/*
 * Copyright Terracotta, Inc.
 *
 * 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.ehcache.config.builders;

import org.ehcache.config.Builder;
import org.ehcache.config.CacheConfiguration;
import org.ehcache.config.Configuration;
import org.ehcache.core.config.DefaultConfiguration;
import org.ehcache.spi.service.ServiceCreationConfiguration;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static java.util.Collections.emptyList;
import static java.util.Collections.emptyMap;
import static java.util.Collections.unmodifiableList;
import static java.util.Collections.unmodifiableMap;

/**
 * Companion type to the {@link CacheManagerBuilder} that handles the {@link Configuration} building.
 *
 * @author Alex Snaps
 */
class ConfigurationBuilder implements Builder<Configuration> {

  private final Map<String, CacheConfiguration<?, ?>> caches;
  private final List<ServiceCreationConfiguration<?>> serviceConfigurations;
  private final ClassLoader classLoader;

  static ConfigurationBuilder newConfigurationBuilder() {
    return new ConfigurationBuilder();
  }

  private ConfigurationBuilder() {
    this.caches = emptyMap();
    this.serviceConfigurations = emptyList();
    this.classLoader = null;
  }

  private ConfigurationBuilder(ConfigurationBuilder builder, Map<String, CacheConfiguration<?, ?>> caches) {
    this.caches = unmodifiableMap(caches);
    this.serviceConfigurations = builder.serviceConfigurations;
    this.classLoader = builder.classLoader;
  }

  private ConfigurationBuilder(ConfigurationBuilder builder, List<ServiceCreationConfiguration<?>> serviceConfigurations) {
    this.caches = builder.caches;
    this.serviceConfigurations = unmodifiableList(serviceConfigurations);
    this.classLoader = builder.classLoader;
  }

  private ConfigurationBuilder(ConfigurationBuilder builder, ClassLoader classLoader) {
    this.caches = builder.caches;
    this.serviceConfigurations = builder.serviceConfigurations;
    this.classLoader = classLoader;
  }

  @Override
  public Configuration build() {
    return new DefaultConfiguration(caches, classLoader, serviceConfigurations.toArray(new ServiceCreationConfiguration<?>[serviceConfigurations.size()]));
  }

  ConfigurationBuilder addCache(String alias, CacheConfiguration<?, ?> config) {
    Map<String, CacheConfiguration<?, ?>> newCaches = new HashMap<String, CacheConfiguration<?, ?>>(caches);
    newCaches.put(alias, config);
    return new ConfigurationBuilder(this, newCaches);
  }

  public ConfigurationBuilder removeCache(String alias) {
    Map<String, CacheConfiguration<?, ?>> newCaches = new HashMap<String, CacheConfiguration<?, ?>>(caches);
    newCaches.remove(alias);
    return new ConfigurationBuilder(this, newCaches);
  }

  ConfigurationBuilder addService(ServiceCreationConfiguration<?> serviceConfiguration) {
    if (findServiceByClass(serviceConfiguration.getClass()) != null) {
      throw new IllegalArgumentException("There is already a ServiceCreationConfiguration registered for service " + serviceConfiguration
          .getServiceType() + " of type " + serviceConfiguration.getClass());
    }
    List<ServiceCreationConfiguration<?>> newServiceConfigurations = new ArrayList<ServiceCreationConfiguration<?>>(serviceConfigurations);
    newServiceConfigurations.add(serviceConfiguration);
    return new ConfigurationBuilder(this, newServiceConfigurations);
  }

  <T> T findServiceByClass(Class<T> type) {
    for (ServiceCreationConfiguration<?> serviceConfiguration : serviceConfigurations) {
      if (serviceConfiguration.getClass().equals(type)) {
        return type.cast(serviceConfiguration);
      }
    }
    return null;
  }

  ConfigurationBuilder removeService(ServiceCreationConfiguration<?> serviceConfiguration) {
    List<ServiceCreationConfiguration<?>> newServiceConfigurations = new ArrayList<ServiceCreationConfiguration<?>>(serviceConfigurations);
    newServiceConfigurations.remove(serviceConfiguration);
    return new ConfigurationBuilder(this, newServiceConfigurations);
  }

  ConfigurationBuilder withClassLoader(ClassLoader classLoader) {
    return new ConfigurationBuilder(this, classLoader);
  }
}