Implemented a half-way okay-ish user interaction pattern: mouse drag.

src/App.js

@@ -1,27 +1,38 @@
-import React, {useState} from 'react';
+import React, {useReducer} from 'react';
 import Maze from "./Maze";
 import InputForm from "./InputForm";
+import reduce from "./reducer";
+import MessageBanner from "./MessageBanner";
 
 export default function App() {
-    const [maze, setMaze] = useState({});
-    const [showSolution, setShowSolution] = useState(false);
-    const hasValidMaze = !!maze.width &&
-        !!maze.height &&
-        !!maze.id &&
-        !!maze.grid;
+    const [state, dispatch] = useReducer(reduce, {
+            maze: null,
+            loading: false,
+            errorMessage: null,
+            showSolution: false,
+            userPath: []
+        },
+        undefined);
+    const hasValidMaze = !!state.maze;
     return (
         <>
-            <InputForm handleResult={setMaze}/>
+            <MessageBanner state={state}
+                           dispatch={dispatch}/>
+            <InputForm state={state}
+                       dispatch={dispatch}/>
             {hasValidMaze &&
                 <>
-                    <h1>The Maze ({maze.width}x{maze.height}, ID: {maze.id})</h1>
+                    <h1>The Maze ({state.maze.width}x{state.maze.height}, ID: {state.maze.id})</h1>
                     <input type={"checkbox"}
                            onChange={(e) => {
-                               setShowSolution(e.target.checked);
+                               dispatch({
+                                   type: 'toggled_show_solution',
+                                   value: e.target.checked
+                               });
                            }}
                            id={"showSolution"}/><label htmlFor="showSolution">Show Solution</label>
-                    <Maze labyrinth={maze}
-                          showSolution={showSolution}/>
+                    <Maze state={state}
+                          dispatch={dispatch}/>
                 </>
             }
         </>