/**
 * 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.falcon.workflow;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.Option;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.lang.StringUtils;
import org.apache.falcon.FalconException;
import org.apache.falcon.entity.v0.SchemaHelper;
import org.apache.falcon.hadoop.HadoopClientFactory;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsAction;
import org.apache.hadoop.fs.permission.FsPermission;
import org.json.simple.JSONValue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Captures the workflow execution context.
 */
public class WorkflowExecutionContext {

    private static final Logger LOG = LoggerFactory.getLogger(WorkflowExecutionContext.class);

    public static final String INSTANCE_FORMAT = "yyyy-MM-dd-HH-mm"; // nominal time

    public static final String OUTPUT_FEED_SEPARATOR = ",";
    public static final String INPUT_FEED_SEPARATOR = "#";


    /**
     * Workflow execution status.
     */
    public enum Status {SUCCEEDED, FAILED}

    /**
     * Workflow execution type.
     */
    public enum Type {PRE_PROCESSING, POST_PROCESSING}

    /**
     * Entity operations supported.
     */
    public enum EntityOperations {
        GENERATE, DELETE, ARCHIVE, REPLICATE, CHMOD
    }

    public static final WorkflowExecutionArgs[] USER_MESSAGE_ARGS = {
        WorkflowExecutionArgs.CLUSTER_NAME,
        WorkflowExecutionArgs.ENTITY_NAME,
        WorkflowExecutionArgs.ENTITY_TYPE,
        WorkflowExecutionArgs.NOMINAL_TIME,
        WorkflowExecutionArgs.OPERATION,

        WorkflowExecutionArgs.FEED_NAMES,
        WorkflowExecutionArgs.FEED_INSTANCE_PATHS,

        WorkflowExecutionArgs.WORKFLOW_ID,
        WorkflowExecutionArgs.WORKFLOW_USER,
        WorkflowExecutionArgs.RUN_ID,
        WorkflowExecutionArgs.STATUS,
        WorkflowExecutionArgs.TIMESTAMP,
        WorkflowExecutionArgs.LOG_FILE,
    };

    private final Map<WorkflowExecutionArgs, String> context;
    private final long creationTime;

    protected WorkflowExecutionContext(Map<WorkflowExecutionArgs, String> context) {
        this.context = context;
        creationTime = System.currentTimeMillis();
    }

    public String getValue(WorkflowExecutionArgs arg) {
        return context.get(arg);
    }

    public String getValue(WorkflowExecutionArgs arg, String defaultValue) {
        return context.containsKey(arg) ? context.get(arg) : defaultValue;
    }

    public boolean containsKey(WorkflowExecutionArgs arg) {
        return context.containsKey(arg);
    }

    public Set<Map.Entry<WorkflowExecutionArgs, String>> entrySet() {
        return context.entrySet();
    }

    // helper methods
    public boolean hasWorkflowSucceeded() {
        return Status.SUCCEEDED.name().equals(getValue(WorkflowExecutionArgs.STATUS));
    }

    public boolean hasWorkflowFailed() {
        return Status.FAILED.name().equals(getValue(WorkflowExecutionArgs.STATUS));
    }

    public String getContextFile() {
        return getValue(WorkflowExecutionArgs.CONTEXT_FILE);
    }

    public String getLogDir() {
        return getValue(WorkflowExecutionArgs.LOG_DIR);
    }

    public String getLogFile() {
        return getValue(WorkflowExecutionArgs.LOG_FILE);
    }

    String getNominalTime() {
        return getValue(WorkflowExecutionArgs.NOMINAL_TIME);
    }

    /**
     * Returns nominal time as a ISO8601 formatted string.
     * @return a ISO8601 formatted string
     */
    public String getNominalTimeAsISO8601() {
        return SchemaHelper.formatDateUTCToISO8601(getNominalTime(), INSTANCE_FORMAT);
    }

    String getTimestamp() {
        return getValue(WorkflowExecutionArgs.TIMESTAMP);
    }

    /**
     * Returns timestamp as a ISO8601 formatted string.
     * @return a ISO8601 formatted string
     */
    public String getTimeStampAsISO8601() {
        return SchemaHelper.formatDateUTCToISO8601(getTimestamp(), INSTANCE_FORMAT);
    }

    public String getClusterName() {
        return getValue(WorkflowExecutionArgs.CLUSTER_NAME);
    }

    public String getEntityName() {
        return getValue(WorkflowExecutionArgs.ENTITY_NAME);
    }

    public String getEntityType() {
        return getValue(WorkflowExecutionArgs.ENTITY_TYPE);
    }

    public EntityOperations getOperation() {
        return EntityOperations.valueOf(getValue(WorkflowExecutionArgs.OPERATION));
    }

    public String getOutputFeedNames() {
        return getValue(WorkflowExecutionArgs.FEED_NAMES);
    }

    public String[] getOutputFeedNamesList() {
        return getOutputFeedNames().split(OUTPUT_FEED_SEPARATOR);
    }

    public String getOutputFeedInstancePaths() {
        return getValue(WorkflowExecutionArgs.FEED_INSTANCE_PATHS);
    }

    public String[] getOutputFeedInstancePathsList() {
        return getOutputFeedInstancePaths().split(OUTPUT_FEED_SEPARATOR);
    }

    public String getInputFeedNames() {
        return getValue(WorkflowExecutionArgs.INPUT_FEED_NAMES);
    }

