/*
 * 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.
 */

#ifndef _DECAF_UTIL_STLMAP_H_
#define _DECAF_UTIL_STLMAP_H_

#include <map>
#include <memory>
#include <decaf/lang/Pointer.h>
#include <decaf/lang/exceptions/UnsupportedOperationException.h>
#include <decaf/util/ConcurrentModificationException.h>
#include <decaf/util/NoSuchElementException.h>
#include <decaf/util/AbstractSet.h>
#include <decaf/util/AbstractCollection.h>
#include <decaf/util/concurrent/Synchronizable.h>
#include <decaf/util/concurrent/Mutex.h>
#include <decaf/util/comparators/Less.h>
#include <decaf/util/Map.h>
#include <decaf/util/Collection.h>
#include <decaf/util/Set.h>
#include <decaf/util/Iterator.h>

namespace decaf{
namespace util{

    /**
     * Map template that wraps around a std::map to provide
     * a more user-friendly interface and to provide common
     * functions that do not exist in std::map.
     *
     * @since 1.0
     */
    template <typename K, typename V, typename COMPARATOR = decaf::util::comparators::Less<K> >
    class StlMap : public Map<K, V> {
    private:

        std::map<K,V,COMPARATOR> valueMap;
        mutable concurrent::Mutex mutex;
        int modCount;

    private:

        class AbstractMapIterator {
        protected:

            mutable int position;
            int expectedModCount;
            typename std::map<K,V,COMPARATOR>::iterator futureEntry;
            typename std::map<K,V,COMPARATOR>::iterator currentEntry;

            StlMap* associatedMap;

        private:

            AbstractMapIterator(const AbstractMapIterator&);
            AbstractMapIterator& operator= (const AbstractMapIterator&);

        public:

            AbstractMapIterator(StlMap* parent) : position(0),
                                                  expectedModCount(parent->modCount),
                                                  futureEntry(parent->valueMap.begin()),
                                                  currentEntry(parent->valueMap.end()),
                                                  associatedMap(parent) {
            }

            virtual ~AbstractMapIterator() {}

            virtual bool checkHasNext() const {
                if (futureEntry != this->associatedMap->valueMap.end()) {
                    return true;
                }
                return false;
            }

            void checkConcurrentMod() const {
                if (expectedModCount != this->associatedMap->modCount) {
                    throw ConcurrentModificationException(
                        __FILE__, __LINE__, "StlMap modified outside this iterator");
                }
            }

            void makeNext() {
                checkConcurrentMod();

                if (!checkHasNext()) {
                    throw NoSuchElementException(__FILE__, __LINE__, "No next element");
                }

                currentEntry = futureEntry;
                futureEntry++;
            }

            virtual void doRemove() {

                checkConcurrentMod();

                if (currentEntry == this->associatedMap->valueMap.end()) {
                    throw decaf::lang::exceptions::IllegalStateException(
                        __FILE__, __LINE__, "Remove called before call to next()");
                }

                this->associatedMap->valueMap.erase(currentEntry);
                currentEntry = this->associatedMap->valueMap.end();

                expectedModCount++;
                associatedMap->modCount++;
            }
        };

        class EntryIterator : public Iterator< MapEntry<K,V> >, public AbstractMapIterator {
        private:

            EntryIterator(const EntryIterator&);
            EntryIterator& operator= (const EntryIterator&);

        public:

            EntryIterator(StlMap* parent) : AbstractMapIterator(parent) {}

            virtual ~EntryIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual MapEntry<K, V> next() {
                this->makeNext();
                return MapEntry<K, V>(this->currentEntry->first, this->currentEntry->second);
            }

            virtual void remove() {
                this->doRemove();
            }
        };

        class KeyIterator : public Iterator<K>, public AbstractMapIterator {
        private:

            KeyIterator(const KeyIterator&);
            KeyIterator& operator= (const KeyIterator&);

        public:

            KeyIterator(StlMap* parent) : AbstractMapIterator(parent) {}

            virtual ~KeyIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual K next() {
                this->makeNext();
                return this->currentEntry->first;
            }

            virtual void remove() {
                this->doRemove();
            }
        };

        class ValueIterator : public Iterator<V>, public AbstractMapIterator {
        private:

            ValueIterator(const ValueIterator&);
            ValueIterator& operator= (const ValueIterator&);

        public:

