/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 
package org.wamblee.system.adapters;

import org.wamblee.system.core.DefaultRequiredInterface;
import org.wamblee.system.core.RequiredInterface;
import org.wamblee.system.core.Scope;

import java.util.ArrayList;
import java.util.List;

/**
 * Represents parameter values for a method or constructor and allows for the
 * configuration of how these values are retrieved.
 * 
 * @author Erik Brakkee
 */
public class ParameterValues {
    private String[] names;

    private Class[] types;

    private ValueProvider[] values;

    /**
     * Constructs the configuration. By default no constructor is selected and
     * one of {@link #select(Class...)} or {@link #greedy()} must be called.
     * 
     * @param aClass
     *            Class to construct.
     */
    public ParameterValues(Class[] aTypes) {
        names = new String[aTypes.length];

        for (int i = 0; i < aTypes.length; i++) {
            names[i] = "arg" + i;
        }

        types = aTypes;
        resetValues();
    }

    /**
     * Constructs the configuration. By default no constructor is selected and
     * one of {@link #select(Class...)} or {@link #greedy()} must be called.
     * 
     * @param aNames
     *            Names of the arguments.
     * @param aClass
     *            Class to construct.
     */
    public ParameterValues(String[] aNames, Class[] aTypes) {
        assert aNames.length == aTypes.length;
        names = aNames;
        types = aTypes;
        resetValues();
    }

    /**
     * The types of the parameter values.
     * 
     * @return Types.
     */
    public Class[] getTypes() {
        return types;
    }

    /**
     * Sets argument i to be optional, meaning that null is allowed to be passed
     * in.
     * 
     * @param aArg
     *            Argument to set.
     * 
     */
    public ParameterValues setOptional(int aArg) {
        values[aArg] = new RequiredInterfaceProvider(
            new DefaultRequiredInterface("arg" + aArg, types[aArg], true));

        return this;
    }

    /**
     * Sets the argument i to a fixed value.
     * 
     * @param aArg
     *            Argument to set.
     * @param aValue
     *            Value.
     * 
     */
    public ParameterValues setValue(int aArg, Object aValue) {
        values[aArg] = new FixedValueProvider(aValue);

        return this;
    }

    /**
     * Resets the values.
     */
    private void resetValues() {
        values = new ValueProvider[types.length];

        for (int i = 0; i < values.length; i++) {
            values[i] = new RequiredInterfaceProvider(
                new DefaultRequiredInterface(names[i], types[i]));
        }
    }

    /**
     * Gets the required interfaces to provide values that are not provided in
     * another way.
     * 
     * @return Required interfaces.
     */
    public List<RequiredInterface> getRequiredInterfaces() {
        List<RequiredInterface> result = new ArrayList<RequiredInterface>();

        for (ValueProvider provider : values) {
            if (provider instanceof RequiredInterfaceProvider) {
                result.add(((RequiredInterfaceProvider) provider)
                    .getRequiredInterface());
            }
        }

        return result;
    }

    /**
     * Returns the values to use in the given scope.
     * 
     * @param aScope
     *            Scope within which to retrieve the values.
     * 
     * @return Values.
     */
    public Object[] values(Scope aScope) {
        Object[] valueArray = new Object[values.length];

        for (int i = 0; i < values.length; i++) {
            valueArray[i] = values[i].getValue(aScope);
        }

        return valueArray;
    }
}