/*
 * The MIT License
 * Copyright (c) 2012 Microsoft Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package microsoft.exchange.webservices.data.property.complex.time;

import microsoft.exchange.webservices.data.core.EwsServiceXmlReader;
import microsoft.exchange.webservices.data.core.EwsServiceXmlWriter;
import microsoft.exchange.webservices.data.core.XmlAttributeNames;
import microsoft.exchange.webservices.data.core.XmlElementNames;
import microsoft.exchange.webservices.data.core.enumeration.misc.ExchangeVersion;
import microsoft.exchange.webservices.data.core.enumeration.misc.XmlNamespace;
import microsoft.exchange.webservices.data.core.enumeration.property.time.DayOfTheWeek;
import microsoft.exchange.webservices.data.core.exception.service.local.InvalidOrUnsupportedTimeZoneDefinitionException;
import microsoft.exchange.webservices.data.core.exception.service.local.ServiceLocalException;
import microsoft.exchange.webservices.data.core.exception.service.local.ServiceXmlSerializationException;
import microsoft.exchange.webservices.data.property.complex.ComplexProperty;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * Represents a time zone as defined by the EWS schema.
 */
public class TimeZoneDefinition extends ComplexProperty implements Comparator<TimeZoneTransition> {

  /**
   * Prefix for generated ids.
   */
  private static String NoIdPrefix = "NoId_";

  /**
   * The Standard period id.
   */
  protected final String StandardPeriodId = "Std";

  /**
   * The Standard period name.
   */
  protected final String StandardPeriodName = "Standard";

  /**
   * The Daylight period id.
   */
  protected final String DaylightPeriodId = "Dlt";

  /**
   * The Daylight period name.
   */
  protected final String DaylightPeriodName = "Daylight";

  /**
   * The name.
   */
  public String name;

  /**
   * The id.
   */
  public String id;

  /**
   * The periods.
   */
  private Map<String, TimeZonePeriod> periods =
      new HashMap<String, TimeZonePeriod>();

  /**
   * The transition groups.
   */
  private Map<String, TimeZoneTransitionGroup> transitionGroups =
      new HashMap<String, TimeZoneTransitionGroup>();

  /**
   * The transitions.
   */
  private List<TimeZoneTransition> transitions =
      new ArrayList<TimeZoneTransition>();

  /**
   * Compares the transitions.
   *
   * @param x The first transition.
   * @param y The second transition.
   * @return A negative number if x is less than y, 0 if x and y are equal, a
   * positive number if x is greater than y.
   */
  @Override
  public int compare(final TimeZoneTransition x, final TimeZoneTransition y) {
    if (x == y) {
      return 0;
    } else if (x != null && y != null) {
      if (x instanceof AbsoluteDateTransition && y instanceof AbsoluteDateTransition) {
        final AbsoluteDateTransition firstTransition = (AbsoluteDateTransition) x;
        final AbsoluteDateTransition secondTransition = (AbsoluteDateTransition) y;

        final Date firstDateTime = firstTransition.getDateTime();
        final Date secondDateTime = secondTransition.getDateTime();

        return firstDateTime.compareTo(secondDateTime);

      } else if (y instanceof TimeZoneTransition) {
        return 1;
      }
    } else if (y == null) {
      return 1;
    }
    return -1;
  }

  /**
   * Initializes a new instance of the TimeZoneDefinition class.
   */
  public TimeZoneDefinition() {
    super();
  }


  /**
   * Adds a transition group with a single transition to the specified period.
   *
   * @param timeZonePeriod the time zone period
   * @return A TimeZoneTransitionGroup.
   */
  private TimeZoneTransitionGroup createTransitionGroupToPeriod(
      TimeZonePeriod timeZonePeriod) {
    TimeZoneTransition transitionToPeriod = new TimeZoneTransition(this,
        timeZonePeriod);

    TimeZoneTransitionGroup transitionGroup = new TimeZoneTransitionGroup(
        this, String.valueOf(this.transitionGroups.size()));
    transitionGroup.getTransitions().add(transitionToPeriod);
    this.transitionGroups.put(transitionGroup.getId(), transitionGroup);
    return transitionGroup;
  }

