package com.avaje.ebeaninternal.server.persist.dmlbind;

import com.avaje.ebean.bean.EntityBean;
import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
import com.avaje.ebeaninternal.server.deploy.BeanProperty;
import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocOne;

/**
 * Matches local embedded id properties to 'matching' properties from a
 * ManyToOne associated bean that is a 'imported primary key'.
 * <p>
 * This object is designed to help BindableIdEmbedded and BindableIdMap to
 * create a concatenated id from the id values from ManyToOne associated beans.
 * This can be done when those ManyToOne associated beans make up the primary
 * key. This typically means the BindableIdEmbedded is for a intersection table
 * of a Many to Many relationship.
 * </p>
 */
class MatchedImportedProperty {

  private final BeanPropertyAssocOne<?> assocOne;

  private final BeanProperty foreignProp;

  private final BeanProperty localProp;

  protected MatchedImportedProperty(BeanPropertyAssocOne<?> assocOne, BeanProperty foreignProp,
                                    BeanProperty localProp) {
    this.assocOne = assocOne;
    this.foreignProp = foreignProp;
    this.localProp = localProp;
  }

  protected void populate(EntityBean sourceBean, EntityBean destBean) {
    Object assocBean = assocOne.getValue(sourceBean);
    if (assocBean == null) {
      String msg = "The assoc bean for " + assocOne + " is null?";
      throw new NullPointerException(msg);
    }

    Object value = foreignProp.getValue((EntityBean) assocBean);
    localProp.setValue(destBean, value);
  }

  /**
   * Create the array of matchedImportedProperty based on the properties and descriptor.
   */
  protected static MatchedImportedProperty[] build(BeanProperty[] props, BeanDescriptor<?> desc) {

    MatchedImportedProperty[] matches = new MatchedImportedProperty[props.length];

    for (int i = 0; i < props.length; i++) {
      // find matching assoc one property for dbColumn
      matches[i] = MatchedImportedProperty.findMatch(props[i], desc);
      if (matches[i] == null) {
        // ok, the assoc ones are not on the bean?
        return null;
      }
    }
    return matches;
  }

  private static MatchedImportedProperty findMatch(BeanProperty prop, BeanDescriptor<?> desc) {

    // find matching against the local database column
    String dbColumn = prop.getDbColumn();

    BeanPropertyAssocOne<?>[] assocOnes = desc.propertiesOne();
    for (int i = 0; i < assocOnes.length; i++) {
      if (assocOnes[i].isImportedPrimaryKey()) {

        // search using the ImportedId from the assoc one
        BeanProperty foreignMatch = assocOnes[i].getImportedId().findMatchImport(dbColumn);

        if (foreignMatch != null) {
          return new MatchedImportedProperty(assocOnes[i], foreignMatch, prop);
        }
      }
    }

    // there was no matching assoc one property.
    // example UserRole bean missing assoc one to User?
    return null;
  }

}
