local P = {}

function P.parse(line)
--   info("inter_parse: line="..line)

  line = string.sub(line, 1, string.find(line, "\r"))
  line = line:gsub("^%s+", "")
  line = line:gsub("%s+$", "")

  local args = {}
  local i = string.find(line, " ")
  if not i then
--    info("inter_parse: invalid line: no command, line="..line)
  return string.len(line) > 0 and line or nil, args
  end
  local cmd = string.sub(line, 1, i - 1)
  -- info("inter_parse: cmd="..cmd)

  local last = i + 1
  while i do
    local key
    local value

    i = string.find(line, " ", last)
    arg = string.sub(line, last, i)
    arg = arg:gsub("%s+", "")

    if #arg > 0 then
--      info("inter_parse: arg: "..arg)
      j = string.find(arg, "=")
      if not j then
        if #arg > 0 then
          key = arg
          args[key] = true
--          info("inter_parse: key="..key.."=true")
        end
      else
        key = string.sub(arg, 1, j-1)
        value = string.sub(arg, j+1)
        args[key] = value
--        info("inter_parse: key="..key..", value="..value)
      end
    end

    if not i then
      break
    end
    last = i + 1
  end

  return cmd, args
end

local cb
function inter_on_line(line)
  info("line:"..line)

  local cmd, args = P.parse(line)
  if not cmd then
    return
  end

  if cb then
    cb(cmd, args)
  end
end

function P.init(callback)
  cb = callback

  uart.on("data", "\r", inter_on_line, 0)
end

return P