package org.test4j.datafilling.filler.pojo;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import org.test4j.datafilling.Filler;
import org.test4j.datafilling.common.AttributeInfo;
import org.test4j.datafilling.filler.PoJoFiller;
import org.test4j.datafilling.strategy.DataFactory;
import org.test4j.module.core.utility.MessageHelper;

public class FactoryMethodFiller extends PoJoFiller {

    public FactoryMethodFiller(DataFactory strategy, Map<String, Type> argsTypeMap) {
        super(strategy, argsTypeMap);
    }

    /**
     * If no publicly accessible constructors are available, the best we can do
     * is to find a constructor (e.g. getInstance())<br>
     * A candidate factory method is a method which returns the Class type
     * 
     * @param clazz
     * @param typeArgsMap
     * @param genericTypeArgs
     * @return
     * @throws Exception
     */
    public Object newInstanceUseFactoryMethod(AttributeInfo attrinbute) throws Exception {
        List<Method> factoryMethods = attrinbute.getFactoryMethods();
        for (Method method : factoryMethods) {
            Object[] parameterValues = getMethodParaValues(attrinbute, method);
            try {
                MessageHelper.info("Could create an instance using " + method);
                return method.invoke(attrinbute.getAttrClaz(), parameterValues);
            } catch (Throwable t) {
                MessageHelper.warn("Could not create an instance for constructor: " + method
                        + ". Will try another one...");
            }
        }
        return null;
    }

    private Object[] getMethodParaValues(AttributeInfo attrinbute, Method method) throws Exception {
        Annotation[][] parameterAnnotations = method.getParameterAnnotations();
        Type[] parameterTypes = method.getGenericParameterTypes();
        Object[] parameterValues = new Object[method.getParameterTypes().length];

        int index = 0;
        for (Type paramType : parameterTypes) {
            List<Annotation> annotations = Arrays.asList(parameterAnnotations[index]);
            AttributeInfo paraAttribute = AttributeInfo.exactArgAttributeInfo(paramType, argsTypeMap);
            paraAttribute.setAttrAnnotations(annotations);
            Object paraInstance = new Filler(this.strategy, argsTypeMap).fillingAttribute(paraAttribute);
            parameterValues[index] = paraInstance;
            index++;
        }
        return parameterValues;
    }
}