ardour { ["type"] = "EditorAction", name = "Marker Split",
	license     = "MIT",
	author      = "Ardour Team",
	description = [[Split regions on selected tracks at all locations markers]]
}

function factory (params) return function ()

	local loc = Session:locations () -- all marker locations

	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
	local sel = Editor:get_selection ()

	-- prepare undo operation
	-- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Session
	Session:begin_reversible_command ("Auto Region Split")
	local add_undo = false -- keep track if something has changed

	-- Track/Bus Selection -- iterate over all Editor-GUI selected tracks
	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:TrackSelection
	for r in sel.tracks:routelist ():iter () do
		-- each of the items 'r' is-a
		-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Route

		local track = r:to_track () -- see if it's a track
		if track:isnil () then
			-- if not, skip it
			goto continue
		end

		-- get track's playlist
		-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Playlist
		local playlist = track:playlist ()

		-- clear existing changes, prepare "diff" of state for undo
		playlist:to_stateful ():clear_changes ()

		-- iterate over all location markers
		for l in loc:list ():iter () do
			if l:is_mark() then
				-- get all regions on the given track's playlist (may be stacked)
				for reg in playlist:regions_at (l:start ()):iter () do
					playlist:split_region (reg, ARDOUR.MusicSample (l:start(), 0))
					-- the above operation will invalidate the playlist's region list:
					-- split creates 2 new regions.
					--
					-- Hence this script does it the way it does: the inner-most loop
					-- is over playlist-regions.
				end
			end
		end

		-- collect undo data
		if not Session:add_stateful_diff_command (playlist:to_statefuldestructible ()):empty () then
			-- is something has changed, we need to save it at the end.
			add_undo = true
		end

		::continue::
	end

	-- all done, commit the combined Undo Operation
	if add_undo then
		-- the 'nil' Command here mean to use the collected diffs added above
		Session:commit_reversible_command (nil)
	else
		Session:abort_reversible_command ()
	end

end end


-- render an icon for the toolbar action-button
-- this is generally square width == height.
-- The background is set according to the theme (leave transparent when drawing).
-- A foreground color is passed as parameter 'fg'
--
-- ctx is-a http://manual.ardour.org/lua-scripting/class_reference/#Cairo:Context
-- 2D vector graphics http://cairographics.org/
function icon (params) return function (ctx, width, height, fg)
	local mh = height - 3.5;
	local m3 = width / 3;
	local m6 = width / 6;

	ctx:set_line_width (.5)

	-- compare to gtk2_ardour/marker.cc "Marker"
	ctx:set_source_rgba (.8, .8, .2, 1.0)
	ctx:move_to (width / 2 - m6, 2)
	ctx:rel_line_to (m3, 0)
	ctx:rel_line_to (0, mh * 0.4)
	ctx:rel_line_to (-m6, mh * 0.6)
	ctx:rel_line_to (-m6, -mh * 0.6)
	ctx:close_path ()
	ctx:fill_preserve ()
	ctx:set_source_rgba (.0, .0, .0, 1.0)
	ctx:stroke ()

	-- draw an arrow  <--|--> on top, using the foreground color
	ctx:set_source_rgba (ARDOUR.LuaAPI.color_to_rgba (fg))
	ctx:set_line_width (1)

	ctx:move_to (width * .5, height * .4)
	ctx:line_to (width * .5, height * .6)
	ctx:stroke ()

	ctx:move_to (2, height * .5)
	ctx:line_to (width - 2, height * .5)
	ctx:stroke ()

	ctx:move_to (width - 2, height * .5)
	ctx:rel_line_to (-m6, -m6)
	ctx:rel_line_to (0, m3)
	ctx:close_path ()
	ctx:fill ()

	ctx:move_to (2, height * .5)
	ctx:rel_line_to (m6, -m6)
	ctx:rel_line_to (0, m3)
	ctx:close_path ()
	ctx:fill ()
end end