Class: SortableElementForNestedSet::TreeMoveCalculator

Inherits:
Object
  • Object
show all
Defined in:
lib/tree_calc.rb

Overview

Calculate the new position of a moved tree within a nested set. The new placement and sort order is given as a hash, as created by draggable_element Javascript helper.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sort_order) ⇒ TreeMoveCalculator

Calculate the left, right and parent values from the parameter generated by draggable_element JS helper



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# File 'lib/tree_calc.rb', line 10

def initialize(sort_order)
  @nodes = TreeMoveCalculator.create_tree_nodes(sort_order)
end

Instance Attribute Details

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/tree_calc.rb', line 6

def nodes
  @nodes
end

Class Method Details

.create_tree_nodes(tree) ⇒ Object

Create Array of TreeNodes from the parameter generated by draggable_element JS helper.



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# File 'lib/tree_calc.rb', line 54

def self.create_tree_nodes(tree)
  tree = to_hash(tree) if tree.is_a?(Array)
  
  result = []
  
  tree.keys.sort.each do |key|
    node = TreeNode.new(tree[key]["id"].to_i)
    node.children = create_tree_nodes( tree[key].reject {|k, v| k == "id"} )  if tree[key].many?
    result << node
  end
  
  return result
end

.to_hash(array) ⇒ Object

Convert an array of ids to the required hash format.



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# File 'lib/tree_calc.rb', line 69

def self.to_hash(array)
  result = {}
  
  array.each_with_index {|id, i| result[i.to_s] = {"id" => id.to_s } }
  
  return result
end

Instance Method Details

#left_of(target_id) ⇒ Object 



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# File 'lib/tree_calc.rb', line 32

def left_of(target_id)
  array_with_target_node = find_array_with_target_node(target_id)
  
  if (array_with_target_node.first.id == target_id)
    return nil
  else 
    return array_with_target_node[array_with_target_node.collect(&:id).index(target_id) - 1].id
  end
end

#parent_of(val_to_find) ⇒ Object 



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# File 'lib/tree_calc.rb', line 42

def parent_of(val_to_find) 
  return nil if @nodes.collect(&:id).include?(val_to_find)
  
  parent = nil
  
  @nodes.each do |node|
    parent = find_parent_of(val_to_find, node)
    return parent if parent
  end
end

#placement_of(target_id) ⇒ Object 



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# File 'lib/tree_calc.rb', line 24

def placement_of(target_id)
  # Note that this swaps left and right as the consumer views it differently.
  
  {:parent => parent_of(target_id),
   :move_to_right_of => left_of(target_id),
   :move_to_left_of => right_of(target_id) }
end

#right_of(target_id) ⇒ Object 



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# File 'lib/tree_calc.rb', line 14

def right_of(target_id)
  array_with_target_node = find_array_with_target_node(target_id)
  
  if (array_with_target_node.last.id == target_id)
    return nil
  else 
    return array_with_target_node[array_with_target_node.collect(&:id).index(target_id) + 1].id
  end
end