class Ransack::Context

def association_path(str, base = @base)
  base = klassify(base)
  str ||= ''
  path = []
  segments = str.split(/_/)
  association_parts = []
  if (segments = str.split(/_/)).size > 0
    while segments.size > 0 && !base.columns_hash[segments.join('_')] && association_parts << segments.shift do
      assoc, klass = unpolymorphize_association(association_parts.join('_'))
      if found_assoc = get_association(assoc, base)
        path += association_parts
        association_parts = []
        base = klassify(klass || found_assoc)
      end
    end
  end
  path.join('_')
end

def bind(object, str)
  object.parent, object.attr_name = @bind_pairs[str]
end

def can_accept?(object)
  method_defined? DISPATCH[object.class]
end

def contextualize(str)
  parent, attr_name = @bind_pairs[str]
  table_for(parent)[attr_name]
end

def for(object)
  context = Class === object ? for_class(object) : for_object(object)
  context or raise ArgumentError, "Don't know what context to use for #{object}"
end

def for_class(klass)
  if klass < ActiveRecord::Base
    Adapters::ActiveRecord::Context.new(klass)
  end
end

def for_object(object)
  case object
  when ActiveRecord::Relation
    Adapters::ActiveRecord::Context.new(object.klass)
  end
end

def initialize(object)
  @object = object.scoped
  @klass = @object.klass
  @join_dependency = join_dependency(@object)
  @base = @join_dependency.join_base
  @engine = @base.arel_engine
  @arel_visitor = Arel::Visitors.visitor_for @engine
  @default_table = Arel::Table.new(@base.table_name, :as => @base.aliased_table_name, :engine => @engine)
  @bind_pairs = Hash.new do |hash, key|
    parent, attr_name = get_parent_and_attribute_name(key.to_s)
    if parent && attr_name
      hash[key] = [parent, attr_name]
    end
  end
end

def ransackable_association?(str, klass)
  klass.ransackable_associations(auth_object).include? str
end

def ransackable_attribute?(str, klass)
  klass.ransackable_attributes(auth_object).include? str
end

def searchable_associations(str = '')
  traverse(str).ransackable_associations(auth_object)
end

def searchable_attributes(str = '')
  traverse(str).ransackable_attributes(auth_object)
end

def traverse(str, base = @base)
  str ||= ''
  if (segments = str.split(/_/)).size > 0
    association_parts = []
    found_assoc = nil
    while !found_assoc && segments.size > 0 && association_parts << segments.shift do
      # Strip the _of_Model_type text from the association name, but hold
      # onto it in klass, for use as the next base
      assoc, klass = unpolymorphize_association(association_parts.join('_'))
      if found_assoc = get_association(assoc, base)
        base = traverse(segments.join('_'), klass || found_assoc.klass)
      end
    end
    raise UntraversableAssociationError, "No association matches #{str}" unless found_assoc
  end
  klassify(base)
end

def unpolymorphize_association(str)
  if (match = str.match(/_of_(.+?)_type$/)) && Kernel.const_defined?(match.captures.first)
    [match.pre_match, Kernel.const_get(match.captures.first)]
  else
    [str, nil]
  end
end