/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.metadata.dublincore;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.text.SimpleDateFormat;
  import java.util.ArrayList;
  import java.util.Map;
  import java.util.TimeZone;
  
  /**
   * This is a generic and very abstract view of a certain field/property in a metadata catalog. The main purpose of this
   * class is to have a generic access to the variety of information stored in metadata catalogs.
   */
  public class MetadataField {
  
    private static final Logger logger = LoggerFactory.getLogger(MetadataField.class);
  
    /** Keys for the different values in the configuration file */
    public static final String CONFIG_COLLECTION_ID_KEY = "collectionID";
    private static final String CONFIG_PATTERN_KEY = "pattern";
    private static final String CONFIG_DELIMITER_KEY = "delimiter";
    public static final String CONFIG_INPUT_ID_KEY = "inputID";
    public static final String CONFIG_LABEL_KEY = "label";
    public static final String CONFIG_LIST_PROVIDER_KEY = "listprovider";
    private static final String CONFIG_NAMESPACE_KEY = "namespace";
    private static final String CONFIG_ORDER_KEY = "order";
    private static final String CONFIG_OUTPUT_ID_KEY = "outputID";
    public static final String CONFIG_PROPERTY_PREFIX = "property";
    public static final String CONFIG_READ_ONLY_KEY = "readOnly";
    public static final String CONFIG_REQUIRED_KEY = "required";
    public static final String CONFIG_TYPE_KEY = "type";
  
    /**
     * Possible types for the metadata field. The types are used in the frontend and backend to know how the metadata
     * fields should be formatted (if needed).
     */
    public enum Type {
      BOOLEAN, DATE, DURATION, ITERABLE_TEXT, MIXED_TEXT, ORDERED_TEXT, LONG, START_DATE, START_TIME, TEXT, TEXT_LONG
    }
  
    /** The id of a collection to validate values against. */
    private String collectionID;
    /** The format to use for temporal date properties. */
    private String pattern;
    /** The delimiter used to display and parse list values. */
    private String delimiter;
    /** The id of the field used to identify it in the dublin core. */
    private final String inputID;
    /** The i18n id for the label to show the property. */
    private final String label;
    /** The provider to populate the property with. */
    private final String listprovider;
    /** The optional namespace of the field used if a field can be found in more than one namespace */
    private final String namespace;
    /**
     * In the order of properties where this property should be oriented in the UI i.e. 0 means the property should come
     * first, 1 means it should come second etc.
     */
    private final Integer order;
    /** The optional id of the field used to output for the ui, if not present will assume the same as the inputID. */
    private final String outputID;
    /** Whether the property should not be edited. */
    private boolean readOnly;
    /** Whether the property is required to update the metadata. */
    private final boolean required;
    /** The type of the metadata for example text, date etc. */
    private Type type;
  
    private Object value;
    private Boolean translatable;
    private boolean updated = false;
    private Map<String, String> collection;
  
    // this can only be true if the metadata field is representing multiple events with different values
    private Boolean hasDifferentValues = null;
  
   /**
    * Copy constructor
    *
    * @param other
    *          Other metadata field
    */
   public MetadataField(final MetadataField other) {
     this.inputID = other.inputID;
     this.outputID = other.outputID;
     this.label = other.label;
     this.readOnly = other.readOnly;
     this.required = other.required;
     this.value = other.value;
     this.translatable = other.translatable;
     this.hasDifferentValues = other.hasDifferentValues;
     this.type = other.type;
     this.collection = other.collection;
     this.collectionID = other.collectionID;
     this.order = other.order;
     this.namespace = other.namespace;
     this.updated = other.updated;
     this.pattern = other.pattern;
     this.delimiter = other.delimiter;
     this.listprovider = other.listprovider;
   }
 
