class Mongoid::Atomic::Modifiers

def add_each_operation(mods, field, value)
  if mods.has_key?(field)
    value.each do |val|
      mods[field]["$each"].push(val)
    end
  else
    mods[field] = { "$each" => value }
  end
end

def add_operation(mods, field, value)
  if mods.has_key?(field)
    if mods[field].is_a?(Array)
      value.each do |val|
        mods[field].push(val)
      end
    elsif mods[field]['$each']
      mods[field]['$each'].concat(value['$each'])
    end
  else
    mods[field] = value
  end
end

def add_to_set(modifications)
  modifications.each_pair do |field, value|
    if add_to_sets.has_key?(field)
      value.each do |val|
        add_to_sets[field]["$each"].push(val)
      end
    else
      add_to_sets[field] = { "$each" => value }
    end
  end
end

def add_to_sets
  self["$addToSet"] ||= {}
end

def conflicting_pulls
  conflicts["$pullAll"] ||= {}
end

def conflicting_pushes
  conflicts["$push"] ||= {}
end

def conflicting_sets
  conflicts["$set"] ||= {}
end

def conflicts
  self[:conflicts] ||= {}
end

def pull(modifications)
  modifications.each_pair do |field, value|
    pulls[field] = value
    pull_fields[field.split(".", 2)[0]] = field
  end
end

def pull_all(modifications)
  modifications.each_pair do |field, value|
    add_operation(pull_alls, field, value)
    pull_fields[field.split(".", 2)[0]] = field
  end
end

def pull_alls
  self["$pullAll"] ||= {}
end

def pull_fields
  @pull_fields ||= {}
end

def pulls
  self["$pull"] ||= {}
end

def push(modifications)
  modifications.each_pair do |field, value|
    push_fields[field] = field
    mods = push_conflict?(field) ? conflicting_pushes : pushes
    add_operation(mods, field, { '$each' => Array.wrap(value) })
  end
end

def push_conflict?(field)
  name = field.split(".", 2)[0]
  set_fields.has_key?(name) || pull_fields.has_key?(name) ||
    (push_fields.keys.count { |item| item =~ /#{name}/ } > 1)
end

def push_fields
  @push_fields ||= {}
end

def pushes
  self["$push"] ||= {}
end

def set(modifications)
  modifications.each_pair do |field, value|
    next if field == "_id"
    mods = set_conflict?(field) ? conflicting_sets : sets
    add_operation(mods, field, value)
    set_fields[field.split(".", 2)[0]] = field
  end
end

def set_conflict?(field)
  name = field.split(".", 2)[0]
  pull_fields.has_key?(name) || push_fields.has_key?(name)
end

def set_fields
  @set_fields ||= {}
end

def sets
  self["$set"] ||= {}
end

def unset(modifications)
  modifications.each do |field|
    unsets.update(field => true)
  end
end

def unsets
  self["$unset"] ||= {}
end