/*
 * 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.apache.flink.runtime.clusterframework;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.core.fs.Path;

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

import static org.apache.flink.util.Preconditions.checkArgument;

/**
 * Encapsulates a container specification, including artifacts, environment variables,
 * system properties, and Flink configuration settings.
 *
 * The specification is mutable.
 *
 * Note that the Flink configuration settings are considered dynamic overrides of whatever
 * static configuration file is present in the container.  For example, a container might be
 * based on a Docker image with a normal Flink installation with customized settings, which these
 * settings would (partially) override.
 *
 * Artifacts are copied into a sandbox directory within the container, which any Flink process
 * launched in the container is assumed to use as a working directory.  This assumption allows
 * for relative paths to be used in certain environment variables.
 */
public class ContainerSpecification implements java.io.Serializable {

	private static final long serialVersionUID = 1L;

	private final Configuration systemProperties;

	private final List<Artifact> artifacts;

	private final Map<String,String> environmentVariables;

	private final Configuration dynamicConfiguration;

	public ContainerSpecification() {
		this.artifacts = new LinkedList<>();
		this.environmentVariables = new HashMap<String,String>();
		this.systemProperties = new Configuration();
		this.dynamicConfiguration = new Configuration();
	}

	/**
	 * Get the container artifacts.
     */
	public List<Artifact> getArtifacts() {
		return artifacts;
	}

	/**
	 * Get the environment variables.
     */
	public Map<String, String> getEnvironmentVariables() {
		return environmentVariables;
	}

	/**
	 * Get the dynamic configuration.
     */
	public Configuration getDynamicConfiguration() {
		return dynamicConfiguration;
	}

	/**
	 * Get the system properties.
     */
	public Configuration getSystemProperties() {
		return systemProperties;
	}

	@Override
	protected Object clone() throws CloneNotSupportedException {
		ContainerSpecification clone = new ContainerSpecification();
		clone.artifacts.addAll(this.artifacts);
		clone.environmentVariables.putAll(this.environmentVariables);
		clone.systemProperties.addAll(this.systemProperties);
		clone.dynamicConfiguration.addAll(this.dynamicConfiguration);
		return clone;
	}

	@Override
	public String toString() {
		return "ContainerSpecification{" +
			"environmentVariables=" + environmentVariables +
			", systemProperties=" + systemProperties +
			", dynamicConfiguration=" + dynamicConfiguration +
			", artifacts=" + artifacts +
			'}';
	}

	/**
	 * An artifact to be copied into the container.
	 */
	public static class Artifact {

		public Artifact(Path source, Path dest, boolean executable, boolean cachable, boolean extract) {
			checkArgument(source.isAbsolute(), "source must be absolute");
			checkArgument(!dest.isAbsolute(), "destination must be relative");
			this.source = source;
			this.dest = dest;
			this.executable = executable;
			this.cachable = cachable;
			this.extract = extract;
		}

		public final Path source;
		public final Path dest;
		public final boolean executable;
		public final boolean cachable;
		public final boolean extract;

		@Override
		public String toString() {
			return "Artifact{" +
				"source=" + source +
				", dest=" + dest +
				", executable=" + executable +
				", cachable=" + cachable +
				", extract=" + extract +
				'}';
		}

		public static Builder newBuilder() { return new Builder(); }

		public static class Builder {

			public Path source;
			public Path dest;
			public boolean executable = false;
			public boolean cachable = true;
			public boolean extract = false;

			public Builder setSource(Path source) {
				this.source = source;
				return this;
			}

			public Builder setDest(Path dest) {
				this.dest = dest;
				return this;
			}

			public Builder setCachable(boolean cachable) {
				this.cachable = cachable;
				return this;
			}

			public Builder setExtract(boolean extract) {
				this.extract = extract;
				return this;
			}

			public Builder setExecutable(boolean executable) {
				this.executable = executable;
				return this;
			}

			public Artifact build() {
				return new Artifact(source, dest, executable, cachable, extract);
			}
		}
	}

	/**
	 * Format the system properties as a shell-compatible command-line argument.
     */
	public static String formatSystemProperties(Configuration jvmArgs) {
		StringBuilder sb = new StringBuilder();
		for(Map.Entry<String,String> entry : jvmArgs.toMap().entrySet()) {
			if(sb.length() > 0) {
				sb.append(" ");
			}
			boolean quoted = entry.getValue().contains(" ");
			if(quoted) {
				sb.append("\"");
			}
			sb.append("-D").append(entry.getKey()).append('=').append(entry.getValue());
			if(quoted) {
				sb.append("\"");
			}
		}
		return sb.toString();
	}
}