   /**
    * Metadata field constructor
    *
    * @param inputID
    *          The identifier of the new metadata field
    * @param label
    *          the label of the field. The string displayed next to the field value on the frontend. This is usually be a
    *          translation key
    * @param readOnly
    *          Define if the new metadata field can be or not edited
    * @param required
    *          Define if the new metadata field is or not required
    * @param value
    *          The metadata field value
    * @param type
    *          The metadata field type @ EventMetadata.Type}
    * @param collection
    *          If the field has a limited list of possible value, the option should contain this one. Otherwise it should
    *          be none. This is also possible to use the collectionId parameter for that.
    * @param collectionID
    *          The id of the limit list of possible value that should be get through the resource endpoint.
    * @param listprovider An optional list provider ID
    * @param pattern Pattern for time/date fields
    * @param delimiter Delimiter
    * @throws IllegalArgumentException
    *           if the id, label, type parameters is/are null
    */
   public MetadataField(
           final String inputID,
           final String outputID,
           final String label,
           final boolean readOnly,
           final boolean required,
           final Object value,
           final Boolean translatable,
           final Type type,
           final Map<String, String> collection,
           final String collectionID,
           final Integer order,
           final String namespace,
           final String listprovider,
           final String pattern,
           final String delimiter) throws IllegalArgumentException {
     if (StringUtils.isBlank(inputID)) {
       throw new IllegalArgumentException("The metadata input id must not be null.");
     }
     if (StringUtils.isBlank(label)) {
       throw new IllegalArgumentException("The metadata label must not be null.");
     }
     if (type == null) {
       throw new IllegalArgumentException("The metadata type must not be null.");
     }
     this.inputID = inputID;
     this.outputID = outputID;
     this.label = label;
     this.readOnly = readOnly;
     this.required = required;
     this.value = value;
     this.translatable = translatable;
     this.type = type;
     this.collection = collection;
     this.collectionID = collectionID;
     this.order = order;
     this.namespace = namespace;
     this.listprovider = listprovider;
     this.pattern = pattern;
     this.delimiter = delimiter;
   }
 
   /**
    * Set the option of a limited list of possible values.
    *
    * @param collection
    *          The option of a limited list of possible values
    */
   public void setCollection(final Map<String, String> collection) {
     this.collection = collection;
   }
 
   public Map<String, String> getCollection() {
     return collection;
   }
 
   public Object getValue() {
     return value;
   }
 
   public Boolean isTranslatable() {
     return translatable;
   }
 
   public boolean isUpdated() {
     return updated;
   }
 
   public void setValue(final Object value) {
     setValue(value, true);
   }
 
   public void setValue(final Object value, final boolean setUpdated) {
     this.value = value;
 
     if (setUpdated) {
       this.updated = true;
     }
   }
 
   public void setIsTranslatable(final Boolean translatable) {
     this.translatable = translatable;
   }
 
   public static SimpleDateFormat getSimpleDateFormatter(final String pattern) {
     final SimpleDateFormat dateFormat;
     if (StringUtils.isNotBlank(pattern)) {
       dateFormat = new SimpleDateFormat(pattern);
     } else {
       dateFormat = new SimpleDateFormat();
     }
     dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
     return dateFormat;
   }
 
   public static MetadataField createMetadataField(final Map<String,String> configuration) {
     final String inputID = configuration.get(CONFIG_INPUT_ID_KEY);
     final String label = configuration.get(CONFIG_LABEL_KEY);
 
     final String collectionID = configuration.get(CONFIG_COLLECTION_ID_KEY);
     final String delimiter = configuration.get(CONFIG_DELIMITER_KEY);
     final String outputID = configuration.get(CONFIG_OUTPUT_ID_KEY);
     final String listprovider = configuration.get(CONFIG_LIST_PROVIDER_KEY);
     final String namespace = configuration.get(CONFIG_NAMESPACE_KEY);
 
     final Type type = configuration.containsKey(CONFIG_TYPE_KEY)
             ? Type.valueOf(configuration.get(CONFIG_TYPE_KEY).toUpperCase()) : null;
     final boolean required = configuration.containsKey(CONFIG_REQUIRED_KEY) && Boolean
             .parseBoolean(configuration.get(CONFIG_REQUIRED_KEY).toUpperCase());
     final boolean readOnly = configuration.containsKey(CONFIG_READ_ONLY_KEY) && Boolean
             .parseBoolean(configuration.get(CONFIG_READ_ONLY_KEY).toUpperCase());
 
     final String pattern = configuration.getOrDefault(CONFIG_PATTERN_KEY, "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
 
