refactor: merge patch default values to the existing config for theme and plugin setting (#3616)

#### What type of PR is this?
/kind improvement
/area core
/milestone 2.4.x

#### What this PR does / why we need it:
修复升级主题或插件时新增加的配置默认值没有更新的问题

how to test it?
1. 安装包含设置的主题后获取主题的 ConfigMap 并记下
2. 修改（增加/更新）主题的设置（Setting）的默认值，模拟更新主题
3. 期望默认值改变不会影响到之前已有的配置，对于新增加的配置的默认值会被合并到已有的 ConfigMap 中

#### Which issue(s) this PR fixes:
Fixes #3446

#### Does this PR introduce a user-facing change?
```release-note
修复升级主题或插件时新增加的配置默认值没有更新的问题
```

application/src/main/java/run/halo/app/core/extension/reconciler/PluginReconciler.java

@@ -38,7 +38,6 @@ import run.halo.app.core.extension.Plugin;
 import run.halo.app.core.extension.ReverseProxy;
 import run.halo.app.core.extension.Setting;
 import run.halo.app.core.extension.theme.SettingUtils;
-import run.halo.app.extension.ConfigMap;
 import run.halo.app.extension.ExtensionClient;
 import run.halo.app.extension.GroupVersionKind;
 import run.halo.app.extension.Metadata;
@@ -223,19 +222,7 @@ public class PluginReconciler implements Reconciler<Request> {
             return false;
         }
 
-        boolean existConfigMap = client.fetch(ConfigMap.class, configMapNameToUse)
-            .isPresent();
-        if (existConfigMap) {
-            return false;
-        }
-
-        var data = SettingUtils.settingDefinedDefaultValueMap(settingOption.get());
-        // Create with or without default value
-        ConfigMap configMap = new ConfigMap();
-        configMap.setMetadata(new Metadata());
-        configMap.getMetadata().setName(configMapNameToUse);
-        configMap.setData(data);
-        client.create(configMap);
+        SettingUtils.createOrUpdateConfigMap(client, settingName, configMapNameToUse);
         return false;
     }
 

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

@@ -1,5 +1,7 @@
 package run.halo.app.core.extension.reconciler;
 
+import static org.apache.commons.lang3.ObjectUtils.defaultIfNull;
+
 import java.io.IOException;
 import java.nio.file.Path;
 import java.time.Instant;
@@ -9,7 +11,6 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.UUID;
-import org.apache.commons.lang3.ObjectUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.retry.support.RetryTemplate;
 import org.springframework.stereotype.Component;
@@ -18,9 +19,7 @@ import run.halo.app.core.extension.AnnotationSetting;
 import run.halo.app.core.extension.Setting;
 import run.halo.app.core.extension.Theme;
 import run.halo.app.core.extension.theme.SettingUtils;
-import run.halo.app.extension.ConfigMap;
 import run.halo.app.extension.ExtensionClient;
-import run.halo.app.extension.Metadata;
 import run.halo.app.extension.MetadataUtil;
 import run.halo.app.extension.controller.Controller;
 import run.halo.app.extension.controller.ControllerBuilder;
@@ -87,7 +86,7 @@ public class ThemeReconciler implements Reconciler<Request> {
     void reconcileStatus(String name) {
         client.fetch(Theme.class, name).ifPresent(theme -> {
             final Theme.ThemeStatus status =
-                ObjectUtils.defaultIfNull(theme.getStatus(), new Theme.ThemeStatus());
+                defaultIfNull(theme.getStatus(), new Theme.ThemeStatus());
             final Theme.ThemeStatus oldStatus = JsonUtils.deepCopy(status);
             theme.setStatus(status);
 
@@ -143,23 +142,8 @@ public class ThemeReconciler implements Reconciler<Request> {
 
         final String configMapNameToUse =
             StringUtils.defaultIfBlank(userDefinedConfigMapName, newConfigMapName);
-
-        boolean existConfigMap = client.fetch(ConfigMap.class, configMapNameToUse)
-            .isPresent();
-        if (existConfigMap) {
-            return;
-        }
-
-        client.fetch(Setting.class, theme.getSpec().getSettingName())
-            .ifPresent(setting -> {
-                var data = SettingUtils.settingDefinedDefaultValueMap(setting);
-                // Whether there is a default value or not
-                ConfigMap configMap = new ConfigMap();
-                configMap.setMetadata(new Metadata());
-                configMap.getMetadata().setName(configMapNameToUse);
-                configMap.setData(data);
-                client.create(configMap);
-            });
+        SettingUtils.createOrUpdateConfigMap(client, theme.getSpec().getSettingName(),
+            configMapNameToUse);
     }
 
     private void addFinalizerIfNecessary(Theme oldTheme) {

application/src/main/java/run/halo/app/core/extension/theme/SettingUtils.java

@@ -1,14 +1,27 @@
 package run.halo.app.core.extension.theme;
 
