From b2c4088ec62bc8afb650008258ce750d4e52b2ae Mon Sep 17 00:00:00 2001
From: Yann Amsellem <yann@agnostic.engineering>
Date: Mon, 17 Feb 2025 18:17:38 +0100
Subject: [PATCH] feat: Rename Logger into EventEmitter

---
 src/lib/olap-engine/EventEmitter.ts  | 27 +++++++++++++++++++++++++++
 src/lib/olap-engine/Logger.ts        | 25 -------------------------
 src/lib/olap-engine/engine-chdb.ts   | 13 ++++++++-----
 src/lib/olap-engine/engine-remote.ts | 10 ++++++----
 src/lib/olap-engine/index.ts         |  6 ++++--
 5 files changed, 45 insertions(+), 36 deletions(-)
 create mode 100644 src/lib/olap-engine/EventEmitter.ts
 delete mode 100644 src/lib/olap-engine/Logger.ts

diff --git a/src/lib/olap-engine/EventEmitter.ts b/src/lib/olap-engine/EventEmitter.ts
new file mode 100644
index 0000000..47036e1
--- /dev/null
+++ b/src/lib/olap-engine/EventEmitter.ts
@@ -0,0 +1,27 @@
+type Callback = (...param: any[]) => void;
+
+type OptionalRecord<K extends keyof any, T> = { [P in K]?: T };
+
+export interface IEventEmitter<Events extends string> {
+	on(event: Events, fn: Callback): () => void;
+	emit(event: Events, param: any): void;
+}
+
+export abstract class EventEmitter<Events extends string> implements IEventEmitter<Events> {
+	#listeners: OptionalRecord<Events, Set<Callback>> = {};
+
+	on(event: Events, fn: Callback) {
+		this.#listeners[event] ??= new Set<Callback>();
+
+		this.#listeners[event].add(fn);
+		return () => this.#listeners[event]?.delete(fn);
+	}
+
+	emit(event: Events, ...param: any[]) {
+		if (!this.#listeners[event]?.size) return;
+
+		queueMicrotask(() => {
+			if (this.#listeners[event]) for (const fn of this.#listeners[event]) fn(...param);
+		});
+	}
+}
diff --git a/src/lib/olap-engine/Logger.ts b/src/lib/olap-engine/Logger.ts
deleted file mode 100644
index 694bc9a..0000000
--- a/src/lib/olap-engine/Logger.ts
+++ /dev/null
@@ -1,25 +0,0 @@
-type Callback = (param: any) => void;
-
-export interface ILogger {
-	on(level: 'error', fn: Callback): () => void;
-	log(level: 'error', param: any): void;
-}
-
-export abstract class Logger implements ILogger {
-	#listeners: { [key: string]: Set<Callback> } = {};
-
-	on(logEvent: 'error', fn: Callback) {
-		this.#listeners[logEvent] ??= new Set<Callback>();
-
-		this.#listeners[logEvent].add(fn);
-		return () => this.#listeners[logEvent].delete(fn);
-	}
-
-	log(level: 'error', param: any) {
-		if (!this.#listeners[level]?.size) return;
-
-		queueMicrotask(() => {
-			for (const fn of this.#listeners[level]) fn(param);
-		});
-	}
-}
diff --git a/src/lib/olap-engine/engine-chdb.ts b/src/lib/olap-engine/engine-chdb.ts
index a246cc0..975a0f0 100644
--- a/src/lib/olap-engine/engine-chdb.ts
+++ b/src/lib/olap-engine/engine-chdb.ts
@@ -1,12 +1,12 @@
 import { invoke } from '@tauri-apps/api/core';
-import type { OLAPEngine, OLAPResponse, Table } from './index';
-import { Logger } from './Logger';
+import { EventEmitter } from './EventEmitter';
+import type { Events, OLAPEngine, OLAPResponse, Table } from './index';
 
 import CLICKHOUSE_GET_SCHEMA from './queries/clickhouse_get_schema.sql?raw';
 import CLICKHOUSE_GET_UDFS from './queries/clickhouse_get_udfs.sql?raw';
 import CLICKHOUSE_INIT_DB from './queries/clickhouse_init_db.sql?raw';
 
-export class CHDBEngine extends Logger implements OLAPEngine {
+export class CHDBEngine extends EventEmitter<Events> implements OLAPEngine {
 	async init() {
 		await this.exec(CLICKHOUSE_INIT_DB);
 	}
@@ -15,12 +15,15 @@ export class CHDBEngine extends Logger implements OLAPEngine {
 		try {
 			const r: string = await invoke('query', { query });
 			if (!r) return;
+			const data = JSON.parse(r) as OLAPResponse;
 
-			return JSON.parse(r) as OLAPResponse;
+			this.emit('success', query, data);
+
+			return data;
 		} catch (e) {
 			if (typeof e === 'string') e = new Error(e);
 			console.error(e);
-			this.log('error', e);
+			this.emit('error', e);
 		}
 	}
 
diff --git a/src/lib/olap-engine/engine-remote.ts b/src/lib/olap-engine/engine-remote.ts
index 77b88dd..e96b918 100644
--- a/src/lib/olap-engine/engine-remote.ts
+++ b/src/lib/olap-engine/engine-remote.ts
@@ -1,10 +1,10 @@
-import type { OLAPEngine, OLAPResponse, Table } from './index';
-import { Logger } from './Logger';
+import { EventEmitter } from './EventEmitter';
+import type { Events, OLAPEngine, OLAPResponse, Table } from './index';
 
 import CLICKHOUSE_GET_SCHEMA from './queries/clickhouse_get_schema.sql?raw';
 import CLICKHOUSE_GET_UDFS from './queries/clickhouse_get_udfs.sql?raw';
 
-export class RemoteEngine extends Logger implements OLAPEngine {
+export class RemoteEngine extends EventEmitter<Events> implements OLAPEngine {
 	async init() {}
 
 	async exec(query: string) {
@@ -22,10 +22,12 @@ export class RemoteEngine extends Logger implements OLAPEngine {
 
 			if ('exception' in data) throw new Error(data.exception);
 
+			this.emit('success', query, data);
+
 			return data;
 		} catch (e) {
 			console.error(e);
-			this.log('error', e);
+			this.emit('error', e);
 		}
 	}
 
diff --git a/src/lib/olap-engine/index.ts b/src/lib/olap-engine/index.ts
index fe1f6ac..4bc511b 100644
--- a/src/lib/olap-engine/index.ts
+++ b/src/lib/olap-engine/index.ts
@@ -1,6 +1,6 @@
 import { CHDBEngine } from './engine-chdb';
 import { RemoteEngine } from './engine-remote';
-import type { ILogger } from './Logger';
+import type { IEventEmitter } from './EventEmitter';
 
 export type OLAPResponse = {
 	meta: Array<ColumnDescriptor>;
@@ -24,7 +24,9 @@ export interface Table {
 	columns: ColumnDescriptor[];
 }
 
-export interface OLAPEngine extends ILogger {
+export type Events = 'error' | 'success';
+
+export interface OLAPEngine extends IEventEmitter<Events> {
 	init(): Promise<void>;
 	exec(query: string): Promise<OLAPResponse | undefined>;
 	getSchema(): Promise<Table[]>;