/*
 * 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.sling.event.impl.jobs;

import java.text.MessageFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.sling.api.resource.ValueMap;
import org.apache.sling.api.wrappers.ValueMapDecorator;
import org.apache.sling.event.impl.support.ResourceHelper;
import org.apache.sling.event.jobs.Job;
import org.apache.sling.event.jobs.NotificationConstants;
import org.apache.sling.event.jobs.Queue;

/**
 * This object encapsulates all information about a job.
 */
public class JobImpl implements Job, Comparable<JobImpl> {

    public enum ReadErrorType {
        NONE,
        RUNTIMEEXCEPTION,
        CLASSNOTFOUNDEXCEPTION,
        OTHER_EXCEPTION
    }

    /** Internal job property containing the resource path. */
    public static final String PROPERTY_RESOURCE_PATH = "slingevent:path";

    /** Internal job property containing optional delay override. */
    public static final String PROPERTY_DELAY_OVERRIDE = ":slingevent:delayOverride";

    /**
     * Internal job property specifying when the job was put into the queue.
     */
    public static final String PROPERTY_JOB_QUEUED = "event.job.queued.time";

    /**
     * This property contains the finished state of a job once it's marked as finished.
     * The value is either "CANCELLED" or "SUCCEEDED".
     * This property is read-only and can't be specified when the job is created.
     */
    public static final String PROPERTY_FINISHED_STATE = "slingevent:finishedState";

    private final ValueMap properties;

    private final String topic;

    private final String path;

    private final String jobId;

    private final List<Exception> readErrorList;

    private final long counter;

    /**
     * Create a new job instance
     *
     * @param topic The job topic
     * @param name  The unique job name (optional)
     * @param jobId The unique (internal) job id
     * @param properties Non-null map of properties, at least containing {@link #PROPERTY_RESOURCE_PATH}
     */
    @SuppressWarnings("unchecked")
    public JobImpl(final String topic,
                   final String jobId,
                   final Map<String, Object> properties) {
        this.topic = topic;
        this.jobId = jobId;
        this.path = (String)properties.remove(PROPERTY_RESOURCE_PATH);
        this.readErrorList = (List<Exception>) properties.remove(ResourceHelper.PROPERTY_MARKER_READ_ERROR_LIST);

        this.properties = new ValueMapDecorator(properties);
        this.properties.put(NotificationConstants.NOTIFICATION_PROPERTY_JOB_ID, jobId);
        final int lastPos = jobId.lastIndexOf('_');
        this.counter = Long.valueOf(jobId.substring(lastPos + 1));
    }

    /**
     * Get the full resource path.
     */
    public String getResourcePath() {
        return this.path;
    }

    /**
     * Did we have read errors?
     */
    public boolean hasReadErrors() {
        return this.readErrorList != null;
    }

    public ReadErrorType getReadErrorType() {
        if ( this.readErrorList == null || this.readErrorList.isEmpty() ) {
            return ReadErrorType.NONE;
        } else {
            for(final Exception e : this.readErrorList) {
                if ( e instanceof RuntimeException ) {
                    return ReadErrorType.RUNTIMEEXCEPTION;
                } else if ( e.getCause() != null && e.getCause() instanceof ClassNotFoundException ) {
                    return ReadErrorType.CLASSNOTFOUNDEXCEPTION;
                }
            }
            return ReadErrorType.OTHER_EXCEPTION;
        }
    }

    /**
     * Is the error recoverable?
     */
    public boolean isReadErrorRecoverable() {
        return getReadErrorType() != ReadErrorType.RUNTIMEEXCEPTION;
    }

    /**
     * Get all properties
     */
    public Map<String, Object> getProperties() {
        return this.properties;
    }

