-- File Dialog API by CrazedProgrammer
-- You can find info and documentation on these pages:
--
-- You may use this in your ComputerCraft programs and modify it without asking.
-- However, you may not publish this API under your name without asking me.
-- If you have any suggestions, bug reports or questions then please send an email to:
-- crazedprogrammer@gmail.com

local function list(dir)
	local fullList = fs.list(dir)
	table.sort(fullList, function (a, b) return string.lower(a) < string.lower(b) end)
	local displayList = { }
	for i = 1, #fullList do if fs.isDir(dir.."/"..fullList[i]) then displayList[#displayList + 1] = fullList[i] end end
	for i = 1, #fullList do if not fs.isDir(dir.."/"..fullList[i]) then displayList[#displayList + 1] = fullList[i] end end
	return displayList
end

local function draw(dir, offset)
	local width, height = term.getSize()
	term.setBackgroundColor(colors.white)
	term.clear()
	term.setCursorPos(1, 2 - offset)
	term.setBackgroundColor(colors.yellow)
	term.setTextColor(colors.black)
	term.write(".."..string.rep(" ", width - 2))
	for k,v in pairs(list(dir)) do
		term.setCursorPos(1, k + 2 - offset)
		if fs.isDir(dir.."/"..v) then
			term.setBackgroundColor(colors.yellow)
			term.write(v..string.rep(" ", width - #v))
		else
			term.setBackgroundColor(colors.white)
			term.write(v)
		end
	end
	term.setCursorPos(1, 1)
	term.setBackgroundColor(colors.gray)
	term.setTextColor(colors.white)
	if dir ~= "" then
		term.write("/"..dir..string.rep(" ", width - #dir - 2))
	else
		term.write("/"..string.rep(" ", width - 2))
	end
	term.setBackgroundColor(colors.red)
	term.write("X")
	term.setBackgroundColor(colors.gray)
	term.setCursorPos(width, 2)
	term.write("^")
	term.setCursorPos(width, height - 1)
	term.write("v")
	term.setCursorPos(1, height)
	term.setBackgroundColor(colors.lightGray)
	term.setTextColor(colors.black)
	term.write(string.rep(" ", width))
end

local function reset()
	term.setCursorPos(1, 1)
	term.setBackgroundColor(colors.black)
	term.setTextColor(colors.white)
	term.clear()
end

function open(dir)
	dir = dir or ""
	local offset, width, height = 0, term.getSize()
	draw(dir, offset)
	while true do
		local e = {os.pullEvent()}
		if e[1] == "mouse_click" then
			local x, y = e[3], e[4]
			if x == width and y == 1 then
				reset()
				return
			elseif x == width and y == 2 then
				offset = offset - math.floor(height / 3) + 1
				if offset < 0 then
					offset = 0
				end
			elseif x == width and y == height - 1 then
				offset = offset + math.floor(height / 3) - 1
			elseif y > 1 and y < height then
				if y + offset == 2 and dir ~= "" then
					dir = fs.getDir(dir)
				else
					for k,v in pairs(list(dir)) do
						if k == y + offset - 2 then
							if fs.isDir(dir.."/"..v) then
								dir = fs.getDir(dir.."/"..v.."/_")
							else
								reset()
								return fs.getDir(dir.."/"..v.."/_")
							end
						end
					end
				end
			elseif y == height then
				term.setCursorPos(1, height)
				local file = read()
				if file == "" then
				elseif file == ".." and dir ~= "" then
					dir = fs.getDir(dir)
				elseif file:sub(1, 1) == "/" then
					if fs.isDir(file) then
						dir = file:sub(2, #file)
					else
						reset()
						return file:sub(2, #file)
					end
				elseif fs.isDir(dir.."/"..file) then
					dir = fs.getDir(dir.."/"..file.."/_")
				else
					reset()
					return fs.getDir(dir.."/"..file.."/_")
				end
			end
		elseif e[1] == "mouse_scroll" then
			offset = offset + e[2] * (math.floor(height / 3) - 1)
			if offset < 0 then
				offset = 0
			end
		elseif e[1] == "term_resize" then
			width, height = term.getSize()
		end
		draw(dir, offset)
	end
end