local frame
local basefolder = "ExpressionGate"

local function SetStatus(str)
	if !frame.Status then return end
	str = str or ""
	frame.Status:SetText(str)
end

local function UpFolder(folder)
	local orig = folder
	
	local last = string.sub(folder, -1)
	if last == "/" || last == "\\" then
		folder = string.sub(folder, 1, string.len(folder) - 1)
	end
	
	for i = string.len(folder), 1, -1 do
		local char = string.sub(folder, i, i)
		if char == "/" || char == "\\" then
			return string.sub(folder, 1, i - 1)
		end
	end
	
	return ""
end
local function Browse(folder)
	if !frame.Browser then return end
	
	// Allows us to refresh, and prevents us from errors.
	if !folder then folder = frame.Browser.Folder end
	if !folder then return end
	frame.Browser.Folder = folder
	
	frame.Browser:Clear()
	
	if folder != "" then folder = folder .. "/" end
	local path = basefolder .. "/" .. folder
	
	local found = file.Find(path .. "*")
	// Sort them into alphabetical order, with folders first.
	table.sort(found, function(a, b)
		if file.IsDir(path .. a) && !file.IsDir(path .. b) then
			return true
		elseif file.IsDir(path .. b) && !file.IsDir(path .. a) then
			return false
		end
		
		local t = {a, b}
		table.sort(t)
		if t[1] == a then
			return true
		end
		
		return false
	end)
	
	local up = frame.Browser:AddItem("../")
	up.DoClick = function() RunConsoleCommand("expresseditor_browse", UpFolder(folder)) end
	
	for _, filename in ipairs(found) do
		if file.IsDir(path .. filename) then
			local item = frame.Browser:AddItem(filename .. "/")
			item.DoClick = function() RunConsoleCommand("expresseditor_browse", folder .. filename) end
		else
			local item = frame.Browser:AddItem(filename)
			item.DoClick = function() RunConsoleCommand("expresseditor_target", folder .. filename) end
		end
	end
end
concommand.Add("expresseditor_browse", function(_, _, args) Browse(args[1]) end)

local function Target(_, _, args)
	frame.BrowserTarget:SetText(args[1] or "")
end
concommand.Add("expresseditor_target", Target)
local function GetTarget()
	local target = frame.BrowserTarget:GetValue()
	if string.sub(target, -4) != ".txt" then target = target .. ".txt" end
	return basefolder .. "/" .. target
end

local function Open()
	local path = GetTarget()
	if !file.Exists(path) then SetStatus("File not found.") return end
	local text = file.Read(path)
	if !text then SetStatus("File could not be read.") return end
	
	// Load basic info.
	local set = {["N@"] = "Name"; ["I@"] = "Inputs"; ["O@"] ="Outputs";}
	local finished = ""
	for i, line in pairs(string.Explode("\n", text)) do
		local found = false
		for symbol, textbox in pairs(set) do
			if string.sub(line, 1, string.len(symbol)) == symbol && frame[textbox] then
				frame[textbox]:SetText(string.sub(line, string.len(symbol) + 1))
				set[symbol] = nil
				found = true
			end
		end
		if !found then
			finished = finished .. line .. "\n"
		end
	end
	finished = string.sub(finished, 1, string.len(finished) - 1)
	
	frame.Editor:SetText(finished)
	frame.Editor:SetEditable(true)
	
	SetStatus("Loaded '" .. path .. "' successfully.")
end
concommand.Add("expresseditor_open", Open)

local function Save()
	local path = GetTarget()
	local text = frame.Editor:GetValue()
	if !text or text == "" then SetStatus("No text to save.") return end
	file.Write(path, text)
	
	SetStatus("Successfully saved '" .. path .. "'.")
	Browse() // Refresh.
end
concommand.Add("expresseditor_save", Save)

local delete
local function Delete()
	local path = GetTarget()
	
	if !file.Exists(path) then
		SetStatus("File not found.")
		delete = nil
		return
	end
	
	if !delete || delete != path then
		delete = path
		SetStatus("Are you sure you to delete '" .. path .. "'?")
		return
	end
	
	file.Delete(path)
	SetStatus("Successfully deleted '" .. path .. "'.")
	
	delete = nil
	Browse() // Refresh.
end
concommand.Add("expresseditor_delete", Delete)

local function Validate()
	local text = frame.Editor:GetValue() or ""
	local parser = WireGateExpressionParser:New(text, frame.Inputs:GetValue() or "", frame.Outputs:GetValue() or "")
	
	local err = parser:GetError()
	if err then
		SetStatus("Error: " .. err )
		
		for num in string.gmatch(err, "at line (%w)") do
			local pos = 0
			for i, line in pairs(string.Explode("\n", text)) do
				if i == tonumber(num) then frame.Editor:SetCaretPos(pos) break end
				pos = pos + string.len(line) + 1
			end
			break
		end
	else
		SetStatus("Successfully validated!")
	end
end
concommand.Add("expresseditor_validate", Validate)

