/*
 * Copyright 2008 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 java.util.ArrayList;
import java.util.List;

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

/**
 * 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; 
	}
	
}