From 806138a35e0d24a48498674f41e54cf6e5bca1bb Mon Sep 17 00:00:00 2001
From: Adhiraj Singh <adhirajsingh1001@gmail.com>
Date: Tue, 29 Mar 2022 18:25:42 +0530
Subject: [PATCH] feat: add logging event stream

---
 src/Utils/baileys-event-stream.ts | 66 +++++++++++++++++++++++++++++++
 src/Utils/index.ts                |  3 +-
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 src/Utils/baileys-event-stream.ts

diff --git a/src/Utils/baileys-event-stream.ts b/src/Utils/baileys-event-stream.ts
new file mode 100644
index 0000000..6518f69
--- /dev/null
+++ b/src/Utils/baileys-event-stream.ts
@@ -0,0 +1,66 @@
+import EventEmitter from 'events'
+import { createReadStream } from 'fs'
+import { writeFile } from 'fs/promises'
+import { createInterface } from 'readline'
+import type { CommonBaileysEventEmitter } from '../Types'
+import { delay } from './generics'
+import { makeMutex } from './make-mutex'
+
+/**
+ * Captures events from a baileys event emitter & stores them in a file
+ * @param ev The event emitter to read events from
+ * @param filename File to save to
+ */
+export const captureEventStream = (ev: CommonBaileysEventEmitter<any>, filename: string) => {
+	const oldEmit = ev.emit
+	// write mutex so data is appended in order
+	const writeMutex = makeMutex()
+	// monkey patch eventemitter to capture all events
+	ev.emit = function(...args: any[]) {
+		const content = JSON.stringify({ timestamp: Date.now(), event: args[0], data: args[1] }) + '\n'
+		const result = oldEmit.apply(ev, args)
+
+		writeMutex.mutex(
+			async() => {
+				await writeFile(filename, content, { flag: 'a' })
+			}
+		)
+
+		return result
+	}
+}
+
+/**
+ * Read event file and emit events from there
+ * @param filename filename containing event data
+ * @param delayIntervalMs delay between each event emit
+ */
+export const readAndEmitEventStream = (filename: string, delayIntervalMs: number = 0) => {
+	const ev = new EventEmitter() as CommonBaileysEventEmitter<any>
+
+	const fireEvents = async() => {
+		// from: https://stackoverflow.com/questions/6156501/read-a-file-one-line-at-a-time-in-node-js
+		const fileStream = createReadStream(filename)
+
+		const rl = createInterface({
+			input: fileStream,
+			crlfDelay: Infinity
+		})
+		// Note: we use the crlfDelay option to recognize all instances of CR LF
+		// ('\r\n') in input.txt as a single line break.
+		for await (const line of rl) {
+			if(line) {
+				const { event, data } = JSON.parse(line)
+				ev.emit(event, data)
+				delayIntervalMs && await delay(delayIntervalMs)
+			}
+		}
+
+		fileStream.close()
+	}
+
+	return {
+		ev,
+		task: fireEvents()
+	}
+}
\ No newline at end of file
diff --git a/src/Utils/index.ts b/src/Utils/index.ts
index 76448aa..dee1f9f 100644
--- a/src/Utils/index.ts
+++ b/src/Utils/index.ts
@@ -10,4 +10,5 @@ export * from './history'
 export * from './chat-utils'
 export * from './lt-hash'
 export * from './auth-utils'
-export * from './legacy-msgs'
\ No newline at end of file
+export * from './legacy-msgs'
+export * from './baileys-event-stream'
\ No newline at end of file