Move plugins to a plugin directory

packages/client/src/plugins/plaintext.ts

@@ -0,0 +1,27 @@
+import {decrypt} from "@welshman/signer"
+import type {Maybe} from "@welshman/lib"
+import type {TrustedEvent} from "@welshman/util"
+import {MapPlugin} from "./base.js"
+
+/**
+ * A cache of decrypted event content, keyed by event id.
+ */
+export class Plaintext extends MapPlugin<string> {
+  ensure = async (event: TrustedEvent): Promise<Maybe<string>> => {
+    if (this.ctx.user?.pubkey !== event.pubkey) return
+
+    let result = this.get(event.id)
+    if (event.content && result === undefined) {
+      try {
+       result = await decrypt(this.ctx.user.signer, event.pubkey, event.content)
+       this.set(event.id, result)
+      } catch (e: any) {
+        if (!String(e).match(/invalid base64/)) {
+          throw e
+        }
+      }
+    }
+
+    return result
+  }
+}