refactor(workflows): rework types & instances

2020-05-08 15:07:38 +02:00 · 2020-05-08 15:07:38 +02:00 · 8943c3e3bf
commit 8943c3e3bf
parent c2169423e6
6 changed files with 271 additions and 313 deletions
--- a/models/workflows.model
+++ b/models/workflows.model
@ -1,20 +1,21 @@
 WorkflowDefinition
-    graph       WorkflowGraph
+    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)
    scope       WorkflowInstanceScope'
    name        (CI Text)
    UniqueWorkflowDefinition name scope

 WorkflowInstance
    definition  WorkflowDefinition
-    graph       (WorkflowGraph Int64 Int64)  -- FileId, UserId
-    scope       (WorkflowInstanceScope Int64 Int64 Int64)  -- TermId, SchoolId, CourseId
+    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)  -- FileId, UserId
+    scope       (WorkflowInstanceScope SqlBackendKey SqlBackendKey SqlBackendKey)  -- TermId, SchoolId, CourseId
    name        (CI Text)
    category    (CI Text) Maybe
    UniqueWorkflowInstance name scope

 WorkflowWorkflow
    instance    WorkflowInstance
-    graph       WorkflowGraph
-    initiator   UserId Maybe
-    payload     WorkflowPayload
-    currentNode WorkflowGraphNodeLabel Maybe
+    graph       (WorkflowGraph SqlBackendKey SqlBackendKey)  -- FileId, UserId
+    initUser    UserId Maybe
+    initTime    UTCTime
+    state       (WorkflowState SqlBackendKey SqlBackendKey)  -- FileId, UserId
+    currentNode WorkflowGraphNodeLabel
--- a/src/Import/NoModel.hs
+++ b/src/Import/NoModel.hs
@ -7,7 +7,7 @@ module Import.NoModel

 import ClassyPrelude.Yesod    as Import
  hiding ( formatTime
-         , derivePersistFieldJSON
+         , derivePersistFieldJSON, toPersistValueJSON, fromPersistValueJSON
         , getMessages, addMessage, addMessageI
         , (.=)
         , MForm
--- a/src/Model.hs
+++ b/src/Model.hs
@ -21,6 +21,11 @@ import Settings.Cluster (ClusterSettingsKey)

 import Text.Blaze (ToMarkup(..))

+import Database.Persist.Sql (BackendKey(..))
+
+
+type SqlBackendKey = BackendKey SqlBackend
+

 -- You can define all of your database entities in the entities file.
 -- You can find more information on persistent and how to declare entities
--- a/src/Model/Types/Security.hs
+++ b/src/Model/Types/Security.hs
@ -89,8 +89,8 @@ data AuthTag -- sortiert nach gewünschter Reihenfolge auf /authpreds, d.h. Prä
  | AuthDeprecated
  | AuthDevelopment
  | AuthFree
-  deriving (Eq, Ord, Enum, Bounded, Read, Show, Generic, Typeable)
-  deriving anyclass (Universe, Finite, Hashable)
+  deriving (Eq, Ord, Enum, Bounded, Read, Show, Data, Generic, Typeable)
+  deriving anyclass (Universe, Finite, Hashable, Binary)

 nullaryPathPiece ''AuthTag $ camelToPathPiece' 1
 pathPieceJSON ''AuthTag
@ -149,7 +149,7 @@ instance PathPiece a => PathPiece (PredLiteral a) where


 newtype PredDNF a = PredDNF { dnfTerms :: Set (NonNull (Set (PredLiteral a))) }
-  deriving (Eq, Ord, Read, Show, Generic, Typeable)
+  deriving (Eq, Ord, Read, Show, Data, Generic, Typeable)
  deriving newtype (Semigroup, Monoid)
  deriving anyclass (Binary, Hashable)

--- a/src/Model/Types/TH/JSON.hs
+++ b/src/Model/Types/TH/JSON.hs
@ -1,11 +1,8 @@
-module Model.Types.TH.JSON
-  ( derivePersistFieldJSON
-  , predNFAesonOptions
-  ) where
+module Model.Types.TH.JSON where

-import ClassyPrelude.Yesod hiding (derivePersistFieldJSON)
+import ClassyPrelude.Yesod hiding (derivePersistFieldJSON, toPersistValueJSON, fromPersistValueJSON)
 import Data.List (foldl)
-import Database.Persist.Sql
+import Database.Persist.Sql hiding (toPersistValueJSON, fromPersistValueJSON)

 import qualified Data.ByteString.Lazy as LBS
 import qualified Data.Text.Encoding as Text
@ -18,6 +15,21 @@ import Language.Haskell.TH.Datatype
 import Utils.PathPiece


+toPersistValueJSON :: ToJSON a => a -> PersistValue
+toPersistValueJSON = PersistDbSpecific . LBS.toStrict . JSON.encode
+
+fromPersistValueJSON :: FromJSON a => PersistValue -> Either Text a
+fromPersistValueJSON = \case
+  PersistDbSpecific bs   -> decodeBS bs
+  PersistByteString bs   -> decodeBS bs
+  PersistText       text -> decodeBS $ Text.encodeUtf8 text
+  _other                 -> Left "JSON values must be converted from PersistDbSpecific, PersistText, or PersistByteString"
+  where decodeBS = first pack . JSON.eitherDecodeStrict'
+
+sqlTypeJSON :: SqlType
+sqlTypeJSON = SqlOther "jsonb"
+
+
 derivePersistFieldJSON :: Name -> DecsQ
 derivePersistFieldJSON tName = do
  DatatypeInfo{..} <- reifyDatatype tName
@ -32,24 +44,15 @@ derivePersistFieldJSON tName = do
  sequence
    [ instanceD iCxt ([t|PersistField|] `appT` t)
      [ funD 'toPersistValue
-        [ clause [] (normalB [e|PersistDbSpecific . LBS.toStrict . JSON.encode|]) []
+        [ clause [] (normalB [e|toPersistValueJSON|]) []
        ]
      , funD 'fromPersistValue
-        [ do
-            bs <- newName "bs"
-            clause [[p|PersistDbSpecific $(varP bs)|]] (normalB [e|first pack $ JSON.eitherDecodeStrict' $(varE bs)|]) []
-        , do
-            bs <- newName "bs"
-            clause [[p|PersistByteString $(varP bs)|]] (normalB [e|first pack $ JSON.eitherDecodeStrict' $(varE bs)|]) []
-        , do
-            text <- newName "text"
-            clause [[p|PersistText $(varP text)|]] (normalB [e|first pack . JSON.eitherDecodeStrict' $ Text.encodeUtf8 $(varE text)|]) []
-        , clause [wildP] (normalB [e|Left "JSON values must be converted from PersistDbSpecific, PersistText, or PersistByteString"|]) []
+        [ clause [] (normalB [e|fromPersistValueJSON|]) []
        ]
      ]
    , instanceD sqlCxt ([t|PersistFieldSql|] `appT` t)
      [ funD 'sqlType
-        [ clause [wildP] (normalB [e|SqlOther "jsonb"|]) []
+        [ clause [wildP] (normalB [e|sqlTypeJSON|]) []
        ]
      ]
    ]
@ -64,4 +67,20 @@ predNFAesonOptions = defaultOptions
  , sumEncoding = ObjectWithSingleField
  , tagSingleConstructors = True
  }
+  

