Add sync history backend

plugin/src/tracing/logger.ts

@@ -0,0 +1,77 @@
+import { Notice } from "obsidian";
+
+export enum LogLevel {
+	DEBUG = "DEBUG",
+	INFO = "INFO",
+	WARNING = "WARNING",
+	ERROR = "ERROR",
+}
+
+class LogLine {
+	public constructor(public level: LogLevel, public message: string) {}
+
+	public toString(): string {
+		return `${this.formatLevel()}: ${this.message}`;
+	}
+
+	private formatLevel(): string {
+		switch (this.level) {
+			case LogLevel.DEBUG:
+				return "DEBUG";
+			case LogLevel.INFO:
+				return "INFO";
+			case LogLevel.WARNING:
+				return "WARNING";
+			case LogLevel.ERROR:
+				return "ERROR";
+			default:
+				return "UNKNOWN";
+		}
+	}
+}
+
+export class Logger {
+	private static readonly MAX_MESSAGES = 1000;
+
+	private static instance: Logger | null = null;
+	private readonly messages: LogLine[] = [];
+
+	private constructor() {} // eslint-disable-line @typescript-eslint/no-empty-function
+
+	public static getInstance(): Logger {
+		if (!Logger.instance) {
+			Logger.instance = new Logger();
+		}
+		return Logger.instance;
+	}
+
+	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);
+		new Notice(message, 5000);
+	}
+
+	public getMessages(mininumSeverity: LogLevel): LogLine[] {
+		return this.messages.filter(
+			(message) => message.level >= mininumSeverity
+		);
+	}
+
+	private pushMessage(message: string, level: LogLevel): void {
+		this.messages.push(new LogLine(level, message));
+		if (this.messages.length > Logger.MAX_MESSAGES) {
+			this.messages.shift();
+		}
+	}
+}