/*
Copyright (c) 2011+, HL7, Inc
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice, this 
   list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
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   and/or other materials provided with the distribution.
 * Neither the name of HL7 nor the names of its contributors may be used to 
   endorse or promote products derived from this software without specific 
   prior written permission.

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*/

package org.hl7.fhir.r4.model;

import ca.uhn.fhir.model.api.TemporalPrecisionEnum;
import ca.uhn.fhir.model.api.annotation.DatatypeDef;
import org.apache.commons.lang3.Validate;

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;

/**
 * Primitive type "date" in FHIR: any day in a gregorian calendar
 */

/**
 * Represents a FHIR date datatype. Valid precisions values for this type are:
 * <ul>
 * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#YEAR}
 * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#MONTH}
 * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#DAY}
 * </ul>
 */
@DatatypeDef(name = "date")
public class DateType extends BaseDateTimeType {

  /**
   * The default precision for this type
   */
  public static final TemporalPrecisionEnum DEFAULT_PRECISION = TemporalPrecisionEnum.DAY;
  private static final long serialVersionUID = 3L;

  /**
   * Constructor
   */
  public DateType() {
    super();
  }

  /**
   * Constructor which accepts a date value and uses the {@link #DEFAULT_PRECISION} for this type
   */
  public DateType(Date theDate) {
    super(theDate, DEFAULT_PRECISION);
  }

  /**
   * Constructor which accepts a date value and a precision value. Valid precisions values for this type are:
   * <ul>
   * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#YEAR}
   * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#MONTH}
   * <li>{@link ca.uhn.fhir.model.api.TemporalPrecisionEnum#DAY}
   * </ul>
   *
   * @throws ca.uhn.fhir.parser.DataFormatException If the specified precision is not allowed for this type
   */
  public DateType(Date theDate, TemporalPrecisionEnum thePrecision) {
    super(theDate, thePrecision);
  }

  /**
   * Constructor which accepts a date as a string in FHIR format
   *
   * @throws ca.uhn.fhir.parser.DataFormatException If the precision in the date string is not allowed for this type
   */
  public DateType(String theDate) {
    super(theDate);
  }

  /**
   * Constructor which accepts a date value and uses the {@link #DEFAULT_PRECISION} for this type.
   */
  public DateType(Calendar theCalendar) {
    super(theCalendar.getTime(), DEFAULT_PRECISION);
    setTimeZone(theCalendar.getTimeZone());
  }

  /**
   * Constructor which accepts a date value and uses the {@link #DEFAULT_PRECISION} for this type.
   * <p>
   * <b>Use caution when using this constructor</b>: The month is 0-indexed but the day is 1-indexed
   * in order to match the bahaviour of the Java {@link Calendar} type.
   * </p>
   *
   * @param theYear  The year, e.g. 2015
   * @param theMonth The month, e.g. 0 for January
   * @param theDay   The day (1 indexed) e.g. 1 for the first day of the month
   */
  public DateType(int theYear, int theMonth, int theDay) {
    this(toCalendarZulu(theYear, theMonth, theDay));
  }

  @Override
  public DateType copy() {
    return new DateType(getValueAsString());
  }

  @Override
  public String fhirType() {
    return "date";
  }

  /**
   * Returns the default precision for this datatype
   *
   * @see #DEFAULT_PRECISION
   */
  @Override
  protected TemporalPrecisionEnum getDefaultPrecisionForDatatype() {
    return DEFAULT_PRECISION;
  }

  @Override
  boolean isPrecisionAllowed(TemporalPrecisionEnum thePrecision) {
    switch (thePrecision) {
      case YEAR:
      case MONTH:
      case DAY:
        return true;
      default:
        return false;
    }
  }

  /**
   * Creates a new instance by parsing an HL7 v3 format date time string
   */
  public static DateType parseV3(String theV3String) {
    DateType retVal = new DateType();
    retVal.setValueAsV3String(theV3String);
    return retVal;
  }

  private static GregorianCalendar toCalendarZulu(int theYear, int theMonth, int theDay) {
    Validate.isTrue(theMonth >= 0, "theMonth must be between 0 and 11");
    Validate.isTrue(theMonth <= 11, "theMonth must be between 0 and 11");
    Validate.isTrue(theDay >= 1, "theMonth must be between 0 and 11");
    Validate.isTrue(theDay <= 31, "theMonth must be between 0 and 11");

    GregorianCalendar retVal = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
    retVal.set(Calendar.YEAR, theYear);
    retVal.set(Calendar.MONTH, theMonth);
    retVal.set(Calendar.DATE, theDay);
    return retVal;
  }

  public static InstantType today() {
    return new InstantType(new Date(), TemporalPrecisionEnum.DAY, TimeZone.getDefault());
  }
}