Replace Subscription with Subscribe, add NetworkContext

packages/network/Tracker.ts

@@ -0,0 +1,54 @@
+import {writable} from '@coracle.social/lib'
+
+export class Tracker {
+  links: Tracker[] = []
+  data = writable(new Map<string, Set<string>>())
+
+  getRelays = (eventId: string) => {
+    const relays = new Set<string>()
+
+    for (const relay of this.data.get().get(eventId) || []) {
+      relays.add(relay)
+    }
+
+    for (const link of this.links) {
+      for (const relay of link.getRelays(eventId)) {
+        relays.add(relay)
+      }
+    }
+
+    return relays
+  }
+
+  hasRelay = (eventId: string, relay: string) => {
+    return this.getRelays(eventId).has(relay)
+  }
+
+  addRelay = (eventId: string, relay: string) => {
+    const relays = this.data.get().get(eventId) || new Set()
+
+    relays.add(relay)
+
+    this.data.update(m => {
+      m.set(eventId, relays)
+
+      return m
+    })
+  }
+
+  track = (eventId: string, relay: string) => {
+    if (this.hasRelay(eventId, relay)) return true
+
+    this.addRelay(eventId, relay)
+
+    return false
+  }
+
+  link = (tracker: Tracker) => this.links.push(tracker)
+
+  copy = (eventId1: string, eventId2: string) => {
+    for (const relay of this.getRelays(eventId1)) {
+      this.addRelay(eventId2, relay)
+    }
+  }
+}