/*
 * Copyright 2002-2017 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
 *
 *      https://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.springframework.web.context.support;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.support.StaticApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.lang.Nullable;
import org.springframework.ui.context.Theme;
import org.springframework.ui.context.ThemeSource;
import org.springframework.ui.context.support.UiApplicationContextUtils;
import org.springframework.util.Assert;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.ServletConfigAware;
import org.springframework.web.context.ServletContextAware;

/**
 * Static {@link org.springframework.web.context.WebApplicationContext}
 * implementation for testing. Not intended for use in production applications.
 *
 * <p>Implements the {@link org.springframework.web.context.ConfigurableWebApplicationContext}
 * interface to allow for direct replacement of an {@link XmlWebApplicationContext},
 * despite not actually supporting external configuration files.
 *
 * <p>Interprets resource paths as servlet context resources, i.e. as paths beneath
 * the web application root. Absolute paths, e.g. for files outside the web app root,
 * can be accessed via "file:" URLs, as implemented by
 * {@link org.springframework.core.io.DefaultResourceLoader}.
 *
 * <p>In addition to the special beans detected by
 * {@link org.springframework.context.support.AbstractApplicationContext},
 * this class detects a bean of type {@link org.springframework.ui.context.ThemeSource}
 * in the context, under the special bean name "themeSource".
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see org.springframework.ui.context.ThemeSource
 */
public class StaticWebApplicationContext extends StaticApplicationContext
                implements ConfigurableWebApplicationContext, ThemeSource {

        @Nullable
        private ServletContext servletContext;

        @Nullable
        private ServletConfig servletConfig;

        @Nullable
        private String namespace;

        @Nullable
        private ThemeSource themeSource;


        public StaticWebApplicationContext() {
                setDisplayName("Root WebApplicationContext");
        }


        /**
         * Set the ServletContext that this WebApplicationContext runs in.
         */
        @Override
        public void setServletContext(@Nullable ServletContext servletContext) {
                this.servletContext = servletContext;
        }

        @Override
        @Nullable
        public ServletContext getServletContext() {
                return this.servletContext;
        }

        @Override
        public void setServletConfig(@Nullable ServletConfig servletConfig) {
                this.servletConfig = servletConfig;
                if (servletConfig != null && this.servletContext == null) {
                        this.servletContext = servletConfig.getServletContext();
                }
        }

        @Override
        @Nullable
        public ServletConfig getServletConfig() {
                return this.servletConfig;
        }

        @Override
        public void setNamespace(@Nullable String namespace) {
                this.namespace = namespace;
                if (namespace != null) {
                        setDisplayName("WebApplicationContext for namespace '" + namespace + "'");
                }
        }

        @Override
        @Nullable
        public String getNamespace() {
                return this.namespace;
        }

        /**
         * The {@link StaticWebApplicationContext} class does not support this method.
         * @throws UnsupportedOperationException <b>always</b>
         */
        @Override
        public void setConfigLocation(String configLocation) {
                throw new UnsupportedOperationException("StaticWebApplicationContext does not support config locations");
        }

        /**
         * The {@link StaticWebApplicationContext} class does not support this method.
         * @throws UnsupportedOperationException <b>always</b>
         */
        @Override
        public void setConfigLocations(String... configLocations) {
                throw new UnsupportedOperationException("StaticWebApplicationContext does not support config locations");
        }

        @Override
        public String[] getConfigLocations() {
                return null;
        }


        /**
         * Register request/session scopes, a {@link ServletContextAwareProcessor}, etc.
         */
        @Override
        protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
                beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext, this.servletConfig));
                beanFactory.ignoreDependencyInterface(ServletContextAware.class);
                beanFactory.ignoreDependencyInterface(ServletConfigAware.class);

                WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);
                WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext, this.servletConfig);
        }

        /**
         * This implementation supports file paths beneath the root of the ServletContext.
         * @see ServletContextResource
         */
        @Override
        protected Resource getResourceByPath(String path) {
                Assert.state(this.servletContext != null, "No ServletContext available");
                return new ServletContextResource(this.servletContext, path);
        }

        /**
         * This implementation supports pattern matching in unexpanded WARs too.
         * @see ServletContextResourcePatternResolver
         */
        @Override
        protected ResourcePatternResolver getResourcePatternResolver() {
                return new ServletContextResourcePatternResolver(this);
        }

        /**
         * Create and return a new {@link StandardServletEnvironment}.
         */
        @Override
        protected ConfigurableEnvironment createEnvironment() {
                return new StandardServletEnvironment();
        }

        /**
         * Initialize the theme capability.
         */
        @Override
        protected void onRefresh() {
                this.themeSource = UiApplicationContextUtils.initThemeSource(this);
        }

        @Override
        protected void initPropertySources() {
                WebApplicationContextUtils.initServletPropertySources(getEnvironment().getPropertySources(),
                                this.servletContext, this.servletConfig);
        }

        @Override
        @Nullable
        public Theme getTheme(String themeName) {
                Assert.state(this.themeSource != null, "No ThemeSource available");
                return this.themeSource.getTheme(themeName);
        }

}