import os
import platform
import socket
from datetime import datetime, timedelta
from getpass import getuser

import psutil

from colors import Fore, Style, bright_colored, colored, colorize_percent
from humanize import humanize_bytes, humanize_timedelta


def get_system_info():
  info_lines = []

  def info(name, value, *format_args):
    line = bright_colored(name + ":", Fore.YELLOW) + " " + value
    if format_args:
      line = line % format_args
    info_lines.append(line)

  username = getuser()
  hostname = _get_hostname()

  info_lines.append(bright_colored(username, Fore.BLUE) + "@" + bright_colored(hostname, Fore.RED))
  info_lines.append("")

  distro_id, distro_name, distro_version, distro_codename = _get_distro_info()
  info("OS", " ".join([distro_name, distro_version, distro_codename]))

  logo_path = os.path.join(os.path.dirname(__file__), "logos", distro_id)
  with open(logo_path) as logo_file:
    logo_lines = logo_file.read().splitlines()

  info("Kernel", "%s %s", platform.system(), platform.release())

  info("Uptime", humanize_timedelta(_get_uptime()))

  users_info = _get_users()
  if users_info:
    info("Users", users_info)

  shell = _get_shell()
  if shell is not None:
    info("Shell", shell)

  info_lines.append("")

  cpu_usage_info = _get_cpu_usage()
  if cpu_usage_info is not None:
    info("CPU Usage", "%s", cpu_usage_info)
  info("Memory", "%s / %s (%s)", *_get_memory())

  for disk_info in _get_disks():
    info("Disk (%s)", "%s / %s (%s)", *disk_info)

  battery_info = _get_battery()
  if battery_info is not None:
    info("Battery", "%s (%s)", *battery_info)

  info_lines.append("")

  for local_ip_address in _get_local_ipv4_addresses():
    info("Local IPv4 Address (%s)", "%s", *local_ip_address)

  return logo_lines, info_lines


def _get_hostname():
  hostname = socket.gethostname()
  return hostname


def _get_uptime():
  return datetime.now() - datetime.fromtimestamp(psutil.boot_time())


def _get_users():
  users = {}

  for user in psutil.users():
    name = user.name
    terminal = user.terminal
    if name in users:
      users[name].append(terminal)
    else:
      users[name] = [terminal]

  result = []

  for name in users:
    terminals = users[name]

    colored_name = bright_colored(name, Fore.BLUE)
    colored_terminals = [colored(str(term), Style.DIM, Fore.WHITE) for term in terminals]

    terminals_str = ", ".join(colored_terminals)
    if len(colored_terminals) > 1:
      terminals_str = "(%s)" % terminals_str
    result.append(colored_name + "@" + terminals_str)

  return ", ".join(result)


def _get_shell():
  return os.environ.get("SHELL")


def _get_cpu_usage():
  try:
    percent = psutil.cpu_percent()
  except Exception as e:
    print("Error in _get_cpu_usage:", e)
    return None

  return colorize_percent(percent, warning=60, critical=80)


def _get_memory():
  memory = psutil.virtual_memory()
  return (
    humanize_bytes(memory.used),
    humanize_bytes(memory.total),
    colorize_percent(memory.percent, warning=60, critical=80),
  )


def _get_disks():
  result = []

  for disk in psutil.disk_partitions(all=False):
    if psutil.WINDOWS and ("cdrom" in disk.opts or disk.fstype == ""):
      # skip cd-rom drives with no disk in it on Windows; they may raise
      # ENOENT, pop-up a Windows GUI error for a non-ready partition or
      # just hang
      continue

    usage = psutil.disk_usage(disk.mountpoint)
    result.append((
      disk.mountpoint,
      humanize_bytes(usage.used),
      humanize_bytes(usage.total),
      colorize_percent(usage.percent, warning=70, critical=85),
    ))

  return result


def _get_battery():
  if not hasattr(psutil, "sensors_battery"):
    return None

  try:
    battery = psutil.sensors_battery()
  except Exception as e:
    print("Error in _get_battery:", e)
    return None

  if battery is None:
    return None

  percent = battery.percent
  if battery.power_plugged:
    status = "charging" if percent < 100 else "fully charged"
  else:
    status = "%s left" % humanize_timedelta(timedelta(seconds=battery.secsleft))
  return colorize_percent(percent, critical=10, warning=20, inverse=True), status


def _get_local_ipv4_addresses():
  result = []

  for interface, addresses in psutil.net_if_addrs().items():
    for address in addresses:
      if address.family != socket.AF_INET:
        # allow only IPv4 addresses (skip IPv6 and MAC, for example)
        continue
      if interface.startswith("lo"):
        # skip loopback interfaces
        continue

      result.append((interface, address.address))

  return result


def _get_distro_info():
  if psutil.WINDOWS:
    return "windows", platform.system(), platform.release(), ""
  elif psutil.OSX:
    import plistlib

    with open("/System/Library/CoreServices/SystemVersion.plist", "rb") as f:
      sw_vers = plistlib.load(f)
    return "mac", sw_vers["ProductName"], sw_vers["ProductVersion"], ""
  elif _is_android():
    from subprocess import check_output

    android_version = check_output(["getprop", "ro.build.version.release"])
    return "android", "Android", android_version.decode().strip(), ""
  elif psutil.LINUX:
    import distro

    return distro.id(), distro.name(), distro.version(), distro.codename()

  raise NotImplementedError("unsupported OS")


def _is_android():
  return os.path.isdir("/system/app") and os.path.isdir("/system/priv-app")