/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.brooklyn.core.effector;

import java.util.Collections;
import java.util.Map;

import org.apache.brooklyn.api.effector.Effector;
import org.apache.brooklyn.api.effector.ParameterType;
import org.apache.brooklyn.api.entity.EntityInitializer;
import org.apache.brooklyn.api.entity.EntityLocal;
import org.apache.brooklyn.config.ConfigKey;
import org.apache.brooklyn.core.config.ConfigKeys;
import org.apache.brooklyn.core.config.MapConfigKey;
import org.apache.brooklyn.core.effector.Effectors.EffectorBuilder;
import org.apache.brooklyn.core.entity.EntityInternal;
import org.apache.brooklyn.util.core.config.ConfigBag;
import org.apache.brooklyn.util.text.Strings;

import com.google.common.annotations.Beta;
import com.google.common.base.Preconditions;

/** 
 * Entity initializer which adds an effector to an entity.
 * <p>
 * This instance provides a {@link #newEffectorBuilder(Class, ConfigBag)} 
 * which returns an abstract (body-less) effector defining:
 * <li> the name from {@link #EFFECTOR_NAME};
 * <li> the description from {@link #EFFECTOR_DESCRIPTION}
 * <li> the parameters from {@link #EFFECTOR_PARAMETER_DEFS}
 * <p>
 * Callers should pass the effector to instantiate into the constructor.
 * Often subclasses will supply a constructor which takes a ConfigBag of parameters,
 * and a custom {@link #newEffectorBuilder(Class, ConfigBag)} which adds the body
 * before passing to this class.
 * <p>
 * Note that the parameters passed to the call method in the body of the effector implementation
 * are only those supplied by a user at runtime; in order to merge with default
 * values, use {@link #getMergedParams(Effector, ConfigBag)}.
 *  
 * @since 0.7.0 */
@Beta
public class AddEffector implements EntityInitializer {
    
    public static final ConfigKey<String> EFFECTOR_NAME = ConfigKeys.newStringConfigKey("name");
    public static final ConfigKey<String> EFFECTOR_DESCRIPTION = ConfigKeys.newStringConfigKey("description");
    
    public static final ConfigKey<Map<String,Object>> EFFECTOR_PARAMETER_DEFS = new MapConfigKey<Object>(Object.class, "parameters");

    final Effector<?> effector;
    
    public AddEffector(Effector<?> effector) {
        this.effector = Preconditions.checkNotNull(effector, "effector");
    }
    
    @Override
    public void apply(EntityLocal entity) {
        ((EntityInternal)entity).getMutableEntityType().addEffector(effector);
    }
    
    public static <T> EffectorBuilder<T> newEffectorBuilder(Class<T> type, ConfigBag params) {
        String name = Preconditions.checkNotNull(params.get(EFFECTOR_NAME), "name must be supplied when defining an effector: %s", params);
        EffectorBuilder<T> eff = Effectors.effector(type, name);
        eff.description(params.get(EFFECTOR_DESCRIPTION));
        
        Map<String, Object> paramDefs = params.get(EFFECTOR_PARAMETER_DEFS);
        if (paramDefs!=null) {
            for (Map.Entry<String, Object> paramDef: paramDefs.entrySet()){
                if (paramDef!=null) {
                    String paramName = paramDef.getKey();
                    Object value = paramDef.getValue();
                    if (value==null) value = Collections.emptyMap();
                    if (!(value instanceof Map)) {
                        if (value instanceof CharSequence && Strings.isBlank((CharSequence) value)) 
                            value = Collections.emptyMap();
                    }
                    if (!(value instanceof Map))
                        throw new IllegalArgumentException("Illegal argument of type "+value.getClass()+" value '"+value+"' supplied as parameter definition "
                            + "'"+paramName);
                    eff.parameter(ConfigKeys.DynamicKeys.newNamedInstance(paramName, (Map<?, ?>) value));
                }
            }
        }
        
        return eff;
    }

    /** returns a ConfigBag containing the merger of the supplied parameters with default values on the effector-defined parameters */
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static ConfigBag getMergedParams(Effector<?> eff, ConfigBag params) {
        ConfigBag result = ConfigBag.newInstanceCopying(params);
        for (ParameterType<?> param: eff.getParameters()) {
            ConfigKey key = Effectors.asConfigKey(param);
            if (!result.containsKey(key))
                result.configure(key, params.get(key));
        }
        return result;
    }

}