package com.atlassian.pageobjects.elements.query;
   
   import com.atlassian.pageobjects.elements.timeout.TimeoutType;
   import com.atlassian.pageobjects.elements.timeout.Timeouts;
   import com.google.common.base.Supplier;
   import com.google.common.collect.Iterables;
   import org.apache.commons.lang.ArrayUtils;
   import org.hamcrest.Matcher;
   import org.hamcrest.StringDescription;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static com.atlassian.pageobjects.elements.util.StringConcat.asString;
  import static com.google.common.base.Preconditions.checkNotNull;
  import static org.hamcrest.Matchers.equalTo;
  
  /**
   * Utilities to create miscellaneous {@link TimedCondition}s.
   *
   */
  public final class Conditions
  {
      private static final Logger log = LoggerFactory.getLogger(Conditions.class);
  
      private static final int DEFAULT_TIMEOUT = 100;
  
  
      private Conditions()
      {
          throw new AssertionError("No way");
      }
  
      /**
       * Return new timed condition that is a negation of <tt>condition</tt>.
       *
       * @param condition condition to be negated
       * @return negated {@link TimedCondition} instance.
       */
      public static TimedQuery<Boolean> not(TimedQuery<Boolean> condition)
      {
          if (condition instanceof Not)
          {
              return asDecorator(condition).wrapped;
          }
          return new Not(condition);
      }
  
      /**
       * <p>
       * Return new combinable condition that is logical product of <tt>conditions</tt>.
       *
       * <p>
       * The resulting condition will have interval of the first condition
       * in the <tt>conditions</tt> array,
       *
       * @param conditions conditions to conjoin
       * @return product of <tt>conditions</tt>
       * @throws IllegalArgumentException if <tt>conditions</tt> array is <code>null</code> or empty
       *
       * @see TimedCondition#interval()
       */
      public static CombinableCondition and(TimedQuery<Boolean>... conditions)
      {
          return new And(conditions);
      }
  
      /**
       * <p>
       * Return new combinable condition that is logical product of <tt>conditions</tt>.
       *
       * <p>
       * The resulting condition will have interval of the first condition
       * in the <tt>conditions</tt> array,
       *
       * @param conditions conditions to conjoin
       * @return product of <tt>conditions</tt>
       * @throws IllegalArgumentException if <tt>conditions</tt> array is <code>null</code> or empty
       *
       * @see TimedCondition#interval()
       */
      public static CombinableCondition and(Iterable<TimedQuery<Boolean>> conditions)
      {
          return and(Iterables.toArray(conditions, TimedQuery.class));
      }
  
      /**
       * <p>
       * Return new combinable condition that is logical sum of <tt>conditions</tt>.
       *
       * <p>
       * The resulting condition will have interval of the first condition
       * in the <tt>conditions</tt> array,
       *
       * @param conditions conditions to sum
       * @return logical sum of <tt>conditions</tt>
       * @throws IllegalArgumentException if <tt>conditions</tt> array is <code>null</code> or empty
       *
       * @see TimedCondition#interval()
       */
     public static CombinableCondition or(TimedQuery<Boolean>... conditions)
     {
         return new Or(conditions);
     }
 
     /**
      * <p>
      * Return new combinable condition that is logical sum of <tt>conditions</tt>.
      *
      * <p>
      * The resulting condition will have interval of the first condition
      * in the <tt>conditions</tt> array,
      *
      * @param conditions conditions to sum
      * @return logical sum of <tt>conditions</tt>
      * @throws IllegalArgumentException if <tt>conditions</tt> array is <code>null</code> or empty
      *
      * @see TimedCondition#interval()
      */
     public static CombinableCondition or(Iterable<TimedQuery<Boolean>> conditions)
     {
         return or(Iterables.toArray(conditions, TimedQuery.class));
     }
 
     /**
      * <p>
      * Returns a condition that combines <tt>original</tt> and <tt>dependant</tt> in a manner that dependant condition
      * will only ever be retrieved if the <tt>original</tt> condition is <code>true</code>. This is useful
      * when dependant condition may only be retrieved given the original condition is <code>true</code>.
      * </p>
      *
      * <p>
      * The supplier for dependant condition is allowed to return <code>null</code> or throw exception if the
      * original condition returns false. But it <i>may not</i> do so given the original condition is <code>true</code>,
      * as this will lead to <code>NullPointerException</code> or the raised exception be propagated by
      * this condition respectively.
      * </p>
      *
      * @param original original condition
      * @param dependant supplier for dependant condition that will only be evaluated given the original condition
      * evaluates to <code>true</code>
      * @return new dependant condition
      */
     public static TimedCondition dependantCondition(TimedQuery<Boolean> original, Supplier<TimedQuery<Boolean>> dependant)
     {
         return new DependantCondition(original, dependant);
     }
 
