@@ -453,7 +456,8 @@ class DansV0Bag private(private[v0] val locBag: LocBag) extends DansBag {
   /**
    * @inheritdoc
    */
-  override def addPayloadFile(inputStream: InputStream)(pathInData: RelativePath): Try[DansV0Bag] = Try {
+  override def addPayloadFile(inputStream: InputStream)
+                             (pathInData: RelativePath): Try[DansV0Bag] = Try {
     val file = pathInData(data)
 
     if (file.exists)
@@ -633,6 +637,22 @@ class DansV0Bag private(private[v0] val locBag: LocBag) extends DansBag {
     ManifestWriter.writeTagManifests(locBag.getTagManifests, baseDir, baseDir, fileEncoding)
   }
 
+  /**
+   * @inheritdoc
+   */
+  override def isComplete: Either[String, Unit] = {
+    Try { new ManagedResource(new BagVerifier()).apply(_.isComplete(this.locBag, false)) }
+      .toEither.left.map(_.getMessage)
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override def isValid: Either[String, Unit] = {
+    Try { new ManagedResource(new BagVerifier()).apply(_.isValid(this.locBag, false)) }
+      .toEither.left.map(_.getMessage)
+  }
+
   protected def validateURL(url: URL): Unit = {
     if (url.getProtocol != "http" && url.getProtocol != "https")
       throw new IllegalArgumentException("url can only have protocol 'http' or 'https'")

src/test/scala/nl/knaw/dans/bag/fixtures/FetchFileMetadata.scala

@@ -17,11 +17,17 @@ package nl.knaw.dans.bag.fixtures
 
 import java.net.URL
 
+import better.files.File
 import nl.knaw.dans.bag.RelativePath
 
 trait FetchFileMetadata {
   this: TestSupportFixture =>
 
+  def findFile(pathRelativeToTestResources: String): File = {
+    File(getClass.getResource(pathRelativeToTestResources))
+  }
+
+  val lipsum1File: File = findFile("/fetch-files/lipsum1.txt")
   val lipsum1URL: URL = new URL("https://raw.githubusercontent.com/rvanheest-DANS-KNAW/" +
     "dans-bag-lib/c8681a5932e4081dfec95680abefc9a07740a97a/src/test/resources/fetch-files/" +
     "lipsum1.txt")
@@ -33,6 +39,7 @@ trait FetchFileMetadata {
     "19d5cdbb6f0f84be9145643ac793dd63eaee407e51d6dacd5ba3c1d8f6fe07da"
   val lipsum1Size: Long = 485L
 
+  val lipsum2File: File = findFile("/fetch-files/lipsum2.txt")
   val lipsum2URL: URL = new URL("https://raw.githubusercontent.com/rvanheest-DANS-KNAW/" +
     "dans-bag-lib/c8681a5932e4081dfec95680abefc9a07740a97a/src/test/resources/fetch-files/" +
     "lipsum2.txt")
@@ -44,6 +51,7 @@ trait FetchFileMetadata {
     "d4086396119e2ebaadd79548d623d8dfa350f854af6271da68311abb1c0e73e8"
   val lipsum2Size: Long = 989L
 
+  val lipsum3File: File = findFile("/fetch-files/lipsum3.txt")
   val lipsum3URL: URL = new URL("https://raw.githubusercontent.com/rvanheest-DANS-KNAW/" +
     "dans-bag-lib/c8681a5932e4081dfec95680abefc9a07740a97a/src/test/resources/fetch-files/" +
     "lipsum3.txt")
@@ -55,6 +63,7 @@ trait FetchFileMetadata {
     "647c11784b75eed3a20ac60efda146f040daeaa3837fa3aba9a2b94e30da0965"
   val lipsum3Size: Long = 1641L
 
+  val lipsum4File: File = findFile("/fetch-files/lipsum4.txt")
   val lipsum4URL: URL = new URL("https://raw.githubusercontent.com/rvanheest-DANS-KNAW/" +
     "dans-bag-lib/c8681a5932e4081dfec95680abefc9a07740a97a/src/test/resources/fetch-files/" +
     "lipsum4.txt")
@@ -66,6 +75,7 @@ trait FetchFileMetadata {
     "e7e3639cba8c3a864fea8a6f58fc0a37310b3f4550466d8ff2c9ba0835bb3231"
   val lipsum4Size: Long = 2095L
 
+  val lipsum5File: File = findFile("/fetch-files/lipsum5.txt")
   val lipsum5URL: URL = new URL("https://raw.githubusercontent.com/rvanheest-DANS-KNAW/" +
     "dans-bag-lib/c8681a5932e4081dfec95680abefc9a07740a97a/src/test/resources/fetch-files/" +
     "lipsum5.txt")

src/test/scala/nl/knaw/dans/bag/fixtures/TestSupportFixture.scala

@@ -21,4 +21,5 @@ trait TestSupportFixture extends FlatSpec
   with Matchers
   with Inside
   with OptionValues
+  with EitherValues
   with Inspectors