module DFHack
    class << self
        # return an Unit
        # with no arg, return currently selected unit in df UI ('v' or 'k' menu)
        # with numeric arg, search unit by unit.id
        # with an argument that respond to x/y/z (eg cursor), find first unit at this position
        def unit_find(what=:selected)
            if what == :selected
                case ui.main.mode
                when :ViewUnits
                    # nobody selected => idx == 0
                    v = world.units.active[ui_selected_unit]
                    v if v and v.pos.z == cursor.z
                when :LookAround
                    k = ui_look_list.items[ui_look_cursor]
                    k.unit if k.type == :Unit
                end
            elsif what.kind_of?(Integer)
                world.units.all.binsearch(what)
            elsif what.respond_to?(:x) or what.respond_to?(:pos)
                world.units.all.find { |u| same_pos?(what, u) }
            else
                raise "what what?"
            end
        end

        # returns an Array of all units that are current fort citizen (dwarves, on map, not hostile)
        def unit_citizens
            race = ui.race_id
            civ = ui.civ_id
            world.units.active.find_all { |u| 
                u.race == race and u.civ_id == civ and !u.flags1.dead and !u.flags1.merchant and
                !u.flags1.diplomat and !u.flags2.resident and !u.flags3.ghostly and
                !u.curse.add_tags1.OPPOSED_TO_LIFE and !u.curse.add_tags1.CRAZED and
                u.mood != :Berserk
                # TODO check curse ; currently this should keep vampires, but may include werebeasts
            }
        end

        # list workers (citizen, not crazy / child / inmood / noble)
        def unit_workers
            unit_citizens.find_all { |u|
                u.mood == :None and
                u.profession != :CHILD and
                u.profession != :BABY and
                # TODO MENIAL_WORK_EXEMPTION_SPOUSE
                !unit_entitypositions(u).find { |pos| pos.flags[:MENIAL_WORK_EXEMPTION] }
            }
        end

        # list currently idle workers
        def unit_idlers
            unit_workers.find_all { |u|
                # current_job includes eat/drink/sleep/pickupequip
                !u.job.current_job and 
                # filter 'attend meeting'
                u.meetings.length == 0 and
                # filter soldiers (TODO check schedule)
                u.military.squad_index == -1 and
                # filter 'on break'
                !u.status.misc_traits.find { |t| id == :OnBreak }
            }
        end

        def unit_entitypositions(unit)
            list = []
            return list if not hf = world.history.figures.binsearch(unit.hist_figure_id)
            hf.entity_links.each { |el|
                next if el._rtti_classname != :histfig_entity_link_positionst
                next if not ent = world.entities.all.binsearch(el.entity_id)
                next if not pa = ent.positions.assignments.binsearch(el.assignment_id)
                next if not pos = ent.positions.own.binsearch(pa.position_id)
                list << pos
            }
            list
        end
    end
end