            ValueIterator(StlMap* parent) : AbstractMapIterator(parent) {
            }

            virtual ~ValueIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual V next() {
                this->makeNext();
                return this->currentEntry->second;
            }

            virtual void remove() {
                this->doRemove();
            }
        };

    private:

        class ConstAbstractMapIterator {
        protected:

            mutable int position;
            int expectedModCount;
            typename std::map<K,V,COMPARATOR>::const_iterator futureEntry;
            typename std::map<K,V,COMPARATOR>::const_iterator currentEntry;

            const StlMap* associatedMap;

        private:

            ConstAbstractMapIterator(const ConstAbstractMapIterator&);
            ConstAbstractMapIterator& operator= (const ConstAbstractMapIterator&);

        public:

            ConstAbstractMapIterator(const StlMap* parent) : position(0),
                                                             expectedModCount(parent->modCount),
                                                             futureEntry(parent->valueMap.begin()),
                                                             currentEntry(parent->valueMap.end()),
                                                             associatedMap(parent) {
            }

            virtual ~ConstAbstractMapIterator() {}

            virtual bool checkHasNext() const {
                if (futureEntry != this->associatedMap->valueMap.end()) {
                    return true;
                }
                return false;
            }

            void checkConcurrentMod() const {
                if (expectedModCount != this->associatedMap->modCount) {
                    throw ConcurrentModificationException(
                        __FILE__, __LINE__, "StlMap modified outside this iterator");
                }
            }

            void makeNext() {
                checkConcurrentMod();

                if (!checkHasNext()) {
                    throw NoSuchElementException(__FILE__, __LINE__, "No next element");
                }

                currentEntry = futureEntry;
                futureEntry++;
            }
        };

        class ConstEntryIterator : public Iterator< MapEntry<K,V> >, public ConstAbstractMapIterator {
        private:

            ConstEntryIterator(const ConstEntryIterator&);
            ConstEntryIterator& operator= (const ConstEntryIterator&);

        public:

            ConstEntryIterator(const StlMap* parent) : ConstAbstractMapIterator(parent) {}

            virtual ~ConstEntryIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual MapEntry<K, V> next() {
                this->makeNext();
                return MapEntry<K, V>(this->currentEntry->first, this->currentEntry->second);
            }

            virtual void remove() {
                throw lang::exceptions::UnsupportedOperationException(
                    __FILE__, __LINE__, "Cannot write to a const Iterator." );
            }
        };

        class ConstKeyIterator : public Iterator<K>, public ConstAbstractMapIterator {
        private:

            ConstKeyIterator(const ConstKeyIterator&);
            ConstKeyIterator& operator= (const ConstKeyIterator&);

        public:

            ConstKeyIterator(const StlMap* parent) : ConstAbstractMapIterator(parent) {
            }

            virtual ~ConstKeyIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual K next() {
                this->makeNext();
                return this->currentEntry->first;
            }

            virtual void remove() {
                throw lang::exceptions::UnsupportedOperationException(
                    __FILE__, __LINE__, "Cannot write to a const Iterator." );
            }
        };

        class ConstValueIterator : public Iterator<V>, public ConstAbstractMapIterator {
        private:

            ConstValueIterator(const ConstValueIterator&);
            ConstValueIterator& operator= (const ConstValueIterator&);

        public:

            ConstValueIterator(const StlMap* parent) : ConstAbstractMapIterator(parent) {}

            virtual ~ConstValueIterator() {}

            virtual bool hasNext() const {
                return this->checkHasNext();
            }

            virtual V next() {
                this->makeNext();
                return this->currentEntry->second;
            }

            virtual void remove() {
                throw lang::exceptions::UnsupportedOperationException(
                    __FILE__, __LINE__, "Cannot write to a const Iterator." );
            }
        };

    private:

        // Special Set implementation that is backed by this HashMap
        class StlMapEntrySet : public AbstractSet< MapEntry<K, V> > {
        private:

            StlMap* associatedMap;

        private:

            StlMapEntrySet(const StlMapEntrySet&);
            StlMapEntrySet& operator= (const StlMapEntrySet&);

        public:

            StlMapEntrySet(StlMap* parent) : AbstractSet< MapEntry<K,V> >(), associatedMap(parent) {}

            virtual ~StlMapEntrySet() {}

            virtual int size() const {
                return associatedMap->size();
            }

            virtual void clear() {
                associatedMap->clear();
            }

            virtual bool remove(const MapEntry<K,V>& entry) {
                if (this->associatedMap->containsKey(entry.getKey()) &&
                    this->associatedMap->get(entry.getKey()) == entry.getValue()) {
                    associatedMap->remove(entry.getKey());
                    return true;
                }

                return false;
            }

            virtual bool contains(const MapEntry<K,V>& entry) const {
                if (this->associatedMap->containsKey(entry.getKey()) &&
                    this->associatedMap->get(entry.getKey()) == entry.getValue()) {
                    return true;
                }
                return false;
            }

            virtual Iterator< MapEntry<K, V> >* iterator() {
                return new EntryIterator(associatedMap);
            }

            virtual Iterator< MapEntry<K, V> >* iterator() const {
                return new ConstEntryIterator(associatedMap);
            }
        };

