package org.kuali.rice.krad.service.impl;

 import org.kuali.rice.core.api.criteria.Predicate;

 import org.kuali.rice.core.api.search.SearchOperator;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.List;

 import java.util.Map;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import static org.kuali.rice.core.api.criteria.PredicateFactory.*;

 /**

  * Contains methods used in the predicate factory related to the lookup framework.

  * ***************************************************************************************************************

  * FIXME: issues to talk to the group about.

  * http://kuali.org/rice/documentation/1.0.3/UG_Global/Documents/lookupwildcards.htm

  *

  * 1) Should we support isNotNull, isNull, as wildcards?  Then do we still translate

  * null values into isNull predicates.  I believe the lookup framework right now

  * barfs on null values but that is a guess.

  *

  * 2) We need to support case insensitivity in the old lookup framework.  Right now the lookup

  * framework looks at Data dictionary entries.  This can still be configured in the DD

  * but should be placed in the lookup criteria. We could have a "flag" section on a

  * lookup sequence like foo.bar=(?i)ba*|bing

  *

  * This would translate to

  *

  * or(like("foo.bar", "ba*"), equalsIgnoreCase("foo.bar", "bing"))

  *

  * Btw.  My flag format was stolen from regex but we could use anything really.

  * http://download.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html#CASE_INSENSITIVE

  *

  * I'm currently supporting this.

  *

  * 3) In the above example, I used a case insensitive flag but Like doesn't support case

  * insensitive.  Should it?

  *

  * 4) Do we need to support escaping in the lookup framework & criteria api.  Right now the

  * lookup framework looks at Data dictionary entries.  This can still be configured in the DD

  * but should be placed in the lookup criteria.  Escaping is tricky and I worry if we support

  * it in the criteria api then it will make the criteria service much harder to make custom

  * implementations.  To me it seems it's better to make escaping behavior undefined.

  *

  * If we do support an escape character then we should probably also support a flag to treat

  * escape chars as literal like (?l) (that doesn't exist in java regex)

  *

  * http://download.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html#LITERAL

  *

  * 5) Maybe we should just support what is in the {@link org.kuali.rice.core.framework.logic.SearchOperator} class

  *

  * 6) Maybe the predicate class could have a toLookupString, toLookupMap() methods on them to translate

  * to various formats of criteria?  Or maybe this factory method & related methods should get placed into

  * krad or somewhere else?

  * ***************************************************************************************************************

  */

 class PredicateFactoryLookup {

     private static final Pattern FLAGS_PATTERN = Pattern.compile("^\\(\\?[a-z]+\\)");

     private PredicateFactoryLookup() {

         throw new IllegalArgumentException("do not call");

     }

     /**

      * This take a criteria map that is commonly used in krad-based

      * applications and transforms it to a predicate.

      *

      * The incoming map takes the form of the following possibilities:

      *

      * <ul>

      * <li>propertyPath=value</li>

      * <li>propertyPath=criteriaSequence</li>

      * </ul>

      *

      * <p>

      * The values in the map can either be a String or a Collection<Object>.

      * A String value is directly parsed into predicates.  If a collection

      * is found it is recursively parsed into predicates where each entry in the Collection

      * is anded together.

      * </p>

      *

      * <p>

      * Note: that the Collection can contain other collections or strings

      * but eventually must resolve to a string value or string criteria sequence.

      * </p>

      *

      * a simple example of a propertyPath=value:

      * <pre>

      * foo.bar=baz

      * </pre>

      * would yield

      * <pre>

      * equals("foo.bar", "baz")

      * </pre>

      *

      * a simple example of a propertyPath=criteriaSequence

      * <pre>

      * foo.bar=ba*|bing

      * </pre>

      * would yield

      * <pre>

      * or(like("foo.bar", "ba*"), equals("foo.bar", "bing"))

      * </pre>

      *

      * a compound example of a of a propertyPath=criteriaSequence

      * <pre>

      * foo.bar=[ba*,bing]      * note: [] shows a collection literal

      * </pre>

      * would yield

      * <pre>

      * and(like("foo.bar", "ba*"), equals("foo.bar", "bing"))

      * </pre>

      *

      * <p>

      * Related to null values:  Null values will be translated to isNull predicates.

      * </p>

      *

      * The criteria string may also contain flags similar to regex flags.  The current

      * supported flags are:

      *

      * <ul>

      *     <li>(?i) case insensitive</li>

      * </ul>

      *

      * To use the 'i' and 'm' flags prepend them to the criteria value, for example:

      *

      * (?im)foo

      *

      * Only the first flag sequence will be honored.  All others will be treated as literals.

      *

      * @param the root class to build the predicate on.  Cannot be null.

      * @param criteria the crtieria map.  Cannot be null or empty.

      * @throws IllegalArgumentException if clazz is null or criteria is null or empty

      */

     static Predicate fromCriteriaMap(Class<?> clazz, Map<String, ?> criteria) {

         if (clazz == null) {

             throw new IllegalArgumentException("clazz is null");

         }

         if (criteria == null || criteria.isEmpty()) {

             throw new IllegalArgumentException("criteria is null or empty");

         }

         final List<Predicate> toAnd = new ArrayList<Predicate>();

         for (Map.Entry<String, ?> entry : criteria.entrySet()) {

             final String key = entry.getKey();

             if (key == null) {

                 throw new IllegalArgumentException("criteria contains a null key");

             }

             toAnd.add(createPredicate(clazz, key, entry.getValue()));

         }

         return and(toAnd.toArray(new Predicate[]{}));

     }

     private static Predicate createPredicate(Class<?> clazz, final String key, final Object value) {

         if (value == null) {

             return isNull(key);

         } else if (value instanceof String) {

             final String flagStr = getFlagsStr((String) value);

             final String strValue = removeFlag((String) value, flagStr);

             return containsOperator(strValue) ? createFromComplexCriteriaValue(clazz, key, strValue, flagStr) :

                     createFromSimpleCriteriaValue(clazz, key, strValue, flagStr);

         } else if (value instanceof Collection) {

             final List<Predicate> ps = new ArrayList<Predicate>();

             for (Object v : (Collection<?>) value) {

                 //recurs

                 ps.add(createPredicate(clazz, key, v));

             }

             return and(ps.toArray(new Predicate[]{}));

         } else {

             throw new IllegalArgumentException(

                     "criteria map contained a value that was non supported :" + value.getClass().getName());

         }

     }

     private static Predicate createFromComplexCriteriaValue(Class<?> clazz, final String key, final String strValue,

             final String flagStr) {

         final boolean caseInsensitive = isCaseInsensitive(flagStr);

         return null;

     }

     private static Predicate createFromSimpleCriteriaValue(Class<?> clazz, final String key, final String strValue,

             final String flagStr) {

         final boolean caseInsensitive = isCaseInsensitive(flagStr);

         return caseInsensitive ? equalIgnoreCase(key, strValue) : equal(key, strValue);

     }

     private static String removeFlag(final String strValue, final String flagStr) {

         return flagStr.length() > 1 ? (strValue).substring(flagStr.length() - 1) : strValue;

     }

     //does not handle escaping, assumes non-null

     private static boolean containsOperator(String value) {

         for (SearchOperator o : SearchOperator.values()) {

             if (value.contains(o.op())) {

                 return true;

             }

         }

         return false;

     }

     private static String getFlagsStr(String criteria) {

         Matcher m = FLAGS_PATTERN.matcher(criteria);

         if (m.find()) {

             return m.group();

         }

         return "";

     }

     private static boolean isCaseInsensitive(String flagStr) {

         return flagStr.contains("i");

     }

 }