using System.Collections;
using System.Collections.Generic;
using System.Text;
using System;

namespace Rokojori
{
  public class Lists
  {
    public static List<T> CombineAll<T>( params List<T>[] lists )
    {
      var list = new List<T>();

      foreach ( var l in lists )
      {
        list.AddRange( l );
      }

      return list;
    }

    public static List<T> ToList<T>( T[] array )
    {
      var list = new List<T>();
      list.AddRange( array );
      return list;
    }

    public static bool Has<T>( List<T> list, T item )
    {
      return list.IndexOf( item ) != - 1;
    }

    public static T Pop<T>( List<T> list )
    {
      if ( list.Count == 0 ){ return default(T); }

      var element = list[ list.Count - 1 ];
      list.RemoveAt( list.Count - 1 );
      return element;
    }

    public static T Last<T>( List<T> list )
    {
      return list.Count == 0 ? default(T) : list[ list.Count - 1 ];
    }

    public static void RemoveIncreasingIndices<T>( List<T> list, List<int> removals )
    {
      for ( var i = removals.Count - 1; i >= 0; i-- )
      {
        list.RemoveAt( i );
      }
    }


    public static int CountItems<T>( List<T> list, Predicate<T> test )
    {
      var result = 0;
      
      for ( int i = 0; i < list.Count; i++ )
      {
        if ( test( list[ i ] ) )
        {
          result++;
        }
      }

      return result;
    }

    public static int CountItems<T>( T[] list, Predicate<T> test )
    {
      var result = 0;
      
      for ( int i = 0; i < list.Length; i++ )
      {
        if ( test( list[ i ] ) )
        {
          result++;
        }
      }

      return result;
    }

    public static bool AreEntriesEqual<T>( List<T> a, List<T> b )
    {
      if ( a.Count != b.Count )
      {
        return false;
      }

      for ( int i = 0; i < a.Count; i++ )
      {
        var isEqual = EqualityComparer<T>.Default.Equals( a[ i ], b[ i ]);

        if ( ! isEqual )
        {
          return false;
        }
      }

      return true;
    }

    

    public static string Join<T>( List<T> array, string seperator = ", " )
    {
      var sb = new StringBuilder();

      for ( var i = 0; i < array.Count; i++ )
      {
        if ( i != 0 )
        {
          sb.Append( seperator );
        }

        sb.Append( array[ i ] );        
      }

      return sb.ToString();
    }

    public static List<T> From<T>( T[] array )
    {
      var copy = new List<T>();
      copy.AddRange( array );
      return copy;
    }

    public static List<T> From<T>( List<T> list )
    {
      var copy = new List<T>();
      copy.AddRange( list );
      return copy;
    }

    public static List<T> From<[Godot.MustBeVariant] T>( Godot.Collections.Array<T> list )
    {
      var copy = new List<T>();
      copy.AddRange( list );
      return copy;
    }

    public static void Filter<T>( List<T> inputList, List<T> list, Func<T,int,bool> filter )
    {      
      for ( int i = 0; i < inputList.Count; i++ )
      { 
        if ( filter( inputList[ i ], i ) )
        {
          list.Add( inputList[ i ] );
        }
      }
    }

    public static void Filter<T>( List<T> inputList, List<T> list, Func<T,bool> filter )
    {      
      for ( int i = 0; i < inputList.Count; i++ )
      { 
        if ( filter( inputList[ i ] ) )
        {
          list.Add( inputList[ i ] );
        }
      }
    }

    public static List<T> Filter<T>( List<T> inputList, Func<T,bool> filter )
    {      
      var list = new List<T>();

      for ( int i = 0; i < inputList.Count; i++ )
      { 
        if ( filter( inputList[ i ] ) )
        {
          list.Add( inputList[ i ] );
        }
      }

      return list;
    } 

    public static List<R> FilterType<T,R>( List<T> inputList ) where R:T
    {
      var list = new List<R>();

      inputList.ForEach
      ( 
        e => 
        {
          if ( e == null || ! typeof( R ).IsAssignableFrom( e.GetType() ) )
          {
            return;
          }

          list.Add( (R) e );
        }
      );

      return list;
    }

    public static T Find<T>( List<T> list, Func<T,bool> callback )
    {
      for ( int i = 0; i < list.Count; i++ )
      {
        if ( callback( list[ i ] ) )
        {
          return list[ i ];
        }
      }

      return default( T );
    }

    public static List<U> Map<T,U>( List<T> inputList, Func<T,int,U> mapper, List<U> list = null )
    {
      if ( list == null )
      {
        list = new List<U>();
      }

      for ( int i = 0; i < inputList.Count; i++ )
      { 
        list.Add( mapper( inputList[ i ], i ) );        
      }

      return list;
    }

    public static List<U> Map<T,U>( T[] inputList, Func<T,int,U> mapper, List<U> list = null ) 
    {
      if ( list == null )
      {
        list = new List<U>();
      }

      for ( int i = 0; i < inputList.Length; i++ )
      { 
        list.Add( mapper( inputList[ i ], i ) );        
      }

      return list;
    }

    public static List<U> Map<T,U>( List<T> inputList, Func<T,U> mapper, List<U> list = null  )
    {
      if ( list == null )
      {
        list = new List<U>();
      }

      for ( int i = 0; i < inputList.Count; i++ )
      { 
        list.Add( mapper( inputList[ i ] ) );        
      }

      return list;
    }

    public static List<U> Map<[Godot.MustBeVariant]T,U>( Godot.Collections.Array<T> inputList, Func<T,U> mapper, List<U> list  = null )
    {
      if ( list == null )
      {
        list = new List<U>();
      }

      for ( int i = 0; i < inputList.Count; i++ )
      { 
        list.Add( mapper( inputList[ i ] ) );        
      }

      return list;
    }

    public static List<U> Map<T,U>( T[] inputList, Func<T,U> mapper, List<U> list  = null )
    {
      if ( list == null )
      {
        list = new List<U>();
      }

      for ( int i = 0; i < inputList.Length; i++ )
      { 
        list.Add( mapper( inputList[ i ] ) );        
      }

      return list;
    }

    
  }
}