content: package act.data;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   * 
   * 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.
   * #L%
   */
  
  import act.app.App;
  import act.data.util.StringOrPattern;
  import act.util.ActContext;
  import act.util.PropertySpec;
  import org.osgl.$;
  import org.osgl.util.AdaptiveMap;
  import org.osgl.util.C;
  import org.osgl.util.S;
  import org.osgl.util.Str;
  
  import java.util.*;
  import java.util.regex.Pattern;
  
  class OutputFieldsCache {
  
      // Key to index final output fields. Key includes:
      // 1. excluded - developer declared excluded field list
      // 2. outputs - developer declared output field list
      // 3. component type - the type of the entity where field data get extracted
      private class K {
          Set<String> excluded;
          List<S.Pair> outputs;
          Class<?> componentType;
          K(Set<String> ss, List<S.Pair> ls, Class<?> componentType) {
              excluded = ss;
              outputs = ls;
              this.componentType = componentType;
          }
  
          @Override
          public int hashCode() {
              return $.hc(excluded, outputs, componentType);
          }
  
          @Override
          public boolean equals(Object obj) {
              if (obj == this) {
                  return true;
              }
              if (obj instanceof K) {
                  K that = (K) obj;
                  return $.eq(that.excluded, this.excluded)
                          && $.eq(that.outputs, this.outputs)
                          && $.eq(that.componentType, this.componentType);
              }
              return false;
          }
      }
  
      private Map<K, List<S.Pair>> cache = new HashMap<>();
  
      public List<S.Pair> getOutputFields(PropertySpec.MetaInfo spec, Class<?> componentClass, Object firstElement, ActContext context) {
          K k = new K(spec.excludedFields(context), spec.outputFieldsAndLabel(context), componentClass);
          List<S.Pair> outputs = cache.get(k);
          if (null == outputs) {
              outputs = calculateOutputs(k, firstElement);
              cache.put(k, outputs);
          }
          return outputs;
      }
  
      List<S.Pair> calculateOutputs(K k, Object firstElement) {
          Class<?> type = k.componentType;
          if ($.isSimpleType(type) && k.excluded.isEmpty() && k.outputs.isEmpty()) {
              return C.list();
          }
          List<StringOrPattern> outputs = new ArrayList<>();
          boolean hasPattern = hasPattern2(k.outputs, outputs);
          Set<String> excluded = k.excluded;
          DataPropertyRepository repo = App.instance().service(DataPropertyRepository.class);
          List<S.Pair> allFields = repo.propertyListOf(k.componentType);
          if (AdaptiveMap.class.isInstance(firstElement)) {
              Set<String> mapped = new HashSet<>();
              for (S.Pair pair : allFields) {
                  mapped.add(pair._1);
              }
              AdaptiveMap am = $.cast(firstElement);
              Map map = am.internalMap();
              for (Object o : map.keySet()) {
                  String key = S.string(o);
                  if (!mapped.contains(key)) {
                      allFields.add(S.pair(key, key));
                  }
              }
          } else if (Map.class.isInstance(firstElement)) {
              Set<String> mapped = new HashSet<>();
              List<S.Pair> toBeRemoved = new ArrayList<>();
              for (S.Pair pair : allFields) {
                  if ("empty".equalsIgnoreCase(pair._1)) {
                      toBeRemoved.add(pair);
                  } else if ("innerMap.empty".equalsIgnoreCase(pair._1)) {
                      toBeRemoved.add(pair);
                  } else {
                      mapped.add(pair._1);
                  }
              }
              allFields.removeAll(toBeRemoved);
              Map map = $.cast(firstElement);
              for (Object o : map.keySet()) {
                  String key = S.string(o);
                  if (!mapped.contains(key)) {
                      allFields.add(S.pair(key, key));
                  }
              }
          }
          if (hasPattern || outputs.isEmpty()) {
              if (!excluded.isEmpty()) {
                  List<S.Pair> finalOutputs;
                  List<StringOrPattern> lsp = new ArrayList<>();
                  boolean excludeHasPattern = hasPattern(excluded, lsp);
                  if (!excludeHasPattern) {
                      List<S.Pair> ret = new ArrayList<>(allFields);
                      for (S.Pair pair : allFields) {
                          for (String s : excluded) {
                              if (pair._1.equals(s)) {
                                  ret.remove(pair);
                                  break;
                              }
                          }
                      }
                      return ret;
                  } else {
                      finalOutputs = C.newList(allFields);
                      outer:
                      for (S.Pair pair : allFields) {
                          for (StringOrPattern sp: lsp) {
                              if (sp.matches(pair._1)) {
                                  finalOutputs.remove(pair);
                                  continue  outer;
                              }
                          }
                      }
                      return finalOutputs;
                  }
              } else {
                  if (outputs.isEmpty()) {
                      return allFields;
                  }
                  // excluded is empty and output fields has pattern
                  List<S.Pair> finalOutputs = new ArrayList<>();
                  for (StringOrPattern sp: outputs) {
                      if (sp.isPattern()) {
                          Pattern p = sp.p();
                          for (S.Pair pair: allFields) {
                              if (p.matcher(pair._1).matches()) {
                                  finalOutputs.add(pair);
                              }
                          }
                      } else {
                          for (S.Pair pair : allFields) {
                              if (S.eq(pair._1, sp.s())) {
                                  finalOutputs.add(pair);
                                  break;
                              }
                          }
                      }
                  }
                  return finalOutputs;
              }
          } else {
              if (AdaptiveMap.class.isAssignableFrom(k.componentType)) {
                  return k.outputs;
              }
              List<S.Pair> pairs = new ArrayList<>(k.outputs.size());
              for (S.Pair pair : k.outputs) {
                  if (null != pair._2) {
                      pairs.add(pair);
                  } else {
                      for (S.Pair pair0 : allFields) {
                          if (S.eq(pair._1, pair0._1)) {
                              pairs.add(pair0);
                              break;
                          }
                      }
                  }
              }
              return pairs;
          }
      }
  
      private boolean hasPattern(Collection<String> ls, List<StringOrPattern> lsp) {
          boolean b = false;
          for (String s: ls) {
              StringOrPattern sp = new StringOrPattern(s);
              b = b || sp.isPattern();
              lsp.add(sp);
          }
          return b;
      }
  
      private boolean hasPattern2(Collection<S.Pair> ls, List<StringOrPattern> lsp) {
          boolean b = false;
          for (S.Pair pair: ls) {
              StringOrPattern sp = new StringOrPattern(pair._1);
              b = b || sp.isPattern();
              lsp.add(sp);
          }
          return b;
      }
  
  
  }
  