feat(webUI): handle error while performing commands

Refs: #27

src/main/java/ru/ewc/checklogic/server/CommandPage.java

@@ -29,6 +29,7 @@
 import com.renomad.minum.web.WebFramework;
 import java.util.Map;
 import ru.ewc.checklogic.Computation;
+import ru.ewc.decisions.api.DecitaException;
 
 /**
  * I am a configuration object for all the command-related endpoints.
@@ -44,7 +45,12 @@ public final class CommandPage implements Endpoints {
     /**
      * The template processor for the Command page.
      */
-    private final TemplateProcessor template;
+    private final TemplateProcessor description;
+
+    /**
+     * The template processor for the error page.
+     */
+    private final TemplateProcessor error;
 
     /**
      * Ctor.
@@ -53,9 +59,12 @@ public final class CommandPage implements Endpoints {
      */
     public CommandPage(final Computation computation) {
         this.computation = computation;
-        this.template = TemplateProcessor.buildProcessor(
+        this.description = TemplateProcessor.buildProcessor(
             WebResource.readFileFromResources("templates/command-info.html")
         );
+        this.error = TemplateProcessor.buildProcessor(
+            WebResource.readFileFromResources("templates/command-error.html")
+        );
     }
 
     @Override
@@ -65,16 +74,28 @@ public void register(final WebFramework web) {
     }
 
     // @todo #25 Pass the filled parameters to the command
-    // @todo #25 Handle the errors gracefully (show some modal with error description?)
     public Response executeCommand(final Request request) {
         final String command = request.body().asString("command");
-        this.computation.perform(command);
-        return Response.htmlOk("OK", Map.of("HX-Redirect", "/"));
+        Response response;
+        try {
+            this.computation.perform(command);
+            response = Response.htmlOk("OK", Map.of("HX-Redirect", "/"));
+        } catch (final DecitaException exception) {
+            response = Response.htmlOk(
+                this.error.renderTemplate(
+                    Map.of(
+                        "error", exception.getMessage()
+                    )
+                )
+            );
+        }
+        return response;
     }
 
     // @todo #25 Extract all the required parameters from the command's description
+    // @todo #25 Implement the check for the command's decision table
     public Response commandInfo(final Request request) {
         final String command = request.requestLine().queryString().getOrDefault("command", "");
-        return Response.htmlOk(this.template.renderTemplate(Map.of("command_name", command)));
+        return Response.htmlOk(this.description.renderTemplate(Map.of("command_name", command)));
     }
 }

src/main/resources/templates/command-error.html

@@ -0,0 +1,31 @@
+<!--
+  ~ MIT License
+  ~
+  ~ Copyright (c) 2024 Decision-Driven Development
+  ~
+  ~ Permission is hereby granted, free of charge, to any person obtaining a copy
+  ~ of this software and associated documentation files (the "Software"), to deal
+  ~ in the Software without restriction, including without limitation the rights
+  ~ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  ~ copies of the Software, and to permit persons to whom the Software is
+  ~ furnished to do so, subject to the following conditions:
+  ~
+  ~ The above copyright notice and this permission notice shall be included in all
+  ~ copies or substantial portions of the Software.
+  ~
+  ~ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  ~ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  ~ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  ~ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  ~ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  ~ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  ~ SOFTWARE.
+  -->
+<div id="modal" _="on closeModal add .closing then wait for animationend then remove me">
+    <div class="modal-underlay" _="on click trigger closeModal"></div>
+    <div class="modal-content">
+        <h1>Error</h1>
+        <p>{{ error }}</p>
+        <button _="on click trigger closeModal">Close</button>
+    </div>
+</div>

src/main/resources/templates/command-info.html

@@ -29,6 +29,7 @@ <h1>{{ command_name }}</h1>
         <br>
         <br>
         <input id="command" type="hidden" name="command" value="{{ command_name }}"/>
-        <button _="on click trigger closeModal" hx-post="/command" hx-include="#command">Execute</button>
+        <button hx-post="/command" hx-include="#command"
+                hx-target="#modal" hx-swap="outerHTML">Execute</button>
     </div>
 </div>

src/main/resources/templates/state.html

@@ -22,12 +22,13 @@
   ~ SOFTWARE.
   -->
 <!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
     <title>Simple HTML Page</title>
     <script src="https://unpkg.com/htmx.org@1.9.12"
             integrity="sha384-ujb1lZYygJmzgSwoxRggbCHcjc0rB2XoQrxeTUQyRjrOnlCoYta87iKBWq3EsdM2"
             crossorigin="anonymous"></script>
+    <script src="https://unpkg.com/hyperscript.org@0.9.12"></script>
     <link rel="stylesheet" href="static/main.css">
 </head>
 <body>
@@ -36,6 +37,5 @@ <h1>State entities</h1>
 <hr>
 <h1>Commands</h1>
 {{ commands }}
-<button hx-get="/command" hx-target="body" hx-swap="beforeend" hx-vals='{"command":"initialize"}'>Initialize</button>
 </body>
 </html>