example: add ToDoDemo

More complex usage of lenses

Author: bvlj

example/src/main/java/jtamaro/example/interaction/ToDoDemo.java

@@ -0,0 +1,146 @@
+package jtamaro.example.interaction;
+
+import jtamaro.data.Function2;
+import jtamaro.data.Sequence;
+import jtamaro.data.Sequences;
+import jtamaro.graphic.Actionable;
+import jtamaro.graphic.Graphic;
+import jtamaro.graphic.Graphics;
+import jtamaro.interaction.KeyboardChar;
+import jtamaro.interaction.KeyboardKey;
+import jtamaro.optics.Glasses;
+import jtamaro.optics.Lens;
+
+import static jtamaro.data.Sequences.cons;
+import static jtamaro.data.Sequences.empty;
+import static jtamaro.graphic.Colors.BLACK;
+import static jtamaro.graphic.Colors.GREEN;
+import static jtamaro.graphic.Colors.RED;
+import static jtamaro.graphic.Colors.TRANSPARENT;
+import static jtamaro.graphic.Colors.WHITE;
+import static jtamaro.graphic.Fonts.SANS_SERIF;
+import static jtamaro.graphic.Graphics.beside;
+import static jtamaro.graphic.Graphics.compose;
+import static jtamaro.graphic.Graphics.pin;
+import static jtamaro.graphic.Graphics.rectangle;
+import static jtamaro.graphic.Graphics.text;
+import static jtamaro.graphic.Points.CENTER_LEFT;
+import static jtamaro.io.IO.interact;
+
+public final class ToDoDemo {
+
+  @Glasses
+  record Entry(String content, boolean isChecked) {
+
+  }
+
+  @Glasses
+  record Model(
+      String currentInput,
+      Sequence<Entry> entries,
+      Function2<Model, String, Model> onEnter
+  ) {
+
+  }
+
+  private static Graphic renderInputField(Model model) {
+    return compose(
+        pin(CENTER_LEFT,
+            text(model.currentInput, SANS_SERIF, 20, WHITE)),
+        pin(CENTER_LEFT,
+            rectangle(500, 50, BLACK))
+    );
+  }
+
+  private static Graphic renderEntry(Lens<Model, Model, Entry, Entry> lens, Model model) {
+    final Entry entry = lens.view(model);
+    final Graphic textGraphic = text(entry.content, SANS_SERIF, 20, BLACK);
+    final Graphic checkedGraphic = rectangle(
+        20,
+        20,
+        entry.isChecked ? GREEN : RED
+    );
+
+    final Graphic actionableCheckbox = new Actionable<Model>(checkedGraphic)
+        .withMouseReleaseHandler((m, $$, $$$) ->
+            lens.then(ToDoDemo$EntryLenses.isChecked).over(b -> !b, m))
+        .asGraphic();
+
+    final Graphic entryGraphic = compose(
+        pin(CENTER_LEFT,
+            beside(actionableCheckbox,
+                beside(rectangle(10, 0, TRANSPARENT),
+                    textGraphic))),
+        pin(CENTER_LEFT,
+            rectangle(500, 50, WHITE))
+    );
+
+    return new Actionable<Model>(entryGraphic).withMouseReleaseHandler(
+        (m, $$, $$$) -> new Model(
+            entry.content,
+            m.entries,
+            (mo, newContent) -> ToDoDemo$ModelLenses.currentInput.set(
+                "",
+                ToDoDemo$ModelLenses.onEnter.set(
+                    ToDoDemo::addNewEntry,
+                    lens.then(ToDoDemo$EntryLenses.content).set(newContent, mo)
+                )
+            )
+        )
+    ).asGraphic();
+  }
+
+  private static Graphic render(Model model) {
+    return Sequences.traverseEvery(ToDoDemo$ModelLenses.entries).foldMap(
+        renderInputField(model),
+        Graphics::above,
+        lens -> renderEntry(lens, model),
+        model
+    );
+  }
+
+  private static Model onKeyType(Model model, KeyboardChar keyboardChar) {
+    final char c = keyboardChar.keyChar();
+    if (Character.isLetterOrDigit(c) || Character.isSpaceChar(c)) {
+      return ToDoDemo$ModelLenses.currentInput.over(
+          input -> input + c,
+          model
+      );
+    } else {
+      return model;
+    }
+  }
+
+  private static Model onKeyPress(Model model, KeyboardKey key) {
+    return switch (key.keyCode()) {
+      // Remove last char
+      case KeyboardKey.BACK_SPACE -> ToDoDemo$ModelLenses.currentInput.over(
+          input -> switch (input.length()) {
+            case 0, 1 -> "";
+            default -> input.substring(0, input.length() - 1);
+          },
+          model
+      );
+      // onEnterAction
+      case KeyboardKey.ENTER -> model.onEnter.apply(model, model.currentInput);
+      default -> model;
+    };
+  }
+
+  private static Model addNewEntry(Model current, String content) {
+    return new Model(
+        "",
+        cons(new Entry(current.currentInput, false), current.entries),
+        ToDoDemo::addNewEntry
+    );
+  }
+
+  public static void main(String[] args) {
+    interact(new Model("Hello!", empty(), ToDoDemo::addNewEntry))
+        .withCanvasSize(500, 400)
+        .withRenderer(ToDoDemo::render)
+        .withKeyTypeHandler(ToDoDemo::onKeyType)
+        .withKeyPressHandler(ToDoDemo::onKeyPress)
+        .run();
+  }
+}