feat: add theme uninstall endpoint (#2315)

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#### What type of PR is this?
/kind feature
/milestone 2.0
/area core
/kind api-change
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#### What this PR does / why we need it:
新增主题卸载 endpoint

#### Which issue(s) this PR fixes:

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Fixes #2306

#### Special notes for your reviewer:
/cc @halo-dev/sig-halo 
#### Does this PR introduce a user-facing change?

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```release-note
None
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src/main/java/run/halo/app/config/ExtensionConfiguration.java

@@ -9,10 +9,12 @@ import org.springframework.web.reactive.function.server.ServerResponse;
 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.PluginReconciler;
 import run.halo.app.core.extension.reconciler.RoleBindingReconciler;
 import run.halo.app.core.extension.reconciler.RoleReconciler;
+import run.halo.app.core.extension.reconciler.ThemeReconciler;
 import run.halo.app.core.extension.reconciler.UserReconciler;
 import run.halo.app.core.extension.service.RoleService;
 import run.halo.app.extension.DefaultExtensionClient;
@@ -28,6 +30,7 @@ import run.halo.app.extension.controller.ControllerBuilder;
 import run.halo.app.extension.controller.ControllerManager;
 import run.halo.app.extension.router.ExtensionCompositeRouterFunction;
 import run.halo.app.extension.store.ExtensionStoreClient;
+import run.halo.app.infra.properties.HaloProperties;
 import run.halo.app.plugin.HaloPluginManager;
 import run.halo.app.plugin.resources.JsBundleRuleProvider;
 
@@ -99,6 +102,14 @@ public class ExtensionConfiguration {
                 .extension(new Plugin())
                 .build();
         }
+
+        @Bean
+        Controller themeController(ExtensionClient client, HaloProperties haloProperties) {
+            return new ControllerBuilder("theme-controller", client)
+                .reconciler(new ThemeReconciler(client, haloProperties))
+                .extension(new Theme())
+                .build();
+        }
     }
 
 }

src/main/java/run/halo/app/core/extension/endpoint/ThemeEndpoint.java

@@ -42,7 +42,7 @@ import run.halo.app.core.extension.Theme;
 import run.halo.app.extension.ConfigMap;
 import run.halo.app.extension.ExtensionClient;
 import run.halo.app.extension.Unstructured;
-import run.halo.app.infra.ThemeInstallationException;
+import run.halo.app.infra.exception.ThemeInstallationException;
 import run.halo.app.infra.properties.HaloProperties;
 import run.halo.app.infra.utils.FileUtils;
 import run.halo.app.infra.utils.YamlUnstructuredLoader;

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

@@ -0,0 +1,64 @@
+package run.halo.app.core.extension.reconciler;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.util.FileSystemUtils;
+import run.halo.app.core.extension.Setting;
+import run.halo.app.core.extension.Theme;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.controller.Reconciler;
+import run.halo.app.infra.exception.ThemeUninstallException;
+import run.halo.app.infra.properties.HaloProperties;
+import run.halo.app.theme.ThemePathPolicy;
+
+/**
+ * Reconciler for theme.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+public class ThemeReconciler implements Reconciler {
+
+    private final ExtensionClient client;
+    private final ThemePathPolicy themePathPolicy;
+
+    public ThemeReconciler(ExtensionClient client, HaloProperties haloProperties) {
+        this.client = client;
+        themePathPolicy = new ThemePathPolicy(haloProperties.getWorkDir());
+    }
+
+    @Override
+    public Result reconcile(Request request) {
+        client.fetch(Theme.class, request.name())
+            .ifPresent(theme -> {
+                if (isDeleted(theme)) {
+                    reconcileThemeDeletion(theme);
+                }
+            });
+        return new Result(false, null);
+    }
+
+    private void reconcileThemeDeletion(Theme theme) {
+        deleteThemeFiles(theme);
+        // delete theme setting form
+        String settingName = theme.getSpec().getSettingName();
+        if (StringUtils.isNotBlank(settingName)) {
+            client.fetch(Setting.class, settingName)
+                .ifPresent(client::delete);
+        }
+    }
+
+    private void deleteThemeFiles(Theme theme) {
+        Path themeDir = themePathPolicy.generate(theme);
+        try {
+            FileSystemUtils.deleteRecursively(themeDir);
+        } catch (IOException e) {
+            throw new ThemeUninstallException("Failed to delete theme files.", e);
+        }
+    }
+
+    private boolean isDeleted(Theme theme) {
+        return theme.getMetadata().getDeletionTimestamp() != null;
+    }
+}

src/main/java/run/halo/app/infra/exception/NotFoundException.java

@@ -1,4 +1,4 @@
-package run.halo.app.infra;
+package run.halo.app.infra.exception;
 
 /**
  * Not found exception.

src/main/java/run/halo/app/infra/exception/ThemeInstallationException.java

@@ -1,4 +1,4 @@
-package run.halo.app.infra;
+package run.halo.app.infra.exception;
 