        // Special Set implementation that is backed by this HashMap
        class ConstStlMapEntrySet : public AbstractSet< MapEntry<K, V> > {
        private:

            const StlMap* associatedMap;

        private:

            ConstStlMapEntrySet(const ConstStlMapEntrySet&);
            ConstStlMapEntrySet& operator= (const ConstStlMapEntrySet&);

        public:

            ConstStlMapEntrySet(const StlMap* parent) : AbstractSet< MapEntry<K,V> >(), associatedMap(parent) {
            }

            virtual ~ConstStlMapEntrySet() {}

            virtual int size() const {
                return associatedMap->size();
            }

            virtual void clear() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't clear a const collection");
            }

            virtual bool remove(const MapEntry<K,V>& entry DECAF_UNUSED) {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't remove from const collection");
            }

            virtual bool contains(const MapEntry<K,V>& entry) const {
                if (this->associatedMap->containsKey(entry.getKey()) &&
                    this->associatedMap->get(entry.getKey()) == entry.getValue()) {
                    return true;
                }
                return false;
            }

            virtual Iterator< MapEntry<K, V> >* iterator() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't return a non-const iterator for a const collection");
            }

            virtual Iterator< MapEntry<K, V> >* iterator() const {
                return new ConstEntryIterator(associatedMap);
            }
        };

    private:

        class StlMapKeySet : public AbstractSet<K> {
        private:

            StlMap* associatedMap;

        private:

            StlMapKeySet(const StlMapKeySet&);
            StlMapKeySet& operator= (const StlMapKeySet&);

        public:

            StlMapKeySet(StlMap* parent) : AbstractSet<K>(), associatedMap(parent) {}

            virtual ~StlMapKeySet() {}

            virtual bool contains(const K& key) const {
                return this->associatedMap->containsKey(key);
            }

            virtual int size() const {
                return this->associatedMap->size();
            }

            virtual void clear() {
                this->associatedMap->clear();
            }

            virtual bool remove(const K& key) {
                if (this->associatedMap->containsKey(key)) {
                    associatedMap->remove(key);
                    return true;
                }
                return false;
            }

            virtual Iterator<K>* iterator() {
                return new KeyIterator(this->associatedMap);
            }

            virtual Iterator<K>* iterator() const {
                return new ConstKeyIterator(this->associatedMap);
            }
        };

        class ConstStlMapKeySet : public AbstractSet<K> {
        private:

            const StlMap* associatedMap;

        private:

            ConstStlMapKeySet(const ConstStlMapKeySet&);
            ConstStlMapKeySet& operator= (const ConstStlMapKeySet&);

        public:

            ConstStlMapKeySet(const StlMap* parent) : AbstractSet<K>(), associatedMap(parent) {}

            virtual ~ConstStlMapKeySet() {}

            virtual bool contains(const K& key) const {
                return this->associatedMap->containsKey(key);
            }

            virtual int size() const {
                return this->associatedMap->size();
            }

            virtual void clear() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't modify a const collection");
            }

            virtual bool remove(const K& key DECAF_UNUSED) {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't modify a const collection");
            }

            virtual Iterator<K>* iterator() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't return a non-const iterator for a const collection");
            }

            virtual Iterator<K>* iterator() const {
                return new ConstKeyIterator(this->associatedMap);
            }
        };

    private:

        class StlMapValueCollection : public AbstractCollection<V> {
        private:

            StlMap* associatedMap;

        private:

            StlMapValueCollection(const StlMapValueCollection&);
            StlMapValueCollection& operator= (const StlMapValueCollection&);

        public:

            StlMapValueCollection(StlMap* parent) : AbstractCollection<V>(), associatedMap(parent) {}

            virtual ~StlMapValueCollection() {}

            virtual bool contains(const V& value) const {
                return this->associatedMap->containsValue(value);
            }

            virtual int size() const {
                return this->associatedMap->size();
            }

            virtual void clear() {
                this->associatedMap->clear();
            }

            virtual Iterator<V>* iterator() {
                return new ValueIterator(this->associatedMap);
            }

            virtual Iterator<V>* iterator() const {
                return new ConstValueIterator(this->associatedMap);
            }
        };

        class ConstStlMapValueCollection : public AbstractCollection<V> {
        private:

            const StlMap* associatedMap;

        private:

