feat: Add fallback analyzer

build.gradle.kts

@@ -166,7 +166,7 @@ tasks.shadowJar {
 
     doFirst {
         val temp = temporaryDir.resolve("plugin.json")
-        temp.writeText(metadata.toJson())
+        temp.writeText(ModMetadata.toJson(metadata))
         from(temp)
     }
 

src/main/kotlin/com/xpdustry/nohorny/NoHornyConfig.kt

@@ -68,5 +68,7 @@ internal data class NoHornyConfig(
         }
 
         data class ModerateContent(val moderateContentToken: Secret) : Analyzer
+
+        data class Fallback(val primary: Analyzer, val secondary: Analyzer) : Analyzer
     }
 }

src/main/kotlin/com/xpdustry/nohorny/NoHornyPlugin.kt

@@ -32,6 +32,7 @@ import com.sksamuel.hoplite.ConfigException
 import com.sksamuel.hoplite.ConfigLoaderBuilder
 import com.sksamuel.hoplite.addPathSource
 import com.xpdustry.nohorny.analyzer.DebugImageAnalyzer
+import com.xpdustry.nohorny.analyzer.FallbackAnalyzer
 import com.xpdustry.nohorny.analyzer.ImageAnalyzer
 import com.xpdustry.nohorny.analyzer.ModerateContentAnalyzer
 import com.xpdustry.nohorny.analyzer.SightEngineAnalyzer
@@ -128,14 +129,7 @@ public class NoHornyPlugin : Plugin(), NoHornyAPI {
         }
 
         val config = loader.loadConfigOrThrow<NoHornyConfig>()
-        val analyzer =
-            when (config.analyzer) {
-                is NoHornyConfig.Analyzer.None -> ImageAnalyzer.None
-                is NoHornyConfig.Analyzer.Debug -> DebugImageAnalyzer(directory.resolve("debug"))
-                is NoHornyConfig.Analyzer.ModerateContent ->
-                    ModerateContentAnalyzer(config.analyzer, http)
-                is NoHornyConfig.Analyzer.SightEngine -> SightEngineAnalyzer(config.analyzer, http)
-            }
+        val analyzer = createAnalyzer(config.analyzer)
 
         this.config = config
         this.analyzer = analyzer
@@ -146,6 +140,16 @@ public class NoHornyPlugin : Plugin(), NoHornyAPI {
         NoHornyLogger.debug("Set cache to $cache")
     }
 
+    private fun createAnalyzer(config: NoHornyConfig.Analyzer): ImageAnalyzer =
+        when (config) {
+            is NoHornyConfig.Analyzer.None -> ImageAnalyzer.None
+            is NoHornyConfig.Analyzer.Debug -> DebugImageAnalyzer(directory.resolve("debug"))
+            is NoHornyConfig.Analyzer.ModerateContent -> ModerateContentAnalyzer(config, http)
+            is NoHornyConfig.Analyzer.SightEngine -> SightEngineAnalyzer(config, http)
+            is NoHornyConfig.Analyzer.Fallback ->
+                FallbackAnalyzer(createAnalyzer(config.primary), createAnalyzer(config.secondary))
+        }
+
     private object NoHornyThreadFactory : ThreadFactory {
         private val count = AtomicInteger(0)
 

src/main/kotlin/com/xpdustry/nohorny/analyzer/FallbackAnalyzer.kt

@@ -0,0 +1,39 @@
+/*
+ * This file is part of NoHorny. The plugin securing your server against nsfw.
+ *
+ * MIT License
+ *
+ * Copyright (c) 2023 Xpdustry
+ *
+ * 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.
+ */
+package com.xpdustry.nohorny.analyzer
+
+import com.xpdustry.nohorny.NoHornyLogger
+import java.awt.image.BufferedImage
+import java.util.concurrent.CompletableFuture
+
+internal class FallbackAnalyzer(val primary: ImageAnalyzer, val secondary: ImageAnalyzer) :
+    ImageAnalyzer {
+    override fun analyse(image: BufferedImage): CompletableFuture<ImageAnalyzer.Result> =
+        primary.analyse(image).exceptionallyCompose { throwable ->
+            NoHornyLogger.debug("Primary analyzer failed, switching to secondary", throwable)
+            secondary.analyse(image)
+        }
+}