+workflowGraphAesonOptions, workflowGraphEdgeAesonOptions, workflowGraphNodeAesonOptions, workflowActionAesonOptions :: Options
+workflowGraphAesonOptions = defaultOptions
+  { fieldLabelModifier = camelToPathPiece' 1
+  }
+workflowGraphEdgeAesonOptions = defaultOptions
+  { constructorTagModifier = camelToPathPiece' 3
+  , fieldLabelModifier = camelToPathPiece' 1
+  , sumEncoding = TaggedObject "mode" $ error "There should be no field called ‘mode’"
+  }
+workflowGraphNodeAesonOptions = defaultOptions
+  { fieldLabelModifier = camelToPathPiece' 1
+  }
+workflowActionAesonOptions = defaultOptions
+  { fieldLabelModifier = camelToPathPiece' 1
+  }
--- a/src/Model/Types/Workflow.hs
+++ b/src/Model/Types/Workflow.hs
@ -3,29 +3,26 @@ module Model.Types.Workflow
  , WorkflowGraphNodeLabel
  , WorkflowInstanceScope(..)
  , WorkflowInstanceScope'(..)
-  , WorkflowPayload(..)
-  , WorkflowPayload'(..)
+  , WorkflowState
+  , WorkflowAction(..)
  ) where

 import Import.NoModel

 import Model.Types.Security (AuthDNF)
--import Model.Types.Security (AuthDNF, PredDNF(..), AuthTag(..), PredLiteral(..))

 import Database.Persist.Sql (PersistFieldSql(..))

-import qualified Data.Set as Set (toList)
--import qualified Data.Set as Set (toList, fromList)
--import qualified Data.Map as Map
--import qualified Data.Sequence as Seq
 import Data.Scientific
 import Data.Maybe (fromJust)

+import Data.Aeson (genericToJSON, genericParseJSON)
 import qualified Data.Aeson as JSON
+import qualified Data.Aeson.Types as JSON
+import Data.Aeson.Lens (_Null)
 import Data.Aeson.Types (Parser)

-- TODO remove
--import Data.ByteString.Lazy.Internal (ByteString)
+import Type.Reflection (eqTypeRep, typeOf, (:~~:)(..))


 -----  WORKFLOW GRAPH  -----
@ -34,15 +31,17 @@ data WorkflowGraph fileid userid = WorkflowGraph
  { wgNodes          :: Map WorkflowGraphNodeLabel (WorkflowGraphNode fileid userid)
  , wgPayloadViewers :: Map WorkflowPayloadLabel (NonNull (Set (WorkflowRole userid)))
  }
-  deriving (Show, Eq)
+  deriving (Eq, Ord, Show, Generic, Typeable)


 -----  WORKFLOW GRAPH: NODES  -----

-newtype WorkflowGraphNodeLabel = WorkflowGraphNodeLabel (CI Text)
-  deriving newtype (Eq, Ord, Show, Read, Typeable, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)
-newtype WorkflowGraphEdgeLabel = WorkflowGraphEdgeLabel (CI Text)
-  deriving newtype (Eq, Ord, Show, Read, Typeable, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)
+newtype WorkflowGraphNodeLabel = WorkflowGraphNodeLabel { unWorkflowGraphNodeLabel :: CI Text }
+  deriving stock (Eq, Ord, Read, Show, Data, Generic, Typeable)
+  deriving newtype (IsString, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)
+newtype WorkflowGraphEdgeLabel = WorkflowGraphEdgeLabel { unWorkflowGraphEdgeLabel :: CI Text }
+  deriving stock (Eq, Ord, Read, Show, Data, Generic, Typeable)
+  deriving newtype (IsString, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)

 data WorkflowGraphNode fileid userid = WGN
  { wgnDisplayLabel :: Maybe Text
@ -56,157 +55,166 @@ data WorkflowGraphNode fileid userid = WGN

 -----  WORKFLOW GRAPH: EDGES  -----

-data WorkflowGraphEdge fileid userid = WGE
-  { wgeTarget    :: WorkflowGraphNodeLabel
-  , wgeAutomatic :: Bool
-  , wgeActors    :: Set (WorkflowRole userid)
-  , wgeForm      :: NonNull (Map WorkflowPayloadLabel (WorkflowPayloadSpec fileid userid))
-  }
-  deriving Show
-
-instance (Eq fileid, Eq userid) => Eq (WorkflowGraphEdge fileid userid) where
-  e1@WGE{} == e2@WGE{} = wgeTarget e1 == wgeTarget e2 && wgeActors e1 == wgeActors e2 && wgeForm e1 == wgeForm e2
-
-instance (Ord fileid, Ord userid) => Ord (WorkflowGraphEdge fileid userid) where
-  compare = mconcat [comparing wgeTarget, comparing wgeActors, comparing wgeForm]
+data WorkflowGraphEdge fileid userid
+  = WorkflowGraphEdgeManual
+    { wgeTarget    :: WorkflowGraphNodeLabel
+    , wgeActors    :: Set (WorkflowRole userid)
+    , wgeForm      :: Map WorkflowPayloadLabel (NonNull (Set (WorkflowPayloadSpec fileid userid)))
+      -- ^ field requirement forms a cnf:
+      --
+      -- - all labels must be filled
+      -- - for each label any field must be filled
+      -- - optional fields are always considered to be filled
+      -- 
+      -- since fields can reference other labels this allows arbitrary requirements to be encoded.
+    }
+  | WorkflowGraphEdgeAutomatic
+    { wgeTarget    :: WorkflowGraphNodeLabel
+    }
+  deriving (Eq, Ord, Show, Generic, Typeable)


 -----  WORKFLOW GRAPH: ROLES / ACTORS  -----

 data WorkflowRole userid
-                  = WorkflowRoleUser       userid
-                  | WorkflowRoleAuthorized AuthDNF
-                  | WorkflowRoleInitiator
-  deriving (Eq, Ord, Show, Read, Generic, Typeable)
+  = WorkflowRoleUser       { workflowRoleUser       :: userid  }
+  | WorkflowRoleAuthorized { workflowRoleAuthorized :: AuthDNF }
+  | WorkflowRoleInitiator
+  deriving (Eq, Ord, Show, Read, Data, Generic, Typeable)


