lfm

local unpack = unpack or table.unpack

local focus = "folders"
--fileTable is a flat table, numerically indexed, of all files/folders in the system
local fileTable
--fileTree is a filename-indexed table, wherein each directory is a table of tables, and each file is a reference to the fileTable entry for that file.
local fileTree
--fileLookup is a path-indexed table, wherein each entry is a reference to the fileTable entry for that path.
local fileLookup = {}
--displayTree is used for collapsed/expanded states of folders
local displayTree
--the currently selected folder, used for file view on the right pane.
local currentFolder = "/"

local folderListState = {
	totalHeight = 1,
	cursor = 1,
	offset = 1,
}

local function navigateToFolder(path)
	if path == "" or path == "/" then
		return fileTree
	end
end

local function buildFileList(path, treeEntry)
	local list = {}
	for k, v in pairs(treeEntry) do
		table.insert(list, fs.combine(path, k))
	end
	return list
end

local function parseFolder(path, fileTable, fileTree)
	for _, file in ipairs(fs.list(path)) do
		local fullPath = fs.combine(path, file)
		local fTable = {name = file, path = fullPath}
		if fs.isDir(file) then
			fTable.type = "directory"
			table.insert(fileTable, fTable)
			fileLookup[fullPath] = fTable
			_, fileTree[file] = parseFolder(fullPath, fileTable, {})
		else
			fTable.type = "file"
			table.insert(fileTable, fTable)
			fileTree[file] = fTable
			fileLookup[fullPath] = fTable
		end
	end
	return fileTable, fileTree
end

fileTable, fileTree = parseFolder("/", {}, {})

local function walkFileTree(tree, depth, result)
	if not result then result = {} end
	for k, v in pairs(tree) do
		if not v.type then
			table.insert(result, {name = k, depth = depth, collapsed = true})
			walkFileTree(v, depth + 1, result)
		end
	end
	return result
end

displayTree = walkFileTree(fileTree, 1)
table.insert(displayTree, 1, {name = "/", depth = 0, collapsed = false})

local function drawFolderList()
	local function prepareLines(displayTable, width)
		--prepares a displayable set of lines given a displayTree table and a width
		local displayedLines = {}
		local drawDepth = 0
		for i = 1, #displayTable do
			if displayTable[i].depth <= drawDepth then
				if drawDepth > displayTable[i].depth then drawDepth = displayTable[i].depth end
				table.insert(displayedLines, string.rep(" ", displayTable[i].depth)..(displayTable[i].collapsed and "+ " or "- ")..displayTable[i].name)
				if not displayTable[i].collapsed then
					drawDepth = displayTable[i].depth + 1
				end
			end
		end
		return displayedLines
	end

	local lines = prepareLines(displayTree, 19)

	term.clear()
	term.setCursorPos(1, 1)
	for i = 1, #lines do
		print(lines[i])
	end
end

local fileSorts = {
	alpha = function(fileList)
		local dirs, files = {}, {}
		for _, file in ipairs(fileList) do
			if fs.isDir(file) then
				table.insert(dirs, file)
			else
				table.insert(files, file)
			end
		end
		local function alphaSort(a, b)
			return a:lower() < b:lower()
		end
		table.sort(dirs, alphaSort)
		table.sort(files, alphaSort)
		for i = 1, #files do
			dirs[#dirs + 1] = files[i]
		end
		return dirs
	end,
}


--fileViews must be redirected to contain them.
local fileViews = {
	detailed = function(fileList)
		local list = fileSorts.alpha(fileList)
		term.clear()
		local x, y = term.getSize()
		for i = 1, math.min(#list, y) do
			term.setCursorPos(1, i)
			term.write(fs.getName(list[i]))
			term.setCursorPos(x - 5, i)
			term.write(tostring(fs.getSize(list[i])))
		end
	end,
}

local x, y = term.getSize()
local color = term.isColor()

local fileView = framebuffer.new(x - 16, y, color, 18, 1)
local oldFileView = framebuffer.new(x - 16, y, color, 18, 1)
local folderView = framebuffer.new(15, y, color)
local oldFolderView = framebuffer.new(15, y, color)

local list = buildFileList("/", navigateToFolder("/"))

term.clear()
for i = 1, y do
	term.setCursorPos(16, i)
	term.write("|")
end

while true do
	local _old = term.redirect(folderView)
	drawFolderList()
	if _old then
		term.redirect(_old)
	else
		term.restore()
	end
	local _old = term.redirect(fileView)
	fileViews.detailed(list)
	if _old then
		term.redirect(_old)
	else
		term.restore()
	end
	framebuffer.draw(folderView.buffer, oldFolderView.buffer)
	framebuffer.draw(fileView.buffer, oldFileView.buffer)
	os.pullEvent()
end