    public String[] getInputFeedNamesList() {
        return getInputFeedNames().split(INPUT_FEED_SEPARATOR);
    }

    public String getInputFeedInstancePaths() {
        return getValue(WorkflowExecutionArgs.INPUT_FEED_PATHS);
    }

    public String[] getInputFeedInstancePathsList() {
        return getInputFeedInstancePaths().split(INPUT_FEED_SEPARATOR);
    }

    public String getWorkflowEngineUrl() {
        return getValue(WorkflowExecutionArgs.WF_ENGINE_URL);
    }

    public String getUserWorkflowEngine() {
        return getValue(WorkflowExecutionArgs.USER_WORKFLOW_ENGINE);
    }

    public String getUserWorkflowVersion() {
        return getValue(WorkflowExecutionArgs.USER_WORKFLOW_VERSION);
    }

    public String getWorkflowId() {
        return getValue(WorkflowExecutionArgs.WORKFLOW_ID);
    }

    public String getUserSubflowId() {
        return getValue(WorkflowExecutionArgs.USER_SUBFLOW_ID);
    }

    public int getWorkflowRunId() {
        return Integer.parseInt(getValue(WorkflowExecutionArgs.RUN_ID));
    }

    public String getWorkflowRunIdString() {
        return String.valueOf(Integer.parseInt(getValue(WorkflowExecutionArgs.RUN_ID)));
    }

    public String getWorkflowUser() {
        return getValue(WorkflowExecutionArgs.WORKFLOW_USER);
    }

    public long getExecutionCompletionTime() {
        return creationTime;
    }

    /**
     * this method is invoked from with in the workflow.
     *
     * @throws java.io.IOException
     * @throws org.apache.falcon.FalconException
     */
    public void serialize() throws IOException, FalconException {
        serialize(getContextFile());
    }

    /**
     * this method is invoked from with in the workflow.
     *
     * @param contextFile file to serialize the workflow execution metadata
     * @throws org.apache.falcon.FalconException
     */
    public void serialize(String contextFile) throws FalconException {
        LOG.info("Saving context to: [{}]", contextFile);
        OutputStream out = null;
        Path file = new Path(contextFile);
        try {
            FileSystem fs = HadoopClientFactory.get().createFileSystem(file.toUri());
            out = fs.create(file);

            // making sure falcon can read this file
            FsPermission permission = new FsPermission(FsAction.ALL, FsAction.ALL, FsAction.ALL);
            fs.setPermission(file, permission);

            out.write(JSONValue.toJSONString(context).getBytes());
        } catch (IOException e) {
            throw new FalconException("Error serializing context to: " + contextFile,  e);
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException ignore) {
                    // ignore
                }
            }
        }
    }

    @SuppressWarnings("unchecked")
    public static WorkflowExecutionContext deSerialize(String contextFile) throws FalconException {
        try {
            Path lineageDataPath = new Path(contextFile); // file has 777 permissions
            FileSystem fs = HadoopClientFactory.get().createFileSystem(lineageDataPath.toUri());

            BufferedReader in = new BufferedReader(new InputStreamReader(fs.open(lineageDataPath)));
            return new WorkflowExecutionContext((Map<WorkflowExecutionArgs, String>) JSONValue.parse(in));
        } catch (IOException e) {
            throw new FalconException("Error opening context file: " + contextFile, e);
        }
    }

    public static String getFilePath(String logDir, String entityName) {
        // LOG_DIR is sufficiently unique
        return new Path(logDir, entityName + "-wf-post-exec-context.json").toString();
    }

    public static WorkflowExecutionContext create(String[] args, Type type) throws FalconException {
        Map<WorkflowExecutionArgs, String> wfProperties = new HashMap<WorkflowExecutionArgs, String>();

        try {
            CommandLine cmd = getCommand(args);
            for (WorkflowExecutionArgs arg : WorkflowExecutionArgs.values()) {
                String optionValue = arg.getOptionValue(cmd);
                if (StringUtils.isNotEmpty(optionValue)) {
                    wfProperties.put(arg, optionValue);
                }
            }
        } catch (ParseException e) {
            throw new FalconException("Error parsing wf args", e);
        }

        wfProperties.put(WorkflowExecutionArgs.CONTEXT_TYPE, type.name());
        wfProperties.put(WorkflowExecutionArgs.CONTEXT_FILE,
                getFilePath(wfProperties.get(WorkflowExecutionArgs.LOG_DIR),
                        wfProperties.get(WorkflowExecutionArgs.ENTITY_NAME)));

        return new WorkflowExecutionContext(wfProperties);
    }

    private static CommandLine getCommand(String[] arguments) throws ParseException {
        Options options = new Options();

        for (WorkflowExecutionArgs arg : WorkflowExecutionArgs.values()) {
            addOption(options, arg, arg.isRequired());
        }

        return new GnuParser().parse(options, arguments, false);
    }

    private static void addOption(Options options, WorkflowExecutionArgs arg, boolean isRequired) {
        Option option = arg.getOption();
        option.setRequired(isRequired);
        options.addOption(option);
    }

    public static WorkflowExecutionContext create(Map<WorkflowExecutionArgs, String> wfProperties) {
        wfProperties.put(WorkflowExecutionArgs.CONTEXT_TYPE, Type.POST_PROCESSING.name());
        return new WorkflowExecutionContext(wfProperties);
    }
}