/**

* 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.jooby.ftl;

import static java.util.Objects.requireNonNull;

import java.util.Properties;

import java.util.function.BiConsumer;

import org.jooby.Env;

import org.jooby.Jooby;

import org.jooby.Renderer;

import org.jooby.internal.ftl.Engine;

import org.jooby.internal.ftl.GuavaCacheStorage;

import org.jooby.internal.ftl.XssDirective;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import com.google.common.cache.CacheBuilder;

import com.google.common.cache.CacheBuilderSpec;

import com.google.inject.Binder;

import com.google.inject.multibindings.Multibinder;

import com.typesafe.config.Config;

import com.typesafe.config.ConfigFactory;

import freemarker.cache.ClassTemplateLoader;

import freemarker.cache.NullCacheStorage;

import freemarker.template.Configuration;

import freemarker.template.TemplateException;

/**

* Exposes a {@link Configuration} and a {@link Renderer}.

*

* <h1>usage</h1>

* <p>

* It is pretty straightforward:

* </p>

*

* <pre>

* {

* use(new Ftl());

*

* get("/", req {@literal ->} Results.html("index").put("model", new MyModel());

* }

* </pre>

* <p>

* public/index.html:

* </p>

*

* <pre>

* ${model}

* </pre>

*

* <p>

* Templates are loaded from root of classpath: <code>/</code> and must end with: <code>.html</code>

* file extension.

* </p>

*

* <h1>configuration</h1>

* <p>

* There are two ways of changing a Freemarker configuration:

* </p>

* <h2>application.conf</h2>

* <p>

* Just add a <code>freemarker.*</code> option to your <code>application.conf</code> file:

* </p>

*

* <pre>

* freemarker.default_encoding = UTF-8

* </pre>

*

* <h2>programmatically</h2>

*

* <pre>

* {

* use(new Ftl().doWith((freemarker, config) {@literal ->} {

* freemarker.setDefaultEncoding("UTF-8");

* });

* }

* </pre>

*

* <p>

* Keep in mind this is just an example and you don't need to set the default encoding. Default

* encoding is set to: <code>application.charset</code> which is <code>UTF-8</code> by default.

* </p>

*

* <h1>template loader</h1>

* <p>

* Templates are loaded from the root of classpath and must end with <code>.html</code>. You can

* change the default template location and extensions too:

* </p>

*

* <pre>

* {

* use(new Ftl("/", ".ftl"));

* }

* </pre>

*

* <h1>cache</h1>

* <p>

* Cache is OFF when <code>env=dev</code> (useful for template reloading), otherwise is ON.

* </p>

* <p>

* Cache is backed by Guava and default cache will expire after <code>100</code> entries.

* </p>

* <p>

* If <code>100</code> entries is not enough or you need a more advanced cache setting, just set the

* <code>freemarker.cache</code> option:

* </p>

*

* <pre>

* freemarker.cache = "expireAfterWrite=1h"

* </pre>

*

* <p>

* See {@link CacheBuilderSpec}.

* </p>

*

* <p>

* That's all folks! Enjoy it!!!

* </p>

*

* @author edgar

* @since 0.5.0

*/

public class Ftl implements Jooby.Module {

/** The logging system. */

private final Logger log = LoggerFactory.getLogger(getClass());

private final String prefix;

private final String suffix;

private BiConsumer<Configuration, Config> configurer;

public Ftl(final String prefix, final String suffix) {

this.prefix = requireNonNull(prefix, "Template prefix is required.");

this.suffix = requireNonNull(suffix, "Template suffix is required.");

}

public Ftl(final String prefix) {

this(prefix, ".html");

}

public Ftl() {

this("/");

}

public Ftl doWith(final BiConsumer<Configuration, Config> configurer) {

this.configurer = requireNonNull(configurer, "Configurer is required.");

return this;

}

@Override

public void configure(final Env env, final Config config, final Binder binder)

throws TemplateException {

Configuration freemarker = new Configuration(Configuration.DEFAULT_INCOMPATIBLE_IMPROVEMENTS);

log.debug("Freemarker: {}", Configuration.getVersion());

freemarker.setSettings(properties(config));

freemarker.setTemplateLoader(new ClassTemplateLoader(getClass().getClassLoader(), prefix));

// cache

if ("dev".equals(env.name()) || config.getString("freemarker.cache").isEmpty()) {

// noop cache

freemarker.setCacheStorage(NullCacheStorage.INSTANCE);

} else {

freemarker.setCacheStorage(

new GuavaCacheStorage(

CacheBuilder

.from(config.getString("freemarker.cache"))

.build()));

}

if (configurer != null) {

configurer.accept(freemarker, config);

}

binder.bind(Configuration.class).toInstance(freemarker);

Engine engine = new Engine(freemarker, suffix, new XssDirective(env));

Multibinder.newSetBinder(binder, Renderer.class)

.addBinding().toInstance(engine);

}

@Override

public Config config() {

return ConfigFactory.parseResources(getClass(), "freemarker.conf");

}

private Properties properties(final Config config) {

Properties props = new Properties();

// dump

config.getConfig("freemarker").entrySet().forEach(e -> {

String name = e.getKey();

String value = e.getValue().unwrapped().toString();

log.debug(" freemarker.{} = {}", name, value);

props.setProperty(name, value);

});

// this is a jooby option

props.remove("cache");

return props;

}

}