import * as is from '../is';
import Collection from '../collection';

let corefn = ({

  // get a collection
  // - empty collection on no args
  // - collection of elements in the graph on selector arg
  // - guarantee a returned collection when elements or collection specified
  collection: function( eles, opts ){

    if( is.string( eles ) ){
      return this.$( eles );

    } else if( is.elementOrCollection( eles ) ){
      return eles.collection();

    } else if( is.array( eles ) ){
      if (!opts) {
        opts = {};
      }
      return new Collection( this, eles, opts.unique, opts.removed );
    }

    return new Collection( this );
  },

  nodes: function( selector ){
    let nodes = this.$( function( ele ){
      return ele.isNode();
    } );

    if( selector ){
      return nodes.filter( selector );
    }

    return nodes;
  },

  edges: function( selector ){
    let edges = this.$( function( ele ){
      return ele.isEdge();
    } );

    if( selector ){
      return edges.filter( selector );
    }

    return edges;
  },

  // search the graph like jQuery
  $: function( selector ){
    let eles = this._private.elements;

    if( selector ){
      return eles.filter( selector );
    } else {
      return eles.spawnSelf();
    }
  },

  mutableElements: function(){
    return this._private.elements;
  }

});

// aliases
corefn.elements = corefn.filter = corefn.$;

export default corefn;