  /**
   * Reads the attribute from XML.
   *
   * @param reader the reader
   * @throws Exception the exception
   */
  @Override
  public void readAttributesFromXml(EwsServiceXmlReader reader)
      throws Exception {
    this.name = reader.readAttributeValue(XmlAttributeNames.Name);
    this.id = reader.readAttributeValue(XmlAttributeNames.Id);

    // E14:319057 -- EWS can return a TimeZone definition with no Id. Generate a new Id in this case.
    if (this.id == null || this.id.isEmpty()) {
      String nameValue = (this.getName() == null || this.
          getName().isEmpty()) ? "" : this.getName();
      this.setId(NoIdPrefix + Math.abs(nameValue.hashCode()));
    }
  }

  /**
   * Writes the attribute to XML.
   *
   * @param writer the writer
   * @throws ServiceXmlSerializationException the service xml serialization exception
   */
  @Override
  public void writeAttributesToXml(EwsServiceXmlWriter writer)
      throws ServiceXmlSerializationException {
    // The Name attribute is only supported in Exchange 2010 and above.
    if (writer.getService().getRequestedServerVersion() != ExchangeVersion.Exchange2007_SP1) {
      writer.writeAttributeValue(XmlAttributeNames.Name, this.name);
    }

    writer.writeAttributeValue(XmlAttributeNames.Id, this.id);
  }

  /**
   * Tries to read element from XML.
   *
   * @param reader the reader
   * @return True if element was read.
   * @throws Exception the exception
   */
  @Override
  public boolean tryReadElementFromXml(EwsServiceXmlReader reader)
      throws Exception {
    if (reader.getLocalName().equals(XmlElementNames.Periods)) {
      do {
        reader.read();
        if (reader.isStartElement(XmlNamespace.Types,
            XmlElementNames.Period)) {
          TimeZonePeriod period = new TimeZonePeriod();
          period.loadFromXml(reader);

          this.periods.put(period.getId(), period);
        }
      } while (!reader.isEndElement(XmlNamespace.Types,
          XmlElementNames.Periods));

      return true;
    } else if (reader.getLocalName().equals(
        XmlElementNames.TransitionsGroups)) {
      do {
        reader.read();
        if (reader.isStartElement(XmlNamespace.Types,
            XmlElementNames.TransitionsGroup)) {
          TimeZoneTransitionGroup transitionGroup =
              new TimeZoneTransitionGroup(
                  this);

          transitionGroup.loadFromXml(reader);

          this.transitionGroups.put(transitionGroup.getId(),
              transitionGroup);
        }
      } while (!reader.isEndElement(XmlNamespace.Types,
          XmlElementNames.TransitionsGroups));

      return true;
    } else if (reader.getLocalName().equals(XmlElementNames.Transitions)) {
      do {
        reader.read();
        if (reader.isStartElement()) {
          TimeZoneTransition transition = TimeZoneTransition.create(
              this, reader.getLocalName());

          transition.loadFromXml(reader);

          this.transitions.add(transition);
        }
      } while (!reader.isEndElement(XmlNamespace.Types,
          XmlElementNames.Transitions));

      return true;
    } else {
      return false;
    }
  }

  /**
   * Loads from XML.
   *
   * @param reader the reader
   * @throws Exception the exception
   */
  public void loadFromXml(EwsServiceXmlReader reader) throws Exception {
    this.loadFromXml(reader, XmlElementNames.TimeZoneDefinition);
    Collections.sort(this.transitions, new TimeZoneDefinition());
  }

  /**
   * Writes elements to XML.
   *
   * @param writer the writer
   * @throws Exception the exception
   */
  @Override
  public void writeElementsToXml(EwsServiceXmlWriter writer)
      throws Exception {
    // We only emit the full time zone definition against Exchange 2010
    // servers and above.
    if (writer.getService().getRequestedServerVersion() != ExchangeVersion.Exchange2007_SP1) {
      if (this.periods.size() > 0) {
        writer.writeStartElement(XmlNamespace.Types,
            XmlElementNames.Periods);

