feat: start/stop engine (WIP)

client/src/composables/useEngine.ts

@@ -1,16 +1,30 @@
+import { useState } from '#app'
+
 export interface useEngine {
     start(): void
     stop(): void
 }
 
 export default (): useEngine => {
+    const isActive = useState('engine__is-active', () => false)
+    const shouldStop = useState('engine__should-stop', () => false)
+
     return {
         start: (): void => {
+            if (isActive.value && !shouldStop.value) {
+                console.warn('attempt to start already running engine!')
+                return
+            }
+            isActive.value = true
+            shouldStop.value = false
             console.log('start engine')
         },
 
         stop: (): void => {
-            console.log('stop engine')
+            if (isActive.value) {
+                shouldStop.value = true
+                console.log('shut down engine')
+            }
         },
     }
 }