/*
 * Copyright 2007 the original author or authors.
 *
 * 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.
 */

package org.gradle.api.internal;

import groovy.lang.Closure;
import groovy.lang.MissingPropertyException;
import org.gradle.api.InvalidUserDataException;
import org.gradle.api.internal.plugins.DefaultConvention;
import org.gradle.api.plugins.Convention;
import org.gradle.internal.reflect.JavaReflectionUtil;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;

import static org.gradle.util.GUtil.uncheckedCall;

public class ConventionAwareHelper implements ConventionMapping, HasConvention {
    //prefix internal fields with _ so that they don't get into the way of propertyMissing()
    private final Convention _convention;
    private final IConventionAware _source;
    private final Set<String> _propertyNames;
    private final Map<String, MappedPropertyImpl> _mappings = new HashMap<String, MappedPropertyImpl>();

    /**
     * @see org.gradle.api.internal.AsmBackedClassGenerator.ClassBuilderImpl#mixInConventionAware()
     */
    public ConventionAwareHelper(IConventionAware source) {
        this(source, new DefaultConvention());
    }

    public ConventionAwareHelper(IConventionAware source, Convention convention) {
        this._source = source;
        this._convention = convention;
        this._propertyNames = JavaReflectionUtil.propertyNames(source);
    }

    private interface Value<T> {
        T getValue(Convention convention, IConventionAware conventionAwareObject);
    }

    private MappedProperty map(String propertyName, Value<?> value) {
        if (!_propertyNames.contains(propertyName)) {
            throw new InvalidUserDataException(
                    "You can't map a property that does not exist: propertyName=" + propertyName);
        }

        MappedPropertyImpl mappedProperty = new MappedPropertyImpl(value);
        _mappings.put(propertyName, mappedProperty);
        return mappedProperty;
    }

    public MappedProperty map(String propertyName, final Closure<?> value) {
        return map(propertyName, new Value<Object>() {
            public Object getValue(Convention convention, IConventionAware conventionAwareObject) {
                switch (value.getMaximumNumberOfParameters()) {
                    case 0:
                        return value.call();
                    case 1:
                        return value.call(convention);
                    default:
                        return value.call(convention, conventionAwareObject);
                }
            }
        });
    }

    public MappedProperty map(String propertyName, final Callable<?> value) {
        return map(propertyName, new Value<Object>() {
            public Object getValue(Convention convention, IConventionAware conventionAwareObject) {
                return uncheckedCall(value);
            }
        });
    }

    public void propertyMissing(String name, Object value) {
        if (value instanceof Closure) {
            map(name, (Closure) value);
        } else {
            throw new MissingPropertyException(name, getClass());
        }
    }

    public <T> T getConventionValue(T actualValue, String propertyName, boolean isExplicitValue) {
        if (isExplicitValue) {
            return actualValue;
        }

        Object returnValue = actualValue;
        if (_mappings.containsKey(propertyName)) {
            boolean useMapping = true;
            if (actualValue instanceof Collection && !((Collection<?>) actualValue).isEmpty()) {
                useMapping = false;
            } else if (actualValue instanceof Map && !((Map<?, ?>) actualValue).isEmpty()) {
                useMapping = false;
            }
            if (useMapping) {
                returnValue = _mappings.get(propertyName).getValue(_convention, _source);
            }
        }
        return (T) returnValue;
    }

    public Convention getConvention() {
        return _convention;
    }

    private static class MappedPropertyImpl implements MappedProperty {
        private final Value<?> value;
        private boolean haveValue;
        private boolean cache;
        private Object cachedValue;

        private MappedPropertyImpl(Value<?> value) {
            this.value = value;
        }

        public Object getValue(Convention convention, IConventionAware conventionAwareObject) {
            if (!cache) {
                return value.getValue(convention, conventionAwareObject);
            }
            if (!haveValue) {
                cachedValue = value.getValue(convention, conventionAwareObject);
                haveValue = true;
            }
            return cachedValue;
        }

        public void cache() {
            cache = true;
            cachedValue = null;
        }
    }
}

@@ -1989,131 +1989,8 @@
  %7D%0A%0A
-    private interface Value%3CT%3E %7B%0A        T getValue(Convention convention, IConventionAware conventionAwareObject);%0A    %7D%0A%0A
     
@@ -2037,30 +2037,42 @@
 tyName, 
-Value%3C?%3E value
+MappedPropertyImpl mapping
 ) %7B%0A    
@@ -2185,20 +2185,16 @@
         
-    
 %22You can
@@ -2279,83 +2279,8 @@
  %7D%0A%0A
-        MappedPropertyImpl mappedProperty = new MappedPropertyImpl(value);%0A
     
@@ -2315,26 +2315,19 @@
 me, mapp
-edProperty
+ing
 );%0A     
@@ -2340,26 +2340,19 @@
 urn mapp
-edProperty
+ing
 ;%0A    %7D%0A
@@ -2462,37 +2462,42 @@
 tyName, new 
-Value%3CObject%3E
+MappedPropertyImpl
 () %7B%0A       
@@ -2507,33 +2507,35 @@
   public Object 
-g
+doG
 etValue(Conventi
@@ -3088,21 +3088,26 @@
 new 
-Value%3CObject%3E
+MappedPropertyImpl
 () %7B
@@ -3125,33 +3125,35 @@
   public Object 
-g
+doG
 etValue(Conventi
@@ -3709,22 +3709,17 @@
         
-Object
+T
  returnV
@@ -4163,16 +4163,20 @@
 nValue =
+ (T)
  _mappin
@@ -4266,20 +4266,16 @@
   return
- (T)
  returnV
@@ -4381,16 +4381,25 @@
  static 
+abstract 
 class Ma
@@ -4447,46 +4447,8 @@
 y %7B%0A
-        private final Value%3C?%3E value;%0A
     
@@ -4550,104 +4550,8 @@
 e;%0A%0A
-        private MappedPropertyImpl(Value%3C?%3E value) %7B%0A            this.value = value;%0A        %7D%0A%0A
     
@@ -4691,23 +4691,19 @@
  return 
-value.g
+doG
 etValue(
@@ -4812,23 +4812,19 @@
 Value = 
-value.g
+doG
 etValue(
@@ -4942,32 +4942,50 @@
 lue;%0A        %7D%0A%0A
+        @Override%0A
         public v
@@ -5061,21 +5061,121 @@
 l;%0A        %7D
+%0A%0A        abstract Object doGetValue(Convention convention, IConventionAware conventionAwareObject);
 %0A    %7D%0A%7D%0A

Make convention mapping more memory efficient