class Ransack::Context

def association_path(str, base = @base)
  base = klassify(base)
  str ||= ''.freeze
  path = []
  segments = str.split(Constants::UNDERSCORE)
  association_parts = []
  unless segments.empty?
    while !segments.empty? &&
          !base.columns_hash[segments.join(Constants::UNDERSCORE)] &&
          association_parts << segments.shift
      assoc, klass = unpolymorphize_association(
        association_parts.join(Constants::UNDERSCORE)
      )
      next unless found_assoc = get_association(assoc, base)
      path += association_parts
      association_parts = []
      base = klassify(klass || found_assoc)
    end
  end
  path.join(Constants::UNDERSCORE)
end

def bind(object, str)
  return nil unless str
  object.parent, object.attr_name = bind_pair_for(str)
end

def bind_pair_for(key)
  @bind_pairs ||= {}
  @bind_pairs[key] ||= begin
    parent, attr_name = get_parent_and_attribute_name(key.to_s)
    [parent, attr_name] if parent && attr_name
  end
end

def chain_scope(scope, args)
  return unless @klass.method(scope) && args != false
  @object = if scope_arity(scope) < 1 && args == true
              @object.public_send(scope)
            else
              @object.public_send(scope, *args)
            end
end

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

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

def for_class(klass, options = {})
  if klass < ActiveRecord::Base
    Adapters::ActiveRecord::Context.new(klass, options)
  end
end

def for_object(object, options = {})
  case object
  when ActiveRecord::Relation
    Adapters::ActiveRecord::Context.new(object.klass, options)
  end
end

def initialize(object, options = {})
  @object = relation_for(object)
  @klass = @object.klass
  @join_dependency = join_dependency(@object)
  @join_type = options[:join_type] || Polyamorous::OuterJoin
  @search_key = options[:search_key] || Ransack.options[:search_key]
  @associations_pot = {}
  @tables_pot = {}
  @lock_associations = []
  @base = @join_dependency.instance_variable_get(:@join_root)
end

def klassify(obj)
  if Class === obj && ::ActiveRecord::Base > obj
    obj
  elsif obj.respond_to? :klass
    obj.klass
  else
    raise ArgumentError, "Don't know how to klassify #{obj.inspect}"
  end
end

def ransackable_alias(str)
  klass._ransack_aliases.fetch(str, str)
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) ||
    klass.ransortable_attributes(auth_object).include?(str)
end

def ransackable_scope?(str, klass)
  klass.ransackable_scopes(auth_object).any? { |s| s.to_sym == str.to_sym }
end

def ransackable_scope_skip_sanitize_args?(str, klass)
  klass.ransackable_scopes_skip_sanitize_args.any? { |s| s.to_sym == str.to_sym }
end

def scope_arity(scope)
  @klass.method(scope).arity
end

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

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

def sortable_attributes(str = ''.freeze)
  traverse(str).ransortable_attributes(auth_object)
end

def traverse(str, base = @base)
  str ||= ''.freeze
  segments = str.split(Constants::UNDERSCORE)
  unless segments.empty?
    remainder = []
    found_assoc = nil
    until found_assoc || segments.empty?
      # 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(
        segments.join(Constants::UNDERSCORE)
      )
      if found_assoc = get_association(assoc, base)
        base = traverse(
          remainder.join(Constants::UNDERSCORE), klass || found_assoc.klass
        )
      end
      remainder.unshift segments.pop
    end
    unless found_assoc
      raise(UntraversableAssociationError,
            "No association matches #{str}")
    end
  end
  klassify(base)
end

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