/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.
   */
  package org.apache.commons.jexl3.internal;
  
  import org.apache.commons.jexl3.JexlContext;
  import org.apache.commons.jexl3.JexlOptions;
  import org.apache.commons.jexl3.parser.ASTJexlLambda;
  
  import java.util.Arrays;
  import java.util.Objects;
  
  /**
   * A Script closure.
   */
  public class Closure extends Script {
      /** The frame. */
      protected final Frame frame;
      /** The options. */
      protected final JexlOptions options;
  
      /**
       * Creates a closure.
       * @param theCaller the calling interpreter
       * @param lambda the lambda
       */
      protected Closure(final Interpreter theCaller, final ASTJexlLambda lambda) {
          super(theCaller.jexl, null, lambda);
          frame = lambda.createFrame(theCaller.frame);
          final JexlOptions callerOptions = theCaller.options;
          options = callerOptions != null ? callerOptions.copy() :  null;
      }
  
      /**
       * Creates a curried version of a script.
       * @param base the base script
       * @param args the script arguments
       */
      protected Closure(final Script base, final Object[] args) {
          super(base.jexl, base.source, base.script);
          final Frame sf = (base instanceof Closure) ? ((Closure) base).frame :  null;
          frame = sf == null
                  ? script.createFrame(args)
                  : sf.assign(args);
          JexlOptions closureOptions = null;
          if (base instanceof Closure) {
              closureOptions = ((Closure) base).options;
          }
          options = closureOptions != null ? closureOptions.copy() :  null;
      }
  
      @Override
      public int hashCode() {
          // CSOFF: Magic number
          int hash = 17;
          hash = 31 * hash + Objects.hashCode(jexl);
          hash = 31 * hash + Objects.hashCode(source);
          hash = 31 * hash + (frame != null ? Arrays.deepHashCode(frame.nocycleStack(this)) : 0);
          // CSON: Magic number
          return hash;
      }
  
      @Override
      public boolean equals(final Object obj) {
          if (obj == null) {
              return false;
          }
          if (getClass() != obj.getClass()) {
              return false;
          }
          final Closure other = (Closure) obj;
          if (this.jexl != other.jexl) {
              return false;
          }
          if (!Objects.equals(this.source, other.source)) {
              return false;
          }
          if (this.frame == other.frame) {
              return true;
          }
          return Arrays.deepEquals(
                  this.frame.nocycleStack(this),
                  other.frame.nocycleStack(other));
      }
  
      @Override
     public String[] getUnboundParameters() {
         return frame.getUnboundParameters();
     }
 
     /**
      * Sets the captured index of a given symbol, ie the target index of a parent
      * captured symbol in this closure's frame.
      * <p>This is meant to allow a locally defined function to "see" and call
      * itself as a local (captured) variable;
      * in other words, this allows recursive call of a function.
      * @param symbol the symbol index (in the caller of this closure)
      * @param value the value to set in the local frame
      */
     public void setCaptured(final int symbol, final Object value) {
         if (script instanceof ASTJexlLambda) {
             final ASTJexlLambda lambda = (ASTJexlLambda) script;
             final Scope scope = lambda.getScope();
             if (scope != null) {
                 final Integer reg = scope.getCaptured(symbol);
                 if (reg != null) {
                     frame.set(reg, value);
                 }
             }
         }
     }
 
     @Override
     public Object evaluate(final JexlContext context) {
         return execute(context, (Object[])null);
     }
 
     @Override
     public Object execute(final JexlContext context) {
         return execute(context, (Object[])null);
     }
 
     @Override
     public Object execute(final JexlContext context, final Object... args) {
         final Frame local = frame != null? frame.assign(args) : null;
         final Interpreter interpreter = createInterpreter(context, local, options);
         return interpreter.runClosure(this, null);
     }
 
     @Override
     public Callable callable(final JexlContext context, final Object... args) {
         final Frame local = frame != null? frame.assign(args) : null;
         return new Callable(createInterpreter(context, local, options)) {
             @Override
             public Object interpret() {
                 return interpreter.runClosure(Closure.this, null);
             }
         };
     }
 }