From 90b4d249d47b461324c33b24884cede4468e9760 Mon Sep 17 00:00:00 2001
From: Dermot Duffy <dermot.duffy@gmail.com>
Date: Sat, 18 Feb 2023 16:58:53 -0800
Subject: [PATCH] Avoid duplicate engine creation.

---
 src/camera-manager/engine-factory.ts |  2 +-
 src/camera-manager/manager.ts        | 55 +++++++++++++++++++---------
 src/camera-manager/store.ts          |  9 ++---
 3 files changed, 42 insertions(+), 24 deletions(-)

diff --git a/src/camera-manager/engine-factory.ts b/src/camera-manager/engine-factory.ts
index 896e4251..850dddd2 100644
--- a/src/camera-manager/engine-factory.ts
+++ b/src/camera-manager/engine-factory.ts
@@ -22,7 +22,7 @@ export class CameraManagerEngineFactory {
     this._cardWideConfig = cardWideConfig;
   }
 
-  public async createEngine(engine: Engine): Promise<CameraManagerEngine | null> {
+  public createEngine(engine: Engine): CameraManagerEngine | null {
     let cameraManagerEngine: CameraManagerEngine | null = null;
     switch (engine) {
       case Engine.Generic:
diff --git a/src/camera-manager/manager.ts b/src/camera-manager/manager.ts
index 9665a167..1a707984 100644
--- a/src/camera-manager/manager.ts
+++ b/src/camera-manager/manager.ts
@@ -30,6 +30,7 @@ import {
   RecordingSegmentsQueryResultsMap,
   ResultsMap,
   CameraEndpoints,
+  Engine,
 } from './types.js';
 import orderBy from 'lodash-es/orderBy';
 import { CameraManagerEngineFactory } from './engine-factory.js';
@@ -106,26 +107,39 @@ export class CameraManager {
     this._store = new CameraManagerStore();
   }
 
+  protected async _getEnginesForCameras(
+    hass: HomeAssistant,
+    camerasConfig: CamerasConfig,
+  ): Promise<Map<CameraConfig, CameraManagerEngine>> {
+    const output: Map<CameraConfig, CameraManagerEngine> = new Map();
+    const engines: Map<Engine, CameraManagerEngine> = new Map();
+
+    for (const cameraConfig of camerasConfig) {
+      const engineType = await this._engineFactory.getEngineForCamera(
+        hass,
+        cameraConfig,
+      );
+      const engine = engineType
+        ? engines.get(engineType) ?? this._engineFactory.createEngine(engineType)
+        : null;
+      if (!engine || !engineType) {
+        throw new CameraInitializationError(
+          localize('error.no_camera_engine'),
+          cameraConfig,
+        );
+      }
+      engines.set(engineType, engine);
+      output.set(cameraConfig, engine);
+    }
+    return output;
+  }
+
   protected async _initializeCamera(
     hass: HomeAssistant,
+    engine: CameraManagerEngine,
     entityRegistryManager: EntityRegistryManager,
     inputCameraConfig: CameraConfig,
   ): Promise<InitializedCamera> {
-    const engineType = await this._engineFactory.getEngineForCamera(
-      hass,
-      inputCameraConfig,
-    );
-    const engine = engineType
-      ? this._store.getEngineOfType(engineType) ??
-        (await this._engineFactory.createEngine(engineType))
-      : null;
-    if (!engine) {
-      throw new CameraInitializationError(
-        localize('error.no_camera_engine'),
-        inputCameraConfig,
-      );
-    }
-
     const initializedConfig = await engine.initializeCamera(
       hass,
       entityRegistryManager,
@@ -159,10 +173,15 @@ export class CameraManager {
       await entityRegistryManager.fetchEntityList(hass);
     }
 
+    // Engines are created sequentially, to avoid duplicate creation of the same
+    // engine. See: https://github.com/dermotduffy/frigate-hass-card/issues/941
+    const engineByConfig = await this._getEnginesForCameras(hass, camerasConfig);
+
+    // Configuration is initialized in parallel.
     const results = await allPromises(
-      camerasConfig,
-      async (cameraConfig) =>
-        await this._initializeCamera(hass, entityRegistryManager, cameraConfig),
+      engineByConfig.entries(),
+      async ([cameraConfig, engine]) =>
+        await this._initializeCamera(hass, engine, entityRegistryManager, cameraConfig),
     );
 
     // Do the additions based off the result-order, to ensure the map order is
diff --git a/src/camera-manager/store.ts b/src/camera-manager/store.ts
index 7d13415c..c6203a20 100644
--- a/src/camera-manager/store.ts
+++ b/src/camera-manager/store.ts
@@ -1,4 +1,3 @@
-import uniq from 'lodash-es/uniq';
 import { CameraConfig } from '../types';
 import { ViewMedia } from '../view/media';
 import { CameraManagerEngine } from './engine';
@@ -8,7 +7,7 @@ type CameraManagerEngineCameraIDMap = Map<CameraManagerEngine, Set<string>>;
 
 export class CameraManagerStore {
   protected _configs: Map<string, CameraConfig> = new Map();
-  protected _engines: Map<string, CameraManagerEngine> = new Map();
+  protected _enginesByCamera: Map<string, CameraManagerEngine> = new Map();
   protected _enginesByType: Map<Engine, CameraManagerEngine> = new Map();
 
   public addCamera(
@@ -17,7 +16,7 @@ export class CameraManagerStore {
     engine: CameraManagerEngine,
   ): void {
     this._configs.set(cameraID, cameraConfig);
-    this._engines.set(cameraID, engine);
+    this._enginesByCamera.set(cameraID, engine);
     this._enginesByType.set(engine.getEngineType(), engine);
   }
 
@@ -54,7 +53,7 @@ export class CameraManagerStore {
   }
 
   public getEngineForCameraID(cameraID: string): CameraManagerEngine | null {
-    return this._engines.get(cameraID) ?? null;
+    return this._enginesByCamera.get(cameraID) ?? null;
   }
 
   public getEnginesForCameraIDs(
@@ -84,6 +83,6 @@ export class CameraManagerStore {
   }
 
   public getAllEngines(): CameraManagerEngine[] {
-    return uniq([...this._engines.values()]);
+    return [...this._enginesByType.values()];
   }
 }