module Propellor.Property.Apt where

import Data.Maybe
import Control.Applicative
import Data.List
import System.IO
import Control.Monad

import Propellor
import qualified Propellor.Property.File as File
import Propellor.Property.File (Line)

sourcesList :: FilePath
sourcesList = "/etc/apt/sources.list"

type Url = String
type Section = String

showSuite :: DebianSuite -> String
showSuite Stable = "stable"
showSuite Testing = "testing"
showSuite Unstable = "unstable"
showSuite Experimental = "experimental"
showSuite (DebianRelease r) = r

debLine :: DebianSuite -> Url -> [Section] -> Line
debLine suite mirror sections = unwords $
	["deb", mirror, showSuite suite] ++ sections

srcLine :: Line -> Line
srcLine l = case words l of
	("deb":rest) -> unwords $ "deb-src" : rest
	_ -> ""

stdSections :: [Section]
stdSections = ["main", "contrib", "non-free"]

debCdn :: DebianSuite -> [Line]
debCdn suite = [l, srcLine l]
  where
	l = debLine suite "http://cdn.debian.net/debian" stdSections

{- | Makes sources.list have a standard content using the mirror CDN,
 - with a particular DebianSuite. -}
stdSourcesList :: DebianSuite -> Property
stdSourcesList suite = setSourcesList (debCdn suite)
	`describe` ("standard sources.list for " ++ show suite)

setSourcesList :: [Line] -> Property
setSourcesList ls = sourcesList `File.hasContent` ls `onChange` update

runApt :: [String] -> Property
runApt ps = cmdProperty' "apt-get" ps env
  where
	env =
		[ ("DEBIAN_FRONTEND", "noninteractive")
		, ("APT_LISTCHANGES_FRONTEND", "none")
		]

update :: Property
update = runApt ["update"]
	`describe` "apt update"

upgrade :: Property
upgrade = runApt ["-y", "dist-upgrade"]
	`describe` "apt dist-upgrade"

type Package = String

installed :: [Package] -> Property
installed ps = check (isInstallable ps) go
	`describe` (unwords $ "apt installed":ps)
  where
	go = runApt $ ["-y", "install"] ++ ps

removed :: [Package] -> Property
removed ps = check (or <$> isInstalled' ps) go
	`describe` (unwords $ "apt removed":ps)
  where
	go = runApt $ ["-y", "remove"] ++ ps

buildDep :: [Package] -> Property
buildDep ps = check (isInstallable ps) go
	`describe` (unwords $ "apt build-dep":ps)
  where
	go = runApt $ ["-y", "build-dep"] ++ ps

isInstallable :: [Package] -> IO Bool
isInstallable ps = do
	l <- isInstalled' ps
	return $ any (== False) l && not (null l)

isInstalled :: Package -> IO Bool
isInstalled p = (== [True]) <$> isInstalled' [p]

-- | Note that the order of the returned list will not always
-- correspond to the order of the input list. The number of items may
-- even vary. If apt does not know about a package at all, it will not
-- be included in the result list.
isInstalled' :: [Package] -> IO [Bool]
isInstalled' ps = catMaybes . map parse . lines
	<$> readProcess "apt-cache" ("policy":ps)
  where
	parse l
		| "Installed: (none)" `isInfixOf` l = Just False
		| "Installed: " `isInfixOf` l = Just True
		| otherwise = Nothing

autoRemove :: Property
autoRemove = runApt ["-y", "autoremove"]
	`describe` "apt autoremove"

unattendedUpgrades :: Bool -> Property
unattendedUpgrades enabled =
	(if enabled then installed else removed) ["unattended-upgrades"]
	`onChange` reConfigure "unattended-upgrades"
		[("unattended-upgrades/enable_auto_updates" , "boolean", v)]
	`describe` ("unattended upgrades " ++ v)
  where
	v
		| enabled = "true"
		| otherwise = "false"

-- | Preseeds debconf values and reconfigures the package so it takes
-- effect.
reConfigure :: Package -> [(String, String, String)] -> Property
reConfigure package vals = reconfigure `requires` setselections
	`describe` ("reconfigure " ++ package)
  where
	setselections = Property "preseed" $ makeChange $
		withHandle StdinHandle createProcessSuccess
			(proc "debconf-set-selections" []) $ \h -> do
				forM_ vals $ \(template, tmpltype, value) ->
					hPutStrLn h $ unwords [package, template, tmpltype, value]
				hClose h
	reconfigure = cmdProperty "dpkg-reconfigure" ["-fnone", package]