local shell=require("shell")
local fs=require("filesystem")

local args,ops=shell.parse(...)
local path=nil
local verbose=false

if ops.help then
print(
[[Usage cd [dir]
For more options, run: man cd]])
return
end

if#args==0 then
local home=os.getenv("HOME")
if not home then
io.stderr:write("cd: HOME not set\n")
return 1
end
path=home
elseif args[1]=='-'then
verbose=true
local oldpwd=os.getenv("OLDPWD");
if not oldpwd then
io.stderr:write("cd: OLDPWD not set\n")
return 1
end
path=oldpwd
else
path=args[1]
end

local resolved=shell.resolve(path)
if not fs.exists(resolved)then
io.stderr:write("cd: ",path,": No such file or directory\n")
return 1
end

path=resolved
local oldpwd=shell.getWorkingDirectory()
local result,reason=shell.setWorkingDirectory(path)
if not result then
io.stderr:write("cd: ",path,": ",reason)
return 1
else
os.setenv("OLDPWD",oldpwd)
end
if verbose then
os.execute("pwd")
end