+ has_many :comments, -> { where(:visible => true).order(:created_at) }, :class_name => "ChangesetComment"
+ has_and_belongs_to_many :subscribers, :class_name => "User", :join_table => "changesets_subscribers", :association_foreign_key => "subscriber_id"
+
+ validates :id, :uniqueness => true, :presence => { :on => :update },
+ :numericality => { :on => :update, :integer_only => true }
+ validates :user_id, :presence => true,
+ :numericality => { :integer_only => true }
+ validates :num_changes, :presence => true,
+ :numericality => { :integer_only => true,
+ :greater_than_or_equal_to => 0 }
+ validates :created_at, :closed_at, :presence => true
+ validates :min_lat, :max_lat, :min_lon, :max_lat, :allow_nil => true,
+ :numericality => { :integer_only => true }
+
+ before_save :update_closed_at
+
+ # over-expansion factor to use when updating the bounding box
+ EXPAND = 0.1
+
+ # maximum number of elements allowed in a changeset
+ MAX_ELEMENTS = 10000
+
+ # maximum time a changeset is allowed to be open for.
+ MAX_TIME_OPEN = 1.day
+
+ # idle timeout increment, one hour seems reasonable.
+ IDLE_TIMEOUT = 1.hour
+
+ # Use a method like this, so that we can easily change how we
+ # determine whether a changeset is open, without breaking code in at
+ # least 6 controllers
+ def is_open?
+ # a changeset is open (that is, it will accept further changes) when
+ # it has not yet run out of time and its capacity is small enough.
+ # note that this may not be a hard limit - due to timing changes and
+ # concurrency it is possible that some changesets may be slightly
+ # longer than strictly allowed or have slightly more changes in them.
+ ((closed_at > Time.now.getutc) && (num_changes <= MAX_ELEMENTS))
+ end