feat(events): publish and synchronize Discord forum posts (T-222)

README.md

@@ -120,3 +120,33 @@ If some common data setup is required for the API endpoint (e.g. `/api/events` r
     to the repository, the contributors are additionally granting VATPRC staffs an
     unrevokeable right to use the code freely for any purposes related to VATSIM or
     VATPRC.
+
+### Discord event posts
+
+Set `discord.event_forum_channel_id` to a Discord forum channel ID, in addition
+to enabling the bot and configuring its token. If the forum requires tags, set
+`discord.event_forum_tag_ids` to the permitted tag IDs. The bot needs View Channel,
+Send Messages, Embed Links, Read Message History, and Send Messages in Threads
+permissions there. Locked posts additionally require Manage Threads to reopen.
+
+Event coordinators can publish a saved website event from its edit dialog. The
+service stores the forum thread and guild IDs and returns `discord_message` in the
+event API. `PUT /api/events/{id}/discord` creates the post once, or synchronizes
+its existing title and starter message. Event updates automatically synchronize
+linked posts. A failed sync preserves the website changes and exposes
+`discord_message.status = OutOfSync`; the editor offers a retry. Unpublished events are never
+automatically published. Long descriptions are shortened to Discord's embed
+limit, with a link to the full website event. Mentions are disabled.
+
+Run database migrations before deploying this version. Discord associations live
+in `event_discord_message`, keyed by `event_id`. Its `status` column is a text enum
+restricted to `Sync` and `OutOfSync`; `synced_at` records the last successful sync.
+Failed updates retain that timestamp. First publication failures create no
+association and return an API error.
+
+Discord requests run after website changes are committed, without holding a
+transaction or row lock. Concurrent first publications can create duplicate posts;
+there is no cross-system atomicity. Local tests use a mock Discord HTTP server.
+
+The API exposes `discord_message` with string `guild_id` and `message_id`
+snowflakes, `status`, and `synced_at`.

assets/config/settings.default.toml

@@ -52,6 +52,9 @@ endpoint = "http://localhost:4318/v1/traces"
 headers = {}
 
 [discord]
+# Target Discord forum channel for website event posts (optional).
+# event_forum_channel_id = 123456789012345678
+# event_forum_tag_ids = [123456789012345678]
 enabled = false
 token = ""
 

migrations/20260908000000_add_event_discord_post.sql

@@ -0,0 +1,7 @@
+CREATE TABLE public.event_discord_message (
+    event_id uuid PRIMARY KEY REFERENCES public.event(id) ON DELETE CASCADE,
+    guild_id text NOT NULL,
+    message_id text NOT NULL,
+    status text NOT NULL CHECK (status IN ('Sync', 'OutOfSync')),
+    synced_at timestamptz NOT NULL
+);