local InputContainer = require("ui/widget/container/inputcontainer")
local Device = require("ui/device")
local DEBUG = require("dbg")
local _ = require("gettext")

local ReaderPanning = InputContainer:new{
	-- defaults
	panning_steps = {
		normal = 50,
		alt = 25,
		shift = 10,
		altshift = 5
	},
}

function ReaderPanning:init()
	if Device:isTouchDevice() then
	else
		self.key_events = {
			-- these will all generate the same event, just with different arguments
			MoveUp = {
				{ "Up" }, doc = _("move visible area up"),
				event = "Panning", args = {0, -1} },
			MoveDown = {
				{ "Down" }, doc = _("move visible area down"),
				event = "Panning", args = {0,  1} },
			MoveLeft = {
				{ "Left" }, doc = _("move visible area left"),
				event = "Panning", args = {-1, 0} },
			MoveRight = {
				{ "Right" }, doc = _("move visible area right"),
				event = "Panning", args = {1,  0} },
		}
	end
end

function ReaderPanning:onSetDimensions(dimensions)
	self.dimen = dimensions
end

function ReaderPanning:onPanning(args, key)
	local dx, dy = unpack(args)
	DEBUG("key =", key)
	-- for now, bounds checking/calculation is done in the view
	self.view:PanningUpdate(
		dx * self.panning_steps.normal * self.dimen.w / 100,
		dy * self.panning_steps.normal * self.dimen.h / 100)
	return true
end

return ReaderPanning
