/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.datamodel.metadata;
  
  import java.text.NumberFormat;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Objects;
  import java.util.stream.Collectors;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.mycore.common.MCRException;
  import org.mycore.common.MCRUtils;
  import org.mycore.common.config.MCRConfiguration2;
  import org.mycore.datamodel.common.MCRXMLMetadataManager;
  
  import com.fasterxml.jackson.annotation.JsonClassDescription;
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonFormat;
  import com.fasterxml.jackson.annotation.JsonValue;
  
  /**
   * This class holds all informations and methods to handle the MyCoRe Object ID.
   * The MyCoRe Object ID is a special ID to identify each metadata object with
   * three parts, they are the project identifier, the type identifier and a
   * string with a number. The syntax of the ID is "<em>projectID</em>_
   * <em>typeID</em>_ <em>number</em>" as "<em>String_String_Integer</em>".
   *
   * @author Jens Kupferschmidt
   * @author Thomas Scheffler (yagee)
   * @version $Revision$ $Date$
   */
  @JsonClassDescription("MyCoRe ObjectID in form {project}_{type}_{int32}, "
      + "where project is a namespace and type defines the datamodel")
  @JsonFormat(shape = JsonFormat.Shape.STRING)
  public final class MCRObjectID implements Comparable<MCRObjectID> {
      /**
       * public constant value for the MCRObjectID length
       */
      public static final int MAX_LENGTH = 64;
  
      private static final MCRObjectIDFormat ID_FORMAT = new MCRObjectIDDefaultFormat();
  
      private static final Logger LOGGER = LogManager.getLogger(MCRObjectID.class);
  
      // counter for the next IDs per project base ID
      private static HashMap<String, Integer> lastNumber = new HashMap<>();
  
      private static HashSet<String> VALID_TYPE_LIST;
  
      static {
          final String confPrefix = "MCR.Metadata.Type.";
          VALID_TYPE_LIST = MCRConfiguration2.getPropertiesMap()
              .entrySet()
              .stream()
              .filter(p -> p.getKey().startsWith(confPrefix))
              .filter(p -> Boolean.parseBoolean(p.getValue()))
              .map(prop -> prop.getKey().substring(confPrefix.length()))
              .collect(Collectors.toCollection(HashSet::new));
      }
  
      // data of the ID
      private String projectId, objectType, combinedId;
  
      private int numberPart;
  
      /**
       * The constructor for MCRObjectID from a given string.
       *
       * @exception MCRException
       *                if the given string is not valid.
       */
      MCRObjectID(String id) throws MCRException {
          if (!setID(id)) {
              throw new MCRException("The ID is not valid: " + id
                  + " , it should match the pattern String_String_Integer");
          }
      }
  
     /**
      * Returns a MCRObjectID from a given base ID string. A base ID is
      * <em>project_id</em>_<em>type_id</em>. The number is computed by this
      * method. It is the next free number of an item in the database for the
      * given project ID and type ID, with the following additional restriction:
      * The ID returned can be divided by idFormat.numberDistance without remainder.
      * The ID returned minus the last ID returned is at least idFormat.numberDistance.
      *
      * Example for number distance of 1 (default):
      *   last ID = 7, next ID = 8
      *   last ID = 8, next ID = 9
      *
      * Example for number distance of 2:
      *   last ID = 7, next ID = 10
      *   last ID = 8, next ID = 10
      *   last ID = 10, next ID = 20
      *
      * @param baseId
      *            <em>project_id</em>_<em>type_id</em>
      */
     public static synchronized MCRObjectID getNextFreeId(String baseId) {
         return getNextFreeId(baseId, 0);
     }
 
     /**
      * Returns a MCRObjectID from a given the components of a base ID string. A base ID is
      * <em>project_id</em>_<em>type_id</em>. The number is computed by this
      * method. It is the next free number of an item in the database for the
      * given project ID and type ID, with the following additional restriction:
      * The ID returned can be divided by idFormat.numberDistance without remainder.
      * The ID returned minus the last ID returned is at least idFormat.numberDistance.
      *
      * Example for number distance of 1 (default):
      *   last ID = 7, next ID = 8
      *   last ID = 8, next ID = 9
      *
      * Example for number distance of 2:
      *   last ID = 7, next ID = 10
      *   last ID = 8, next ID = 10
      *   last ID = 10, next ID = 20
      *
      * @param projectId
      *            The first component of <em>project_id</em>_<em>type_id</em>
      * @param type
      *            The second component of <em>project_id</em>_<em>type_id</em>
      */
     public static synchronized MCRObjectID getNextFreeId(String projectId, String type) {
         return getNextFreeId(projectId + "_" + type);
     }
 