 
     /**
      * <p>
      * Return condition that will be <code>true</code>, if given <tt>matcher</tt> will match the <tt>query</tt>. Any
      * Hamcrest matcher implementation may be used.
      * </p>
      * <p>
      * Example:<br>
      *
      * <code>
      *     TimedCondition textEquals = Conditions.forMatcher(element.getText(), isEqualTo("blah"));
      * </code>
      * </p>
      *
      * @param query timed query to match
      * @param matcher matcher for the query
      * @param <T> type of the result
      * @return new matching condition
      */
     public static <T> TimedCondition forMatcher(TimedQuery<T> query, Matcher<? super T> matcher)
     {
         return new MatchingCondition<T>(query, matcher);
     }
 
     /**
      * Returns timed condition verifying that given query will evaluate to value equal to <tt>value</tt>. The timeouts
      * are inherited from the provided <tt>query</tt>
      *
      * @param value value that <tt>query</tt> should be equalt to
      * @param query the timed query
      * @param <T> type of the value
      * @return timed condition for query equality to value
      */
     public static <T> TimedCondition isEqual(T value, TimedQuery<T> query)
     {
         return forMatcher(query, equalTo(value));
     }
 
 
     /**
      * Returns a timed condition, whose current evaluation is based on a value provided by given <tt>supplier</tt>.
      *
      * @param supplier supplier of the current condition value
      * @return new query based on supplier
      */
     public static TimedCondition forSupplier(final Supplier<Boolean> supplier)
     {
         return forSupplier(DEFAULT_TIMEOUT, supplier);
     }
 
     /**
      * Returns a timed condition, whose current evaluation is based on a value provided by given <tt>supplier</tt>.
      *
      * @param defaultTimeout default timeout of the condition
      * @param supplier supplier of the current condition value
      * @return new query based on supplier
      */
     public static TimedCondition forSupplier(long defaultTimeout, final Supplier<Boolean> supplier)
     {
         return new AbstractTimedCondition(defaultTimeout, PollingQuery.DEFAULT_INTERVAL) {
             @Override
             protected Boolean currentValue() {
                 return supplier.get();
             }
         };
     }
 
     /**
      * Returns a timed condition, whose current evaluation is based on a value provided by given <tt>supplier</tt>.
      *
      * @param timeouts an instance of timeouts to use for the new condition
      * @param supplier supplier of the current condition value
      * @return new query based on supplier
      */
     public static TimedCondition forSupplier(Timeouts timeouts, final Supplier<Boolean> supplier)
     {
         return new AbstractTimedCondition(timeouts.timeoutFor(TimeoutType.DEFAULT), timeouts.timeoutFor(TimeoutType.EVALUATION_INTERVAL)) {
             @Override
             protected Boolean currentValue() {
                 return supplier.get();
             }
         };
     }
 
     /**
      * A timed condition that always returns <code>true</code>
      *
      * @return timed condition that always returns true
      */
     public static TimedCondition alwaysTrue()
     {
         return new StaticCondition(true);
     }
 
     /**
      * A timed condition that always returns <code>false</code>
      *
      * @return timed condition that always returns false
      */
     public static TimedCondition alwaysFalse()
     {
         return new StaticCondition(false);
     }
 
     private static AbstractConditionDecorator asDecorator(TimedQuery<Boolean> condition)
     {
         return (AbstractConditionDecorator) condition;
     }
 
 
     private static class StaticCondition extends AbstractTimedCondition
     {
         private final Boolean value;
 
         public StaticCondition(Boolean value)
         {
             super(DEFAULT_TIMEOUT, DEFAULT_INTERVAL);
             this.value = checkNotNull(value);
         }
 
         @Override
         protected Boolean currentValue()
         {
             return value;
         }
     }
 
 
     /**
      * A timed condition that may be logically combined with others, by means of basic logical operations: 'and'/'or'. 
      *
      */
     public static interface CombinableCondition extends TimedCondition
     {
         /**
          * Combine <tt>other</tt> condition with this condition logical query, such that the resulting condition
          * represents a logical product of this condition and <tt>other</tt>.
          *
          * @param other condition to combine with this one
          * @return new combined 'and' condition
          */
         CombinableCondition and(TimedCondition other);
 
         /**
          * Combine <tt>other</tt> condition with this condition logical query, such that the resulting condition
          * represents a logical sum of this condition and <tt>other</tt>.
          *
          * @param other condition to combine with this one
          * @return new combined 'or' condition
          */
         CombinableCondition or(TimedCondition other);
 
     }
 
 
     private abstract static class AbstractConditionDecorator extends AbstractTimedCondition
     {
         protected final TimedQuery<Boolean> wrapped;
 
         public AbstractConditionDecorator(TimedQuery<Boolean> wrapped)
         {
             super(wrapped);
             this.wrapped = checkNotNull(wrapped, "wrapped");
         }
     }
 
     private abstract static class AbstractConditionsDecorator extends AbstractTimedCondition implements CombinableCondition
     {
         protected final TimedQuery<Boolean>[] conditions;
 
         public AbstractConditionsDecorator(TimedQuery<Boolean>... conditions)
         {
             super(conditions[0]);
             this.conditions = conditions;
         }
 
