//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="PartialDictionary"
// Project: StgSharp
// AuthorGroup: Nitload
// Copyright (c) Nitload. All rights reserved.
//     
// 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.
//     
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Net.Http.Headers;
using System.Text;

namespace StgSharp.Collections
{
    public partial class PartialDictionary<TKey, TValue> : IDictionary<TKey, TValue>
    {

        private readonly Dictionary<TKey, TValue> _source;
        private readonly HashSet<TKey> _keys;
        private readonly PartialDictionaryValues _values;

        public PartialDictionary(Dictionary<TKey, TValue> source, TKey[] index)
        {
            _source = source;
            _keys = new HashSet<TKey>(index);
            foreach (TKey item in _keys)
            {
                if (!_source.ContainsKey(item)) {
                    _source.Add(item, default!);
                }
            }
            _values = new PartialDictionaryValues(this);
        }

        public PartialDictionary(Dictionary<TKey, TValue> source, HashSet<TKey> keys)
        {
            _source = source;
            _keys = keys;
            foreach (TKey item in _keys)
            {
                if (!_source.ContainsKey(item)) {
                    _source.Add(item, default!);
                }
            }
            _values = new PartialDictionaryValues(this);
        }

        public PartialDictionary(Dictionary<TKey, TValue> source, TKey[] index, IHashMultiplexer<TKey> multiplexer)
        {
            _source = source;
            _keys = new HashSet<TKey>(index);
            foreach (TKey item in _keys)
            {
                if (!_source.ContainsKey(item)) {
                    _source.Add(item, default!);
                }
            }
            _values = new PartialDictionaryValues(this);
        }

        public TValue this[TKey key]
        {
            get
            {
                if (_keys.Contains(key)) {
                    return _source[key];
                }
                throw new KeyNotFoundException();
            }
            set
            {
                if (_keys.Contains(key)) {
                    _source[key] = value;
                }
                throw new KeyNotFoundException();
            }
        }

        public ICollection<TKey> Keys => _keys;

        public ICollection<TValue> Values => _values;

        public int Count => _keys.Count;

        public bool Contains(KeyValuePair<TKey, TValue> item)
        {
            return _keys.Contains(item.Key) && _source.Contains(item);
        }

        public bool ContainsKey(TKey key)
        {
            return _keys.Contains(key);
        }

        public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
        {
            throw new NotImplementedException();
        }

        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
        {
            foreach (TKey item in _keys) {
                yield return new KeyValuePair<TKey, TValue>(item, _source[item]);
            }
        }

        public bool TryGetValue(TKey key, out TValue value)
        {
            if (_keys.Contains(key))
            {
                value = _source[key];
                return true;
            }
            value = default!;
            return false;
        }

        void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
        {
            return;
        }

        void ICollection<KeyValuePair<TKey, TValue>>.Clear()
        {
            throw new NotSupportedException();
        }

        bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
        {
            throw new NotSupportedException();
        }

        bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly => true;

        void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
        {
            return;
        }

        bool IDictionary<TKey, TValue>.Remove(TKey key)
        {
            throw new NotSupportedException();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

    }
}