     /**
      * Returns a MCRObjectID from a given base ID string. Same as
      * {@link #getNextFreeId(String)} but the additional parameter acts as a
      * lower limit for integer part of the ID.
      *
      * @param baseId
      *            <em>project_id</em>_<em>type_id</em>
      * @param maxInWorkflow
      *            returned integer part of id will be at least
      *            <code>maxInWorkflow + 1</code>
      */
     public static synchronized MCRObjectID getNextFreeId(String baseId, int maxInWorkflow) {
         int last = Math.max(getLastIDNumber(baseId), maxInWorkflow);
         int numberDistance = ID_FORMAT.numberDistance();
         int next = last + numberDistance;
 
         int rest = next % numberDistance;
         if (rest != 0) {
             next += numberDistance - rest;
         }
 
         lastNumber.put(baseId, next);
         String[] idParts = getIDParts(baseId);
         return getInstance(formatID(idParts[0], idParts[1], next));
     }
 
     /**
      * Returns the last ID number used or reserved for the given object base
      * type. This may return the value 0 when there is no ID last used or in the
      * store.
      */
     private static int getLastIDNumber(String baseId) {
         int lastIDKnown = lastNumber.getOrDefault(baseId, 0);
 
         String[] idParts = getIDParts(baseId);
         int highestStoredID = MCRXMLMetadataManager.instance().getHighestStoredID(idParts[0], idParts[1]);
 
         return Math.max(lastIDKnown, highestStoredID);
     }
 
     /**
      * Returns the last ID used or reserved for the given object base type.
      *
      * @return a valid MCRObjectID, or null when there is no ID for the given
      *         type
      */
     public static MCRObjectID getLastID(String baseId) {
         int lastIDNumber = getLastIDNumber(baseId);
         if (lastIDNumber == 0) {
             return null;
         }
 
         String[] idParts = getIDParts(baseId);
         return getInstance(formatID(idParts[0], idParts[1], lastIDNumber));
     }
 
     /**
      * This method instantiate this class with a given identifier in MyCoRe schema.
      *
      * @param id
      *          the MCRObjectID
      * @return an MCRObjectID class instance
      * @exception MCRException if the given identifier is not valid
      */
     @JsonCreator(mode = JsonCreator.Mode.DELEGATING)
     public static MCRObjectID getInstance(String id) {
         return MCRObjectIDPool.getMCRObjectID(Objects.requireNonNull(id, "'id' must not be null."));
     }
 
     /**
      * Normalizes to a object ID of form <em>project_id</em>_ <em>type_id</em>_
      * <em>number</em>, where number has leading zeros.
      * @return <em>project_id</em>_<em>type_id</em>_<em>number</em>
      */
     public static String formatID(String projectID, String type, int number) {
         if (projectID == null) {
             throw new IllegalArgumentException("projectID cannot be null");
         }
         if (type == null) {
             throw new IllegalArgumentException("type cannot be null");
         }
         if (number < 0) {
             throw new IllegalArgumentException("number must be non negative integer");
         }
         return projectID + '_' + type.toLowerCase(Locale.ROOT) + '_' + ID_FORMAT.numberFormat().format(number);
     }
 
     /**
      * Normalizes to a object ID of form <em>project_id</em>_ <em>type_id</em>_
      * <em>number</em>, where number has leading zeros.
      *
      * @param baseID
      *            is <em>project_id</em>_<em>type_id</em>
      * @return <em>project_id</em>_<em>type_id</em>_<em>number</em>
      */
     public static String formatID(String baseID, int number) {
         String[] idParts = getIDParts(baseID);
         return formatID(idParts[0], idParts[1], number);
     }
 
     /**
      * Splits the submitted <code>id</code> in its parts.
      * <code>MyCoRe_document_00000001</code> would be transformed in { "MyCoRe",
      * "document", "00000001" }
      *
      * @param id
      *            either baseID or complete ID
      */
     public static String[] getIDParts(String id) {
         return id.split("_");
     }
 
     /**
      * Returns a list of available mycore object types.
      */
     public static List<String> listTypes() {
         return new ArrayList<>(VALID_TYPE_LIST);
     }
 
     /**
      * Check whether the type passed is a valid type in the current mycore environment.
      * That being said property <code>MCR.Metadata.Type.&#60;type&#62;</code> must be set to <code>true</code> in mycore.properties.
      *
      * @param type the type to check
      * @return true if valid, false otherwise
      */
     public static boolean isValidType(String type) {
         return VALID_TYPE_LIST.contains(type);
     }
 
     /**
      * Checks if the given id is a valid mycore id in the form of {project}_{object_type}_{number}.
      *
      * @param id the id to check
      * @return true if the id is valid, false otherwise
      */
     public static boolean isValid(String id) {
         if (id == null) {
             return false;
         }
         String mcrId = id.trim();
         if (mcrId.length() > MAX_LENGTH) {
             return false;
         }
         String[] idParts = getIDParts(mcrId);
         if (idParts.length != 3) {
             return false;
         }
         String objectType = idParts[1].toLowerCase(Locale.ROOT).intern();
         if (!MCRConfiguration2.getBoolean("MCR.Metadata.Type." + objectType).orElse(false)) {
             LOGGER.warn("Property MCR.Metadata.Type.{} is not set. Thus {} cannot be a valid id", objectType, id);
             return false;
         }
         try {
             Integer numberPart = Integer.parseInt(idParts[2]);
             if (numberPart < 0) {
                 return false;
             }
         } catch (NumberFormatException e) {
             return false;
         }
         return true;
     }
 