local loading = false
timer.Remove("ExpressEditor.LoadUp")
local function LoadUp()
	if !loading then
		local name = frame.Name:GetValue() or ""
		local inputs = frame.Inputs:GetValue() or ""
		local outputs = frame.Outputs:GetValue() or ""
		// Remove the extension from the filename.
		local filename = frame.BrowserTarget:GetValue() or ""
		if string.sub(filename, -4) == ".txt" then
			filename = string.sub(filename, 1, string.len(filename) - 4)
		end
		RunConsoleCommand("wire_gate_expression_label", name)
		RunConsoleCommand("wire_gate_expression_inputs", inputs)
		RunConsoleCommand("wire_gate_expression_outputs", outputs)
		RunConsoleCommand("wire_gate_expression_filename", filename)
		
		local text = frame.Editor:GetValue() or ""
		local lines = string.Explode("\n", text)
		local i = 1
		timer.Create("ExpressEditor.LoadUp", 0.2, 0, function()
			if i >= 60 then
				timer.Remove("ExpressEditor.LoadUp")
				SetStatus("Loading complete.")
			else
				// Loop through any lines the same.
				while string.Trim(lines[i] or "") == string.Trim(GetConVarString("wire_gate_expression_line" .. i)) && i < 60 do
					i = i + 1
				end
				RunConsoleCommand("wire_gate_expression_line" .. i, lines[i] or "")
				SetStatus("Loading " .. math.floor(math.min(i/#lines, 1)*100) .. "%")
				i = i + 1
			end
		end)
	else
		timer.Remove("ExpressEditor.LoadUp")
		SetStatus("Loading cancelled.")
	end
end
concommand.Add("expresseditor_loadtool", LoadUp)

local function Spacer(h)
	local s = vgui.Create("DPanel")
		s:SetTall(h)
		s:SetPaintBackground(false)
	return s
end
local function Initialize()
	if frame then frame:SetVisible(true) return end
	
	frame = vgui.Create("DFrame")
		frame:SetTitle("ExpressEditor - Expression Gate Editor by RabidToaster")
		frame:SetVisible(false)
		frame:SetDeleteOnClose(false)
		frame:MakePopup()
		
		local w, h = 800, 600
		frame:SetSize(w, h)
		frame:Center()
	
	local divider = vgui.Create("DHorizontalDivider", frame)
		divider:SetPos(10, 30)
		divider:SetSize(w - 20, h - 40)
		divider:SetLeftWidth(w - 200)
	
	local leftSide = vgui.Create("DPanelList", divider)
	divider:SetLeft(leftSide)
	
	local editor = vgui.Create("DTextEntry", frame)
		editor:SetPos(10, 30)
		editor:SetSize(w - 200, h - 60)
		editor:SetMultiline(true)
		frame.Editor = editor
	leftSide:AddItem(editor)
	
	local status = vgui.Create("DTextEntry", frame)
		frame.Status = status
	leftSide:AddItem(status)
	status:SetEditable(false)
	
	local controls = vgui.Create("DVerticalDivider", frame)
	divider:SetRight(controls)
	
	// File browser.
	local browser = vgui.Create("DComboBox", controls)
		browser:SetTall(150)
		browser:SetMultiple(false)
		frame.Browser = browser
		Browse("")
	controls:SetTop(browser)	
	
	// Bottom set of controls.
	local botControls = vgui.Create("DPanelList", controls)
		botControls:EnableVerticalScrollbar()
	controls:SetBottom(botControls)
	
	local target = vgui.Create("DTextEntry", botControls)
		frame.BrowserTarget = target
	botControls:AddItem(target)
	
	botControls:AddItem(Spacer(10))
	
	// Name, inputs, outputs.
	local name = vgui.Create("DTextEntry", botControls)
		name:SetText("Name")
		frame.Name = name
	botControls:AddItem(name)
	local inputs = vgui.Create("DTextEntry", botControls)
		inputs:SetText("Inputs")
		frame.Inputs = inputs
	botControls:AddItem(inputs)
	local outputs = vgui.Create("DTextEntry", botControls)
		outputs:SetText("Outputs")
		frame.Outputs = outputs
	botControls:AddItem(outputs)
	
	botControls:AddItem(Spacer(10))
	
	// Open file.
	local open = vgui.Create("DButton", botControls)
		open:SetText("Open")
		open:SetConsoleCommand("expresseditor_open")
	botControls:AddItem(open)
	
	// Save file.
	local save = vgui.Create("DButton", botControls)
		save:SetText("Save")
		save:SetConsoleCommand("expresseditor_save")
	botControls:AddItem(save)
	
	// Delete file.
	local delete = vgui.Create("DButton", botControls)
		delete:SetText("Delete")
		delete:SetConsoleCommand("expresseditor_delete")
	botControls:AddItem(delete)
	
	botControls:AddItem(Spacer(10))
	
	// Validate.
	local validate = vgui.Create("DButton", botControls)
		validate:SetText("Validate")
		validate:SetConsoleCommand("expresseditor_validate")
	botControls:AddItem(validate)
	
	// Load into tool...
	local loadUp = vgui.Create("DButton", botControls)
		loadUp:SetText("Load Into Tool")
		loadUp:SetConsoleCommand("expresseditor_loadtool")
	botControls:AddItem(loadUp)
end
hook.Add("Initialize", "ExpressEditor", Initialize)
if derma then Initialize() end

local function Open()
	if !frame then return end
	frame:SetVisible(true)
end
concommand.Add("expresseditor", Open)