 -----  WORKFLOW GRAPH: PAYLOAD SPECIFICATION  -----

-data WorkflowPayloadSpec fileid userid = forall payload. WorkflowPayloadSpec (WorkflowPayloadField fileid userid payload)
+data WorkflowPayloadSpec fileid userid = forall payload. Typeable payload => WorkflowPayloadSpec (WorkflowPayloadField fileid userid payload)
+  deriving (Typeable)

-instance (Show fileid, Show userid) => Show (WorkflowPayloadSpec fileid userid) where
-  show (WorkflowPayloadSpec payloadField) = show payloadField
-
-newtype WorkflowPayloadFieldLabel = WorkflowPayloadFieldLabel (CI Text)
-  deriving newtype (Eq, Ord, Show, Read, Typeable, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)
+deriving instance (Show fileid, Show userid) => Show (WorkflowPayloadSpec fileid userid)

 data WorkflowPayloadField fileid userid (payload :: Type) where
-  WorkflowPayloadFieldText   :: { wpftLabel       :: Text
-                                , wpftPlaceholder :: Text
-                                , wpftTooltip     :: Maybe Text
-                                , wpftDefault     :: Maybe Text
-                                , wpftOptional    :: Maybe Bool
-                                } -> WorkflowPayloadField fileid userid Text
-  WorkflowPayloadFieldNumber :: { wpfnLabel       :: Text
-                                , wpfnPlaceholder :: Text
-                                , wpfnTooltip     :: Maybe Text
-                                , wpfnDefault     :: Maybe Scientific
-                                , wpfnMin         :: Maybe Scientific
-                                , wpfnMax         :: Maybe Scientific
-                                , wpfnStep        :: Scientific
-                                , wpfnOptional    :: Maybe Bool
-                                } -> WorkflowPayloadField fileid userid Scientific
-  WorkflowPayloadFieldBool   :: { wpfbLabel       :: Text
-                                , wpfbTooltip     :: Maybe Text
-                                , wpfbDefault     :: Maybe Bool
-                                } -> WorkflowPayloadField fileid userid Bool
-  WorkflowPayloadFieldFile   :: { wpffLabel       :: Text
-                                , wpffTooltip     :: Maybe Text
-                                , wpffDefault     :: Maybe fileid
-                                , wpffOptional    :: Maybe Bool
-                                } -> WorkflowPayloadField fileid userid FileInfo
-  WorkflowPayloadFieldUser   :: { wpfuLabel       :: Text
-                                , wpfuTooltip     :: Maybe Text
-                                , wpfuDefault     :: Maybe userid
-                                , wpfuOptional    :: Maybe Bool
-                                } -> WorkflowPayloadField fileid userid userid
+  WorkflowPayloadFieldText      :: { wpftLabel       :: Text
+                                   , wpftPlaceholder :: Maybe Text
+                                   , wpftTooltip     :: Maybe Text
+                                   , wpftDefault     :: Maybe Text
+                                   , wpftOptional    :: Bool
+                                   } -> WorkflowPayloadField fileid userid Text
+  WorkflowPayloadFieldNumber    :: { wpfnLabel       :: Text
+                                   , wpfnPlaceholder :: Maybe Text
+                                   , wpfnTooltip     :: Maybe Text
+                                   , wpfnDefault
+                                   , wpfnMin
+                                   , wpfnMax
+                                   , wpfnStep        :: Maybe Scientific
+                                   , wpfnOptional    :: Bool
+                                   } -> WorkflowPayloadField fileid userid Scientific
+  WorkflowPayloadFieldBool      :: { wpfbLabel       :: Text
+                                   , wpfbTooltip     :: Maybe Text
+                                   , wpfbDefault     :: Maybe Bool
+                                   , wpfbOptional    :: Maybe Text -- ^ Optional if `Just`; encodes label of `Nothing`-Option
+                                   } -> WorkflowPayloadField fileid userid Bool
+  WorkflowPayloadFieldFile      :: { wpffLabel       :: Text
+                                   , wpffTooltip     :: Maybe Text
+                                   , wpffDefault     :: Maybe fileid
+                                   , wpffOptional    :: Bool
+                                   } -> WorkflowPayloadField fileid userid FileInfo
+  WorkflowPayloadFieldUser      :: { wpfuLabel       :: Text
+                                   , wpfuTooltip     :: Maybe Text
+                                   , wpfuDefault     :: Maybe userid
+                                   , wpfuOptional    :: Bool
+                                   } -> WorkflowPayloadField fileid userid userid
+  WorkflowPayloadFieldReference :: { wpfrTarget      :: WorkflowPayloadLabel
+                                   } -> WorkflowPayloadField fileid userid (NonNull (Set (WorkflowFieldPayloadW fileid userid)))
+  deriving (Typeable)

-instance (Show fileid, Show userid) => Show (WorkflowPayloadField fileid userid payload) where
-  show (WorkflowPayloadFieldText{..}  ) =   "TextField{label = " <> show wpftLabel
-                                        <>    ", placeholder = " <> show wpftPlaceholder
-                                        <>        ", tooltip = " <> show wpftTooltip
-                                        <>        ", default = " <> show wpftDefault
-                                        <>       ", optional = " <> show wpftOptional
-                                        <> "}"
-  show (WorkflowPayloadFieldNumber{..}) = "NumberField{label = " <> show wpfnLabel
-                                        <>    ", placeholder = " <> show wpfnPlaceholder
-                                        <>        ", tooltip = " <> show wpfnTooltip
-                                        <>        ", default = " <> show wpfnDefault
-                                        <>            ", min = " <> show wpfnMin
-                                        <>            ", max = " <> show wpfnMax
-                                        <>           ", step = " <> show wpfnStep
-                                        <>       ", optional = " <> show wpfnOptional
-                                        <> "}"
-  show (WorkflowPayloadFieldBool{..}  ) =   "BoolField{label = " <> show wpfbLabel
-                                        <>        ", tooltip = " <> show wpfbTooltip
-                                        <>        ", default = " <> show wpfbDefault
-                                        <> "}"
-  show (WorkflowPayloadFieldFile{..}  ) =   "FileField{label = " <> show wpffLabel
-                                        <>        ", tooltip = " <> show wpffTooltip
-                                        <>        ", default = " <> show wpffDefault
-                                        <>       ", optional = " <> show wpffOptional
-                                        <> "}"
-  show (WorkflowPayloadFieldUser{..}  ) =   "UserField{label = " <> show wpfuLabel
-                                        <>        ", tooltip = " <> show wpfuTooltip
-                                        <>        ", default = " <> show wpfuDefault
-                                        <>       ", optional = " <> show wpfuOptional
-                                        <> "}"
+deriving instance (Show fileid, Show userid) => Show (WorkflowPayloadField fileid userid payload)
+deriving instance (Eq fileid, Eq userid) => Eq (WorkflowPayloadField fileid userid payload)
+deriving instance (Ord fileid, Ord userid) => Ord (WorkflowPayloadField fileid userid payload)

