class RorVsWild::Metrics::Memory

def convert_to_bytes(string)
  value, unit = string.split
  value.to_i * units[unit.downcase]
end

def ram_used
  ram_total - ram_available
end

def read_meminfo
  return unless File.readable?(PROC_MEMINFO)
  File.read(PROC_MEMINFO).split("\n").reduce({}) do |hash, line|
    name, value = line.split(":")
    hash[name] = value.strip
    hash
  end
end

def swap_used
  swap_total - swap_free
end

def units
  @units ||= {"kb" => 1000, "mb" => 1000 * 1000, "gb" => 1000 * 1000 * 1000}.freeze
end

def update
  return unless info = read_meminfo
  @ram_total = convert_to_bytes(info[MEM_TOTAL])
  @ram_free = convert_to_bytes(info[MEM_FREE])
  @ram_available = convert_to_bytes(info[MEM_AVAILABLE])
  @ram_buffers = convert_to_bytes(info[BUFFERS])
  @ram_cached = convert_to_bytes(info[CACHED])
  @swap_total = convert_to_bytes(info[SWAP_TOTAL])
  @swap_free = convert_to_bytes(info[SWAP_FREE])
end