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// ============================================================================
// Copyright (c) 2017-2019 Nawapunth Manusitthipol (NawaMan - http://nawaman.net).
// ----------------------------------------------------------------------------
// MIT License
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// ============================================================================
package functionalj.stream;

import static functionalj.tuple.Tuple.tuple2;

import java.util.Comparator;
import java.util.HashMap;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiConsumer;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import functionalj.function.Func1;
import functionalj.function.FuncUnit1;
import functionalj.list.FuncList;
import functionalj.list.ImmutableList;
import functionalj.map.FuncMap;
import functionalj.map.ImmutableMap;
import functionalj.tuple.Tuple2;
import lombok.val;

public interface StreamPlusAdditionalTerminalOperators {
    
    public Stream stream();
    
    
    public  StreamPlus deriveWith(
            Function, Stream> action);
    
    
    public StreamPlus filter(Predicate predicate);
    
    public  StreamPlus filter(Function mapper, Predicate theCondition);
    
    public  TARGET terminate(Func1, TARGET> action);
    
    public void terminate(FuncUnit1> action);
    
    
    //-- Functionalities --
    
    public default void forEachWithIndex(
            BiConsumer action) {
        terminate(stream -> {
            if (action == null)
                return;
            
            val index = new AtomicInteger();
            stream
            .forEach(each -> action.accept(index.getAndIncrement(), each));
        });
    }
    
    //-- groupingBy --
    
    // Eager
    public default  FuncMap> groupingBy(
            Function classifier) {
        return terminate(stream -> {
            val theMap = new HashMap>();
            stream
                .collect(Collectors.groupingBy(classifier))
                .forEach((key,list)->theMap.put(key, ImmutableList.from(list)));
            return ImmutableMap.from(theMap);
        });
    }
    
    // Eager
    public default  FuncMap groupingBy(
            Function   classifier,
            Function, VALUE> aggregate) {
        return terminate(stream -> {
            val theMap = new HashMap();
            stream
                .collect(Collectors.groupingBy(classifier))
                .forEach((key,list) -> {
                    val valueList      = ImmutableList.from(list);
                    val aggregateValue = aggregate.apply(valueList);
                    theMap.put(key, aggregateValue);
                });
            return ImmutableMap.from(theMap);
        });
    }
    
    // Eager
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public default  FuncMap groupingBy(
            Function classifier,
            StreamProcessor  processor) {
        Function, VALUE> aggregate = (FuncList list) -> {
            return (VALUE)processor.process((StreamPlus)list.stream());
        };
        return groupingBy(classifier, aggregate);
    }
    
    // Eager
    public default  FuncMap groupingBy(
            Function                  classifier,
            Supplier> collectorSupplier) {
        Objects.requireNonNull(collectorSupplier);
        
        val theMap = new ConcurrentHashMap>();
        stream()
        .forEach(each -> {
            val key       = classifier.apply(each);
            val collected = theMap.computeIfAbsent(key, __ -> {
                val collector = collectorSupplier.get();
                return new Collected.ByCollector<>(collector);
            });
            
            collected.accumulate(each);
        });
        
        val mapBuilder = FuncMap.newBuilder();
        theMap
        .forEach((key, collected) -> {
            val target = collected.finish();
            mapBuilder.with(key, target);
        });
        
        val map = mapBuilder.build();
        return map;
    }
    
    //-- min-max --
    
    public default > Optional minBy(
            Func1 mapper) {
        return terminate(stream -> {
            return stream
                    .min((a,b)->mapper.apply(a).compareTo(mapper.apply(b)));
        });
    }
    
    public default > Optional maxBy(
            Func1 mapper) {
        return terminate(stream -> {
            return stream
                    .max((a,b)->mapper.apply(a).compareTo(mapper.apply(b)));
        });
    }
    
    public default  Optional minBy(
            Func1        mapper, 
            Comparator comparator) {
        return terminate(stream -> {
            return stream
                    .min((a,b)->comparator.compare(mapper.apply(a), mapper.apply(b)));
        });
    }
    
    public default  Optional maxBy(
            Func1        mapper, 
            Comparator comparator) {
        return terminate(stream -> {
            return stream
                    .max((a,b)->comparator.compare(mapper.apply(a), mapper.apply(b)));
        });
    }
    