+import static org.apache.commons.lang3.ObjectUtils.defaultIfNull;
+
+import com.fasterxml.jackson.core.JacksonException;
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.github.fge.jsonpatch.JsonPatchException;
+import com.github.fge.jsonpatch.mergepatch.JsonMergePatch;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.stream.Collectors;
 import lombok.experimental.UtilityClass;
 import org.springframework.lang.NonNull;
+import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import run.halo.app.core.extension.Setting;
+import run.halo.app.extension.ConfigMap;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.Metadata;
+import run.halo.app.infra.utils.JsonParseException;
 import run.halo.app.infra.utils.JsonUtils;
 
 @UtilityClass
@@ -45,4 +58,109 @@ public class SettingUtils {
         }
         return data;
     }
+
+    /**
+     * Create or update config map by provided setting name and configMapName.
+     *
+     * @param client extension client
+     * @param settingName a name for {@link Setting}
+     * @param configMapName a name for {@link ConfigMap}
+     */
+    public static void createOrUpdateConfigMap(ExtensionClient client, String settingName,
+        String configMapName) {
+        Assert.notNull(client, "Extension client must not be null");
+        Assert.hasText(settingName, "Setting name must not be blank");
+        Assert.hasText(configMapName, "Config map name must not be blank");
+
+        client.fetch(Setting.class, settingName)
+            .ifPresent(setting -> {
+                final var source = SettingUtils.settingDefinedDefaultValueMap(setting);
+                client.fetch(ConfigMap.class, configMapName)
+                    .ifPresentOrElse(configMap -> {
+                        Map<String, String> modified = defaultIfNull(configMap.getData(), Map.of());
+                        final var oldData = JsonUtils.deepCopy(modified);
+
+                        Map<String, String> merged = SettingUtils.mergePatch(modified, source);
+                        configMap.setData(merged);
+
+                        if (!Objects.equals(oldData, configMap.getData())) {
+                            client.update(configMap);
+                        }
+                    }, () -> {
+                        ConfigMap configMap = new ConfigMap();
+                        configMap.setMetadata(new Metadata());
+                        configMap.getMetadata().setName(configMapName);
+                        configMap.setData(source);
+                        client.create(configMap);
+                    });
+            });
+    }
+
+    /**
+     * Construct a JsonMergePatch from a difference between two Maps and apply patch to
+     * {@code source}.
+     *
+     * @param modified the modified object
+     * @param source the source object
+     * @return patched map object
+     */
+    public static Map<String, String> mergePatch(Map<String, String> modified,
+        Map<String, String> source) {
+        JsonNode modifiedJson = mapToJsonNode(modified);
+        // original
+        JsonNode sourceJson = mapToJsonNode(source);
+        try {
+            // patch
+            JsonMergePatch jsonMergePatch = JsonMergePatch.fromJson(modifiedJson);
+            // apply patch to original
+            JsonNode patchedNode = jsonMergePatch.apply(sourceJson);
+            return jsonNodeToStringMap(patchedNode);
+        } catch (JsonPatchException e) {
+            throw new JsonParseException(e);
+        }
+    }
+
+    JsonNode mapToJsonNode(Map<String, String> map) {
+        ObjectNode objectNode = JsonNodeFactory.instance.objectNode();
+        map.forEach((k, v) -> {
+            if (isJson(v)) {
+                JsonNode value = JsonUtils.jsonToObject(v, JsonNode.class);
+                objectNode.set(k, value);
+                return;
+            }
+            objectNode.put(k, v);
+        });
+        return objectNode;
+    }
+
+    Map<String, String> jsonNodeToStringMap(JsonNode node) {
+        Map<String, String> stringMap = new LinkedHashMap<>();
+        node.fields().forEachRemaining(entry -> {
+            String k = entry.getKey();
+            JsonNode v = entry.getValue();
+            if (v == null || v.isNull() || v.isMissingNode()) {
+                stringMap.put(k, null);
+                return;
+            }
+            if (v.isTextual()) {
+                stringMap.put(k, v.asText());
+                return;
+            }
+            if (v.isContainerNode()) {
+                stringMap.put(k, JsonUtils.objectToJson(v));
+                return;
+            }
+            stringMap.put(k, v.asText());
+        });
+        return stringMap;
+    }
+
+    boolean isJson(String jsonString) {
+        try {
+            JsonUtils.DEFAULT_JSON_MAPPER.readTree(jsonString);
+            return true;
+        } catch (JacksonException e) {
+            return false;
+        }
+    }
 }

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

@@ -25,7 +25,6 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
-import org.mockito.Mockito;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.mockito.stubbing.Answer;
 import org.skyscreamer.jsonassert.JSONAssert;
@@ -271,8 +270,6 @@ class ThemeReconcilerTest {
 
