note
	description: "[
		A list of ships that move as a unit.
		]"
	author: "Jimmy J. Johnson"

class
	TASK_FORCE

inherit

	VITP_ITEM
		undefine
			copy,
			is_equal
		redefine
			make
		end

	JJ_SORTABLE_SET [ATTACK_UNIT]
		rename
			make as list_make,
			extend as list_extend		-- to strengthen the precondition
		export
--			{TASK_FORCE}
--				all
--			{ATTACK_UNIT}

			{ANY}
				item,
--				count,
--				i_th,
--				first,
				start,
				is_after,
				forth
--				has,
--				prunable,
--				is_empty
		redefine
--			default_create,
--			make,
--			make_filled,
--			prune,
			new_filled_list
		end

create
	make

feature {NONE} -- Initialization

	make (a_game: like game)
			-- Initialize Current
		do
			list_make (10)
			Precursor {VITP_ITEM} (a_game)
--			column_count := 1
--			name := "No name"
		end

--	make (a_count: INTEGER)
--			-- Initialize Current to initial capacity of `a_count'
--		do
--			item_make ("No name", Nobody)
--			Precursor {JJ_SORTABLE_SET} (a_count)
--			column_count := 1
--		end

--	make_filled (a_count: INTEGER)
--			-- Initialize Current to initial capacity of `a_count'
--		do
--			item_make ("No name", Nobody)
--			Precursor (a_count)
--			column_count := 1
--		end

	new_filled_list (n: INTEGER): like Current
			-- Redefined to get past void-safety issues, but `duplicate'
			-- from {ARRAYED_LIST} will not work
		do
			check
				do_not_call: False then
					-- because redefined to appease void safety
			end
		end

feature -- Access

	name: STRING_8
			-- The displayed name for this widget
		do
			Result := "{" + generating_type + "} "
			if count >= 1 then
				Result := Result + i_th (1).name
			else
				Result := Result + "  not named"
			end
		end

feature {ATTACK_UNIT} -- Basic operations

	extend (a_unit: like item)
			-- Ensure `a_unit' is included in the force
		require
			unit_exists: a_unit /= Void
			correct_nationality: not is_empty implies not a_unit.is_opposed (first)
			same_location: not is_empty implies a_unit.location = first.location
		local
			old_f: detachable like item
		do
			is_stable := false
			if not is_empty and then not (a_unit.location = first.location) then
				a_unit.set_location (first.location)
			end
			list_extend (a_unit)
--			name := " Task Force " + id.out + "  " + first.name
			nationality := first.nationality
			is_stable := true
		end

	assemble
			-- Bring all units close together.
			-- Graphical elements will be stacked
		do
			is_dispersed := false

		end

	disperse
			-- Spread units out.
			-- Graphical elements will be tiled
		do
			is_dispersed := true
		end

feature -- Status report

	is_dispersed: BOOLEAN
			-- Are the units spread apart?
			-- Changed with `disperse' and `assemble'.

	is_stable: BOOLEAN
			-- Used by invariant for referential integrity checking

feature {NONE} -- Implementation

--	column_count: INTEGER
--			-- The number of columns in which to arrange the force

--	counter: INTEGER_32_REF
--			-- Used to create a unique name when a group is created
--		once
--			create Result
--		end

--	has_invalid_unit: BOOLEAN
--			-- Does Current contain a unit that does not refer back to Current
--			-- For invariant checking
--			-- Should be False
--		require
--			call_only_when_stable: is_stable
--		local
--			u: ATTACK_UNIT
--			c: CURSOR
--		do
--			c := cursor
--			from start
--			until after or Result
--			loop
--				u := item
--				Result := u.is_stable implies u.task_force /= Current
--				forth
--			end
--			go_to (c)
--		end

invariant

--	column_count_big_enough: column_count >= 1
--	column_count_small_enough: column_count <= count

end