ambientlight: Add ambient light API simulator

Add the simulator driver for ambientlight API.

- Write a simulator driver for ambientlight
- Use it as a default driver if no driver is specified

Issue-Id: rzr#5 Add simulators
Environment:
    Darwin 18.2.0
    Node 10.15.1
    Node 9.5.0

Signed-off-by: Anthony Maton <me@anthony-maton.me>

lib/ambientlight/index.js

@@ -18,7 +18,12 @@
 'use strict';
 
 var console = require('console');
-var BH1750 = require('bh1750');
+try {
+  var BH1750 = require('bh1750');
+} catch (err) {
+  // console.log(err);
+}
+var Simulator = require('./simulator');
 
 /**
  * Class inspired by W3C's generic-sensor
@@ -41,7 +46,7 @@ function AmbientLight(options) {
 
   this.options = options || {};
   this.options.frequency = this.options.frequency || 1;
-  this.options.controller = this.options.controller || 'bh1750';
+  this.options.controller = this.options.controller || 'simulator';
 
   return this;
 }
@@ -77,7 +82,9 @@ AmbientLight.prototype.start = function start() {
   this.state = 'activating';
   if (!this.sensor) {
     try {
-      if (this.options.controller === 'bh1750') {
+      if (this.options.controller === 'simulator') {
+        this.sensor = new Simulator();
+      } else if (this.options.controller === 'bh1750') {
         this.sensor = new BH1750(this.options.sensor);
       } else {
         throw new Error("TODO: unsupported controller:" + this.options.controller);

lib/ambientlight/simulator.js

@@ -0,0 +1,42 @@
+/* -*- mode: js; js-indent-level:2; -
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright 2019-present Samsung Electronics France and other contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+'use strict';
+
+var console = require('console');
+
+function Simulator () {
+  this.value = 0;
+}
+
+Simulator.prototype.readLight = function (callback) {
+  this.value = (Math.random() * 200);
+  if (callback) return callback(null, this.value);
+};
+
+module.exports = Simulator;
+
+if (module.parent === null) {
+  var sensor = new Simulator();
+  sensor.read(function (err, value) {
+    if (err) {
+      console.error('error: ' + err);
+      throw err;
+    } else {
+      console.log('log: value=' + JSON.stringify(value));
+    }
+  });
+}

package.json

@@ -13,10 +13,12 @@
     "url": "git+https://github.com/rzr/generic-sensors-lite.git"
   },
   "dependencies": {
-    "bh1750": "^0.0.5",
-    "bmp085-sensor": "^0.0.5",
     "color-sensor-js": "0.0.4"
   },
+  "optionalDependencies": {
+    "bh1750": "^0.0.5",
+    "bmp085-sensor": "^0.0.5"
+  },
   "keywords": [
     "ambiant",
     "ambiantlight",