(#147) ContentProxy: more APIs

Emulsion.ContentProxy/ContentStorage.fs

@@ -1,12 +1,32 @@
 module Emulsion.ContentProxy.ContentStorage
 
 open Emulsion.Database
+open Emulsion.Database.DataStorage
 open Emulsion.Database.Models
+open Emulsion.Database.QueryableEx
 
 type MessageIdentity = {
+    ChatUserName: string
     MessageId: int64
     FileId: string
 }
 
-let getOrCreateMessageRecord (context: EmulsionDbContext) (id: MessageIdentity): Async<TelegramContent> =
-    failwithf "TODO"
+let getOrCreateMessageRecord (context: EmulsionDbContext) (id: MessageIdentity): Async<TelegramContent> = async {
+    let! existingItem =
+        query {
+            for content in context.TelegramContents do
+            where (content.MessageId = id.MessageId && content.FileId = id.FileId)
+            tryExactlyOneAsync
+        }
+    match existingItem with
+    | None ->
+        let newItem = {
+            Id = 0L
+            ChatUsername = id.ChatUserName
+            MessageId = id.MessageId
+            FileId = id.FileId
+        }
+        do! addAsync context.TelegramContents newItem
+        return newItem
+    | Some item -> return item
+}

Emulsion.ContentProxy/Emulsion.ContentProxy.fsproj

@@ -4,10 +4,6 @@
     <TargetFramework>net5.0</TargetFramework>
   </PropertyGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Nanoid" Version="2.1.0" />
-  </ItemGroup>
-
   <ItemGroup>
     <Compile Include="ContentStorage.fs" />
   </ItemGroup>

Emulsion.Database/DataStorage.fs

@@ -17,3 +17,9 @@ let transaction<'a> (settings: DatabaseSettings) (action: EmulsionDbContext -> A
     do! Async.AwaitTask(tran.CommitAsync())
     return result
 }
+
+let addAsync<'a when 'a : not struct> (dbSet: DbSet<'a>) (entity: 'a): Async<unit> = async {
+    let! ct = Async.CancellationToken
+    let! _ = Async.AwaitTask(dbSet.AddAsync(entity, ct).AsTask())
+    return ()
+}

Emulsion.Database/Emulsion.Database.fsproj

@@ -11,6 +11,7 @@
         <Compile Include="Initializer.fs" />
         <Compile Include="DatabaseSettings.fs" />
         <Compile Include="DataStorage.fs" />
+        <Compile Include="QueryableEx.fs" />
     </ItemGroup>
 
     <ItemGroup>

Emulsion.Database/Models.fs

@@ -4,7 +4,7 @@ open System.ComponentModel.DataAnnotations
 
 [<CLIMutable>]
 type TelegramContent = {
-    [<Key>] Id: string
+    [<Key>] Id: int64
     ChatUsername: string
     MessageId: int64
     FileId: string

Emulsion.Database/QueryableEx.fs

@@ -0,0 +1,19 @@
+module Emulsion.Database.QueryableEx
+
+open System.Linq
+
+open Microsoft.EntityFrameworkCore
+open Microsoft.FSharp.Linq
+
+type QueryBuilder with
+    [<CustomOperation("tryExactlyOneAsync")>]
+    member _.TryExactlyOneAsync<'T, 'Q>(source: QuerySource<'T, 'Q>): Async<'T option> = async {
+        let source = source.Source :?> IQueryable<'T>
+        let! ct = Async.CancellationToken
+        let! item = Async.AwaitTask(EntityFrameworkQueryableExtensions.SingleOrDefaultAsync(source, ct))
+
+        // We cannot use Option.ofObj here since not every entity type can be marked with AllowNullLiteral.
+        match box item with
+        | null -> return None
+        | _ -> return Some item
+    }

Emulsion.Tests/ContentProxy/ContentStorageTests.fs

@@ -0,0 +1,11 @@
+module Emulsion.Tests.ContentProxy.ContentStorageTests
+
+open Xunit
+
+[<Fact>]
+let ``getOrCreateMessageRecord returns a new record``() =
+    Assert.True false
+
+[<Fact>]
+let ``getOrCreateMessageRecord returns an existing record``() =
+    Assert.True false

Emulsion.Tests/Emulsion.Tests.fsproj

@@ -28,6 +28,7 @@
     <Compile Include="Xmpp\SharpXmppPingHandlerTests.fs" />
     <Compile Include="Xmpp\EmulsionXmppTests.fs" />
     <Compile Include="Database\InitializerTests.fs" />
+    <Compile Include="ContentProxy\ContentStorageTests.fs" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Akka.TestKit" Version="1.3.12" />

Emulsion/Telegram/LinkGenerator.fs

@@ -32,14 +32,17 @@ let private getFileId(message: FunogramMessage) =
 
 let private getMessageIdentity message: ContentStorage.MessageIdentity option =
     let fileId = getFileId message
-    match fileId with
-    | None -> None
-    | Some fileId -> Some {
-        MessageId = message.MessageId
-        FileId = fileId
-    }
+    match fileId, message.Chat with
+    | Some fileId, { Type = SuperGroup
+                     Username = Some chatName } ->
+        Some {
+            ChatUserName = chatName
+            MessageId = message.MessageId
+            FileId = fileId
+        }
+    | _, _ -> None
 
-// TODO: right type for the databaseSettings
+// TODO: right type for the hostingSettings
 let gatherLinks (databaseSettings: DatabaseSettings option) (message: FunogramMessage): Async<TelegramThreadLinks> = async {
     let getMessageBodyLink message =
         match databaseSettings with
@@ -55,7 +58,7 @@ let gatherLinks (databaseSettings: DatabaseSettings option) (message: FunogramMe
                     let! content = DataStorage.transaction settings (fun ctx ->
                         ContentStorage.getOrCreateMessageRecord ctx id
                     )
-                    return Some content.Id
+                    return Some(failwithf "TODO: Generate URL from hosting settings")
                 }
 
     let! contentLink = getMessageBodyLink message