            ConstStlMapValueCollection(const ConstStlMapValueCollection&);
            ConstStlMapValueCollection& operator= (const ConstStlMapValueCollection&);

        public:

            ConstStlMapValueCollection(const StlMap* parent) : AbstractCollection<V>(), associatedMap(parent) {}

            virtual ~ConstStlMapValueCollection() {}

            virtual bool contains(const V& value) const {
                return this->associatedMap->containsValue(value);
            }

            virtual int size() const {
                return this->associatedMap->size();
            }

            virtual void clear() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't modify a const collection");
            }

            virtual Iterator<V>* iterator() {
                throw decaf::lang::exceptions::UnsupportedOperationException(
                        __FILE__, __LINE__, "Can't return a non-const iterator for a const collection");
            }

            virtual Iterator<V>* iterator() const {
                return new ConstValueIterator(this->associatedMap);
            }
        };

    private:

        // Cached values that are only initialized once a request for them is made.
        decaf::lang::Pointer<StlMapEntrySet> cachedEntrySet;
        decaf::lang::Pointer<StlMapKeySet> cachedKeySet;
        decaf::lang::Pointer<StlMapValueCollection> cachedValueCollection;

        // Cached values that are only initialized once a request for them is made.
        mutable decaf::lang::Pointer<ConstStlMapEntrySet> cachedConstEntrySet;
        mutable decaf::lang::Pointer<ConstStlMapKeySet> cachedConstKeySet;
        mutable decaf::lang::Pointer<ConstStlMapValueCollection> cachedConstValueCollection;

    public:

        /**
         * Default constructor - does nothing.
         */
        StlMap() : Map<K,V>(), valueMap(), mutex(), modCount(0),
                               cachedEntrySet(), cachedKeySet(), cachedValueCollection(),
                               cachedConstEntrySet(), cachedConstKeySet(), cachedConstValueCollection() {
        }

        /**
         * Copy constructor - copies the content of the given map into this one.
         *
         * @param source
         *      The source StlMap whose entries are copied into this Map.
         */
        StlMap(const StlMap& source ) : Map<K,V>(), valueMap(), mutex(), modCount(0),
                                        cachedEntrySet(), cachedKeySet(), cachedValueCollection(),
                                        cachedConstEntrySet(), cachedConstKeySet(), cachedConstValueCollection() {
            copy(source);
        }

        /**
         * Copy constructor - copies the content of the given map into this one.
         *
         * @param source
         *      The source ma whose entries are copied into this Map..
         */
        StlMap(const Map<K,V>& source) : Map<K,V>(), valueMap(), mutex(), modCount(0),
                                         cachedEntrySet(), cachedKeySet(), cachedValueCollection(),
                                         cachedConstEntrySet(), cachedConstKeySet(), cachedConstValueCollection() {
            copy(source);
        }

        virtual ~StlMap() {}

        /**
         * {@inheritDoc}
         */
        virtual bool equals(const StlMap& source) const {
            return this->valueMap == source.valueMap;
        }

        /**
         * {@inheritDoc}
         */
        virtual bool equals(const Map<K,V>& source) const {
            typename std::auto_ptr< Iterator<K> > iterator(this->keySet().iterator());
            while (iterator->hasNext()) {
                K key = iterator->next();
                if (!this->containsKey(key)) {
                    return false;
                }

                if (!(this->get(key) == source.get(key))) {
                    return false;
                }
            }

            return true;
        }

        /**
         * {@inheritDoc}
         */
        virtual void copy(const StlMap& source) {
            this->valueMap.clear();
            this->valueMap.insert( source.valueMap.begin(), source.valueMap.end() );
        }

        /**
         * {@inheritDoc}
         */
        virtual void copy(const Map<K, V>& source) {
            this->clear();
            this->putAll(source);
        }

        /**
         * {@inheritDoc}
         */
        virtual void clear() {
            valueMap.clear();
        }

        /**
         * {@inheritDoc}
         */
        virtual bool containsKey(const K& key) const {
            if (valueMap.empty()) {
                return false;
            }

            typename std::map<K, V, COMPARATOR>::const_iterator iter;
            iter = valueMap.find(key);
            return iter != valueMap.end();
        }

        /**
         * {@inheritDoc}
         */
        virtual bool containsValue(const V& value) const {
            if (valueMap.empty()) {
                return false;
            }

            typename std::map<K, V, COMPARATOR>::const_iterator iter = valueMap.begin();
            for (; iter != valueMap.end(); ++iter) {
                if ((*iter).second == value) {
                    return true;
                }
            }

            return false;
        }

        /**
         * {@inheritDoc}
         */
        virtual bool isEmpty() const {
            return valueMap.empty();
        }

