From 8023cfa7b24f5f241d9fffb804f365a199b5fbfc Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Sun, 31 Dec 2023 22:01:57 -0600
Subject: [PATCH] Use a cleaner API for updating lists

---
 src/controllers/api/accounts.ts | 15 +++++-----
 src/queries.ts                  |  2 +-
 src/utils/web.ts                | 51 ++++++++++++++++++++++++---------
 3 files changed, 46 insertions(+), 22 deletions(-)

diff --git a/src/controllers/api/accounts.ts b/src/controllers/api/accounts.ts
index d10509e..0e0ee16 100644
--- a/src/controllers/api/accounts.ts
+++ b/src/controllers/api/accounts.ts
@@ -4,10 +4,10 @@ import { eventsDB } from '@/db/events.ts';
 import { insertUser } from '@/db/users.ts';
 import { findReplyTag, nip19, z } from '@/deps.ts';
 import { type DittoFilter } from '@/filter.ts';
-import { getAuthor, getFollowedPubkeys, getFollows } from '@/queries.ts';
+import { getAuthor, getFollowedPubkeys } from '@/queries.ts';
 import { booleanParamSchema, fileSchema } from '@/schema.ts';
 import { jsonMetaContentSchema } from '@/schemas/nostr.ts';
-import { hasTag, setTag } from '@/tags.ts';
+import { setTag } from '@/tags.ts';
 import { uploadFile } from '@/upload.ts';
 import { lookupAccount, nostrNow } from '@/utils.ts';
 import { paginated, paginationSchema, parseBody, updateListEvent } from '@/utils/web.ts';
@@ -217,12 +217,11 @@ const followController: AppController = async (c) => {
   const sourcePubkey = c.get('pubkey')!;
   const targetPubkey = c.req.param('pubkey');
 
-  const source = await getFollows(sourcePubkey);
-  const tag = ['p', targetPubkey];
-
-  if (!source || !hasTag(source.tags, tag)) {
-    await updateListEvent(source ?? { kind: 3 }, tag, setTag, c);
-  }
+  await updateListEvent(
+    { kinds: [3], authors: [sourcePubkey] },
+    (tags) => setTag(tags, ['p', targetPubkey]),
+    c,
+  );
 
   const relationship = await renderRelationship(sourcePubkey, targetPubkey);
   return c.json(relationship);
diff --git a/src/queries.ts b/src/queries.ts
index 92500d3..95020d0 100644
--- a/src/queries.ts
+++ b/src/queries.ts
@@ -78,7 +78,7 @@ const getAuthor = async (pubkey: string, opts: GetEventOpts<0> = {}): Promise<Ev
 };
 
 /** Get users the given pubkey follows. */
-const getFollows = async (pubkey: string, signal = AbortSignal.timeout(1000)): Promise<Event<3> | undefined> => {
+const getFollows = async (pubkey: string, signal?: AbortSignal): Promise<Event<3> | undefined> => {
   const [event] = await eventsDB.getEvents([{ authors: [pubkey], kinds: [3], limit: 1 }], { limit: 1, signal });
   return event;
 };
diff --git a/src/utils/web.ts b/src/utils/web.ts
index 0e559c6..e5437d2 100644
--- a/src/utils/web.ts
+++ b/src/utils/web.ts
@@ -1,9 +1,19 @@
 import { type AppContext } from '@/app.ts';
 import { Conf } from '@/config.ts';
-import { type Context, type Event, EventTemplate, HTTPException, parseFormData, type TypeFest, z } from '@/deps.ts';
+import {
+  type Context,
+  type Event,
+  EventTemplate,
+  Filter,
+  HTTPException,
+  parseFormData,
+  type TypeFest,
+  z,
+} from '@/deps.ts';
 import * as pipeline from '@/pipeline.ts';
 import { signAdminEvent, signEvent } from '@/sign.ts';
 import { nostrNow } from '@/utils.ts';
+import { eventsDB } from '@/db/events.ts';
 
 /** EventTemplate with defaults. */
 type EventStub<K extends number = number> = TypeFest.SetOptional<EventTemplate<K>, 'content' | 'created_at' | 'tags'>;
@@ -26,20 +36,34 @@ async function createEvent<K extends number>(t: EventStub<K>, c: AppContext): Pr
   return publishEvent(event, c);
 }
 
-/** Add the tag to the list and then publish the new list, or throw if the tag already exists. */
-function updateListEvent<K extends number, E extends EventStub<K>>(
-  t: E,
-  tag: string[],
-  fn: (tags: string[][], tag: string[]) => string[][],
-  c: AppContext,
-): Promise<Event<K>> {
-  const { kind, content, tags = [] } = t;
-  return createEvent(
-    { kind, content, tags: fn(tags, tag) },
-    c,
-  );
+/** Filter for fetching an existing event to update. */
+interface UpdateEventFilter<K extends number> extends Filter<K> {
+  kinds: [K];
+  limit?: 1;
 }
 
+/** Fetch existing event, update it, then publish the new event. */
+async function updateEvent<K extends number, E extends EventStub<K>>(
+  filter: UpdateEventFilter<K>,
+  fn: (prev: Event<K> | undefined) => E,
+  c: AppContext,
+): Promise<Event<K>> {
+  const [prev] = await eventsDB.getEvents([filter], { limit: 1 });
+  return createEvent(fn(prev), c);
+}
+
+/** Fetch existing event, update its tags, then publish the new event. */
+function updateListEvent<K extends number, E extends EventStub<K>>(
+  filter: UpdateEventFilter<K>,
+  fn: (tags: string[][]) => string[][],
+  c: AppContext,
+): Promise<Event<K>> {
+  return updateEvent(filter, (prev) => ({
+    kind: filter.kinds[0],
+    content: prev?.content,
+    tags: fn(prev?.tags ?? []),
+  }), c);
+}
 /** Publish an admin event through the pipeline. */
 async function createAdminEvent<K extends number>(t: EventStub<K>, c: AppContext): Promise<Event<K>> {
   const event = await signAdminEvent({
@@ -154,5 +178,6 @@ export {
   type PaginationParams,
   paginationSchema,
   parseBody,
+  updateEvent,
   updateListEvent,
 };