    @SuppressWarnings("unchecked")
    public default Tuple2, Optional> minMax(
            Comparator comparator) {
        return terminate(stream -> {
            val minRef = new AtomicReference(StreamPlusHelper.dummy);
            val maxRef = new AtomicReference(StreamPlusHelper.dummy);
            stream
                .sorted(comparator)
                .forEach(each -> {
                    minRef.compareAndSet(StreamPlusHelper.dummy, each);
                    maxRef.set(each);
                });
            val min = minRef.get();
            val max = maxRef.get();
            return Tuple2.of(
                    StreamPlusHelper.dummy.equals(min) ? Optional.empty() : Optional.ofNullable((DATA)min),
                    StreamPlusHelper.dummy.equals(max) ? Optional.empty() : Optional.ofNullable((DATA)max));
        });
    }
    
    @SuppressWarnings("unchecked")
    public default > Tuple2, Optional> minMaxBy(
            Func1 mapper) {
        return terminate(stream -> {
            val minRef = new AtomicReference(StreamPlusHelper.dummy);
            val maxRef = new AtomicReference(StreamPlusHelper.dummy);
            StreamPlus.from(stream)
                .sortedBy(mapper)
                .forEach(each -> {
                    minRef.compareAndSet(StreamPlusHelper.dummy, each);
                    maxRef.set(each);
                });
            val min = minRef.get();
            val max = maxRef.get();
            return tuple2(
                    StreamPlusHelper.dummy.equals(min) ? Optional.empty() : Optional.ofNullable((DATA)min),
                    StreamPlusHelper.dummy.equals(max) ? Optional.empty() : Optional.ofNullable((DATA)max));
        });
    }
    
    @SuppressWarnings("unchecked")
    public default  Tuple2, Optional> minMaxBy(
            Func1        mapper, 
            Comparator comparator) {
        return terminate(stream -> {
            val minRef = new AtomicReference(StreamPlusHelper.dummy);
            val maxRef = new AtomicReference(StreamPlusHelper.dummy);
            StreamPlus.from(stream)
                .sortedBy(mapper, (i1, i2)->comparator.compare(i1, i2))
                .forEach(each -> {
                    minRef.compareAndSet(StreamPlusHelper.dummy, each);
                    maxRef.set(each);
                });
            val min = minRef.get();
            val max = maxRef.get();
            return tuple2(
                    StreamPlusHelper.dummy.equals(min) ? Optional.empty() : Optional.ofNullable((DATA)min),
                    StreamPlusHelper.dummy.equals(max) ? Optional.empty() : Optional.ofNullable((DATA)max));
        });
    }
    
    //-- Find --
    
    public default  Optional findFirst(
            Function mapper, 
            Predicate      theCondition) {
        return filter(mapper, theCondition)
                .findFirst();
    }
    
    public default   Optional findAny(
            Function mapper, 
            Predicate      theCondition) {
        return filter(mapper, theCondition)
                .findAny();
    }
    
    public default Optional findFirst(
            Predicate predicate) {
        return terminate(stream -> {
            return stream
                    .filter(predicate)
                    .findFirst();
        });
    }
    
    public default Optional findAny(
            Predicate predicate) {
        return terminate(stream -> {
            return stream
                    .filter(predicate)
                    .findAny();
        });
    }
    
    //-- toMap --
    
    @SuppressWarnings("unchecked")
    public default  FuncMap toMap(
            Function keyMapper) {
        return terminate(stream -> {
            val theMap = stream.collect(Collectors.toMap(keyMapper, data -> data));
            return (FuncMap)ImmutableMap.from(theMap);
        });
    }
    
    @SuppressWarnings("unchecked")
    public default  FuncMap toMap(
            Function  keyMapper,
            Function valueMapper) {
        return terminate(stream -> {
            val theMap = stream.collect(Collectors.toMap(keyMapper, valueMapper));
            return (FuncMap) ImmutableMap.from(theMap);
        });
    }
    
    @SuppressWarnings("unchecked")
    public default  FuncMap toMap(
            Function   keyMapper,
            Function valueMapper,
            BinaryOperator                   mergeFunction) {
        return terminate(stream -> {
            val theMap = stream.collect(Collectors.toMap(keyMapper, valueMapper, mergeFunction));
            return (FuncMap) ImmutableMap.from(theMap);
        });
    }
    
    @SuppressWarnings("unchecked")
    public default  FuncMap toMap(
            Function keyMapper,
            BinaryOperator                  mergeFunction) {
        return terminate(stream -> {
            val theMap = stream.collect(Collectors.toMap(keyMapper, value -> value, mergeFunction));
            return (FuncMap) ImmutableMap.from(theMap);
        });
    }
}
    

    

    

            

    

            



    
    






    
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