        /**
         * {@inheritDoc}
         */
        virtual int size() const {
            return (int)valueMap.size();
        }

        /**
         * {@inheritDoc}
         */
        virtual V& get(const K& key) {
            typename std::map<K, V, COMPARATOR>::iterator iter;
            iter = valueMap.find(key);
            if (iter == valueMap.end()) {
                throw NoSuchElementException(__FILE__, __LINE__, "Key does not exist in map");
            }

            return iter->second;
        }

        /**
         * {@inheritDoc}
         */
        virtual const V& get(const K& key) const {
            typename std::map<K, V, COMPARATOR>::const_iterator iter;
            iter = valueMap.find(key);
            if (iter == valueMap.end()) {
                throw NoSuchElementException(__FILE__, __LINE__, "Key does not exist in map");
            }

            return iter->second;
        }

        /**
         * {@inheritDoc}
         */
        virtual bool put(const K& key, const V& value) {
            bool result = false;
            if (this->containsKey(key)) {
                result = true;
            }
            valueMap[key] = value;
            modCount++;
            return result;
        }

        /**
         * {@inheritDoc}
         */
        virtual bool put(const K& key, const V& value, V& oldValue) {
            bool result = false;
            if (this->containsKey(key)) {
                result = true;
                oldValue = valueMap[key];
            }
            valueMap[key] = value;
            modCount++;
            return result;
        }

        /**
         * {@inheritDoc}
         */
        virtual void putAll(const StlMap<K, V, COMPARATOR>& other) {
            this->valueMap.insert(other.valueMap.begin(), other.valueMap.end());
            this->modCount++;
        }

        /**
         * {@inheritDoc}
         */
        virtual void putAll(const Map<K, V>& other) {
            typename std::auto_ptr< Iterator<K> > iterator(other.keySet().iterator());
            while (iterator->hasNext()) {
                K key = iterator->next();
                this->put(key, other.get(key));
            }
        }

        /**
         * {@inheritDoc}
         */
        virtual V remove(const K& key) {

            typename std::map<K, V, COMPARATOR>::iterator iter = valueMap.find(key);
            if (iter == valueMap.end()) {
                throw NoSuchElementException(
                        __FILE__, __LINE__, "Key is not present in this Map.");
            }

            V result = iter->second;
            valueMap.erase(iter);
            modCount++;
            return result;
        }

        virtual Set< MapEntry<K, V> >& entrySet() {
            if (this->cachedEntrySet == NULL) {
                this->cachedEntrySet.reset(new StlMapEntrySet(this));
            }
            return *(this->cachedEntrySet);
        }
        virtual const Set< MapEntry<K, V> >& entrySet() const {
            if (this->cachedConstEntrySet == NULL) {
                this->cachedConstEntrySet.reset(new ConstStlMapEntrySet(this));
            }
            return *(this->cachedConstEntrySet);
        }

        virtual Set<K>& keySet() {
            if (this->cachedKeySet == NULL) {
                this->cachedKeySet.reset(new StlMapKeySet(this));
            }
            return *(this->cachedKeySet);
        }

        virtual const Set<K>& keySet() const {
            if (this->cachedConstKeySet == NULL) {
                this->cachedConstKeySet.reset(new ConstStlMapKeySet(this));
            }
            return *(this->cachedConstKeySet);
        }

        virtual Collection<V>& values() {
            if (this->cachedValueCollection == NULL) {
                this->cachedValueCollection.reset(new StlMapValueCollection(this));
            }
            return *(this->cachedValueCollection);
        }

        virtual const Collection<V>& values() const {
            if (this->cachedConstValueCollection == NULL) {
                this->cachedConstValueCollection.reset(new ConstStlMapValueCollection(this));
            }
            return *(this->cachedConstValueCollection);
        }

    public:

        virtual void lock() {
            mutex.lock();
        }

        virtual bool tryLock() {
            return mutex.tryLock();
        }

        virtual void unlock() {
            mutex.unlock();
        }

        virtual void wait() {
            mutex.wait();
        }

        virtual void wait( long long millisecs ) {
            mutex.wait( millisecs );
        }

        virtual void wait( long long millisecs, int nanos ) {
            mutex.wait( millisecs, nanos );
        }

        virtual void notify() {
            mutex.notify();
        }

        virtual void notifyAll() {
            mutex.notifyAll();
        }

    };

}}

#endif /*_DECAF_UTIL_STLMAP_H_*/