MetaList processing

common/implementation/src/main/java/com/dfsek/terra/config/preprocessor/MetaValuePreprocessor.java

@@ -9,6 +9,9 @@ import com.dfsek.terra.api.config.meta.Meta;
 import org.jetbrains.annotations.NotNull;
 
 import java.lang.reflect.AnnotatedType;
+import java.lang.reflect.ParameterizedType;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 public class MetaValuePreprocessor implements ValuePreprocessor<Meta> {
@@ -21,24 +24,64 @@ public class MetaValuePreprocessor implements ValuePreprocessor<Meta> {
     @SuppressWarnings("unchecked")
     @Override
     public @NotNull <T> Result<T> process(AnnotatedType t, T c, ConfigLoader configLoader, Meta annotation) {
-        if(c instanceof String) {
+        if(c instanceof String) { // Can we do standard metaconfig?
             String value = ((String) c).trim();
             if(value.startsWith("$")) { // it's a meta value.
-                String raw = value.substring(1);
+                return (Result<T>) Result.overwrite(getMetaValue(value.substring(1)));
-                int sep = raw.indexOf(':');
-                String file = raw.substring(0, sep);
-                String key = raw.substring(sep + 1);
-
-                if(!configs.containsKey(file)) throw new LoadException("Cannot fetch metavalue: No such config: " + file);
-
-                Configuration config = configs.get(file);
-
-                if(!config.contains(key))
-                    throw new LoadException("Cannot fetch metavalue: No such key " + key + " in configuration " + config.getName());
-
-                return (Result<T>) Result.overwrite(config.get(key));
             }
         }
+
+        if(t.getType() instanceof ParameterizedType) {
+            ParameterizedType parameterizedType = (ParameterizedType) t.getType();
+            if(parameterizedType.getRawType() instanceof Class) { // Should always be true but we check anyways
+                Class<?> baseClass = (Class<?>) parameterizedType.getRawType();
+
+                if(List.class.isAssignableFrom(baseClass) && c instanceof List) { // List metaconfig
+                    List<Object> list = (List<Object>) c;
+
+                    int offset = 0;
+                    List<Object> newList = new ArrayList<>((List<Object>) c);
+
+                    for(int i = 0; i < list.size(); i++) {
+                        Object o = list.get(i);
+                        if(!(o instanceof String)) continue;
+                        String s = ((String) o).trim();
+                        if(!s.startsWith("<< ")) continue;
+                        String meta = s.substring(3);
+
+                        Object metaValue = getMetaValue(meta);
+
+                        if(!(metaValue instanceof List)) {
+                            throw new LoadException("MetaList injection candidate must be list, is type " + metaValue.getClass().getCanonicalName());
+                        }
+
+                        List<Object> metaList = (List<Object>) metaValue;
+
+                        newList.addAll(i + offset, metaList);
+                        offset += metaList.size();
+                    }
+
+                    return (Result<T>) Result.overwrite(newList);
+                }
+            }
+        }
+
         return Result.noOp();
     }
+
+    private Object getMetaValue(String meta) {
+        int sep = meta.indexOf(':');
+        String file = meta.substring(0, sep);
+        String key = meta.substring(sep + 1);
+
+        if(!configs.containsKey(file)) throw new LoadException("Cannot fetch metavalue: No such config: " + file);
+
+        Configuration config = configs.get(file);
+
+        if(!config.contains(key)) {
+            throw new LoadException("Cannot fetch metavalue: No such key " + key + " in configuration " + config.getName());
+        }
+
+        return config.get(key);
+    }
 }