module JoinDependency

# File lib/join_dependency.rb, line 6
def from_relation(relation, &block)
  build(relation, collect_joins(relation, &block))
end

# File lib/join_dependency.rb, line 78
def at_least?(major, minor = 0, tiny = 0)
  ActiveRecord::VERSION::MAJOR > major ||
  (ActiveRecord::VERSION::MAJOR == major && ActiveRecord::VERSION::MINOR >= minor) ||
  (ActiveRecord::VERSION::MAJOR == major && ActiveRecord::VERSION::MINOR == minor && ActiveRecord::VERSION::TINY == tiny)
end

# File lib/join_dependency.rb, line 33
def build(relation, buckets)
  buckets.default = []
  association_joins         = buckets[:association_join]
  stashed_association_joins = buckets[:stashed_join]
  join_nodes                = buckets[:join_node].uniq
  string_joins              = buckets[:string_join].map(&:strip).uniq

  joins = string_joins.map do |join|
    relation.table.create_string_join(Arel.sql(join)) unless join.blank?
  end.compact

  join_list =
    if at_least?(5)
      join_nodes + joins
    else
      relation.send(:custom_join_ast, relation.table.from(relation.table), string_joins)
    end

  if exactly?(5, 2, 0)
    alias_tracker = ::ActiveRecord::Associations::AliasTracker.create(relation.klass.connection, relation.table.name, join_list)
    join_dependency = ::ActiveRecord::Associations::JoinDependency.new(relation.klass, relation.table, association_joins, alias_tracker)
    join_nodes.each do |join|
      join_dependency.send(:alias_tracker).aliases[join.left.name.downcase] = 1
    end
  elsif at_least?(5, 2, 1)
    alias_tracker = ::ActiveRecord::Associations::AliasTracker.create(relation.klass.connection, relation.table.name, join_list)
    join_dependency = ::ActiveRecord::Associations::JoinDependency.new(relation.klass, relation.table, association_joins)
    join_dependency.instance_variable_set(:@alias_tracker, alias_tracker)
    join_nodes.each do |join|
      join_dependency.send(:alias_tracker).aliases[join.left.name.downcase] = 1
    end
  else
    join_dependency = ::ActiveRecord::Associations::JoinDependency.new(relation.klass, association_joins, join_list)
    join_nodes.each do |join|
      join_dependency.send(:alias_tracker).aliases[join.left.name.downcase] = 1
    end
  end

  join_dependency
end

# File lib/join_dependency.rb, line 12
def collect_joins(relation, &block)
  joins = []
  joins += relation.joins_values
  joins += relation.left_outer_joins_values if at_least?(5)

  buckets = joins.group_by do |join|
    case join
    when String
      :string_join
    when Hash, Symbol, Array
      :association_join
    when ActiveRecord::Associations::JoinDependency
      :stashed_join
    when Arel::Nodes::Join
      :join_node
    else
      (block_given? && yield(join)) || raise("unknown class: %s" % join.class.name)
    end
  end
end

# File lib/join_dependency.rb, line 74
def exactly?(major, minor = 0, tiny = 0)
  ActiveRecord::VERSION::MAJOR == major && ActiveRecord::VERSION::MINOR == minor && ActiveRecord::VERSION::TINY == tiny
end