/*
 Copyright (c) 2003-2006 Niels Kokholm and Peter Sestoft

 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.
*/

// C5 example: 2006-01-29

// Compile with 
//   csc /r:C5.dll MultiDictionary.cs 

using System;
using C5;
using SCG = System.Collections.Generic;

namespace MultiDictionaries
{
  using Inner = HashSet<String>;

  using MultiDictionary3;

  public class MyTest
  {
    public static void Main()
    {
      MultiHashDictionary<int, String, Inner> mdict = new MultiHashDictionary<int, String, Inner>();
      mdict.Add(2, "to");
      mdict.Add(2, "deux");
      mdict.Add(2, "two");
      mdict.Add(20, "tyve");
      mdict.Add(20, "tyve");
      mdict.Add(20, "twenty");
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      Console.WriteLine("mdict.Count (keys) is {0}",
                        ((IDictionary<int, Inner>)mdict).Count);
      Console.WriteLine("mdict[2].Count is {0}", mdict[2].Count);
      mdict.Remove(20, "tyve");
      mdict.Remove(20, "twenty");
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      Inner zwei = new Inner();
      zwei.Add("zwei");
      mdict[2] = zwei;
      mdict[-2] = zwei;
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      zwei.Add("kaksi");
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      Inner empty = new Inner();
      mdict[0] = empty;
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      Console.WriteLine("mdict contains key 0: {0}", mdict.Contains(0));
      mdict.Remove(-2);
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      zwei.Remove("kaksi");
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
      zwei.Clear();
      Console.WriteLine(mdict);
      Console.WriteLine("mdict.Count is {0}", mdict.Count);
    }
  }
}

namespace MultiDictionary1
{
  // Here we implement a multivalued dictionary as a hash dictionary
  // from keys to value collections.  The value collections may have set
  // or bag semantics.

  // The value collections are externally modifiable (as in Peter
  // Golde's PowerCollections library), and therefore:
  //
  //  * A value collection associated with a key may be null or
  //  non-empty.  Hence for correct semantics, the Contains(k) method
  //  must check that the value collection associated with a key is
  //  non-null and non-empty.
  //  
  //  * A value collection may be shared between two or more keys.
  //

  // A C5 hash dictionary each of whose keys map to a collection of values.

  public class MultiHashDictionary<K, V> : HashDictionary<K, ICollection<V>>
  {

    // Return total count of values associated with keys.  This basic
    // implementation simply sums over all value collections, and so
    // is a linear-time operation in the total number of values.  

    public new virtual int Count
    {
      get
      {
        int count = 0;
        foreach (KeyValuePair<K, ICollection<V>> entry in this)
          if (entry.Value != null)
            count += entry.Value.Count;
        return count;
      }
    }

    public override Speed CountSpeed
    {
      get { return Speed.Linear; }
    }

    // Add a (key,value) pair

    public virtual void Add(K k, V v)
    {
      ICollection<V> values;
      if (!base.Find(k, out values) || values == null)
      {
        values = new HashSet<V>();
        Add(k, values);
      }
      values.Add(v);
    }

    // Remove a single (key,value) pair, if present; return true if
    // anything was removed, else false

    public virtual bool Remove(K k, V v)
    {
      ICollection<V> values;
      if (base.Find(k, out values) && values != null)
      {
        if (values.Remove(v))
        {
          if (values.IsEmpty)
            base.Remove(k);
          return true;
        }
      }
      return false;
    }

    // Determine whether key k is associated with a value

    public override bool Contains(K k)
    {
      ICollection<V> values;
      return Find(k, out values) && values != null && !values.IsEmpty;
    }

    // Determine whether each key in ks is associated with a value

    public override bool ContainsAll<U>(SCG.IEnumerable<U> ks)
    {
      foreach (K k in ks)
        if (!Contains(k))
          return false;
      return true;
    }

    // Get or set the value collection associated with key k

    public override ICollection<V> this[K k]
    {
      get
      {
        ICollection<V> values;
        return base.Find(k, out values) && values != null ? values : new HashSet<V>();
      }
      set
      {
        base[k] = value;
      }
    }

    // Inherited from base class HashDictionary<K,ICollection<V>>:

    // Add(K k, ICollection<V> values) 
    // AddAll(IEnumerable<KeyValuePair<K,ICollection<V>>> kvs) 
    // Clear
    // Clone
    // Find(K k, out ICollection<V> values)
    // Find(ref K k, out ICollection<V> values)
    // FindOrAdd(K k, ref ICollection<V> values) 
    // Remove(K k) 
    // Remove(K k, out ICollection<V> values) 
    // Update(K k, ICollection<V> values)
    // Update(K k, ICollection<V> values, out ICollection<V> oldValues)
    // UpdateOrAdd(K k, ICollection<V> values)
    // UpdateOrAdd(K k, ICollection<V> values, out ICollection<V> oldValues)
  }
}


namespace MultiDictionary2
{
  // Here we implement a multivalued dictionary as a hash dictionary
  // from keys to value collections.  The value collections may have
  // set or bag semantics.  This version uses event listeners to make
  // the Count operation constant time.

  //  * To avoid recomputing the total number of values for the Count
  //  property, one may cache it and then use event listeners on the
  //  value collections to keep the cached count updated.  In turn, this
  //  requires such event listeners on the dictionary also.