-instance (Eq fileid, Eq userid) => Eq (WorkflowPayloadSpec fileid userid) where
-  (WorkflowPayloadSpec f1@WorkflowPayloadFieldText{}) == (WorkflowPayloadSpec f2@WorkflowPayloadFieldText{}) = wpftLabel f1 == wpftLabel f2 && wpftPlaceholder f1 == wpftPlaceholder f2 && wpftTooltip f1 == wpftTooltip f2 && wpftDefault f1 == wpftDefault f2 && wpftOptional f1 == wpftOptional f2
-  (WorkflowPayloadSpec f1@WorkflowPayloadFieldNumber{}) == (WorkflowPayloadSpec f2@WorkflowPayloadFieldNumber{}) = wpfnLabel f1 == wpfnLabel f2 && wpfnPlaceholder f1 == wpfnPlaceholder f2 && wpfnTooltip f1 == wpfnTooltip f2 && wpfnDefault f1 == wpfnDefault f2 && wpfnOptional f1 == wpfnOptional f2
-  (WorkflowPayloadSpec f1@WorkflowPayloadFieldBool{}) == (WorkflowPayloadSpec f2@WorkflowPayloadFieldBool{}) = wpfbLabel f1 == wpfbLabel f2 && wpfbTooltip f1 == wpfbTooltip f2 && wpfbDefault f1 == wpfbDefault f2
-  (WorkflowPayloadSpec f1@WorkflowPayloadFieldFile{}) == (WorkflowPayloadSpec f2@WorkflowPayloadFieldFile{}) = wpffLabel f1 == wpffLabel f2 && wpffTooltip f1 == wpffTooltip f2 && wpffDefault f1 == wpffDefault f2 && wpffOptional f1 == wpffOptional f2
-  (WorkflowPayloadSpec f1@WorkflowPayloadFieldUser{}) == (WorkflowPayloadSpec f2@WorkflowPayloadFieldUser{}) = wpfuLabel f1 == wpfuLabel f2 && wpfuTooltip f1 == wpfuTooltip f2 && wpfuDefault f1 == wpfuDefault f2 && wpfuOptional f1 == wpfuOptional f2
-  _ == _ = False
+instance (Eq fileid, Eq userid, Typeable fileid, Typeable userid) => Eq (WorkflowPayloadSpec fileid userid) where
+  (WorkflowPayloadSpec a) == (WorkflowPayloadSpec b)
+    = case typeOf a `eqTypeRep` typeOf b of
+        Just HRefl -> a == b
+        Nothing    -> False

-instance (Ord fileid, Ord userid) => Ord (WorkflowPayloadSpec fileid userid) where
-  compare (WorkflowPayloadSpec f1@WorkflowPayloadFieldText{}) (WorkflowPayloadSpec f2@WorkflowPayloadFieldText{}) = mconcat [comparing wpftLabel, comparing wpftPlaceholder, comparing wpftTooltip, comparing wpftDefault, comparing wpftOptional] f1 f2
-  compare (WorkflowPayloadSpec f1@WorkflowPayloadFieldNumber{}) (WorkflowPayloadSpec f2@WorkflowPayloadFieldNumber{}) = mconcat [comparing wpfnLabel, comparing wpfnPlaceholder, comparing wpfnTooltip, comparing wpfnDefault, comparing wpfnMin, comparing wpfnMax, comparing wpfnStep, comparing wpfnOptional] f1 f2
-  compare (WorkflowPayloadSpec f1@WorkflowPayloadFieldBool{}) (WorkflowPayloadSpec f2@WorkflowPayloadFieldBool{}) = mconcat [comparing wpfbLabel, comparing wpfbTooltip, comparing wpfbDefault] f1 f2
-  compare (WorkflowPayloadSpec f1@WorkflowPayloadFieldFile{}) (WorkflowPayloadSpec f2@WorkflowPayloadFieldFile{}) = mconcat [comparing wpffLabel, comparing wpffTooltip, comparing wpffDefault, comparing wpffOptional] f1 f2
-  compare (WorkflowPayloadSpec f1@WorkflowPayloadFieldUser{}) (WorkflowPayloadSpec f2@WorkflowPayloadFieldUser{}) = mconcat [comparing wpfuLabel, comparing wpfuTooltip, comparing wpfuDefault, comparing wpfuOptional] f1 f2
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldText{}  ) _ = LT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldNumber{}) (WorkflowPayloadSpec WorkflowPayloadFieldText{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldNumber{}) _ = LT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldBool{}) (WorkflowPayloadSpec WorkflowPayloadFieldText{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldBool{}) (WorkflowPayloadSpec WorkflowPayloadFieldNumber{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldBool{}) _ = LT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldFile{}) (WorkflowPayloadSpec WorkflowPayloadFieldText{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldFile{}) (WorkflowPayloadSpec WorkflowPayloadFieldNumber{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldFile{}) (WorkflowPayloadSpec WorkflowPayloadFieldBool{}) = GT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldFile{}) _ = LT
-  compare (WorkflowPayloadSpec WorkflowPayloadFieldUser{}) _ = LT
+instance (Ord fileid, Ord userid, Typeable fileid, Typeable userid) => Ord (WorkflowPayloadSpec fileid userid) where
+  (WorkflowPayloadSpec a) `compare` (WorkflowPayloadSpec b)
+    = case typeOf a `eqTypeRep` typeOf b of
+        Just HRefl -> a `compare` b
+        Nothing   -> case (a, b) of
+          (WorkflowPayloadFieldText{}, _) -> LT
+          (WorkflowPayloadFieldNumber{}, WorkflowPayloadFieldText{}) -> GT
+          (WorkflowPayloadFieldNumber{}, _) -> LT
+          (WorkflowPayloadFieldBool{}, WorkflowPayloadFieldText{}) -> GT
+          (WorkflowPayloadFieldBool{}, WorkflowPayloadFieldNumber{}) -> GT
+          (WorkflowPayloadFieldBool{}, _) -> LT
+          (WorkflowPayloadFieldFile{}, WorkflowPayloadFieldText{}) -> GT
+          (WorkflowPayloadFieldFile{}, WorkflowPayloadFieldNumber{}) -> GT
+          (WorkflowPayloadFieldFile{}, WorkflowPayloadFieldBool{}) -> GT
+          (WorkflowPayloadFieldFile{}, _) -> LT
+          (WorkflowPayloadFieldUser{}, WorkflowPayloadFieldText{}) -> GT
+          (WorkflowPayloadFieldUser{}, WorkflowPayloadFieldNumber{}) -> GT
+          (WorkflowPayloadFieldUser{}, WorkflowPayloadFieldBool{}) -> GT
+          (WorkflowPayloadFieldUser{}, WorkflowPayloadFieldFile{}) -> GT
+          (WorkflowPayloadFieldUser{}, _) -> LT
+          (WorkflowPayloadFieldReference{}, _) -> GT