        Iterator<TimeZonePeriod> it = this.periods.values().iterator();
        while (it.hasNext()) {
          it.next().writeToXml(writer);
        }

        writer.writeEndElement(); // Periods
      }

      if (this.transitionGroups.size() > 0) {
        writer.writeStartElement(XmlNamespace.Types,
            XmlElementNames.TransitionsGroups);
        for (int i = 0; i < this.transitionGroups.size(); i++) {
          Object key[] = this.transitionGroups.keySet().toArray();
          this.transitionGroups.get(key[i]).writeToXml(writer);
        }
        writer.writeEndElement(); // TransitionGroups
      }

      if (this.transitions.size() > 0) {
        writer.writeStartElement(XmlNamespace.Types,
            XmlElementNames.Transitions);

        for (TimeZoneTransition transition : this.transitions) {
          transition.writeToXml(writer);
        }

        writer.writeEndElement(); // Transitions
      }
    }
  }

  /**
   * Writes to XML.
   *
   * @param writer The writer.
   * @throws Exception the exception
   */
  protected void writeToXml(EwsServiceXmlWriter writer) throws Exception {
    this.writeToXml(writer, XmlElementNames.TimeZoneDefinition);
  }

  /**
   * Validates this time zone definition.
   *
   * @throws InvalidOrUnsupportedTimeZoneDefinitionException thrown when time zone definition is not valid.
   */
  public void validate() throws ServiceLocalException {
    // The definition must have at least one period, one transition group
    // and one transition,
    // and there must be as many transitions as there are transition groups.
    if (this.periods.size() < 1 || this.transitions.size() < 1
        || this.transitionGroups.size() < 1
        || this.transitionGroups.size() != this.transitions.size()) {
      throw new InvalidOrUnsupportedTimeZoneDefinitionException();
    }

    // The first transition must be of type TimeZoneTransition.
    if (this.transitions.get(0).getClass() != TimeZoneTransition.class) {
      throw new InvalidOrUnsupportedTimeZoneDefinitionException();
    }

    // All transitions must be to transition groups and be either
    // TimeZoneTransition or
    // AbsoluteDateTransition instances.
    for (TimeZoneTransition transition : this.transitions) {
      Class<?> transitionType = transition.getClass();

      if (transitionType != TimeZoneTransition.class
          && transitionType != AbsoluteDateTransition.class) {
        throw new InvalidOrUnsupportedTimeZoneDefinitionException();
      }

      if (transition.getTargetGroup() == null) {
        throw new InvalidOrUnsupportedTimeZoneDefinitionException();
      }
    }

    // All transition groups must be valid.
    for (TimeZoneTransitionGroup transitionGroup : this.transitionGroups
        .values()) {
      transitionGroup.validate();
    }
  }

  /**
   * Gets the name of this time zone definition.
   *
   * @return the name
   */
  public String getName() {
    return this.name;
  }

  /**
   * Sets the name.
   *
   * @param name the new name
   */
  protected void setName(String name) {
    this.name = name;
  }

  /**
   * Gets the Id of this time zone definition.
   *
   * @return the id
   */
  public String getId() {
    return this.id;
  }

  /**
   * Sets the id.
   *
   * @param id the new id
   */
  public void setId(String id) {
    this.id = id;
  }

  /**
   * Adds a transition group with a single transition to the specified period.
   *
   * @return A TimeZoneTransitionGroup.
   */
  public Map<String, TimeZonePeriod> getPeriods() {
    return this.periods;
  }

  /**
   * Gets the transition groups associated with this time zone definition,
   * indexed by Id.
   *
   * @return the transition groups
   */
  public Map<String, TimeZoneTransitionGroup> getTransitionGroups() {
    return this.transitionGroups;
  }

  /**
   * Writes to XML.
   *
   * @param writer         accepts EwsServiceXmlWriter
   * @param xmlElementName accepts String
   * @throws Exception throws Exception
   */
  public void writeToXml(EwsServiceXmlWriter writer, String xmlElementName)
      throws Exception {
    this.writeToXml(writer, this.getNamespace(), xmlElementName);
  }

}