package org.simantics.g3d.scl;

import java.util.HashMap;
import java.util.Map;

import org.cojen.classfile.TypeDesc;
import org.simantics.scl.compiler.environment.specification.EnvironmentSpecification;
import org.simantics.scl.compiler.errors.Failable;
import org.simantics.scl.compiler.internal.codegen.types.JavaTypeTranslator;
import org.simantics.scl.compiler.module.Module;
import org.simantics.scl.compiler.module.repository.ImportFailureException;
import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
import org.simantics.scl.compiler.types.TCon;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.osgi.SCLOsgi;

public class SCLUtil {
	
	static Map<TCon,Class<?>> typeMap = new HashMap<TCon, Class<?>>();
	// copied from org.simantics.scl.db.SCLFunctions
	public static Class<?> possibleFromDynamic(Type expectedType, String moduleName) {
		
		try {

			
			Failable<Module> failable = SCLOsgi.MODULE_REPOSITORY.getModule(moduleName);
			Module module = failable.getResult();
			
			RuntimeEnvironment env = SCLOsgi.MODULE_REPOSITORY.createRuntimeEnvironment(
					EnvironmentSpecification.of(moduleName, ""), module.getParentClassLoader());

			JavaTypeTranslator tr = new JavaTypeTranslator(env.getEnvironment());
			TypeDesc desc = tr.toTypeDesc(expectedType);
			String className = desc.getFullName();
			Class<?> clazz = env.getMutableClassLoader().loadClass(className);
			return clazz;
		} catch (ImportFailureException e) {
			return null;
		} catch (ClassNotFoundException e) {
			return null;
		}
	}
	
	public static Class<?> possibleClass(TCon type) {
		Class<?> clazz = typeMap.get(type);
		if (clazz == null) {
			clazz = possibleFromDynamic(type, type.module);
			typeMap.put(type, clazz);
		}
		return clazz;
	}
	
	public static boolean javaIsInstanceOf(org.simantics.scl.compiler.types.Type t, Object o) {
		if (t instanceof TCon) {
			Class<?> clazz = possibleClass((TCon)t);
			if (clazz == null)
				return false;
			if (!clazz.isAssignableFrom(o.getClass()))
				return false;
	
			return true;
		}
		return false;
	}
	
	public static Object javaSafeCoerce(org.simantics.scl.compiler.types.Type t, Object o) {
		if (t instanceof TCon) {
			Class<?> clazz = possibleClass((TCon)t);
			if (clazz == null)
				return null;
			if (!clazz.isAssignableFrom(o.getClass()))
				return null;
	
			return o;
		}
		return null;
	}

}