         @Override
         public String toString()
         {
             StringBuilder answer = new StringBuilder(conditions.length * 20).append(getClass().getName()).append(":\n");
             for (TimedQuery<Boolean> condition : conditions)
             {
                 answer.append(" -").append(condition.toString()).append('\n');
             }
             return answer.deleteCharAt(answer.length()-1).toString();
         }
     }
 
     private static class Not extends AbstractConditionDecorator
     {
         public Not(TimedQuery<Boolean> other)
         {
             super(other);
         }
 
         public Boolean currentValue()
         {
             return !wrapped.now();
         }
 
         @Override
         public String toString()
         {
             return asString("Negated: <", wrapped, ">");
         }
     }
 
     private static class And extends AbstractConditionsDecorator
     {
         public And(TimedQuery<Boolean>... conditions)
         {
             super(conditions);
         }
 
         And(TimedQuery<Boolean>[] somes, TimedQuery<Boolean>[] more)
         {
             super((TimedCondition[]) ArrayUtils.addAll(somes, more));
         }
 
         And(TimedQuery<Boolean>[] somes, TimedQuery<Boolean> oneMore)
         {
             super((TimedCondition[]) ArrayUtils.add(somes, oneMore));
         }
 
         public Boolean currentValue()
         {
             boolean result = true;
             for (TimedQuery<Boolean> condition : conditions)
             {
                 // null should not really happen if TimedCondition contract is observed
                 final boolean next = condition.now() != null ? condition.now() : false;
                 result &= next;
                 if (!result)
                 {
                     log.debug(asString("[And] Condition <",condition,"> returned false"));
                     break;
                 }
             }
             return result;
         }
 
         public CombinableCondition and(TimedCondition other)
         {
             if (other.getClass().equals(And.class))
             {
                 return new And(this.conditions, ((And) other).conditions);
             }
             return new And(this.conditions, other);
         }
 
         public CombinableCondition or(TimedCondition other)
         {
             if (other instanceof Or)
             {
                 return ((Or)other).or(this);
             }
             return new Or(this, other);
         }
     }
 
     private static class Or extends AbstractConditionsDecorator
     {
         public Or(TimedQuery<Boolean>... conditions)
         {
             super(conditions);
         }
 
         Or(TimedQuery<Boolean>[] somes, TimedQuery<Boolean>[] more)
         {
             super((TimedCondition[]) ArrayUtils.addAll(somes, more));
         }
 
         Or(TimedQuery<Boolean>[] somes, TimedQuery<Boolean> oneMore)
         {
             super((TimedCondition[]) ArrayUtils.add(somes, oneMore));
         }
 
         public Boolean currentValue()
         {
             boolean result = false;
             for (TimedQuery<Boolean> condition : conditions)
             {
                 // null should not really happen if TimedCondition contract is observed
                 final boolean next = condition.now() != null ? condition.now() : false;
                 result |= next;
                 if (result)
                 {
                     break;
                 }
                 log.debug(asString("[Or] Condition <",condition,"> returned false"));
             }
             return result;
         }
 
         public CombinableCondition and(TimedCondition other)
         {
             if (other instanceof And)
             {
                 return ((And)other).and(this);
             }
             return new And(this, other);
         }
 
         public CombinableCondition or(TimedCondition other)
         {
             if (other.getClass().equals(Or.class))
             {
                 return new Or(this.conditions, ((Or) other).conditions);
             }
             return new Or(this.conditions, other);
         }
     }
 
     private static final class DependantCondition extends AbstractConditionDecorator
     {
         private final Supplier<TimedQuery<Boolean>> dependant;
 
         DependantCondition(TimedQuery<Boolean> original, Supplier<TimedQuery<Boolean>> dependant)
         {
             super(original);
             this.dependant = checkNotNull(dependant, "dependant");
         }
 
         @Override
         public Boolean currentValue()
         {
             return wrapped.now() && dependant.get().now();
         }
 
         @Override
         public String toString()
         {
             if (wrapped.now())
             {
                 TimedQuery<Boolean> dep = dependant.get();
                 return asString("DependantCondition[original=",wrapped,",dependant=",dep,"]");
             }
             return asString("DependantCondition[original=",wrapped,"]");
         }
     }
 
 
     static final class MatchingCondition<T> extends AbstractTimedCondition
     {
         final TimedQuery<T> query;
         final Matcher<? super T> matcher;
 
         T lastValue;
 
         public MatchingCondition(final TimedQuery<T> query, final Matcher<? super T> matcher)
         {
             super(query);
             this.query = checkNotNull(query);
             this.matcher = checkNotNull(matcher);
         }
 
         @Override
         protected Boolean currentValue()
         {
             lastValue = query.now();
             return matcher.matches(lastValue);
         }
 
         @Override
         public String toString()
         {
             return super.toString() + new StringDescription().appendText("[query=").appendValue(query)
                     .appendText("][matcher=").appendDescriptionOf(matcher).appendText("]");
         }
     }
 }