    /**
     * Update the information for a retry
     */
    public void retry() {
        final int retries = this.getProperty(Job.PROPERTY_JOB_RETRY_COUNT, Integer.class);
        this.properties.put(Job.PROPERTY_JOB_RETRY_COUNT, retries + 1);
        this.properties.remove(Job.PROPERTY_JOB_STARTED_TIME);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getTopic()
     */
    @Override
    public String getTopic() {
        return this.topic;
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getId()
     */
    @Override
    public String getId() {
        return this.jobId;
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProperty(java.lang.String)
     */
    @Override
    public Object getProperty(final String name) {
        return this.properties.get(name);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProperty(java.lang.String, java.lang.Class)
     */
    @Override
    public <T> T getProperty(final String name, final Class<T> type) {
        return this.properties.get(name, type);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProperty(java.lang.String, java.lang.Object)
     */
    @Override
    public <T> T getProperty(final String name, final T defaultValue) {
        return this.properties.get(name, defaultValue);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getPropertyNames()
     */
    @Override
    public Set<String> getPropertyNames() {
        return this.properties.keySet();
    }

    @Override
    public int getRetryCount() {
        return this.getProperty(Job.PROPERTY_JOB_RETRY_COUNT, Integer.class);
    }

    @Override
    public int getNumberOfRetries() {
        return this.getProperty(Job.PROPERTY_JOB_RETRIES, Integer.class);
    }

    @Override
    public String getQueueName() {
        return this.getProperty(Job.PROPERTY_JOB_QUEUE_NAME, String.class);
    }

    @Override
    public String getTargetInstance() {
        return this.getProperty(Job.PROPERTY_JOB_TARGET_INSTANCE, String.class);
    }

    @Override
    public Calendar getProcessingStarted() {
        return this.getProperty(Job.PROPERTY_JOB_STARTED_TIME, Calendar.class);
    }

    @Override
    public Calendar getCreated() {
        return this.getProperty(Job.PROPERTY_JOB_CREATED, Calendar.class);
    }

    @Override
    public String getCreatedInstance() {
        return this.getProperty(Job.PROPERTY_JOB_CREATED_INSTANCE, String.class);
    }

    /**
     * Update information about the queue.
     */
    public void updateQueueInfo(final Queue queue) {
        this.properties.put(Job.PROPERTY_JOB_QUEUE_NAME, queue.getName());
        this.properties.put(Job.PROPERTY_JOB_RETRIES, queue.getConfiguration().getMaxRetries());
    }

    public void setProperty(final String name, final Object value) {
        if ( value == null ) {
            this.properties.remove(name);
        } else {
            this.properties.put(name, value);
        }
    }

    /**
     * Prepare a new job execution
     */
    public String[] prepare(final Queue queue) {
        this.updateQueueInfo(queue);
        this.properties.remove(JobImpl.PROPERTY_DELAY_OVERRIDE);
        this.properties.remove(Job.PROPERTY_JOB_PROGRESS_LOG);
        this.properties.remove(Job.PROPERTY_JOB_PROGRESS_ETA);
        this.properties.remove(Job.PROPERTY_JOB_PROGRESS_STEPS);
        this.properties.remove(Job.PROPERTY_JOB_PROGRESS_STEP);
        this.properties.remove(Job.PROPERTY_RESULT_MESSAGE);
        this.properties.put(Job.PROPERTY_JOB_STARTED_TIME, Calendar.getInstance());
        return new String[] {Job.PROPERTY_JOB_QUEUE_NAME, Job.PROPERTY_JOB_RETRIES,
                Job.PROPERTY_JOB_PROGRESS_LOG, Job.PROPERTY_JOB_PROGRESS_ETA, PROPERTY_JOB_PROGRESS_STEPS,
                PROPERTY_JOB_PROGRESS_STEP, Job.PROPERTY_RESULT_MESSAGE, Job.PROPERTY_JOB_STARTED_TIME};
    }

    public String[] startProgress(final int steps, final long eta) {
        if ( steps > 0 ) {
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_STEPS, steps);
        }
        if ( eta > 0 ) {
            final Date finishDate = new Date(System.currentTimeMillis() + eta * 1000);
            final Calendar finishCal = Calendar.getInstance();
            finishCal.setTime(finishDate);
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_ETA, finishCal);
        }
        return new String[] {Job.PROPERTY_JOB_PROGRESS_ETA, PROPERTY_JOB_PROGRESS_STEPS};
    }

    public String[] setProgress(final int step) {
        final int steps = this.getProperty(Job.PROPERTY_JOB_PROGRESS_STEPS, -1);
        if ( steps > 0 && step > 0 ) {
            int current = this.getProperty(Job.PROPERTY_JOB_PROGRESS_STEP, 0);
            current += step;
            if ( current > steps ) {
                current = steps;
            }
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_STEP, current);