         // setting exists
         themeSpec.setSettingName("theme-test-setting");
-        when(extensionClient.fetch(eq(ConfigMap.class), any()))
-            .thenReturn(Optional.of(Mockito.mock(ConfigMap.class)));
         assertThat(theme.getSpec().getConfigMapName()).isNull();
         ArgumentCaptor<Theme> captor = ArgumentCaptor.forClass(Theme.class);
         themeReconciler.reconcile(new Reconciler.Request(metadata.getName()));
@@ -291,7 +288,7 @@ class ThemeReconcilerTest {
         when(extensionClient.fetch(eq(Setting.class), eq(themeSpec.getSettingName())))
             .thenReturn(Optional.of(getFakeSetting()));
         themeReconciler.reconcile(new Reconciler.Request(metadata.getName()));
-        verify(extensionClient, times(1))
+        verify(extensionClient, times(2))
             .fetch(eq(Setting.class), eq(themeSpec.getSettingName()));
         ArgumentCaptor<ConfigMap> configMapCaptor = ArgumentCaptor.forClass(ConfigMap.class);
         verify(extensionClient, times(1)).create(any(ConfigMap.class));

application/src/test/java/run/halo/app/core/extension/theme/SettingUtilsTest.java

@@ -1,5 +1,8 @@
 package run.halo.app.core.extension.theme;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Map;
 import org.json.JSONException;
 import org.junit.jupiter.api.Test;
 import org.skyscreamer.jsonassert.JSONAssert;
@@ -27,6 +30,73 @@ class SettingUtilsTest {
             true);
     }
 
+    @Test
+    void mergePatch() throws JSONException {
+        Map<String, String> defaultValue =
+            Map.of("comment", "{\"enable\":true,\"requireReviewForNew\":true}",
+                "basic", "{\"title\":\"guqing's blog\"}",
+                "authProvider", "{\"github\":{\"clientId\":\"fake-client-id\"}}");
+        Map<String, String> modified = Map.of("comment",
+            "{\"enable\":true,\"requireReviewForNew\":true,\"systemUserOnly\":false}",
+            "basic", "{\"title\":\"guqing's blog\", \"subtitle\": \"fake-sub-title\"}");
+
+        Map<String, String> result = SettingUtils.mergePatch(modified, defaultValue);
+        Map<String, String> excepted = Map.of("comment",
+            "{\"enable\":true,\"requireReviewForNew\":true,\"systemUserOnly\":false}",
+            "basic", "{\"title\":\"guqing's blog\",\"subtitle\":\"fake-sub-title\"}",
+            "authProvider", "{\"github\":{\"clientId\":\"fake-client-id\"}}");
+        JSONAssert.assertEquals(JsonUtils.objectToJson(excepted), JsonUtils.objectToJson(result),
+            true);
+    }
+
+    @Test
+    void mergePatchWithMoreType() throws JSONException {
+        Map<String, String> defaultValue = Map.of(
+            "array", "[1,2,3]",
+            "number", "1",
+            "boolean", "false",
+            "string", "new-default-string-value",
+            "object", "{\"name\":\"guqing\"}"
+        );
+        Map<String, String> modified = Map.of(
+            "stringArray", "[\"hello\", \"world\"]",
+            "boolean", "true",
+            "string", "hello",
+            "object", "{\"name\":\"guqing\", \"age\": 18}"
+        );
+        Map<String, String> result = SettingUtils.mergePatch(modified, defaultValue);
+        Map<String, String> excepted = Map.of(
+            "array", "[1,2,3]",
+            "number", "1",
+            "boolean", "true",
+            "string", "hello",
+            "object", "{\"name\":\"guqing\",\"age\":18}",
+            "stringArray", "[\"hello\",\"world\"]"
+        );
+        JSONAssert.assertEquals(JsonUtils.objectToJson(excepted), JsonUtils.objectToJson(result),
+            true);
+    }
+
+    @Test
+    void isJson() {
+        assertThat(SettingUtils.isJson("[1,2,3]")).isTrue();
+        assertThat(SettingUtils.isJson("[\"hello\"]")).isTrue();
+        assertThat(SettingUtils.isJson("{\"name\":\"guqing\",\"age\":18}")).isTrue();
+        assertThat(SettingUtils.isJson("{ \"flag\":true }")).isTrue();
+        assertThat(SettingUtils.isJson("""
+            [
+                { "K1": "value-1", "K2":"value1-2" }
+            ]
+            """)).isTrue();
+        assertThat(SettingUtils.isJson("""
+            {
+                "sites": [{ "name":"halo" , "url":"halo.run" }]
+            }
+            """)).isTrue();
+        assertThat(SettingUtils.isJson("{\"name\":\"guqing\"")).isFalse();
+        assertThat(SettingUtils.isJson("hello")).isFalse();
+    }
+
     private static Setting getFakeSetting() {
         String settingJson = """
             {