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frontend/sync-client/src/tracing/logger.ts

@@ -0,0 +1,79 @@
+export enum LogLevel {
+	DEBUG = "DEBUG",
+	INFO = "INFO",
+	WARNING = "WARNING",
+	ERROR = "ERROR"
+}
+
+const LOG_LEVEL_ORDER = {
+	[LogLevel.DEBUG]: 0,
+	[LogLevel.INFO]: 1,
+	[LogLevel.WARNING]: 2,
+	[LogLevel.ERROR]: 3
+};
+
+export class LogLine {
+	public timestamp = new Date();
+	public constructor(
+		public level: LogLevel,
+		public message: string
+	) {}
+}
+
+export class Logger {
+	private static readonly MAX_MESSAGES = 100000;
+	private readonly messages: LogLine[] = [];
+	private readonly onMessageListeners: ((message: LogLine) => unknown)[] = [];
+
+	public constructor(
+		...onMessageListeners: ((message: LogLine) => unknown)[]
+	) {
+		this.onMessageListeners = onMessageListeners;
+	}
+
+	public debug(message: string): void {
+		this.pushMessage(message, LogLevel.DEBUG);
+	}
+
+	public info(message: string): void {
+		this.pushMessage(message, LogLevel.INFO);
+	}
+
+	public warn(message: string): void {
+		this.pushMessage(message, LogLevel.WARNING);
+	}
+
+	public error(message: string): void {
+		this.pushMessage(message, LogLevel.ERROR);
+	}
+
+	public getMessages(mininumSeverity: LogLevel): LogLine[] {
+		return this.messages.filter(
+			(message) =>
+				LOG_LEVEL_ORDER[message.level] >=
+				LOG_LEVEL_ORDER[mininumSeverity]
+		);
+	}
+
+	public addOnMessageListener(listener: (message: LogLine) => unknown): void {
+		this.onMessageListeners.push(listener);
+	}
+
+	public reset(): void {
+		this.messages.length = 0;
+		this.debug("Logger has been reset");
+	}
+
+	private pushMessage(message: string, level: LogLevel): void {
+		const logLine = new LogLine(level, message);
+		this.messages.push(logLine);
+
+		while (this.messages.length > Logger.MAX_MESSAGES) {
+			this.messages.shift();
+		}
+
+		this.onMessageListeners.forEach((listener) => {
+			listener(logLine);
+		});
+	}
+}