From 4dd675a9fe0c0dd4c28061d7134b107864dab57a Mon Sep 17 00:00:00 2001
From: Pablo Fernandez <p@f7z.io>
Date: Mon, 1 Jul 2024 12:21:28 +0100
Subject: [PATCH] apply limit filter

---
 ndk-cache-dexie/src/index.test.ts | 24 ++++++++++++++++++++++++
 ndk-cache-dexie/src/index.ts      | 14 +++++++++++---
 ndk-cache-dexie/tsconfig.json     |  2 +-
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/ndk-cache-dexie/src/index.test.ts b/ndk-cache-dexie/src/index.test.ts
index 6de32ad7..b95e2b2c 100644
--- a/ndk-cache-dexie/src/index.test.ts
+++ b/ndk-cache-dexie/src/index.test.ts
@@ -5,6 +5,30 @@ const ndk = new NDK()
 ndk.signer = NDKPrivateKeySigner.generate();
 ndk.cacheAdapter = new NDKCacheAdapterDexie();
 
+describe("foundEvents", () => {
+    it('applies limit filter', async () => {
+        const startTime = Math.floor(Date.now() / 1000);
+        const times = [];
+        for (let i = 0; i < 10; i++) {
+            const event = new NDKEvent(ndk);
+            event.kind = 2;
+            event.created_at = startTime - i * 60;
+            times.push(event.created_at);
+            await event.sign();
+            ndk.cacheAdapter!.setEvent(event, []);
+        }
+
+        const subscription = new NDKSubscription(ndk, [{kinds: [2], limit: 2}]);
+        const spy = jest.spyOn(subscription, "eventReceived");
+        await ndk.cacheAdapter!.query(subscription);
+        expect(subscription.eventReceived).toBeCalledTimes(2);
+
+        // the time of the events that were received must be the first two in the list
+        expect(spy.mock.calls[0][0].created_at).toBe(times[0]);
+        expect(spy.mock.calls[1][0].created_at).toBe(times[1]);
+    });
+})
+
 describe("foundEvent", () => {
     beforeAll(async () => {
         // save event
diff --git a/ndk-cache-dexie/src/index.ts b/ndk-cache-dexie/src/index.ts
index a9d384b4..5570b3b7 100644
--- a/ndk-cache-dexie/src/index.ts
+++ b/ndk-cache-dexie/src/index.ts
@@ -518,13 +518,16 @@ export default class NDKCacheAdapterDexie implements NDKCacheAdapter {
         const f = ["kinds"];
         const hasAllKeys = filterKeys.size === f.length && f.every((k) => filterKeys.has(k));
 
+        let events: Event[] = [];
+
         if (!hasAllKeys) return false;
 
         for (const kind of filter.kinds) {
-            const events = Array.from(this.events.getFromIndex("kind", kind));
-            foundEvents(subscription, events, filter);
+            events = [ ...events, ...Array.from(this.events.getFromIndex("kind", kind))]
         }
 
+        foundEvents(subscription, events, filter);
+
         return true;
     }
 }
@@ -558,6 +561,11 @@ export function foundEvents(
     events: Event[],
     filter?: NDKFilter
 ) {
+    // if we have a limit, sort and slice
+    if (filter?.limit && events.length > filter.limit) {
+        events = events.sort((a, b) => b.createdAt - a.createdAt).slice(0, filter.limit);
+    }
+    
     for (const event of events) {
         foundEvent(subscription, event, event.relay, filter);
     }
@@ -575,7 +583,7 @@ export function foundEvent(
         if (filter && !matchFilter(filter, deserializedEvent as any)) return;
 
         const ndkEvent = new NDKEvent(undefined, deserializedEvent);
-        const relay = relayUrl ? subscription.pool.getRelay(relayUrl) : undefined;
+        const relay = relayUrl ? subscription.pool.getRelay(relayUrl, false) : undefined;
         ndkEvent.relay = relay;
         subscription.eventReceived(ndkEvent, relay, true);
     } catch (e) {
diff --git a/ndk-cache-dexie/tsconfig.json b/ndk-cache-dexie/tsconfig.json
index 11ac4ac4..fe257ae3 100644
--- a/ndk-cache-dexie/tsconfig.json
+++ b/ndk-cache-dexie/tsconfig.json
@@ -1,5 +1,5 @@
 {
-    "extends": "@nostr-dev-kit/tsconfig/ndk-cache-dexie.json",
+    "extends": "../packages/tsconfig/ndk-cache-dexie.json",
     "include": ["src/**/*.d.ts", "src/**/*.js", "src/**/*.ts"],
     "exclude": ["dist", "build", "node_modules"]
 }