            final Calendar now = Calendar.getInstance();
            final long elapsed = now.getTimeInMillis() - this.getProcessingStarted().getTimeInMillis();

            final long eta = System.currentTimeMillis() + (elapsed / current) * (steps - current);
            now.setTimeInMillis(eta);
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_ETA, now);
            return new String[] {Job.PROPERTY_JOB_PROGRESS_STEP, Job.PROPERTY_JOB_PROGRESS_ETA};
        }
        return null;
    }

    public String update(final long eta) {
        if ( eta > 0 ) {
            final Date finishDate = new Date(System.currentTimeMillis() + eta * 1000);
            final Calendar finishCal = Calendar.getInstance();
            finishCal.setTime(finishDate);
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_ETA, finishCal);
        } else {
            this.properties.remove(Job.PROPERTY_JOB_PROGRESS_ETA);
        }
        return Job.PROPERTY_JOB_PROGRESS_ETA;
    }

    public String log(final String message, final Object... args) {
        final String logEntry = MessageFormat.format(message, args);
        final String[] entries = this.getProperty(Job.PROPERTY_JOB_PROGRESS_LOG, String[].class);
        if ( entries == null ) {
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_LOG, new String[] {logEntry});
        } else {
            final String[] newEntries = new String[entries.length + 1];
            System.arraycopy(entries, 0, newEntries, 0, entries.length);
            newEntries[entries.length] = logEntry;
            this.setProperty(Job.PROPERTY_JOB_PROGRESS_LOG, newEntries);
        }
        return Job.PROPERTY_JOB_PROGRESS_LOG;
    }

    @Override
    public JobState getJobState() {
        final String enumValue = this.getProperty(JobImpl.PROPERTY_FINISHED_STATE, String.class);
        if ( enumValue == null ) {
            if ( this.getProcessingStarted() != null ) {
                return JobState.ACTIVE;
            }
            return JobState.QUEUED;
        }
        return JobState.valueOf(enumValue);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getFinishedDate()
     */
    @Override
    public Calendar getFinishedDate() {
        return this.getProperty(Job.PROPERTY_FINISHED_DATE, Calendar.class);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getResultMessage()
     */
    @Override
    public String getResultMessage() {
        return this.getProperty(Job.PROPERTY_RESULT_MESSAGE, String.class);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProgressLog()
     */
    @Override
    public String[] getProgressLog() {
        return this.getProperty(Job.PROPERTY_JOB_PROGRESS_LOG, String[].class);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProgressStepCount()
     */
    @Override
    public int getProgressStepCount() {
        return this.getProperty(Job.PROPERTY_JOB_PROGRESS_STEPS, -1);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getFinishedProgressStep()
     */
    @Override
    public int getFinishedProgressStep() {
        return this.getProperty(Job.PROPERTY_JOB_PROGRESS_STEP, 0);
    }

    /**
     * @see org.apache.sling.event.jobs.Job#getProgressETA()
     */
    @Override
    public Calendar getProgressETA() {
        return this.getProperty(Job.PROPERTY_JOB_PROGRESS_ETA, Calendar.class);
    }

    @Override
    public int compareTo(final JobImpl o) {
        int result = this.getCreated().compareTo(o.getCreated());
        if ( result == 0 ) {
            if ( this.counter < o.counter ) {
                result = -1;
            } else if ( this.counter > o.counter ) {
                result = 1;
            } else {
                result = this.jobId.compareTo(o.jobId);
            }
        }
        return result;
    }

    @Override
    public int hashCode() {
        return this.jobId.hashCode();
    }

    @Override
    public boolean equals(final Object obj) {
        if ( obj == this ) {
            return true;
        }
        if ( obj instanceof JobImpl ) {
            return this.jobId.equals(((JobImpl)obj).jobId);
        }
        return false;
    }

    @Override
    public String toString() {
        return "JobImpl [properties=" + properties + ", topic=" + topic
                + ", path=" + path + ", jobId=" + jobId + "]";
    }
}