package org.simantics.scl.compiler.internal.codegen.utils;

import java.lang.reflect.Method;

import org.simantics.scl.runtime.function.FunctionImpl1;
import org.simantics.scl.runtime.function.FunctionImpl2;
import org.simantics.scl.runtime.function.FunctionImpl3;
import org.simantics.scl.runtime.function.FunctionImpl4;
import org.simantics.scl.runtime.function.FunctionImplN;
import org.simantics.scl.runtime.tuple.Tuple0;

public class ValueFromMethod {

    public static Object getValueFromStaticMethod(final Method method) throws ReflectiveOperationException {
        int arity = method.getParameterTypes().length;
        final boolean returnsVoid = method.getReturnType().equals(void.class);
        switch(arity) {
        case 0: {
            Object ret = method.invoke(null);
            return returnsVoid ? Tuple0.INSTANCE : ret;
        }
        case 1:
            return new FunctionImpl1<Object,Object>() {
                @Override
                public Object apply(Object p0) {
                    try {
                        Object ret = method.invoke(null, p0);
                        return returnsVoid ? Tuple0.INSTANCE : ret;
                    } catch (ReflectiveOperationException e) {
                        throw new RuntimeException(e);
                    }
                }
            };
        case 2:
            return new FunctionImpl2<Object,Object,Object>() {
                @Override
                public Object apply(Object p0, Object p1) {
                    try {
                        Object ret = method.invoke(null, p0, p1);
                        return returnsVoid ? Tuple0.INSTANCE : ret;
                    } catch (ReflectiveOperationException e) {
                        throw new RuntimeException(e);
                    }
                }
            };
        case 3:
            return new FunctionImpl3<Object,Object,Object,Object>() {
                @Override
                public Object apply(Object p0, Object p1, Object p2) {
                    try {
                        Object ret = method.invoke(null, p0, p1, p2);
                        return returnsVoid ? Tuple0.INSTANCE : ret;
                    } catch (ReflectiveOperationException e) {
                        throw new RuntimeException(e);
                    }
                }
            };
        case 4:
            return new FunctionImpl4<Object,Object,Object,Object,Object>() {
                @Override
                public Object apply(Object p0, Object p1, Object p2, Object p3) {
                    try {
                        Object ret = method.invoke(null, p0, p1, p2, p3);
                        return returnsVoid ? Tuple0.INSTANCE : ret;
                    } catch (ReflectiveOperationException e) {
                        throw new RuntimeException(e);
                    }
                }
            };
        default:
            return new FunctionImplN(arity) {
                @Override
                public Object doApply(Object... ps) {
                    try {
                        Object ret =  method.invoke(null, ps);
                        return returnsVoid ? Tuple0.INSTANCE : ret;
                    } catch (ReflectiveOperationException e) {
                        throw new RuntimeException(e);
                    }
                }
            };
        }
    }
    
}