 /**
  * @author guqing

src/main/java/run/halo/app/infra/exception/ThemeUninstallException.java

@@ -0,0 +1,16 @@
+package run.halo.app.infra.exception;
+
+/**
+ * @author guqing
+ * @since 2.0.0
+ */
+public class ThemeUninstallException extends RuntimeException {
+
+    public ThemeUninstallException(String message) {
+        super(message);
+    }
+
+    public ThemeUninstallException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/run/halo/app/theme/TemplateEngineManager.java

@@ -11,7 +11,7 @@ import org.thymeleaf.dialect.IDialect;
 import org.thymeleaf.spring6.ISpringWebFluxTemplateEngine;
 import org.thymeleaf.templateresolver.FileTemplateResolver;
 import org.thymeleaf.templateresolver.ITemplateResolver;
-import run.halo.app.infra.NotFoundException;
+import run.halo.app.infra.exception.NotFoundException;
 import run.halo.app.theme.engine.SpringWebFluxTemplateEngine;
 import run.halo.app.theme.message.ThemeMessageResolver;
 

src/main/java/run/halo/app/theme/ThemePathPolicy.java

@@ -0,0 +1,28 @@
+package run.halo.app.theme;
+
+import java.nio.file.Path;
+import org.springframework.util.Assert;
+import run.halo.app.core.extension.Theme;
+
+/**
+ * Policy for generating theme directory path.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+public class ThemePathPolicy {
+    public static final String THEME_WORK_DIR = "themes";
+
+    private final Path workDir;
+
+    public ThemePathPolicy(Path workDir) {
+        Assert.notNull(workDir, "The halo workDir must not be null.");
+        this.workDir = workDir;
+    }
+
+    public Path generate(Theme theme) {
+        Assert.notNull(theme, "The theme must not be null.");
+        String name = theme.getMetadata().getName();
+        return workDir.resolve(THEME_WORK_DIR).resolve(name);
+    }
+}

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

@@ -0,0 +1,102 @@
+package run.halo.app.core.extension.reconciler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.time.Instant;
+import java.util.Optional;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.util.FileSystemUtils;
+import org.springframework.util.ResourceUtils;
+import run.halo.app.core.extension.Setting;
+import run.halo.app.core.extension.Theme;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.Metadata;
+import run.halo.app.extension.controller.Reconciler;
+import run.halo.app.infra.properties.HaloProperties;
+import run.halo.app.theme.ThemePathPolicy;
+
+/**
+ * Tests for {@link ThemeReconciler}.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+@ExtendWith(MockitoExtension.class)
+class ThemeReconcilerTest {
+
+    @Mock
+    private ExtensionClient extensionClient;
+
+    @Mock
+    private HaloProperties haloProperties;
+
+    private File defaultTheme;
+
+    private Path tempDirectory;
+
+    @BeforeEach
+    void setUp() throws IOException {
+        tempDirectory = Files.createTempDirectory("halo-theme-");
+        defaultTheme = ResourceUtils.getFile("classpath:themes/default");
+    }
+
+    @AfterEach
+    void tearDown() throws IOException {
+        FileSystemUtils.deleteRecursively(tempDirectory);
+    }
+
+    @Test
+    void reconcileDelete() throws IOException {
+        Path testWorkDir = tempDirectory.resolve("reconcile-delete");
+        Files.createDirectory(testWorkDir);
+        when(haloProperties.getWorkDir()).thenReturn(testWorkDir);
+
+        ThemeReconciler themeReconciler = new ThemeReconciler(extensionClient, haloProperties);
+        ThemePathPolicy themePathPolicy = new ThemePathPolicy(testWorkDir);
+
+        Theme theme = new Theme();
+        Metadata metadata = new Metadata();
+        metadata.setName("theme-test");
+        metadata.setDeletionTimestamp(Instant.now());
+        theme.setMetadata(metadata);
+        theme.setKind(Theme.KIND);
+        theme.setApiVersion("theme.halo.run/v1alpha1");
+        Theme.ThemeSpec themeSpec = new Theme.ThemeSpec();
+        themeSpec.setSettingName("theme-test-setting");
+        theme.setSpec(themeSpec);
+
+        Path defaultThemePath = themePathPolicy.generate(theme);
+
+        // copy to temp directory
+        FileSystemUtils.copyRecursively(defaultTheme.toPath(), defaultThemePath);
+
+        assertThat(testWorkDir).isNotEmptyDirectory();
+        assertThat(defaultThemePath).exists();
+
+        when(extensionClient.fetch(eq(Theme.class), eq(metadata.getName())))
+            .thenReturn(Optional.of(theme));
+        when(extensionClient.fetch(Setting.class, themeSpec.getSettingName()))
+            .thenReturn(Optional.empty());
+
+        themeReconciler.reconcile(new Reconciler.Request(metadata.getName()));
+
+        verify(extensionClient, times(1)).fetch(eq(Theme.class), eq(metadata.getName()));
+        verify(extensionClient, times(1)).fetch(eq(Setting.class), eq(themeSpec.getSettingName()));
+
+        assertThat(Files.exists(testWorkDir)).isTrue();
+        assertThat(Files.exists(defaultThemePath)).isFalse();
+    }
+}