 -----  WORKFLOW INSTANCE  -----

 data WorkflowInstanceScope termid schoolid courseid
-                           = WISGlobal
-                           | WISTerm   termid
-                           | WISSchool schoolid
-                           | WISCourse courseid
+  = WISGlobal
+  | WISTerm   { wisTerm   :: termid   }
+  | WISSchool { wisSchool :: schoolid }
+  | WISCourse { wisCourse :: courseid }
  deriving (Eq, Ord, Show, Read, Data, Generic, Typeable)

-data WorkflowInstanceScope' = WISGlobal' | WISTerm' | WISSchool' | WISCourse'
-  deriving (Eq, Ord, Enum, Read, Show, Data, Generic, Typeable)
+data WorkflowInstanceScope'
+  = WISGlobal' | WISTerm' | WISSchool' | WISCourse'
+  deriving (Eq, Ord, Enum, Bounded, Read, Show, Data, Generic, Typeable)
+  deriving anyclass (Universe, Finite)


 -----  WORKFLOW: PAYLOAD  -----

-newtype WorkflowPayloadLabel = WorkflowPayloadLabel (CI Text)
-  deriving newtype (Eq, Ord, Show, Read, Typeable, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)
+newtype WorkflowPayloadLabel = WorkflowPayloadLabel { unWorkflowPayloadLabel :: CI Text }
+  deriving stock (Eq, Ord, Show, Read, Data, Generic, Typeable)
+  deriving newtype (IsString, ToJSON, ToJSONKey, FromJSON, FromJSONKey, PersistField, PersistFieldSql)

-type WorkflowPayload fileid userid = Map WorkflowPayloadLabel (Seq (WorkflowPayload' fileid userid))
+type WorkflowState fileid userid = Seq (WorkflowAction fileid userid)

-data WorkflowPayload' fileid userid = WorkflowPayload'
-  { wpPayload    :: Map WorkflowGraphNodeLabel (Map WorkflowGraphEdgeLabel (Map WorkflowPayloadFieldLabel (WorkflowFieldPayloadW fileid userid)))
-  , wpActor      :: Maybe userid
-  , wpActionTime :: UTCTime
+data WorkflowAction fileid userid = WorkflowAction
+  { wpFrom    :: WorkflowGraphNodeLabel
+  , wpVia     :: WorkflowGraphEdgeLabel
+  , wpPayload :: Map WorkflowPayloadLabel (NonNull (Set (WorkflowFieldPayloadW fileid userid)))
+  , wpUser    :: Maybe (Maybe userid) -- ^ Outer `Maybe` encodes automatic/manual, inner `Maybe` encodes whether user was authenticated
+  , wpTime    :: UTCTime
  }
-  deriving Show
+  deriving (Eq, Ord, Show, Generic, Typeable)

-data WorkflowFieldPayload = forall payload. WorkflowFieldPayload (WorkflowFieldPayload' payload)
+data WorkflowFieldPayloadW fileid userid = forall payload. Typeable payload => WorkflowFieldPayloadW (WorkflowFieldPayload fileid userid payload)
+  deriving (Typeable)
+
+instance (Eq fileid, Eq userid, Typeable fileid, Typeable userid) => Eq (WorkflowFieldPayloadW fileid userid) where
+  (WorkflowFieldPayloadW a) == (WorkflowFieldPayloadW b)
+    = case typeOf a `eqTypeRep` typeOf b of
+        Just HRefl -> a == b
+        Nothing    -> False
+
+instance (Ord fileid, Ord userid, Typeable fileid, Typeable userid) => Ord (WorkflowFieldPayloadW fileid userid) where
+  (WorkflowFieldPayloadW a) `compare` (WorkflowFieldPayloadW b)
+    = case typeOf a `eqTypeRep` typeOf b of
+        Just HRefl -> a `compare` b
+        Nothing   -> case (a, b) of
+          (WFPText{}, _) -> LT
+          (WFPNumber{}, WFPText{}) -> GT
+          (WFPNumber{}, _) -> LT
+          (WFPBool{}, WFPText{}) -> GT
+          (WFPBool{}, WFPNumber{}) -> GT
+          (WFPBool{}, _) -> LT
+          (WFPFile{}, WFPText{}) -> GT
+          (WFPFile{}, WFPNumber{}) -> GT
+          (WFPFile{}, WFPBool{}) -> GT
+          (WFPFile{}, _) -> LT
+          (WFPUser{}, _) -> GT

 instance (Show fileid, Show userid) => Show (WorkflowFieldPayloadW fileid userid) where
  show (WorkflowFieldPayloadW payload) = show payload
@ -217,76 +225,45 @@ data WorkflowFieldPayload fileid userid (payload :: Type) where
  WFPBool   :: Bool       -> WorkflowFieldPayload fileid userid Bool
  WFPFile   :: fileid     -> WorkflowFieldPayload fileid userid fileid
  WFPUser   :: userid     -> WorkflowFieldPayload fileid userid userid
+  deriving (Typeable)

-instance (Show fileid, Show userid) => Show (WorkflowFieldPayload fileid userid payload) where
-  show (WFPText   wfptText  ) =     "WFPText{text = " <> show wfptText   <> "}"
-  show (WFPNumber wfpnNumber) = "WFPNumber{number = " <> show wfpnNumber <> "}"
-  show (WFPBool   wfpbBool  ) =     "WFPBool{bool = " <> show wfpbBool   <> "}"
-  show (WFPFile   wfpfFile  ) =     "WFPFile{file = " <> show wfpfFile   <> "}"
-  show (WFPUser   wfpuUser  ) =     "WFPUser{user = " <> show wfpuUser   <> "}"
+deriving instance (Show fileid, Show userid) => Show (WorkflowFieldPayload fileid userid payload)
+deriving instance (Eq fileid, Eq userid) => Eq (WorkflowFieldPayload fileid userid payload)
+deriving instance (Ord fileid, Ord userid) => Ord (WorkflowFieldPayload fileid userid payload)

 data WorkflowFieldPayload'' = WFPText' | WFPNumber' | WFPBool' | WFPFile' | WFPUser'
-  deriving (Eq, Ord, Enum, Show, Read, Data, Generic, Typeable)
+  deriving (Eq, Ord, Enum, Bounded, Show, Read, Data, Generic, Typeable)
+  deriving anyclass (Universe, Finite)


