From e3fecc7fd50b25f44fb83c7bbac02d53a7af411c Mon Sep 17 00:00:00 2001
From: Uriel Fanelli <loweel@gmx.de>
Date: Sat, 10 May 2025 21:08:23 +0200
Subject: [PATCH] /index handler added

---
 src/activitypub_server.app.src |  2 ++
 src/activitypub_server_app.erl |  7 ++++-
 src/hello_handler.erl          |  2 +-
 src/index_handler.erl          | 55 ++++++++++++++++++++++++++++++++++
 src/timeline_db.erl            | 28 +++++++++++++++++
 start.sh                       |  2 ++
 6 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100644 src/index_handler.erl
 create mode 100644 src/timeline_db.erl
 create mode 100755 start.sh

diff --git a/src/activitypub_server.app.src b/src/activitypub_server.app.src
index d43a585..824cc30 100644
--- a/src/activitypub_server.app.src
+++ b/src/activitypub_server.app.src
@@ -6,6 +6,8 @@
     activitypub_server_app,
     activitypub_server_sup,
     hello_handler,
+    timeline_db,
+    user_db,
     webfinger_handler
   ]},
   {registered, []},
diff --git a/src/activitypub_server_app.erl b/src/activitypub_server_app.erl
index 854c43b..3a1b712 100644
--- a/src/activitypub_server_app.erl
+++ b/src/activitypub_server_app.erl
@@ -11,12 +11,17 @@ start(_Type, _Args) ->
 
     %% creiamo un utente di test, solo per vedere se mnesia va
     user_db:init(),
+    timeline_db:init(),
+
+%% aggiungiamo un paio di utenti di esempio. 
     user_db:add_user(<<"admin">>, #{email => <<"admin@example.com">>}),
+    user_db:add_user(<<"alice">>, #{email => <<"alice@example.com">>}),
 
     Dispatch = cowboy_router:compile([
         {'_', [
             {"/", hello_handler, []},
-            {"/.well-known/webfinger", webfinger_handler, []}
+            {"/.well-known/webfinger", webfinger_handler, []},
+            {"/index", index_handler, []}   %% per /index del server
         ]}
     ]),
     {ok, _} = cowboy:start_clear(
diff --git a/src/hello_handler.erl b/src/hello_handler.erl
index 0fd929e..b0c88c4 100644
--- a/src/hello_handler.erl
+++ b/src/hello_handler.erl
@@ -10,4 +10,4 @@ init(Req, State) ->
         <<"Hello, world!">>,
         Req
     ),
-    {ok, Resp, State}.
+    {ok, Resp, State}.
\ No newline at end of file
diff --git a/src/index_handler.erl b/src/index_handler.erl
new file mode 100644
index 0000000..680c8ad
--- /dev/null
+++ b/src/index_handler.erl
@@ -0,0 +1,55 @@
+%% index_handler.erl
+-module(index_handler).
+-behaviour(cowboy_handler).
+-export([init/2]).
+
+init(Req, State) ->
+    {ok, Body, Req2} = cowboy_req:read_body(Req),
+    Activity = jsx:decode(Body, [return_maps]),
+
+    case validate_activity(Activity) of
+        false ->
+            {ok, Resp} = cowboy_req:reply(400, #{}, <<"Invalid ActivityPub message">>, Req2),
+            {ok, Resp, State};
+        true ->
+            io:format("Activity: ~p~n", [Activity]),
+            To = maps:get(<<"to">>, Activity, []),
+            io:format("To: ~p~n", [To]),
+            case has_local_recipient(To) of
+                true ->
+                    {ok, Resp} = cowboy_req:reply(200, #{}, <<"Delivered to local user">>, Req2),
+                    {ok, Resp, State};
+                false ->
+                    timeline_db:add_message(Activity),
+                    {ok, Resp} = cowboy_req:reply(202, #{}, <<"Saved to global timeline">>, Req2),
+                    {ok, Resp, State}
+            end
+    end.
+
+%% Controlla se un destinatario è un utente locale
+is_local_user(Dest) when is_binary(Dest) ->
+    io:format("Controllo utente locale: ~p~n", [Dest]),
+    user_db:get_user(Dest) =/= not_found;
+is_local_user(_) ->
+    false.
+
+%% Controlla se almeno uno dei destinatari è locale
+has_local_recipient(To) when is_list(To) ->
+    lists:any(fun is_local_user/1, To);
+has_local_recipient(To) when is_binary(To) ->
+    is_local_user(To);
+has_local_recipient(_) ->
+    false.
+
+
+
+%% vediamo di controllare se ci sono i campi obbligatori minimi di ActivityPub:
+
+validate_activity(Activity) when is_map(Activity) ->
+    maps:is_key(<<"type">>, Activity) andalso
+    maps:is_key(<<"to">>, Activity) andalso
+    maps:is_key(<<"actor">>, Activity) andalso
+    maps:is_key(<<"object">>, Activity) andalso
+    maps:is_key(<<"content">>, Activity).
+
+
diff --git a/src/timeline_db.erl b/src/timeline_db.erl
new file mode 100644
index 0000000..25922d6
--- /dev/null
+++ b/src/timeline_db.erl
@@ -0,0 +1,28 @@
+%% timeline_db.erl
+-module(timeline_db).
+-export([init/0, add_message/1, all_messages/0]).
+
+-record(global_message, {id, activity, timestamp}).
+
+init() ->
+    %% Crea la tabella Mnesia se non esiste
+    mnesia:create_table(global_message, [
+        {attributes, record_info(fields, global_message)},
+        {disc_copies, [node()]}
+    ]).
+
+add_message(Activity) ->
+    %% Crea un ID unico e un timestamp per il messaggio
+    Id = erlang:unique_integer([monotonic, positive]),
+    Timestamp = erlang:system_time(microsecond),
+    F = fun() ->
+        mnesia:write(#global_message{id=Id, activity=Activity, timestamp=Timestamp})
+    end,
+    mnesia:transaction(F).
+
+all_messages() ->
+    F = fun() ->
+        mnesia:match_object(#global_message{id = '_', activity = '_', timestamp = '_'})
+    end,
+    {atomic, Messages} = mnesia:transaction(F),
+    Messages.
diff --git a/start.sh b/start.sh
new file mode 100755
index 0000000..b19d1a9
--- /dev/null
+++ b/start.sh
@@ -0,0 +1,2 @@
+rebar3 compile
+rebar3 shell --apps activitypub_server