     /**
      * This method get the string with <em>project_id</em>. If the ID is not
      * valid, an empty string was returned.
      *
      * @return the string of the project id
      */
     public String getProjectId() {
         return projectId;
     }
 
     /**
      * This method gets the string with <em>type_id</em>. If the ID is not
      * valid, an empty string will be returned.
      *
      * @return the string of the type id
      */
     public String getTypeId() {
         return objectType;
     }
 
     /**
      * This method gets the string with <em>number</em>. If the ID is not valid,
      * an empty string will be returned.
      *
      * @return the string of the number
      */
     public String getNumberAsString() {
         return ID_FORMAT.numberFormat().format(numberPart);
     }
 
     /**
      * This method gets the integer with <em>number</em>. If the ID is not
      * valid, -1 will be returned.
      *
      * @return the number as integer
      */
     public int getNumberAsInteger() {
         return numberPart;
     }
 
     /**
      * This method gets the basic string with <em>project_id</em>_
      * <em>type_id</em>. If the Id is not valid, an empty string will be
      * returned.
      *
      * @return the string of the schema name
      */
     public String getBase() {
         return projectId + "_" + objectType;
     }
 
     /**
      * This method return the validation value of a MCRObjectId and store the
      * components in this class. The <em>type_id</em> was set to lower case. The
      * MCRObjectID is valid if:
      * <ul>
      * <li>The argument is not null.
      * <li>The syntax of the ID is <em>project_id</em>_<em>type_id</em>_
      * <em>number</em> as <em>String_String_Integer</em>.
      * <li>The ID is not longer as MAX_LENGTH.
      * <li>The ID has only characters, they must not encoded.
      * </ul>
      *
      * @param id
      *            the MCRObjectID
      * @return the validation value, true if the MCRObjectID is correct,
      *         otherwise return false
      */
     private boolean setID(String id) {
         if (!isValid(id)) {
             return false;
         }
         String[] idParts = getIDParts(id.trim());
         projectId = idParts[0].intern();
         objectType = idParts[1].toLowerCase(Locale.ROOT).intern();
         numberPart = Integer.parseInt(idParts[2]);
         this.combinedId = formatID(projectId, objectType, numberPart);
         return true;
     }
 
     /**
      * This method check this data again the input and retuns the result as
      * boolean.
      *
      * @param in
      *            the MCRObjectID to check
      * @return true if all parts are equal, else return false
      */
     public boolean equals(MCRObjectID in) {
         return this == in || (in != null && toString().equals(in.toString()));
     }
 
     /**
      * This method check this data again the input and retuns the result as
      * boolean.
      *
      * @param in
      *            the MCRObjectID to check
      * @return true if all parts are equal, else return false.
      * @see java.lang.Object#equals(Object)
      */
     @Override
     public boolean equals(Object in) {
         if (in instanceof MCRObjectID) {
             return equals((MCRObjectID) in);
         }
         return false;
     }
 
     @Override
     public int compareTo(MCRObjectID o) {
         return MCRUtils.compareParts(this, o,
             MCRObjectID::getProjectId,
             MCRObjectID::getTypeId,
             MCRObjectID::getNumberAsInteger);
     }
 
     /**
      * @see java.lang.Object#toString()
      * @return {@link #formatID(String, String, int)} with
      *         {@link #getProjectId()}, {@link #getTypeId()},
      *         {@link #getNumberAsInteger()}
      */
     @Override
     @JsonValue
     public String toString() {
         return combinedId;
     }
 
     /**
      * returns toString().hashCode()
      *
      * @see #toString()
      * @see java.lang.Object#hashCode()
      */
     @Override
     public int hashCode() {
         return toString().hashCode();
     }
 
     public interface MCRObjectIDFormat {
         int numberDistance();
 
         NumberFormat numberFormat();
     }
 
     private static class MCRObjectIDDefaultFormat implements MCRObjectIDFormat {
 
         private int numberDistance;
 
         /**
          * First invocation may return MCR.Metadata.ObjectID.InitialNumberDistance if set,
          * following invocations will return MCR.Metadata.ObjectID.NumberDistance.
          * The default for both is 1.
          */
         @Override
         public int numberDistance() {
             if (numberDistance == 0) {
                 numberDistance = MCRConfiguration2.getInt("MCR.Metadata.ObjectID.NumberDistance").orElse(1);
                 return MCRConfiguration2.getInt("MCR.Metadata.ObjectID.InitialNumberDistance").orElse(numberDistance);
             }
             return numberDistance;
         }
 
         @Override
         public NumberFormat numberFormat() {
             String numberPattern = MCRConfiguration2.getString("MCR.Metadata.ObjectID.NumberPattern")
                 .orElse("0000000000").trim();
             NumberFormat format = NumberFormat.getIntegerInstance(Locale.ROOT);
             format.setGroupingUsed(false);
             format.setMinimumIntegerDigits(numberPattern.length());
             return format;
         }
 
     }
 
 }