 -----  ToJSON / FromJSON instances  -----

-instance (ToJSON userid) => ToJSON (WorkflowRole userid) where
-  toJSON (WorkflowRoleUser uid) = JSON.object
-    [ "tag"  JSON..= ("user" :: Text)
-    , "user" JSON..= uid
-    ]
-  toJSON (WorkflowRoleAuthorized authDNF) = JSON.object
-    [ "tag"        JSON..= ("authorized" :: Text)
-    , "authorized" JSON..= authDNF
-    ]
-  toJSON WorkflowRoleInitiator = JSON.object
-    [ "tag"        JSON..= ("initiator" :: Text)
-    ]
-instance (FromJSON userid) => FromJSON (WorkflowRole userid) where
-  parseJSON = JSON.withObject "WorkflowRole" $ \o -> do
-    fieldTag <- (o JSON..: "tag" :: Parser Text)
-    case fieldTag of
-      "user" -> do
-        uid <- o JSON..: "user"
-        return $ WorkflowRoleUser uid
-      "authorized" -> do
-        adnf <- o JSON..: "authorized"
-        return $ WorkflowRoleAuthorized adnf
-      "initiator" -> return WorkflowRoleInitiator
-      _ -> terror $ "WorkflowRole parseJSON error: expected role (user|authorized|initiator), but got " <> fieldTag
+omitNothing :: [JSON.Pair] -> [JSON.Pair]
+omitNothing = filter . hasn't $ _2 . _Null
+
+deriveJSON defaultOptions
+  { fieldLabelModifier = camelToPathPiece' 2
+  , constructorTagModifier = camelToPathPiece' 2
+  } ''WorkflowRole

 instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowGraph fileid userid) where
-  toJSON WorkflowGraph{..} = JSON.object
-    [ "nodes"           JSON..= wgNodes
-    , "payload-viewers" JSON..= wgPayloadViewers
-    ]
-instance (FromJSON fileid, FromJSON userid
-         ,     Ord fileid,      Ord userid
+  toJSON = genericToJSON workflowGraphAesonOptions
+instance ( FromJSON fileid, FromJSON userid
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => FromJSON (WorkflowGraph fileid userid) where
-  parseJSON = JSON.withObject "WorkflowGraph" $ \o -> do
-    wgNodes          <- (o JSON..: "nodes" :: Parser (Map WorkflowGraphNodeLabel (WorkflowGraphNode fileid userid)))
-    wgPayloadViewers <-  o JSON..: "payload-viewers"
-    return WorkflowGraph{..}
+  parseJSON = genericParseJSON workflowGraphAesonOptions

 instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowGraphEdge fileid userid) where
-  toJSON (WGE{..}) = JSON.object
-    [ "actors" JSON..= Set.toList wgeActors
-    , "target" JSON..= wgeTarget
-    , "form"   JSON..= wgeForm
-    ]
-instance (FromJSON fileid, FromJSON userid
-         ,     Ord fileid,      Ord userid
+  toJSON = genericToJSON workflowGraphEdgeAesonOptions
+instance ( FromJSON fileid, FromJSON userid
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => FromJSON (WorkflowGraphEdge fileid userid) where
-  parseJSON = JSON.withObject "WorkflowGraphEdge" $ \o -> do
-    wgeActors    <- o JSON..: "actors"
-    wgeTarget    <- o JSON..: "target"
-    wgeAutomatic <- o JSON..: "automatic"
-    wgeForm      <- o JSON..: "form"
-    return WGE{..}
+  parseJSON = genericParseJSON workflowGraphEdgeAesonOptions

 instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowPayloadSpec fileid userid) where
-  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldText{..}) = JSON.object
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldText{..}) = JSON.object $ omitNothing
    [ "tag"         JSON..= ("text" :: Text)
    , "label"       JSON..=  wpftLabel
    , "placeholder" JSON..=  wpftPlaceholder
@ -294,7 +271,7 @@ instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowPayloadSpec fileid us
    , "default"     JSON..=  wpftDefault
    , "optional"    JSON..=  wpftOptional
    ]
-  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldNumber{..}) = JSON.object
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldNumber{..}) = JSON.object $ omitNothing
    [ "tag"         JSON..= ("number" :: Text)
    , "label"       JSON..=  wpfnLabel
    , "placeholder" JSON..=  wpfnPlaceholder
@ -305,137 +282,102 @@ instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowPayloadSpec fileid us
    , "step"        JSON..=  wpfnStep
    , "optional"    JSON..=  wpfnOptional
    ]
-  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldBool{..}) = JSON.object
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldBool{..}) = JSON.object $ omitNothing
    [ "tag"         JSON..= ("bool" :: Text)
    , "label"       JSON..=  wpfbLabel
    , "tooltip"     JSON..=  wpfbTooltip
    , "default"     JSON..=  wpfbDefault
+    , "optional"    JSON..=  wpfbOptional
    ]
-  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldFile{..}) = JSON.object
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldFile{..}) = JSON.object $ omitNothing
    [ "tag"         JSON..= ("file" :: Text)
    , "label"       JSON..=  wpffLabel
    , "tooltip"     JSON..=  wpffTooltip
    , "default"     JSON..=  wpffDefault
    , "optional"    JSON..=  wpffOptional
    ]
-  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldUser{..}) = JSON.object
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldUser{..}) = JSON.object $ omitNothing
    [ "tag"         JSON..= ("user" :: Text)
    , "label"       JSON..=  wpfuLabel
    , "tooltip"     JSON..=  wpfuTooltip
    , "default"     JSON..=  wpfuDefault
    , "optional"    JSON..=  wpfuOptional
    ]
-instance (FromJSON fileid, FromJSON userid
-         ,     Ord fileid,      Ord userid
+  toJSON (WorkflowPayloadSpec WorkflowPayloadFieldReference{..}) = JSON.object
+    [ "tag"         JSON..= ("reference" :: Text)
+    , "target"      JSON..=  wpfrTarget
+    ]
+instance ( FromJSON fileid, FromJSON userid
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => FromJSON (WorkflowPayloadSpec fileid userid) where
  parseJSON = JSON.withObject "WorkflowPayloadSpec" $ \o -> do
    fieldTag <- (o JSON..: "tag" :: Parser Text)
    case fieldTag of
      "text" -> do
        wpftLabel       <-  o JSON..:  "label"
-        wpftPlaceholder <-  o JSON..:  "placeholder"
+        wpftPlaceholder <-  o JSON..:? "placeholder"
        wpftTooltip     <-  o JSON..:? "tooltip"
        wpftDefault     <-  o JSON..:? "default"
-        wpftOptional    <-  o JSON..:? "optional"
+        wpftOptional    <-  o JSON..:  "optional"
        return $ WorkflowPayloadSpec WorkflowPayloadFieldText{..}
      "number" -> do
        wpfnLabel       <-  o JSON..:  "label"
-        wpfnPlaceholder <-  o JSON..:  "placeholder"
+        wpfnPlaceholder <-  o JSON..:? "placeholder"
        wpfnTooltip     <-  o JSON..:? "tooltip"
        wpfnDefault     <- (o JSON..:? "default" :: Parser (Maybe Scientific))
        wpfnMin         <-  o JSON..:? "min"
        wpfnMax         <-  o JSON..:? "max"
        wpfnStep        <-  o JSON..:  "step"
-        wpfnOptional    <-  o JSON..:? "optional"
+        wpfnOptional    <-  o JSON..:  "optional"
        return $ WorkflowPayloadSpec WorkflowPayloadFieldNumber{..}
      "bool" -> do
        wpfbLabel       <-  o JSON..:  "label"
        wpfbTooltip     <-  o JSON..:? "tooltip"
-        wpfbDefault     <- (o JSON..:? "default" :: Parser (Maybe Bool))
+        wpfbOptional    <-  o JSON..:  "optional"
+        wpfbDefault     <- (o JSON..:  "default" :: Parser (Maybe Bool))
        return $ WorkflowPayloadSpec WorkflowPayloadFieldBool{..}
      "file" -> do
        wpffLabel       <-  o JSON..:  "label"
        wpffTooltip     <-  o JSON..:? "tooltip"
        wpffDefault     <- (o JSON..:? "default" :: Parser (Maybe fileid))
-        wpffOptional    <-  o JSON..:? "optional"
+        wpffOptional    <-  o JSON..:  "optional"
        return $ WorkflowPayloadSpec WorkflowPayloadFieldFile{..}
      "user" -> do
        wpfuLabel       <-  o JSON..:  "label"
        wpfuTooltip     <-  o JSON..:? "tooltip"
        wpfuDefault     <- (o JSON..:? "default" :: Parser (Maybe userid))
-        wpfuOptional    <-  o JSON..:? "optional"
+        wpfuOptional    <-  o JSON..:  "optional"
        return $ WorkflowPayloadSpec WorkflowPayloadFieldUser{..}
+      "reference" -> do
+        wpfrTarget      <-  o JSON..:  "target"
+        return $ WorkflowPayloadSpec WorkflowPayloadFieldReference{..}
      _ -> terror $ "WorkflowPayloadSpec parseJSON error: expected field tag (text|number|bool|file|user), but got " <> fieldTag

 instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowGraphNode fileid userid) where
-  toJSON WGN{..} = JSON.object
-    [ "display-label" JSON..= wgnDisplayLabel
-    , "initial"       JSON..= wgnInitial
-    , "finished"      JSON..= wgnFinished
-    , "viewers"       JSON..= wgnViewers
-    , "edges"         JSON..= wgnEdges
-    ]
-instance (FromJSON fileid, FromJSON userid
-         ,     Ord fileid,      Ord userid
+  toJSON = genericToJSON workflowGraphNodeAesonOptions
+instance ( FromJSON fileid, FromJSON userid
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => FromJSON (WorkflowGraphNode fileid userid) where
-  parseJSON = JSON.withObject "WorkflowGraphNode" $ \o -> do
-    wgnDisplayLabel <- o JSON..: "display-label"
-    wgnInitial      <- o JSON..: "initial"
-    wgnFinished     <- o JSON..: "finished"
-    wgnViewers      <- o JSON..: "viewers"
-    wgnEdges        <- o JSON..: "edges"
-    return WGN{..}
-
-instance (ToJSON termid, ToJSON schoolid, ToJSON courseid) => ToJSON (WorkflowInstanceScope termid schoolid courseid) where
-  toJSON  WISGlobal    = JSON.object
-    [ "tag"    JSON..= ("global" :: Text)
-    ]
-  toJSON (WISTerm   t) = JSON.object
-    [ "tag"    JSON..= ("term" :: Text)
-    , "term"   JSON..= t
-    ]
-  toJSON (WISSchool s) = JSON.object
-    [ "tag"    JSON..= ("school" :: Text)
-    , "school" JSON..= s
-    ]
-  toJSON (WISCourse c) = JSON.object
-    [ "tag"    JSON..= ("course" :: Text)
-    , "course" JSON..= c
-    ]
-instance (FromJSON termid, FromJSON schoolid, FromJSON courseid) => FromJSON (WorkflowInstanceScope termid schoolid courseid) where
-  parseJSON = JSON.withObject "WorkflowInstanceScope" $ \o -> do
-    fieldTag <- (o JSON..: "tag" :: Parser Text)
-    case fieldTag of
-      "global" -> return WISGlobal
-      "term"   -> do
-        t <- o JSON..: "term"
-        return $ WISTerm t
-      "school" -> do
-        s <- o JSON..: "school"
-        return $ WISSchool s
-      "course" -> do
-        c <- o JSON..: "course"
-        return $ WISCourse c
-      _ -> terror $ "WorkflowInstanceScope parseJSON error: expected field tag (global|term|school|course), but got " <> fieldTag
+  parseJSON = genericParseJSON workflowGraphNodeAesonOptions

+deriveJSON defaultOptions
+  { constructorTagModifier = camelToPathPiece' 1
+  , fieldLabelModifier = camelToPathPiece' 1
+  } ''WorkflowInstanceScope

 deriveJSON defaultOptions
  { constructorTagModifier = camelToPathPiece' 1 . fromJust . stripSuffix "'"
  } ''WorkflowInstanceScope'

