local side = "left"
local direction = {
	up = colors.green,
	down = colors.red
}
local floors = {
	[1] = {
		call = colors.black,
		here = colors.white
	},
	[2] = {
		call = colors.gray,
		here = colors.lightGray
	},
	[3] = {
		call = colors.blue,
		here = colors.cyan
	}
}

local function waitForChange()
	os.pullEvent("redstone")
end

while true do
	waitForChange()

	local targetFloor, currentFloor
	-- This iterates through the floor objects defined above
	-- and checks if any of their call lines is asserted.
	for ix = 1, #floors do
		if rs.testBundledInput(side, floors[ix].call) then
			targetFloor = ix
		end
		if rs.testBundledInput(side, floors[ix].here) then
			currentFloor = ix
		end
	end

	-- It's guaranteed that currentFloor is set, because
	-- at this point the elevator must be on a floor. Unless
	-- the program somehow crashed while the elevator was going,
	-- in which case you'd have to fix the elevator anyway.
	-- It's not guaranteed that targetFloor ever gets set.
	-- In case it doesn't, we just skip over the move code.
	if targetFloor then
		print("Called from floor " .. targetFloor .. ", currently on " .. currentFloor)
		if targetFloor < currentFloor then
			print("  Going down")
			rs.setBundledOutput(side, direction.down)
		elseif targetFloor > currentFloor then
			print("  Going up")
			rs.setBundledOutput(side, direction.up)
		else
			print("  Going nowhere")
		end

		while true do
			waitForChange()
			if rs.testBundledInput(side, floors[targetFloor].here) then
				break
			end
		end

		rs.setBundledOutput(side, 0)
	end
end

local function read( _sReplaceChar, _tHistory, _fnComplete, initial_sLine ) -- not the new parameter initial_sLine
	term.setCursorBlink( true )

	local sLine = initial_sLine or "" -- empty string used if initial_sLine is not passed (or it nil/false)

	local nHistoryPos
	local nPos = 0
	if _sReplaceChar then
		_sReplaceChar = string.sub( _sReplaceChar, 1, 1 )
	end

	local tCompletions
	local nCompletion
	local function recomplete()
		if _fnComplete and nPos == string.len(sLine) then
			tCompletions = _fnComplete( sLine )
			if tCompletions and #tCompletions > 0 then
				nCompletion = 1
			else
				nCompletion = nil
			end
		else
			tCompletions = nil
			nCompletion = nil
		end
	end

	local function uncomplete()
		tCompletions = nil
		nCompletion = nil
	end

	local w = term.getSize()
	local sx = term.getCursorPos()

	local function redraw( _bClear )
		local nScroll = 0
		if sx + nPos >= w then
			nScroll = (sx + nPos) - w
		end

		local cx,cy = term.getCursorPos()
		term.setCursorPos( sx, cy )
		local sReplace = (_bClear and " ") or _sReplaceChar
		if sReplace then
			term.write( string.rep( sReplace, math.max( string.len(sLine) - nScroll, 0 ) ) )
		else
			term.write( string.sub( sLine, nScroll + 1 ) )
		end

		if nCompletion then
			local sCompletion = tCompletions[ nCompletion ]
			local oldText, oldBg
			if not _bClear then
				oldText = term.getTextColor()
				oldBg = term.getBackgroundColor()
				term.setTextColor( colors.white )
				term.setBackgroundColor( colors.gray )
			end
			if sReplace then
				term.write( string.rep( sReplace, string.len( sCompletion ) ) )
			else
				term.write( sCompletion )
			end
			if not _bClear then
				term.setTextColor( oldText )
				term.setBackgroundColor( oldBg )
			end
		end

		term.setCursorPos( sx + nPos - nScroll, cy )
	end

	local function clear()
		redraw( true )
	end

	recomplete()
	redraw()

	local function acceptCompletion()
		if nCompletion then
			-- Clear
			clear()

			-- Find the common prefix of all the other suggestions which start with the same letter as the current one
			local sCompletion = tCompletions[ nCompletion ]
			sLine = sLine .. sCompletion
			nPos = string.len( sLine )

			-- Redraw
			recomplete()
			redraw()
		end
	end
	while true do
		local sEvent, param = os.pullEvent()
		if sEvent == "char" then
			-- Typed key
			clear()
			sLine = string.sub( sLine, 1, nPos ) .. param .. string.sub( sLine, nPos + 1 )
			nPos = nPos + 1
			recomplete()
			redraw()

		elseif sEvent == "paste" then
			-- Pasted text
			clear()
			sLine = string.sub( sLine, 1, nPos ) .. param .. string.sub( sLine, nPos + 1 )
			nPos = nPos + string.len( param )
			recomplete()
			redraw()

		elseif sEvent == "key" then
			if param == keys.enter then
				-- Enter
				if nCompletion then
					clear()
					uncomplete()
					redraw()
				end
				break

			elseif param == keys.left then
				-- Left
				if nPos > 0 then
					clear()
					nPos = nPos - 1
					recomplete()
					redraw()
				end

			elseif param == keys.right then
				-- Right				
				if nPos < string.len(sLine) then
					-- Move right
					clear()
					nPos = nPos + 1
					recomplete()
					redraw()
				else
					-- Accept autocomplete
					acceptCompletion()
				end

			elseif param == keys.up or param == keys.down then
				-- Up or down
				if nCompletion then
					-- Cycle completions
					clear()
					if param == keys.up then
						nCompletion = nCompletion - 1
						if nCompletion < 1 then
							nCompletion = #tCompletions
						end
					elseif param == keys.down then
						nCompletion = nCompletion + 1
						if nCompletion > #tCompletions then
							nCompletion = 1
						end
					end
					redraw()

				elseif _tHistory then
					-- Cycle history
					clear()
					if param == keys.up then
						-- Up
						if nHistoryPos == nil then
							if #_tHistory > 0 then
								nHistoryPos = #_tHistory
							end
						elseif nHistoryPos > 1 then
							nHistoryPos = nHistoryPos - 1
						end
					else
						-- Down
						if nHistoryPos == #_tHistory then
							nHistoryPos = nil
						elseif nHistoryPos ~= nil then
							nHistoryPos = nHistoryPos + 1
						end						
					end
					if nHistoryPos then
						sLine = _tHistory[nHistoryPos]
						nPos = string.len( sLine )
					else
						sLine = ""
						nPos = 0
					end
					uncomplete()
					redraw()

				end

			elseif param == keys.backspace then
				-- Backspace
				if nPos > 0 then
					clear()
					sLine = string.sub( sLine, 1, nPos - 1 ) .. string.sub( sLine, nPos + 1 )
					nPos = nPos - 1
					recomplete()
					redraw()
				end

			elseif param == keys.home then
				-- Home
				if nPos > 0 then
					clear()
					nPos = 0
					recomplete()
					redraw()
				end

			elseif param == keys.delete then
				-- Delete
				if nPos < string.len(sLine) then
					clear()
					sLine = string.sub( sLine, 1, nPos ) .. string.sub( sLine, nPos + 2 )				
					recomplete()
					redraw()
				end

			elseif param == keys["end"] then
				-- End
				if nPos < string.len(sLine ) then
					clear()
					nPos = string.len(sLine)
					recomplete()
					redraw()
				end

			elseif param == keys.tab then
				-- Tab (accept autocomplete)
				acceptCompletion()

			end

		elseif sEvent == "term_resize" then
			-- Terminal resized
			w = term.getSize()
			redraw()

		end
	end

	local cx, cy = term.getCursorPos()
	term.setCursorBlink( false )
	term.setCursorPos( w + 1, cy )
	print()

	return sLine
end