{-# LANGUAGE OverloadedStrings #-}

-- |
-- SPDX-License-Identifier: BSD-3-Clause
--
-- Query current and upstream Swarm version.
module Swarm.Version (
  -- * PVP version
  isSwarmReleaseTag,
  version,

  -- ** Upstream release
  tagToVersion,
  upstreamReleaseVersion,
  getNewerReleaseVersion,
  NewReleaseFailure (..),
) where

import Control.Exception (catch, displayException)
import Data.Aeson (Array, Value (..), (.:))
import Data.ByteString qualified as BS
import Data.ByteString.Lazy qualified as BSL
import Data.Char (isDigit)
import Data.Either (lefts, rights)
import Data.Foldable (toList)
import Data.Maybe (listToMaybe)
import Data.Text qualified as T
import Data.Version (Version (..), parseVersion, showVersion)
import Data.Yaml (ParseException, Parser, decodeEither', parseEither)
import GitHash (GitInfo, giBranch)
import Network.HTTP.Client (
  HttpException,
  Request (requestHeaders),
  Response (responseBody),
  httpLbs,
  newManager,
  parseRequest,
 )
import Network.HTTP.Client.TLS (tlsManagerSettings)
import Network.HTTP.Types (hUserAgent)
import Paths_swarm qualified
import Swarm.Util (failT, quote)
import Text.ParserCombinators.ReadP (readP_to_S)

-- $setup
-- >>> import Data.Bifunctor (first)
-- >>> import Data.Version (Version (..), parseVersion)
-- >>> import Text.ParserCombinators.ReadP (readP_to_S)

-- | Check that the tag follows the PVP versioning policy.
--
-- Note that this filters out VS Code plugin releases.
isSwarmReleaseTag :: String -> Bool
isSwarmReleaseTag = all (\c -> isDigit c || c == '.')

version :: String
version =
  let v = showVersion Paths_swarm.version
   in if v == "0.0.0.1" then "pre-alpha version" else v

-- | Get the current upstream release version if any.
upstreamReleaseVersion :: IO (Either NewReleaseFailure String)
upstreamReleaseVersion =
  catch
    (either parseFailure getRelease . decodeResp <$> sendRequest)
    (return . Left . queryFailure)
 where
  -- ------------------------------
  -- send request to GitHub API
  sendRequest :: IO (Response BSL.ByteString)
  sendRequest = do
    manager <- newManager tlsManagerSettings
    request <- parseRequest "https://api.github.com/repos/swarm-game/swarm/releases"
    httpLbs
      request {requestHeaders = [(hUserAgent, "swarm-game/swarm-swarmversion")]}
      manager
  -- ------------------------------
  -- get the latest actual release
  getRelease :: Array -> Either NewReleaseFailure String
  getRelease rs =
    let ts = parseReleases rs
        maybeRel = listToMaybe $ rights ts
     in case maybeRel of
          Nothing -> Left $ NoMainUpstreamRelease (lefts ts)
          Just rel -> Right rel
  -- ------------------------------
  -- pretty print failures
  parseFailure :: ParseException -> Either NewReleaseFailure String
  parseFailure e = Left . FailedReleaseQuery $ "Failure during response parsing: " <> displayException e
  queryFailure :: HttpException -> NewReleaseFailure
  queryFailure e = FailedReleaseQuery $ "Failure requesting GitHub releases: " <> displayException e
  -- ------------------------------
  -- parsing helpers
  decodeResp :: Response BSL.ByteString -> Either ParseException Array
  decodeResp resp = decodeEither' (BS.pack . BSL.unpack $ responseBody resp)
  parseReleases :: Array -> [Either String String]
  parseReleases = map (parseEither parseRelease) . toList

parseRelease :: Value -> Parser String
parseRelease = \case
  Object o -> do
    pre <- o .: "prerelease"
    if pre
      then fail "Not a real release!"
      else do
        t <- o .: "tag_name"
        if isSwarmReleaseTag t
          then return t
          else failT ["The release", quote $ T.pack t, "is not main Swarm release!"]
  _otherValue -> fail "The JSON release is not an Object!"

data NewReleaseFailure where
  FailedReleaseQuery :: String -> NewReleaseFailure
  NoMainUpstreamRelease :: [String] -> NewReleaseFailure
  OnDevelopmentBranch :: String -> NewReleaseFailure
  OldUpstreamRelease :: Version -> Version -> NewReleaseFailure

instance Show NewReleaseFailure where
  show = \case
    FailedReleaseQuery e -> "Failed to query upstream release: " <> e
    NoMainUpstreamRelease fs ->
      "No upstream releases found."
        <> if null fs
          then ""
          else " Rejected:\n" <> unlines (zipWith ((<>) . show @Int) [1 ..] fs)
    OnDevelopmentBranch br -> "Currently on development branch '" <> br <> "', skipping release query."
    OldUpstreamRelease up my ->
      "Upstream release '"
        <> showVersion up
        <> "' is not newer than mine ('"
        <> showVersion my
        <> "')."

-- | Read Swarm tag as Version.
--
-- Swarm tags follow the PVP versioning scheme, so comparing them makes sense.
--
-- >>> map (first versionBranch) $ readP_to_S parseVersion "0.1.0.0"
-- [([0],".1.0.0"),([0,1],".0.0"),([0,1,0],".0"),([0,1,0,0],"")]
-- >>> Version [0,0,0,1] [] < tagToVersion "0.1.0.0"
-- True
tagToVersion :: String -> Version
tagToVersion = fst . last . readP_to_S parseVersion

-- | Drop trailing zeros from versions so that we can compare them.
normalize :: Version -> Version
normalize (Version ns tags) = Version (dropTrailing0 ns) tags
 where
  dropTrailing0 = reverse . dropWhile (== 0) . reverse

-- | Get a newer upstream release version.
--
-- This function can fail if the current branch is not main,
-- if there is no Internet connection or no newer release.
getNewerReleaseVersion :: Maybe GitInfo -> IO (Either NewReleaseFailure String)
getNewerReleaseVersion mgi =
  case mgi of
    -- when using cabal install, the git info is unavailable, which is of no interest to players
    Nothing -> (>>= getUpVer) <$> upstreamReleaseVersion
    Just gi ->
      if giBranch gi /= "main"
        then return . Left . OnDevelopmentBranch $ giBranch gi
        else (>>= getUpVer) <$> upstreamReleaseVersion
 where
  myVer :: Version
  myVer = Paths_swarm.version
  getUpVer :: String -> Either NewReleaseFailure String
  getUpVer upTag =
    let upVer = tagToVersion upTag
     in if normalize myVer >= normalize upVer
          then Left $ OldUpstreamRelease upVer myVer
          else Right upTag