Add Menu and MenuItem Extension (#2303)

#### What type of PR is this?

/kind feature
/area core
/kind api-change
/milestone 2.0

#### What this PR does / why we need it:

Add Menu and MenuItem Extension to realise multi menu feature.

#### Does this PR introduce a user-facing change?

```release-note
添加菜单功能
```

src/main/java/run/halo/app/config/ExtensionConfiguration.java

@@ -6,11 +6,15 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.ServerResponse;
+import run.halo.app.core.extension.Menu;
+import run.halo.app.core.extension.MenuItem;
 import run.halo.app.core.extension.Plugin;
 import run.halo.app.core.extension.Role;
 import run.halo.app.core.extension.RoleBinding;
 import run.halo.app.core.extension.Theme;
 import run.halo.app.core.extension.User;
+import run.halo.app.core.extension.reconciler.MenuItemReconciler;
+import run.halo.app.core.extension.reconciler.MenuReconciler;
 import run.halo.app.core.extension.reconciler.PluginReconciler;
 import run.halo.app.core.extension.reconciler.RoleBindingReconciler;
 import run.halo.app.core.extension.reconciler.RoleReconciler;
@@ -103,6 +107,22 @@ public class ExtensionConfiguration {
                 .build();
         }
 
+        @Bean
+        Controller menuController(ExtensionClient client) {
+            return new ControllerBuilder("menu-controller", client)
+                .reconciler(new MenuReconciler(client))
+                .extension(new Menu())
+                .build();
+        }
+
+        @Bean
+        Controller menuItemController(ExtensionClient client) {
+            return new ControllerBuilder("menu-item-controller", client)
+                .reconciler(new MenuItemReconciler(client))
+                .extension(new MenuItem())
+                .build();
+        }
+
         @Bean
         Controller themeController(ExtensionClient client, HaloProperties haloProperties) {
             return new ControllerBuilder("theme-controller", client)

src/main/java/run/halo/app/core/extension/Menu.java

@@ -0,0 +1,37 @@
+package run.halo.app.core.extension;
+
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.util.LinkedHashSet;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.ToString;
+import run.halo.app.extension.AbstractExtension;
+import run.halo.app.extension.GVK;
+
+@Data
+@ToString(callSuper = true)
+@EqualsAndHashCode(callSuper = true)
+@GVK(group = "", version = "v1alpha1", kind = "Menu", plural = "menus", singular = "menu")
+public class Menu extends AbstractExtension {
+
+    @Schema(description = "The spec of menu.", required = true)
+    private Spec spec;
+
+    @Data
+    @Schema(name = "MenuSpec")
+    public static class Spec {
+
+        @Schema(description = "The display name of the menu.", required = true)
+        private String displayName;
+
+        @Schema(description = "Names of menu children below this menu.")
+        @ArraySchema(
+            arraySchema = @Schema(description = "Menu items of this menu."),
+            schema = @Schema(description = "Name of menu item.")
+        )
+        private LinkedHashSet<String> menuItems;
+
+    }
+
+}

src/main/java/run/halo/app/core/extension/MenuItem.java

@@ -0,0 +1,74 @@
+package run.halo.app.core.extension;
+
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.util.LinkedHashSet;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.ToString;
+import run.halo.app.extension.AbstractExtension;
+import run.halo.app.extension.GVK;
+
+@Data
+@ToString(callSuper = true)
+@EqualsAndHashCode(callSuper = true)
+@GVK(group = "", version = "v1alpha1", kind = "MenuItem",
+    plural = "menuitems", singular = "menuitem")
+public class MenuItem extends AbstractExtension {
+
+    @Schema(description = "The spec of menu item.", required = true)
+    private MenuItemSpec spec;
+
+    @Schema(description = "The status of menu item.")
+    private MenuItemStatus status;
+
+    @Data
+    public static class MenuItemSpec {
+
+        @Schema(description = "The display name of menu item.")
+        private String displayName;
+
+        @Schema(description = "The href of this menu item.")
+        private String href;
+
+        @Schema(description = "The priority is for ordering.")
+        private Integer priority;
+
+        @ArraySchema(
+            arraySchema = @Schema(description = "Children of this menu item"),
+            schema = @Schema(description = "The name of menu item child"))
+        private LinkedHashSet<String> children;
+
+        @Schema(description = "Category reference.")
+        private MenuItemRef categoryRef;
+
+        @Schema(description = "Tag reference.")
+        private MenuItemRef tagRef;
+
+        @Schema(description = "Post reference.")
+        private MenuItemRef postRef;
+
+        @Schema(description = "Page reference.")
+        private MenuItemRef pageRef;
+
+    }
+
+    @Data
+    public static class MenuItemRef {
+
+        @Schema(description = "Reference name.", required = true)
+        private String name;
+
+    }
+
+    @Data
+    public static class MenuItemStatus {
+
+        @Schema(description = "Calculated Display name of menu item.")
+        private String displayName;
+
+        @Schema(description = "Calculated href of manu item.")
+        private String href;
+
+    }
+}

