From d097cc84716e86827fb7ed8a29bcac29afcc9934 Mon Sep 17 00:00:00 2001
From: Kir_Antipov <kp.antipov@gmail.com>
Date: Tue, 5 Jul 2022 17:47:28 +0300
Subject: [PATCH] Made a logging version of Stopwatch

---
 src/utils/logging-stopwatch.ts | 46 +++++++++++++++++++
 test/logging-stopwatch.test.ts | 81 ++++++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 src/utils/logging-stopwatch.ts
 create mode 100644 test/logging-stopwatch.test.ts

diff --git a/src/utils/logging-stopwatch.ts b/src/utils/logging-stopwatch.ts
new file mode 100644
index 0000000..3a653a2
--- /dev/null
+++ b/src/utils/logging-stopwatch.ts
@@ -0,0 +1,46 @@
+import Logger from "./logger";
+import Stopwatch from "./stopwatch";
+
+interface StartCallback {
+    (currentDate: Date, stopwatch: Stopwatch): string;
+}
+
+interface StopCallback {
+    (elapsedMilliseconds: number, currentDate: Date, stopwatch: Stopwatch): string;
+}
+
+type VoidCallback<T extends (...args: any[]) => any> = (...args: Parameters<T>) => void;
+
+function toCallback<T extends (...args: any[]) => string>(func: string | T): T {
+    if (typeof func === "string") {
+        return (() => func) as T;
+    }
+    return func;
+}
+
+function loggingCallbackToVoidCallback<T extends (...args: any[]) => any>(logger: Logger, func: T): VoidCallback<T> {
+    if (!func) {
+        return func;
+    }
+
+    return (...args: any[]) => {
+        const msg = func(...args) as string;
+        if (typeof msg === "string") {
+            logger?.info(msg);
+        }
+    };
+}
+
+// eslint-disable-next-line
+// @ts-ignore: ts2417
+export default class LoggingStopwatch extends Stopwatch {
+    public constructor(logger: Logger, onStart?: string | StartCallback, onStop?: string | StopCallback) {
+        super(loggingCallbackToVoidCallback(logger, toCallback(onStart)), loggingCallbackToVoidCallback(logger, toCallback(onStop)));
+    }
+
+    public static startNew(logger: Logger, onStart?: string | StartCallback, onStop?: string | StopCallback): LoggingStopwatch {
+        const stopwatch = new LoggingStopwatch(logger, onStart, onStop);
+        stopwatch.start();
+        return stopwatch;
+    }
+}
diff --git a/test/logging-stopwatch.test.ts b/test/logging-stopwatch.test.ts
new file mode 100644
index 0000000..549aa93
--- /dev/null
+++ b/test/logging-stopwatch.test.ts
@@ -0,0 +1,81 @@
+import { describe, test, expect } from "@jest/globals";
+import sleep from "../src/utils/sleep";
+import Logger from "../src/utils/logger";
+import LogginStopwatch from "../src/utils/logging-stopwatch";
+
+function createLogger(info?: (msg: string) => void): Logger {
+    const notImplementedLogger = () => {
+        throw new Error("Not implemented and should never be called");
+    };
+
+    return {
+        fatal: notImplementedLogger,
+        error: notImplementedLogger,
+        warn: notImplementedLogger,
+        debug: notImplementedLogger,
+        info: info ?? notImplementedLogger
+    };
+}
+
+describe("LogginStopwatch", () => {
+    test("base functionality of LogginStopwatch works", async () => {
+        const stopwatch = new LogginStopwatch(createLogger());
+        expect(stopwatch.isRunning).toBe(false);
+        expect(stopwatch.elapsedMilliseconds).toBe(0);
+        expect(stopwatch.start()).toBe(true);
+        await sleep(100);
+        expect(stopwatch.start()).toBe(false);
+        expect(stopwatch.stop()).toBe(true);
+        expect(stopwatch.stop()).toBe(false);
+        expect(stopwatch.elapsedMilliseconds).toBeGreaterThan(50);
+        expect(stopwatch.elapsedMilliseconds).toBeLessThan(200);
+        stopwatch.reset();
+        expect(stopwatch.elapsedMilliseconds).toBe(0);
+    });
+
+    test("LogginStopwatch executes callbacks on start and end", async () => {
+        let started = 0;
+        let stopped = 0;
+        let ms = 0;
+        const logger = createLogger(msg => {
+            if (msg.startsWith("start")) {
+                ++started;
+            } else if (msg.startsWith("stop")) {
+                ++stopped;
+                ms = +msg.split(" ")[1];
+            } else {
+                throw new Error("Unrecognized message");
+            }
+        });
+
+        const stopwatch = new LogginStopwatch(logger, "start", ms => `stop ${ms}`);
+
+        expect(stopwatch.isRunning).toBe(false);
+        expect(stopwatch.elapsedMilliseconds).toBe(0);
+
+        expect(stopwatch.start()).toBe(true);
+        expect(started).toBe(1);
+        expect(stopped).toBe(0);
+
+        await sleep(100);
+
+        expect(stopwatch.start()).toBe(false);
+        expect(started).toBe(1);
+        expect(stopped).toBe(0);
+
+        expect(stopwatch.stop()).toBe(true);
+        expect(started).toBe(1);
+        expect(stopped).toBe(1);
+
+        expect(stopwatch.stop()).toBe(false);
+        expect(started).toBe(1);
+        expect(stopped).toBe(1);
+
+        expect(stopwatch.elapsedMilliseconds).toBeGreaterThan(50);
+        expect(stopwatch.elapsedMilliseconds).toBeLessThan(200);
+        expect(stopwatch.elapsedMilliseconds).toBe(ms);
+
+        stopwatch.reset();
+        expect(stopwatch.elapsedMilliseconds).toBe(0);
+    });
+});