+deriveToJSON workflowActionAesonOptions ''WorkflowAction

-instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowPayload' fileid userid) where
-  toJSON WorkflowPayload'{..} = JSON.object
-    [ "payload"     JSON..= wpPayload
-    , "actor"       JSON..= wpActor
-    , "action-time" JSON..= wpActionTime
-    ]
-instance (FromJSON fileid, FromJSON userid) => FromJSON (WorkflowPayload' fileid userid) where
-  parseJSON = JSON.withObject "WorkflowPayload'" $ \o -> do
-    wpPayload    <- o JSON..:  "payload"
-    wpActor      <- o JSON..:? "actor"
-    wpActionTime <- o JSON..:  "action-time"
-    return WorkflowPayload'{..}
+instance ( FromJSON fileid, FromJSON userid
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
+         ) => FromJSON (WorkflowAction fileid userid) where
+  parseJSON = genericParseJSON workflowActionAesonOptions

 instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowFieldPayloadW fileid userid) where
  toJSON (WorkflowFieldPayloadW (WFPText   t)) = JSON.object
@ -458,7 +400,7 @@ instance (ToJSON fileid, ToJSON userid) => ToJSON (WorkflowFieldPayloadW fileid
    [ "tag"    JSON..= ("user"   :: Text)
    , "user"   JSON..= uid
    ]
-instance (FromJSON fileid, FromJSON userid) => FromJSON (WorkflowFieldPayloadW fileid userid) where
+instance (FromJSON fileid, FromJSON userid, Typeable fileid, Typeable userid) => FromJSON (WorkflowFieldPayloadW fileid userid) where
  parseJSON = JSON.withObject "WorkflowFieldPayloadW" $ \o -> do
    fieldTag <- (o JSON..: "tag" :: Parser Text)
    case fieldTag of
@ -486,14 +428,16 @@ instance (FromJSON fileid, FromJSON userid) => FromJSON (WorkflowFieldPayloadW f
 instance (   ToJSON fileid,   ToJSON userid
         , FromJSON fileid, FromJSON userid
         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => PersistField (WorkflowGraph fileid userid) where
  toPersistValue   = toPersistValueJSON
  fromPersistValue = fromPersistValueJSON
 instance (   ToJSON fileid,   ToJSON userid
         , FromJSON fileid, FromJSON userid
         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
         ) => PersistFieldSql (WorkflowGraph fileid userid) where
-  sqlType _ = SqlString
+  sqlType _ = sqlTypeJSON


 instance (   ToJSON termid,   ToJSON schoolid,   ToJSON courseid
@ -504,31 +448,20 @@ instance (   ToJSON termid,   ToJSON schoolid,   ToJSON courseid
 instance (   ToJSON termid,   ToJSON schoolid,   ToJSON courseid
         , FromJSON termid, FromJSON schoolid, FromJSON courseid
         ) => PersistFieldSql (WorkflowInstanceScope termid schoolid courseid) where
-  sqlType _ = SqlString
+  sqlType _ = sqlTypeJSON

 derivePersistFieldJSON ''WorkflowInstanceScope'

 instance (   ToJSON fileid,   ToJSON userid
         , FromJSON fileid, FromJSON userid
-         ) => PersistField (WorkflowPayload fileid userid) where
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
+         ) => PersistField (WorkflowState fileid userid) where
  toPersistValue   = toPersistValueJSON
  fromPersistValue = fromPersistValueJSON
 instance (   ToJSON fileid,   ToJSON userid
         , FromJSON fileid, FromJSON userid
-         ) => PersistFieldSql (WorkflowPayload fileid userid) where
-  sqlType _ = SqlString
-
-
-----  TEST DEFS  (TODO remove)  -----
-
--testGraph :: WorkflowGraph Text Text
--testGraph = WorkflowGraph $ Map.fromList [("node1", WGN (Just "someLabel") True (Set.fromList [WGE "node1" (Set.fromList [WorkflowRoleUser "user-id", WorkflowRoleInitiator, WorkflowRoleAuthorized $ PredDNF $ Set.fromList [impureNonNull $ Set.fromList [PLVariable AuthLecturer, PLNegated AuthParticipant]]]) (Map.fromList [("sometext", impureNonNull $ Set.fromList [WorkflowPayloadSpec $ WorkflowPayloadFieldText "text-label" "text-placeholder" (Just "text-tooltip") (Just "text-default") Nothing]),("someuser", impureNonNull $ Set.fromList [WorkflowPayloadSpec $ WorkflowPayloadFieldUser "user-label" Nothing Nothing Nothing]),("someboolandnumber-opt", impureNonNull $ Set.fromList [WorkflowPayloadSpec $ WorkflowPayloadFieldBool "bool-label" Nothing (Just True), WorkflowPayloadSpec $ WorkflowPayloadFieldNumber "number-label" "number-placeholder" Nothing Nothing (Just 1) (Just 5) 0.01 (Just True)])])]))]
-
--testGraphStr :: Data.ByteString.Lazy.Internal.ByteString
--testGraphStr = "{\"nodes\":{\"node1\":{\"display-label\":\"node-label\",\"finished\":true,\"edges\":[{\"actors\":[{\"tag\":\"initiator\"},{\"tag\":\"user\",\"user\":\"user-id\"},{\"tag\":\"authorized\",\"authorized\":{\"dnf\":{\"dnfTerms\":[[{\"plVar\":\"lecturer\",\"val\":\"variable\"},{\"plVar\":\"participant\",\"val\":\"negated\"}]]}}}],\"form\":{\"some-number\":[{\"tag\":\"number\",\"step\":0.01,\"label\":\"number-label\",\"placeholder\":\"number-placeholder\"}]},\"target\":\"node1\"}]}}}"
-
--testPayload :: WorkflowPayload Text Text
--testPayload = Map.fromList [("sometext" :: WorkflowPayloadLabel, Seq.singleton (WorkflowPayload' (Map.fromList [("text-label", WorkflowFieldPayloadW $ WFPText "hello world!"),("file-label", WorkflowFieldPayloadW $ WFPFile "fid"),("user-label", WorkflowFieldPayloadW $ WFPUser "uid")]) (Just "actor-user-id" :: Maybe Text) (UTCTime (ModifiedJulianDay 58946) 57250)))]
-
--testPayloadStr :: Data.ByteString.Lazy.Internal.ByteString
--testPayloadStr = "{\"sometext\":[{\"action-time\":\"2020-04-07T15:54:10Z\",\"actor\":\"actor-user-id\",\"payload\":{\"user-label\":{\"tag\":\"user\",\"user\":\"uid\"},\"file-label\":{\"file\":\"fid\",\"tag\":\"file\"},\"text-label\":{\"text\":\"hello world!\",\"tag\":\"text\"}}}]}"
+         ,      Ord fileid,      Ord userid
+         , Typeable fileid, Typeable userid
+         ) => PersistFieldSql (WorkflowState fileid userid) where
+  sqlType _ = sqlTypeJSON