module B9.B9Config.LibVirtLXC
  ( libVirtLXCConfigToCPDocument,
    defaultLibVirtLXCConfig,
    parseLibVirtLXCConfig,
    LibVirtLXCConfig (..),
    networkId,
    getEmulatorPath,
  )
where

import B9.B9Config.Container
import B9.DiskImages
import B9.ExecEnv
import Control.Lens (makeLenses)
import Control.Monad.IO.Class
import Data.ConfigFile.B9Extras
import Data.Maybe (fromMaybe)
import System.Environment.Blank as SysIO

data LibVirtLXCConfig
  = LibVirtLXCConfig
      { useSudo :: Bool,
        emulator :: Maybe FilePath,
        virshURI :: FilePath,
        _networkId :: Maybe String,
        guestCapabilities :: [ContainerCapability],
        guestRamSize :: RamSize
      }
  deriving (Read, Show, Eq)

makeLenses ''LibVirtLXCConfig

defaultLibVirtLXCConfig :: LibVirtLXCConfig
defaultLibVirtLXCConfig =
  LibVirtLXCConfig
    True
    (Just "/usr/lib/libvirt/libvirt_lxc")
    "lxc:///"
    Nothing
    [ CAP_MKNOD,
      CAP_SYS_ADMIN,
      CAP_SYS_CHROOT,
      CAP_SETGID,
      CAP_SETUID,
      CAP_NET_BIND_SERVICE,
      CAP_SETPCAP,
      CAP_SYS_PTRACE,
      CAP_SYS_MODULE
    ]
    (RamSize 1 GB)

cfgFileSection :: String
cfgFileSection = "libvirt-lxc"

useSudoK :: String
useSudoK = "use_sudo"

emulatorK :: String
emulatorK = "emulator_path"

-- NOTE: This variable name is also specified in the NIX build
-- in @default.nix@.
emulatorEnvVar :: String
emulatorEnvVar = "B9_LIBVIRT_LXC"

virshURIK :: String
virshURIK = "connection"

networkIdK :: String
networkIdK = "network"

guestRamSizeK :: String
guestRamSizeK = "guest_ram_size"

libVirtLXCConfigToCPDocument ::
  LibVirtLXCConfig -> CPDocument -> Either CPError CPDocument
libVirtLXCConfigToCPDocument c cp = do
  cp1 <- addSectionCP cp cfgFileSection
  cp2 <- setShowCP cp1 cfgFileSection useSudoK $ useSudo c
  cp3 <- setShowCP cp2 cfgFileSection emulatorK $ emulator c
  cp4 <- setCP cp3 cfgFileSection virshURIK $ virshURI c
  cp5 <- setShowCP cp4 cfgFileSection networkIdK $ _networkId c
  cp6 <- containerCapsToCPDocument cp5 cfgFileSection $ guestCapabilities c
  setShowCP cp6 cfgFileSection guestRamSizeK $ guestRamSize c

parseLibVirtLXCConfig :: CPDocument -> Either CPError LibVirtLXCConfig
parseLibVirtLXCConfig cp =
  let getr :: (CPGet a) => CPOptionSpec -> Either CPError a
      getr = readCP cp cfgFileSection
   in LibVirtLXCConfig
        <$> getr useSudoK
        <*> getr emulatorK
        <*> getr virshURIK
        <*> getr networkIdK
        <*> parseContainerCapabilities cp cfgFileSection
        <*> getr guestRamSizeK

-- | Return the path to @/usr/lib/libvirt/libexec/libvirt_lxc@
--  the 'emulatorK' field from the config file, or set the path
-- in the environment variable named like the value in 'emulatorEnvVar'
-- dictates.
--
-- @since 0.5.66
getEmulatorPath :: MonadIO m => LibVirtLXCConfig -> m FilePath
getEmulatorPath cfg =
  liftIO (SysIO.getEnvDefault emulatorEnvVar fromCfgOrDefault)
  where
    fromCfgOrDefault = fromMaybe "/usr/lib/libexec/libvirt_lxc" (emulator cfg)
