module Polyamorous::JoinDependencyExtensions

def build(associations, base_klass)
  associations.map do |name, right|
    if name.is_a? Join
      reflection = find_reflection base_klass, name.name
      reflection.check_validity!
      reflection.check_eager_loadable!
      klass = if reflection.polymorphic?
        name.klass || base_klass
      else
        reflection.klass
      end
      JoinAssociation.new(reflection, build(right, klass), name.klass, name.type)
    else
      reflection = find_reflection base_klass, name
      reflection.check_validity!
      reflection.check_eager_loadable!
      if reflection.polymorphic?
        raise ActiveRecord::EagerLoadPolymorphicError.new(reflection)
      end
      JoinAssociation.new(reflection, build(right, reflection.klass))
    end
  end
end

def construct_tables_for_association!(join_root, association)
  tables = table_aliases_for(join_root, association)
  association.table = tables.first
  tables
end

def join_constraints(joins_to_add, alias_tracker, references)
  @alias_tracker = alias_tracker
  @joined_tables = {}
  @references = {}
  references.each do |table_name|
    @references[table_name.to_sym] = table_name if table_name.is_a?(String)
  end
  joins = make_join_constraints(join_root, join_type)
  joins.concat joins_to_add.flat_map { |oj|
    if join_root.match?(oj.join_root) && join_root.table.name == oj.join_root.table.name
      walk join_root, oj.join_root, oj.join_type
    else
      make_join_constraints(oj.join_root, oj.join_type)
    end
  }
end

def table_aliases_for(parent, node)
  node.reflection.chain.map { |reflection|
    alias_tracker.aliased_table_for(reflection.klass.arel_table) do
      root = reflection == node.reflection
      name = reflection.alias_candidate(parent.table_name)
      root ? name : "#{name}_join"
    end
  }
end