started wiring p2phttp into Remote.Git

but we have a cycle, ugh

P2P/Http/Client.hs

@@ -0,0 +1,52 @@
+{- P2P protocol over HTTP, running client actions
+ -
+ - https://git-annex.branchable.com/design/p2p_protocol_over_http/
+ -
+ - Copyright 2024 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU AGPL version 3 or higher.
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module P2P.Http.Client where
+
+import Types
+import Annex.Url
+
+#ifdef WITH_SERVANT
+import Annex.UUID
+import Types.Remote
+import P2P.Protocol (ProtocolVersion(..))
+import P2P.Http.Types
+import P2P.Http.Url
+import Servant.Client
+#endif
+
+p2pHttpClient
+	:: Remote
+	-> (String -> Annex a)
+#ifdef WITH_SERVANT
+	-> (ClientEnv -> ProtocolVersion -> B64UUID ServerSide -> B64UUID ClientSide -> [B64UUID Bypass] -> Maybe Auth -> Annex a)
+#endif
+	-> Annex a
+#ifdef WITH_SERVANT
+p2pHttpClient rmt fallback httpaction =
+	case p2pHttpBaseUrl <$> remoteAnnexP2PHttpUrl (gitconfig rmt) of
+		Nothing -> error "internal"
+		Just baseurl -> do
+			myuuid <- getUUID
+			mgr <- httpManager <$> getUrlOptions
+			let clientenv = mkClientEnv mgr baseurl
+			-- TODO: try other protocol versions
+			-- TODO: authentication
+			-- TODO: catch 404 etc
+			httpaction clientenv 
+				(ProtocolVersion 3)
+				(B64UUID (uuid rmt))
+				(B64UUID myuuid)
+				[]
+				Nothing
+#else
+runP2PHttpClient rmt fallback = fallback "This remote uses an annex+http url, but this version of git-annex is not build with support for that."
+#endif