easy-shell

local args = {...}

local exStr = [[shell.run("/usr/bin/easy-shell execute")]]

local function loadStartup()
	local lines = {}
	if fs.exists("/startup") then
		local handle = io.open("/startup", "r")
		if handle then
			for line in handle:lines() do
				table.insert(lines, line)
			end
			handle:close()
		end
	end
	return lines
end

local function writeStartup(contents)
	local handle = io.open("/startup", "w")
	if handle then
		for i, line in ipairs(contents) do
			handle:write(line.."\n")
		end
		handle:close()
	else
		error("Could not write startup file!")
	end
end

if #args >= 1 then
	if args[1] == "execute" then
		shell.setPath(shell.path()..":/usr/bin")

		local loadAPI = os.loadAPI

		os.loadAPI = function(path)
			if fs.exists(path) then
				return loadAPI(path)
			elseif fs.exists(fs.combine("/usr/apis", path)) then
				return loadAPI(fs.combine("/usr/apis", path))
			end
		end
	elseif args[1] == "install" then
		if tonumber(string.sub(os.version(), 9)) and tonumber(string.sub(os.version(), 9)) > 1.7 and fs.isDir("/startup") then
			--In CraftOS 1.8+, simply add a file to the startup folder.
			local handle = io.open("/startup/easy-shell.lua")
			if handle then
				handle:write(exStr)
				handle:close()
			else
				error("Could not write file!")
			end
		else
			--otherwise, attempt to cleanly add a line to the startup file.
			local contents = loadStartup()
			local changed = false
			if fs.exists("/startup") then
				local exists = false

				for i = 1, #contents do
					if contents[i] == exStr then
						exists = true
						break
					end
				end

				if not exists then
					table.insert(contents, 1, exStr)
					changed = true
				end
			else
				contents[1] = exStr
				changed = true
			end
			if changed then
				writeStartup(contents)
			end
		end
		shell.run("usr/bin/easy-shell execute")
	elseif args[1] == "remove" then
		if tonumber(string.sub(os.version(), 9)) and tonumber(string.sub(os.version(), 9)) > 1.7 and fs.exists("/startup/easy-shell.lua") then
			--in 1.8+, we just have to delete the file we added.
			fs.delete("/startup/easy-shell.lua")
		else
			local contents = loadStartup()
			for i = #contents, 1, -1 do
				 if contents[i] == exStr then
					table.remove(contents, i)
				end
			end
			writeStartup(contents)
		end
	end
end