src/main/java/run/halo/app/core/extension/reconciler/MenuItemReconciler.java

@@ -0,0 +1,48 @@
+package run.halo.app.core.extension.reconciler;
+
+import org.springframework.util.StringUtils;
+import run.halo.app.core.extension.MenuItem;
+import run.halo.app.core.extension.MenuItem.MenuItemStatus;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.controller.Reconciler;
+
+public class MenuItemReconciler implements Reconciler {
+
+    private final ExtensionClient client;
+
+    public MenuItemReconciler(ExtensionClient client) {
+        this.client = client;
+    }
+
+    @Override
+    public Result reconcile(Request request) {
+        client.fetch(MenuItem.class, request.name()).ifPresent(menuItem -> {
+            final var spec = menuItem.getSpec();
+
+            if (menuItem.getStatus() == null) {
+                menuItem.setStatus(new MenuItemStatus());
+            }
+            var status = menuItem.getStatus();
+            if (spec.getCategoryRef() != null) {
+                // TODO resolve permalink from category.
+            } else if (spec.getTagRef() != null) {
+                // TODO resolve permalink from tag.
+            } else if (spec.getPageRef() != null) {
+                // TODO resolve permalink from page.
+            } else if (spec.getPostRef() != null) {
+                // TODO resolve permalink from post.
+            } else {
+                // at last, we resolve href and display name from spec.
+                if (spec.getHref() == null || !StringUtils.hasText(spec.getDisplayName())) {
+                    throw new IllegalArgumentException("Both href and displayName are required");
+                }
+                status.setHref(spec.getHref());
+                status.setDisplayName(spec.getDisplayName());
+                // update status
+                client.update(menuItem);
+            }
+        });
+        return new Result(false, null);
+    }
+
+}

src/main/java/run/halo/app/core/extension/reconciler/MenuReconciler.java

@@ -0,0 +1,19 @@
+package run.halo.app.core.extension.reconciler;
+
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.controller.Reconciler;
+
+public class MenuReconciler implements Reconciler {
+
+    private final ExtensionClient client;
+
+    public MenuReconciler(ExtensionClient client) {
+        this.client = client;
+    }
+
+    @Override
+    public Result reconcile(Request request) {
+        return new Result(false, null);
+    }
+
+}

src/main/java/run/halo/app/infra/SchemeInitializer.java

@@ -4,6 +4,8 @@ import org.springframework.boot.context.event.ApplicationStartedEvent;
 import org.springframework.context.ApplicationListener;
 import org.springframework.lang.NonNull;
 import org.springframework.stereotype.Component;
+import run.halo.app.core.extension.Menu;
+import run.halo.app.core.extension.MenuItem;
 import run.halo.app.core.extension.Plugin;
 import run.halo.app.core.extension.ReverseProxy;
 import run.halo.app.core.extension.Role;
@@ -35,5 +37,7 @@ public class SchemeInitializer implements ApplicationListener<ApplicationStarted
         schemeManager.register(Setting.class);
         schemeManager.register(ConfigMap.class);
         schemeManager.register(Theme.class);
+        schemeManager.register(Menu.class);
+        schemeManager.register(MenuItem.class);
     }
 }

src/test/java/run/halo/app/core/extension/reconciler/MenuItemReconcilerTest.java

@@ -0,0 +1,95 @@
+package run.halo.app.core.extension.reconciler;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import run.halo.app.core.extension.MenuItem;
+import run.halo.app.core.extension.MenuItem.MenuItemSpec;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.Metadata;
+import run.halo.app.extension.controller.Reconciler.Request;
+
+@ExtendWith(MockitoExtension.class)
+class MenuItemReconcilerTest {
+
+    @Mock
+    ExtensionClient client;
+
+    @InjectMocks
+    MenuItemReconciler reconciler;
+
+    @Nested
+    class WhenOtherRefNotSet {
+
+
+        @Test
+        void shouldReEnqueueIfHrefNotSet() {
+            var menuItem = createMenuItem("fake-name", spec -> {
+                spec.setHref(null);
+                spec.setDisplayName("Fake display name");
+            });
+            when(client.fetch(MenuItem.class, "fake-name")).thenReturn(Optional.of(menuItem));
+            assertThrows(IllegalArgumentException.class,
+                () -> reconciler.reconcile(new Request("fake-name")));
+            verify(client).fetch(MenuItem.class, "fake-name");
+            verify(client, never()).update(menuItem);
+        }
+
+        @Test
+        void shouldReEnqueueIfDisplayNameNotSet() {
+            var menuItem = createMenuItem("fake-name", spec -> {
+                spec.setHref("/fake");
+                spec.setDisplayName(null);
+            });
+            when(client.fetch(MenuItem.class, "fake-name")).thenReturn(
+                Optional.of(menuItem));
+
+            assertThrows(IllegalArgumentException.class,
+                () -> reconciler.reconcile(new Request("fake-name")));
+
+            verify(client).fetch(MenuItem.class, "fake-name");
+            verify(client, never()).update(menuItem);
+        }
+
+        @Test
+        void shouldReconcileIfHrefAndDisplayNameSet() {
+            var menuItem = createMenuItem("fake-name", spec -> {
+                spec.setHref("/fake");
+                spec.setDisplayName("Fake display name");
+            });
+
+            when(client.fetch(MenuItem.class, "fake-name")).thenReturn(
+                Optional.of(menuItem));
+
+            var result = reconciler.reconcile(new Request("fake-name"));
+            assertFalse(result.reEnqueue());
+
+            verify(client).fetch(MenuItem.class, "fake-name");
+            verify(client).update(menuItem);
+        }
+    }
+
+    MenuItem createMenuItem(String name, Consumer<MenuItemSpec> specCustomizer) {
+        var metadata = new Metadata();
+        metadata.setName(name);
+        var menuItem = new MenuItem();
+        menuItem.setMetadata(metadata);
+        var spec = new MenuItemSpec();
+        if (specCustomizer != null) {
+            specCustomizer.accept(spec);
+        }
+        menuItem.setSpec(spec);
+        return menuItem;
+    }
+}