/*
 * 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.constretto.spring.internal.resolver;

import org.constretto.spring.resolver.AssemblyContextResolver;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

/**
 * Provides the default assembly environment resolving strategy which is used if no other implementation found in the
 * current sprint context.
 * <p/>
 * <p/>
 * It looks for a system property called CONSTRETTO_ENV, and if that is not found tries to find the variable in the system
 * environment.
 * <p/>
 * <p/>
 * If no system property or system environment variable found, it will for the xml support fall back to the default bean, and
 * When autowiring remove all constretto tagged beans as autowire candidates.
 *
 * @author <a href="mailto:kaare.nilsen@gmail.com">Kaare Nilsen</a>
 */
public class DefaultAssemblyContextResolver implements AssemblyContextResolver {
    public static final String ASSEMBLY_KEY = "CONSTRETTO_ENV";

    public List<String> getAssemblyContext() {
        String tags = getFromSystemPropertyOrSystemEnv();
        if (tags != null) {
            return new ArrayList<String>() {
                {
                    addAll(Arrays.asList(getFromSystemPropertyOrSystemEnv().split(",")));
                }
            };
        } else {
            return Collections.emptyList();
        }
    }

    private String getFromSystemPropertyOrSystemEnv() {
        String assemblyEnvironment = System.getProperty(ASSEMBLY_KEY);
        if (assemblyEnvironment == null) {
            assemblyEnvironment = System.getenv(ASSEMBLY_KEY);
        }
        return assemblyEnvironment;
    }

    @Override
    public String toString() {
        return new StringBuilder(getClass().getName())
                .append("[assemblyContext=")
                .append(getAssemblyContext())
                .append(']')
                .toString();
    }
}