     Integer order = null;
     if (configuration.containsKey(CONFIG_ORDER_KEY)) {
       try {
         order = Integer.parseInt(configuration.get(CONFIG_ORDER_KEY));
       } catch (final NumberFormatException e) {
         logger.warn("Unable to parse order value {} of metadata field {}", configuration.get(CONFIG_ORDER_KEY),
                 inputID, e);
       }
     }
 
     if (type == null) {
       throw new IllegalArgumentException("type is null");
     }
 
     switch (type) {
       case BOOLEAN:
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 null,
                 null,
                 type,
                 null,
                 null,
                 order,
                 namespace,
                 listprovider,
                 null,
                 null);
       case DATE:
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 null,
                 null,
                 type,
                 null,
                 null,
                 order,
                 namespace,
                 listprovider,
                 StringUtils.isNotBlank(pattern) ? pattern : null,
                 null);
       case DURATION:
       case TEXT:
       case ORDERED_TEXT:
       case TEXT_LONG:
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 "",
                 null,
                 type,
                 null,
                 collectionID,
                 order,
                 namespace,
                 listprovider,
                 null,
                 null);
       case ITERABLE_TEXT:
       case MIXED_TEXT:
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 new ArrayList<>(),
                 null,
                 type,
                 null,
                 collectionID,
                 order,
                 namespace,
                 listprovider,
                 null,
                 delimiter);
       case LONG:
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 0L,
                 null,
                 Type.LONG,
                 null,
                 collectionID,
                 order,
                 namespace,
                 listprovider,
                 null, null);
       case START_DATE:
       case START_TIME:
         if (StringUtils.isBlank(pattern)) {
           throw new IllegalArgumentException(
                   "For temporal metadata field " + inputID + " of type " + type + " there needs to be a pattern.");
         }
 
         return new MetadataField(
                 inputID,
                 outputID,
                 label,
                 readOnly,
                 required,
                 null,
                 null,
                 type,
                 null,
                 null,
                 order,
                 namespace,
                 listprovider,
                 pattern,
                 null);
       default:
         throw new IllegalArgumentException("Unknown metadata type! " + type);
     }
   }
 
   public String getCollectionID() {
     return collectionID;
   }
 
   public void setCollectionID(final String collectionID) {
     this.collectionID = collectionID;
   }
 
   public String getInputID() {
     return inputID;
   }
 
   public String getLabel() {
     return label;
   }
 
   public String getListprovider() {
     return listprovider;
   }
 
   public String getNamespace() {
     return namespace;
   }
 
   public Integer getOrder() {
     return order;
   }
 
   /**
    * @return The outputID if available, inputID if it is missing.
    */
   public String getOutputID() {
     if (outputID != null) {
       return outputID;
     }
     return inputID;
   }
 
   public String getPattern() {
     return pattern;
   }
 
   public void setPattern(final String pattern) {
     this.pattern = pattern;
   }
 
   public String getDelimiter() {
     return delimiter;
   }
 
   public void setDelimiter(final String delimiter) {
     this.delimiter = delimiter;
   }
 
   public void setReadOnly(final boolean readOnly) {
     this.readOnly = readOnly;
   }
 
   public boolean isReadOnly() {
     return readOnly;
   }
 
   public boolean isRequired() {
     return required;
   }
 
   public void setUpdated(final boolean updated) {
     this.updated = updated;
   }
 
   public Type getType() {
     return type;
   }
 
   public void setType(final Type type) {
     this.type = type;
   }
 
   public void setDifferentValues() {
     value = null;
     hasDifferentValues = true;
   }
 
   public Boolean hasDifferentValues() {
     return hasDifferentValues;
   }
 
   public MetadataField readOnlyCopy() {
     final MetadataField metadataField = new MetadataField(this);
     metadataField.setReadOnly(true);
     return metadataField;
   }
 }