  // A C5 hash dictionary each of whose keys map to a collection of values.

  public class MultiHashDictionary<K, V> : HashDictionary<K, ICollection<V>>
  {
    private int count = 0;      // Cached value count, updated by events only

    private void IncrementCount(Object sender, ItemCountEventArgs<V> args)
    {
      count += args.Count;
    }

    private void DecrementCount(Object sender, ItemCountEventArgs<V> args)
    {
      count -= args.Count;
    }

    private void ClearedCount(Object sender, ClearedEventArgs args)
    {
      count -= args.Count;
    }

    public MultiHashDictionary()
    {
      ItemsAdded +=
        delegate(Object sender, ItemCountEventArgs<KeyValuePair<K, ICollection<V>>> args)
        {
          ICollection<V> values = args.Item.Value;
          if (values != null)
          {
            count += values.Count;
            values.ItemsAdded += IncrementCount;
            values.ItemsRemoved += DecrementCount;
            values.CollectionCleared += ClearedCount;
          }
        };
      ItemsRemoved +=
        delegate(Object sender, ItemCountEventArgs<KeyValuePair<K, ICollection<V>>> args)
        {
          ICollection<V> values = args.Item.Value;
          if (values != null)
          {
            count -= values.Count;
            values.ItemsAdded -= IncrementCount;
            values.ItemsRemoved -= DecrementCount;
            values.CollectionCleared -= ClearedCount;
          }
        };
    }

    // Return total count of values associated with keys.  

    public new virtual int Count
    {
      get
      {
        return count;
      }
    }

    public override Speed CountSpeed
    {
      get { return Speed.Constant; }
    }

    // Add a (key,value) pair

    public virtual void Add(K k, V v)
    {
      ICollection<V> values;
      if (!base.Find(k, out values) || values == null)
      {
        values = new HashSet<V>();
        Add(k, values);
      }
      values.Add(v);
    }

    // Remove a single (key,value) pair, if present; return true if
    // anything was removed, else false

    public virtual bool Remove(K k, V v)
    {
      ICollection<V> values;
      if (base.Find(k, out values) && values != null)
      {
        if (values.Remove(v))
        {
          if (values.IsEmpty)
            base.Remove(k);
          return true;
        }
      }
      return false;
    }

    // Determine whether key k is associated with a value

    public override bool Contains(K k)
    {
      ICollection<V> values;
      return Find(k, out values) && values != null && !values.IsEmpty;
    }

    // Determine whether each key in ks is associated with a value

    public override bool ContainsAll<U>(SCG.IEnumerable<U> ks)
    {
      foreach (K k in ks)
        if (!Contains(k))
          return false;
      return true;
    }

    // Get or set the value collection associated with key k

    public override ICollection<V> this[K k]
    {
      get
      {
        ICollection<V> values;
        return base.Find(k, out values) && values != null ? values : new HashSet<V>();
      }
      set
      {
        base[k] = value;
      }
    }
  }
}


namespace MultiDictionary3
{
  // Here we implement a multivalued dictionary as a hash dictionary
  // from keys to value collections.  The value collections may have
  // set or bag semantics.  This version uses event listeners to make
  // the Count operation constant time.

  //  * To avoid recomputing the total number of values for the Count
  //  property, one may cache it and then use event listeners on the
  //  value collections to keep the cached count updated.  In turn, this
  //  requires such event listeners on the dictionary also.

  // A C5 hash dictionary each of whose keys map to a collection of values.

  public class MultiHashDictionary<K, V, W> : HashDictionary<K, W> where W : ICollection<V>, new()
  {
    private int count = 0;      // Cached value count, updated by events only

    private void IncrementCount(Object sender, ItemCountEventArgs<V> args)
    {
      count += args.Count;
    }

    private void DecrementCount(Object sender, ItemCountEventArgs<V> args)
    {
      count -= args.Count;
    }

    private void ClearedCount(Object sender, ClearedEventArgs args)
    {
      count -= args.Count;
    }

    public MultiHashDictionary()
    {
      ItemsAdded +=
        delegate(Object sender, ItemCountEventArgs<KeyValuePair<K, W>> args)
        {
          ICollection<V> values = args.Item.Value;
          if (values != null)
          {
            count += values.Count;
            values.ItemsAdded += IncrementCount;
            values.ItemsRemoved += DecrementCount;
            values.CollectionCleared += ClearedCount;
          }
        };
      ItemsRemoved +=
        delegate(Object sender, ItemCountEventArgs<KeyValuePair<K, W>> args)
        {
          ICollection<V> values = args.Item.Value;
          if (values != null)
          {
            count -= values.Count;
            values.ItemsAdded -= IncrementCount;
            values.ItemsRemoved -= DecrementCount;
            values.CollectionCleared -= ClearedCount;
          }
        };
    }

    // Return total count of values associated with keys.  

    public new virtual int Count
    {
      get
      {
        return count;
      }
    }

    public override Speed CountSpeed
    {
      get { return Speed.Constant; }
    }

    // Add a (key,value) pair

    public virtual void Add(K k, V v)
    {
      W values;
      if (!base.Find(k, out values) || values == null)
      {
        values = new W();
        Add(k, values);
      }
      values.Add(v);
    }

    // Remove a single (key,value) pair, if present; return true if
    // anything was removed, else false

    public virtual bool Remove(K k, V v)
    {
      W values;
      if (base.Find(k, out values) && values != null)
      {
        if (values.Remove(v))
        {
          if (values.IsEmpty)
            base.Remove(k);
          return true;
        }
      }
      return false;
    }

    // Determine whether key k is associated with a value

    public override bool Contains(K k)
    {
      W values;
      return Find(k, out values) && values != null && !values.IsEmpty;
    }

    // Determine whether each key in ks is associated with a value

    public override bool ContainsAll<U>(SCG.IEnumerable<U> ks)
    {
      foreach (K k in ks)
        if (!Contains(k))
          return false;
      return true;
    }

    // Get or set the value collection associated with key k

    public override W this[K k]
    {
      get
      {
        W values;
        return base.Find(k, out values) && values != null ? values : new W();
      }
      set
      {
        base[k] = value;
      }
    }
  }
}