From 14058f4b696559b0898e6a8d7feb8aba96dce0ac Mon Sep 17 00:00:00 2001
From: Bram <bram@noordstar.me>
Date: Tue, 19 Dec 2023 02:46:23 +0100
Subject: [PATCH] Add Event type

---
 elm.json                      |   1 +
 src/Internal/Values/Event.elm | 145 ++++++++++++++++++++++++++++++++++
 2 files changed, 146 insertions(+)
 create mode 100644 src/Internal/Values/Event.elm

diff --git a/elm.json b/elm.json
index 3c502e6..f1e9b67 100644
--- a/elm.json
+++ b/elm.json
@@ -18,6 +18,7 @@
         "Internal.Tools.VersionControl",
         "Internal.Values.Context",
         "Internal.Values.Envelope",
+        "Internal.Values.Event",
         "Internal.Values.Vault",
         "Types"
     ],
diff --git a/src/Internal/Values/Event.elm b/src/Internal/Values/Event.elm
new file mode 100644
index 0000000..fb78c02
--- /dev/null
+++ b/src/Internal/Values/Event.elm
@@ -0,0 +1,145 @@
+module Internal.Values.Event exposing
+    ( Event
+    , UnsignedData, age, prevContent, redactedBecause, transactionId
+    , encode, decoder
+    )
+
+{-|
+
+
+# Event
+
+The `Event` module hosts all the information for a single event in the timeline
+of a room.
+
+@docs Event
+
+
+## Unsigned data
+
+@docs UnsignedData, age, prevContent, redactedBecause, transactionId
+
+
+## JSON Coder
+
+@docs encode, decoder
+
+-}
+
+import Internal.Config.Default as Default
+import Internal.Tools.Decode as D
+import Internal.Tools.Encode as E
+import Internal.Tools.Timestamp as Timestamp exposing (Timestamp)
+import Json.Decode as D
+import Json.Encode as E
+
+
+{-| The Event type occurs everywhere on a user's timeline.
+-}
+type alias Event =
+    { content : E.Value
+    , eventId : String
+    , originServerTs : Timestamp
+    , roomId : String
+    , sender : String
+    , stateKey : Maybe String
+    , eventType : String
+    , unsigned : Maybe UnsignedData
+    }
+
+
+{-| Unsigned Data contains a lot of extra information. You can access it through
+helper functions.
+-}
+type UnsignedData
+    = UnsignedData
+        { age : Maybe Int
+        , prevContent : Maybe E.Value
+        , redactedBecause : Maybe Event
+        , transactionId : Maybe String
+        }
+
+
+{-| Get the event's age, if at all provided by the homeserver.
+-}
+age : Event -> Maybe Int
+age event =
+    Maybe.andThen (\(UnsignedData data) -> data.age) event.unsigned
+
+
+{-| Decode an Event from a JSON value.
+-}
+decoder : D.Decoder Event
+decoder =
+    D.map8 Event
+        (D.field "content" D.value)
+        (D.field "eventId" D.string)
+        (D.field "originServerTs" Timestamp.decoder)
+        (D.field "roomId" D.string)
+        (D.field "sender" D.string)
+        (D.opField "stateKey" D.string)
+        (D.field "eventType" D.string)
+        (D.opField "unsigned" decoderUnsignedData)
+
+
+{-| Decode Unsigned Data from a JSON value.
+-}
+decoderUnsignedData : D.Decoder UnsignedData
+decoderUnsignedData =
+    D.map4 (\a b c d -> UnsignedData { age = a, prevContent = b, redactedBecause = c, transactionId = d })
+        (D.opField "age" D.int)
+        (D.opField "prevContent" D.value)
+        (D.opField "redactedBecause" (D.lazy (\_ -> decoder)))
+        (D.opField "transactionId" D.string)
+
+
+{-| Encode an Event into a JSON value.
+-}
+encode : Event -> E.Value
+encode event =
+    E.maybeObject
+        [ ( "content", Just event.content )
+        , ( "eventId", Just <| E.string event.eventId )
+        , ( "originServerTs", Just <| Timestamp.encode event.originServerTs )
+        , ( "roomId", Just <| E.string event.roomId )
+        , ( "sender", Just <| E.string event.sender )
+        , ( "stateKey", Maybe.map E.string event.stateKey )
+        , ( "eventType", Just <| E.string event.eventType )
+        , ( "unsigned", Maybe.map encodeUnsignedData event.unsigned )
+        , ( "version", Just <| E.string Default.currentVersion )
+        ]
+
+
+{-| Encode Unsigned Data into a JSON value.
+-}
+encodeUnsignedData : UnsignedData -> E.Value
+encodeUnsignedData (UnsignedData data) =
+    E.maybeObject
+        [ ( "age", Maybe.map E.int data.age )
+        , ( "prevContent", data.prevContent )
+        , ( "redactedBecause", Maybe.map encode data.redactedBecause )
+        , ( "transactionId", Maybe.map E.string data.transactionId )
+        ]
+
+
+{-| Get the old content, if the event has changed or it has been edited.
+-}
+prevContent : Event -> Maybe E.Value
+prevContent event =
+    Maybe.andThen (\(UnsignedData data) -> data.prevContent) event.unsigned
+
+
+{-| If the event has been redacted, the homeserver can display the event that
+redacted it here.
+-}
+redactedBecause : Event -> Maybe Event
+redactedBecause event =
+    Maybe.andThen (\(UnsignedData data) -> data.redactedBecause) event.unsigned
+
+
+{-| If the user has sent this event to the homeserver, then the homeserver might
+display the original transaction id used for the event.
+-}
+transactionId : Event -> Maybe String
+transactionId event =
+    Maybe.andThen (\(UnsignedData data) -> data.transactionId) event.unsigned