Add connection profiles (#63)

* Add connection setup

* Refactor

* Fix lifecycle

app/src/model/ConnectionOptions.ts

@@ -0,0 +1,82 @@
+import { MqttOptions } from '../../../backend/src/DataSource'
+import { v4 } from 'uuid'
+const sha1 = require('sha1')
+
+export interface ConnectionOptions {
+  type: 'mqtt'
+  id: string
+  host: string
+  protocol: 'mqtt' | 'ws' | 'wss'
+  basePath?: string
+  port: number
+  name: string
+  username?: string
+  password?: string
+  encryption: boolean
+  certValidation: boolean
+  clientId?: string
+  subscriptions: string[]
+}
+
+export function toMqttConnection(options: ConnectionOptions): MqttOptions | undefined {
+  if (options.type !== 'mqtt') {
+    return
+  }
+
+  return {
+    url: `${options.protocol}://${options.host}:${options.port}/${options.basePath || ''}`,
+    username: options.username,
+    password: options.password,
+    tls: options.encryption,
+    certValidation: options.certValidation,
+  }
+}
+
+export function generateClienId() {
+  const clientIdSha = sha1(`${Math.random()}`).slice(0, 8)
+  return `mqtt-explorer-${clientIdSha}`
+}
+
+export function createEmptyConnection(): ConnectionOptions {
+  return {
+    certValidation: true,
+    clientId: generateClienId(),
+    id: v4() as string,
+    name: 'new connection',
+    encryption: false,
+    password: undefined,
+    username: undefined,
+    subscriptions: ['#', '$SYS'],
+    type: 'mqtt',
+    host: '',
+    port: 1883,
+    protocol: 'mqtt',
+  }
+}
+
+export function defaultConnections() {
+  return [
+    {
+      ...createEmptyConnection(),
+      id: 'iot.eclipse.org',
+      name: 'iot.eclipse.org',
+      host: 'iot.eclipse.org',
+    },
+    {
+      ...createEmptyConnection(),
+      id: 'test.mosquitto.org',
+      name: 'test.mosquitto.org',
+      host: 'test.mosquitto.org',
+    },
+    {
+      ...createEmptyConnection(),
+      id: 'wss://broker.hivemq.com:8000/mqtt',
+      name: 'broker.hivemq.com',
+      host: 'broker.hivemq.com',
+      basePath: 'mqtt',
+      encryption: true,
+      protocol: 'ws',
+      port: 8000,
+    },
+  ]
+}