Add separate Settings module

elm.json

@@ -6,7 +6,6 @@
     "version": "2.0.0",
     "exposed-modules": [
         "Matrix",
-        "Matrix.Event",
         "Matrix.Settings",
         "Internal.Config.Default",
         "Internal.Config.Leaks",
@@ -19,7 +18,7 @@
         "Internal.Tools.VersionControl",
         "Internal.Values.Context",
         "Internal.Values.Envelope",
-        "Internal.Values.Event",
+        "Internal.Values.Settings",
         "Internal.Values.Vault",
         "Types"
     ],

src/Internal/Values/Settings.elm

@@ -0,0 +1,93 @@
+module Internal.Values.Settings exposing
+    ( Settings, init
+    , encode, decoder
+    )
+
+{-|
+
+
+# Settings
+
+The Settings module exposes a data type to configure settings in the enveloped
+data types.
+
+@docs Settings, init
+
+
+## JSON coders
+
+@docs encode, decoder
+
+-}
+
+import Internal.Config.Default as Default
+import Internal.Tools.Decode as D
+import Internal.Tools.Encode as E
+import Json.Decode as D
+import Json.Encode as E
+
+
+{-| Custom settings that can be manipulated by the user. These serve as a
+configuration for how the Elm SDK should behave.
+
+Custom settings are always part of the Envelope, allowing all functions to
+behave under the user's preferred settings.
+
+-}
+type alias Settings =
+    { currentVersion : String
+    , deviceName : String
+    , syncTime : Int
+    }
+
+
+{-| Decode settings from a JSON value.
+-}
+decoder : D.Decoder Settings
+decoder =
+    D.map3 Settings
+        (D.opFieldWithDefault "currentVersion" Default.currentVersion D.string)
+        (D.opFieldWithDefault "deviceName" Default.deviceName D.string)
+        (D.opFieldWithDefault "syncTime" Default.syncTime D.int)
+
+
+{-| Encode the settings into a JSON value.
+-}
+encode : Settings -> E.Value
+encode settings =
+    let
+        differentFrom : b -> b -> Maybe b
+        differentFrom defaultValue currentValue =
+            if currentValue == defaultValue then
+                Nothing
+
+            else
+                Just currentValue
+    in
+    E.maybeObject
+        [ ( "currentVersion"
+          , settings.currentVersion
+                |> differentFrom Default.currentVersion
+                |> Maybe.map E.string
+          )
+        , ( "deviceName"
+          , settings.deviceName
+                |> differentFrom Default.deviceName
+                |> Maybe.map E.string
+          )
+        , ( "syncTime"
+          , settings.syncTime
+                |> differentFrom Default.syncTime
+                |> Maybe.map E.int
+          )
+        ]
+
+
+{-| Create a new Settings module based on default values
+-}
+init : Settings
+init =
+    { currentVersion = Default.currentVersion
+    , deviceName = Default.deviceName
+    , syncTime = Default.syncTime
+    }

tests/Test/Values/Settings.elm

@@ -0,0 +1,80 @@
+module Test.Values.Settings exposing (..)
+
+import Expect
+import Fuzz exposing (Fuzzer)
+import Internal.Config.Default as Default
+import Internal.Values.Settings as Settings exposing (Settings)
+import Json.Decode as D
+import Json.Encode as E
+import Test exposing (..)
+
+
+fuzzer : Fuzzer Settings
+fuzzer =
+    Fuzz.map3 Settings
+        (Fuzz.oneOf
+            [ Fuzz.constant Default.currentVersion
+            , Fuzz.string
+            ]
+        )
+        (Fuzz.oneOf
+            [ Fuzz.constant Default.deviceName
+            , Fuzz.string
+            ]
+        )
+        (Fuzz.oneOf
+            [ Fuzz.constant Default.syncTime
+            , Fuzz.int
+            ]
+        )
+
+
+suite : Test
+suite =
+    describe "Settings"
+        [ describe "init"
+            [ test "Current version"
+                (Settings.init
+                    |> .currentVersion
+                    |> Expect.equal Default.currentVersion
+                    |> always
+                )
+            , test "Device name"
+                (Settings.init
+                    |> .deviceName
+                    |> Expect.equal Default.deviceName
+                    |> always
+                )
+            , test "Sync time"
+                (Settings.init
+                    |> .syncTime
+                    |> Expect.equal Default.syncTime
+                    |> always
+                )
+            , test "JSON encode init is {}"
+                (Settings.init
+                    |> Settings.encode
+                    |> E.encode 0
+                    |> Expect.equal "{}"
+                    |> always
+                )
+            , test "JSON decode {} is init"
+                ("{}"
+                    |> D.decodeString Settings.decoder
+                    |> Expect.equal (Ok Settings.init)
+                    |> always
+                )
+            ]
+        , describe "JSON"
+            [ fuzz2 fuzzer
+                Fuzz.int
+                "JSON encode -> JSON decode -> identical"
+                (\settings indent ->
+                    settings
+                        |> Settings.encode
+                        |> E.encode indent
+                        |> D.decodeString Settings.decoder
+                        |> Expect.equal (Ok settings)
+                )
+            ]
+        ]