/*
 * JBoss, Home of Professional Open Source
 * Copyright 2010 Red Hat Inc. and/or its affiliates and other contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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.jboss.arquillian.config.impl.extension;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.jboss.arquillian.config.descriptor.api.ArquillianDescriptor;
import org.jboss.arquillian.config.spi.ConfigurationPlaceholderResolver;
import org.jboss.arquillian.core.api.Instance;
import org.jboss.arquillian.core.api.InstanceProducer;
import org.jboss.arquillian.core.api.annotation.ApplicationScoped;
import org.jboss.arquillian.core.api.annotation.Inject;
import org.jboss.arquillian.core.api.annotation.Observes;
import org.jboss.arquillian.core.api.event.ManagerStarted;
import org.jboss.arquillian.core.spi.ServiceLoader;
import org.jboss.shrinkwrap.descriptor.api.Descriptors;

import java.io.InputStream;
import java.util.Map;
import java.util.Properties;

/**
 * Configurator
 *
 * @author <a href="mailto:aslak@redhat.com">Aslak Knutsen</a>
 * @version $Revision: $
 */
public class ConfigurationRegistrar {
    public static final String ARQUILLIAN_XML_PROPERTY = "arquillian.xml";
    private static final String ARQUILLIAN_XML_DEFAULT = "arquillian.xml";

    public static final String ARQUILLIAN_PROP_PROPERTY = "arquillian.properties";
    private static final String ARQUILLIAN_PROP_DEFAULT = "arquillian.properties";

    private Map<String, String> systemEnvironmentVars = System.getenv();

    @Inject
    @ApplicationScoped
    private InstanceProducer<ArquillianDescriptor> descriptorInst;

    @Inject
    private Instance<ServiceLoader> serviceLoaderInstance;

    public void loadConfiguration(@Observes ManagerStarted event) {
        //Placeholder resolver
        ArquillianDescriptor resolvedDesc = loadConfiguration();

        final List<ConfigurationPlaceholderResolver> configurationPlaceholderResolvers =
            loadAndOrderPlaceholderResolvers();

        for (ConfigurationPlaceholderResolver configurationPlaceholderResolver : configurationPlaceholderResolvers) {
            resolvedDesc = configurationPlaceholderResolver.resolve(resolvedDesc);
        }

        descriptorInst.set(resolvedDesc);
    }

    public ArquillianDescriptor loadConfiguration() {
        final InputStream input = FileUtils.loadArquillianXml(ARQUILLIAN_XML_PROPERTY, ARQUILLIAN_XML_DEFAULT);

        //First arquillian.xml is resolved
        final ArquillianDescriptor descriptor = resolveDescriptor(input);

        //Second arquillian.properties file and system properties are applied
        final PropertiesParser propertiesParser = new PropertiesParser();
        propertiesParser.addProperties(
            descriptor,
            FileUtils.loadArquillianProperties(ARQUILLIAN_PROP_PROPERTY, ARQUILLIAN_PROP_DEFAULT));

        //Fourth arquillian properties from system environment variables are applied
        Properties envProperties = new Properties();
        envProperties.putAll(systemEnvironmentVars);
        propertiesParser.addProperties(descriptor, envProperties);

        return descriptor;
    }

    private List<ConfigurationPlaceholderResolver> loadAndOrderPlaceholderResolvers() {
        final List<ConfigurationPlaceholderResolver> configurationPlaceholderResolvers =
            new ArrayList<ConfigurationPlaceholderResolver>(serviceLoaderInstance.get().all(ConfigurationPlaceholderResolver.class));

        Collections.sort(configurationPlaceholderResolvers, new Comparator<ConfigurationPlaceholderResolver>() {
            public int compare(ConfigurationPlaceholderResolver firstResolver, ConfigurationPlaceholderResolver secondResolver) {
                Integer a = firstResolver.precedence();
                Integer b = secondResolver.precedence();
                return b.compareTo(a);
            }
        });
        return configurationPlaceholderResolvers;
    }

    private ArquillianDescriptor resolveDescriptor(final InputStream input) {
        final ArquillianDescriptor descriptor;

        if (input != null) {
            descriptor = Descriptors.importAs(ArquillianDescriptor.class)
                .fromStream(input);
        } else {
            descriptor = Descriptors.create(ArquillianDescriptor.class);
        }
        return descriptor;
    }

    //testing purposes
    void setEnvironmentVariables(Map<String, String> variables) {
        this.systemEnvironmentVars = variables;
    }
}
