{-# LANGUAGE CPP #-}

-- |
-- Module      :  Distribution.Fedora
-- Copyright   :  (C) 2014-2021  Jens Petersen
--
-- Maintainer  :  Jens Petersen <petersen@fedoraproject.org>
--
-- Explanation: Fedora Dist type and functions

-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.

module Distribution.Fedora
  (Dist(..),
   getReleaseIds,
   getFedoraReleaseIds,
   getFedoraDists,
   getEPELReleaseIds,
   getRawhideDist,
   getLatestFedoraDist,
   getLatestEPELDist,
   rawhideVersionId,
   distBranch,
   distRepo,
   distUpdates,
   distOverride,
   mockConfig,
   distVersion,
   kojicmd,
   rpkg,
   rpmDistTag) where

import Data.Maybe
import qualified Data.Text as T
import Data.Text (Text)
import Data.Version
import Text.Read
import Text.ParserCombinators.ReadP (char, eof, string)

#if !MIN_VERSION_base(4,8,0)
import Control.Applicative ((<$>), (*>))
import Data.Traversable (traverse)
#endif

import Distribution.Fedora.Products
import Distribution.Fedora.Release

-- | The `Dist` datatype specifies the target OS and version.
-- (roughly corresponds to a git branch)
data Dist = RHEL Version -- ^ RHEL version
          | EPEL Int -- ^ EPEL release
          | Fedora Int -- ^ Fedora release
  deriving (Eq, Ord)

instance Show Dist where
  show (Fedora n) = "f" ++ show n
  show (EPEL n) = (if n <= 6 then "el" else "epel") ++ show n
  show (RHEL v) = "rhel-" ++ showVersion v

-- | Read from eg "f35", "epel8"
instance Read Dist where
  readPrec = choice [pFedora, pEPEL, pRHEL] where
    pFedora = Fedora <$> (lift (char 'f') *> readPrec)
    pEPEL = EPEL <$> (lift (string "epel") *> readPrec)
    pRHEL = RHEL <$> lift (do
      v <- string "rhel-" >> parseVersion
      eof
      return v)

getReleases :: IO [Release]
getReleases = reverse . mapMaybe readRelease <$> getProducts

-- | gets list of current releases (Fedora and EPEL)
--
-- The data is stored in ~/.fedora/product-versions.json
-- and refreshed from Fedora PDC if older than 5.5 hours
getReleaseIds :: IO [Text]
getReleaseIds = map releaseProductVersionId <$> getReleases

getProductReleases :: Text -> IO [Release]
getProductReleases name =
  filter (\p -> releaseProduct p == name) <$> getReleases

-- getRelease :: Text -> IO (Maybe Release)
-- getRelease pv =
--   find (\p -> releaseProductVersionId p == pv) <$> getReleases

getFedoraReleases :: IO [Release]
getFedoraReleases =
  getProductReleases (T.pack "fedora")

-- | gets current Fedora releases
getFedoraReleaseIds :: IO [Text]
getFedoraReleaseIds =
  map releaseProductVersionId <$> getFedoraReleases

getEPELReleases :: IO [Release]
getEPELReleases =
  getProductReleases (T.pack "epel")

-- | gets current EPEL releases
getEPELReleaseIds :: IO [Text]
getEPELReleaseIds =
  map releaseProductVersionId <$> getEPELReleases

-- | Rawhide version id
rawhideVersionId :: Text
rawhideVersionId = T.pack "fedora-rawhide"

-- fails on rawhide - only use on other releases
releaseMajorVersion :: Release -> Int
releaseMajorVersion = read . T.unpack . releaseVersion

releaseDist :: Release -> Dist
releaseDist = Fedora . releaseMajorVersion

releaseDists :: [Release] -> [Dist]
releaseDists rels =
  map mkDist rels
  where
    mkDist :: Release -> Dist
    mkDist r | releaseProductVersionId r == rawhideVersionId = newerDist latestbranch
             | otherwise = releaseDist r

    latestbranch = maximum $ filter (\p -> releaseProductVersionId p /= rawhideVersionId) rels

    newerDist = Fedora . (+ 1) . releaseMajorVersion

-- | get list of current Fedora Dist's
getFedoraDists :: IO [Dist]
getFedoraDists = releaseDists <$> getFedoraReleases

-- | get current Dist for Fedora Rawhide
getRawhideDist :: IO Dist
getRawhideDist =
  head . releaseDists <$> getFedoraReleases

-- | get newest Fedora branch
getLatestFedoraDist :: IO Dist
getLatestFedoraDist =
  releaseDist . maximum . filter (\p -> releaseProductVersionId p /= rawhideVersionId) <$> getFedoraReleases

-- | get newest EPEL release
getLatestEPELDist :: IO Dist
getLatestEPELDist =
  EPEL . releaseMajorVersion . maximum <$> getEPELReleases

-- activeRelease :: Text -> IO Bool
-- activeRelease pv = do
--   res <- filter (\p -> releaseProductVersionId p == pv) <$> getReleases
--   return $ not (null res)

-- | Maps `Dist` to package dist-git branch name, relative to latest branch
--
-- > distBranch (Fedora 35) (Fedora 36) == "rawhide"
-- > distBranch (Fedora 35) (Fedora 34) == "f34"
distBranch :: Dist -- ^ latest branch
           -> Dist -> String
distBranch branch (Fedora n) | Fedora n > branch = "rawhide"
distBranch _ d = show d

-- | Map `Dist` to DNF/YUM repo name, relative to latest branch
distRepo :: Dist -> Dist -> String
distRepo branched (Fedora n) | Fedora n > branched = "rawhide"
                             | otherwise = "fedora"
distRepo _ (EPEL _) = "epel"
distRepo _ (RHEL _) = "rhel"

-- | Map `Dist` to Maybe the DNF/YUM updates repo name, relative to latest branch
distUpdates :: Dist -> Dist -> Maybe String
distUpdates branched (Fedora n) | Fedora n > branched  = Nothing
distUpdates _ (Fedora _) = Just "updates"
distUpdates _ _ = Nothing

-- | Whether dist has overrides in Bodhi, relative to latest branch
distOverride :: Dist -> Dist -> Bool
distOverride branch (Fedora n) = Fedora n <= branch
distOverride _ (EPEL n) = n < 9
distOverride _ _ = False

-- | OS release major version for `Dist`, relative to latest branch
distVersion :: Dist -> Dist -> String
distVersion branch (Fedora n) | Fedora n > branch = "rawhide"
distVersion _ (Fedora n) = show n
distVersion _ (EPEL n) = show n
distVersion _ (RHEL n) = show n

-- | Mock configuration for `Dist` and arch, relative to latest branch
mockConfig :: Dist -> Dist -> String -> String
mockConfig branch dist arch =
  let prefix =
        case dist of
          Fedora _ -> "fedora"
          _ -> distRepo branch dist
  in
  prefix ++ "-" ++ distVersion branch dist ++ "-" ++ arch

-- | `Dist` tag (appended to rpm package release field)
rpmDistTag :: Dist -> String
rpmDistTag (Fedora n) = ".fc" ++ show n
rpmDistTag (EPEL n) = ".el" ++ show n
rpmDistTag (RHEL v) = ".el" ++ (show . head . versionBranch) v

-- | Command line tool for `Dist` (eg "koji")
kojicmd :: Dist -> String
kojicmd (RHEL _) = "brew"
kojicmd _ =  "koji"

-- | rpkg command for `Dist` (eg "fedpkg")
rpkg :: Dist -> String
rpkg (RHEL _) = "rhpkg"
rpkg _ = "fedpkg"