module SlackBuilder.Download
    ( clone
    , cloneAndArchive
    , commit
    , download
    , hostedSources
    , remoteFileExists
    , updateSlackBuildVersion
    , uploadCommand
    ) where

import Data.ByteString (ByteString)
import qualified Data.ByteString as ByteString
import Data.Map.Strict (Map)
import qualified Data.Map.Strict as Map
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.IO as Text.IO
import SlackBuilder.Config
import SlackBuilder.Trans
import Control.Monad.Trans.Reader (asks)
import Control.Monad.IO.Class (MonadIO(liftIO))
import System.IO (IOMode(..), withFile)
import System.FilePath ((</>), (<.>), takeBaseName, splitPath, joinPath)
import System.Process
    ( CreateProcess(..)
    , StdStream(..)
    , proc
    , readCreateProcessWithExitCode
    , callProcess
    )
import System.Exit (ExitCode(..))
import Control.Monad (unless)
import Text.URI (URI(..), mkURI)
import Network.HTTP.Req
    ( useHttpsURI
    , HEAD(..)
    , NoReqBody(..)
    , req
    , runReq
    , defaultHttpConfig
    , ignoreResponse
    , responseStatusCode
    , HttpConfig(..)
    , GET(..)
    , reqBr
    )
import Data.Functor ((<&>))
import Network.HTTP.Client (BodyReader, Response(..), brRead)
import Conduit
    ( ConduitT
    , yield
    , runConduitRes
    , sinkFile
    , (.|)
    , ZipSink(..)
    , await
    , sourceFile
    )
import Crypto.Hash (Digest, MD5, hashInit, hashFinalize, hashUpdate)
import Data.Void (Void)

updateSlackBuildVersion :: Text -> Text -> Map Text Text -> SlackBuilderT ()
updateSlackBuildVersion packagePath version additionalDownloads = do
    repository' <- SlackBuilderT $ asks repository
    let name = Text.unpack $ snd $ Text.breakOnEnd "/" packagePath
        slackbuildFilename = repository'
            </> Text.unpack packagePath
            </> (name <.> "SlackBuild")
    slackbuildContents <- liftIO $ Text.IO.readFile slackbuildFilename
    let slackbuildLines = replaceLine . updateLineVariable "VERSION" version
            <$> Text.lines slackbuildContents
 
    liftIO $ Text.IO.writeFile slackbuildFilename $ Text.unlines slackbuildLines
  where
    replaceLine line = Map.foldrWithKey updateLineDependencyVersion line additionalDownloads
    updateLineDependencyVersion dependencyName = updateLineVariable
        $ dependencyName <> "_VERSION"
    updateLineVariable variableName variableValue line
        | Text.isPrefixOf (variableName <> "=") line =
            variableName <> "=${" <> variableName <> ":-" <> variableValue <> "}"
        | otherwise = line

commit :: Text -> Text -> SlackBuilderT ()
commit packagePath version = do
    branch' <- SlackBuilderT $ Text.unpack <$> asks branch
    repository' <- SlackBuilderT $ asks repository
    signature' <- SlackBuilderT $ asks $ signature . maintainer
    let message = Text.unpack
            $ packagePath <> ": Updated for version " <> version
        mainCommitArguments = ["-C", repository', "commit", "-m", message]
        commitArguments =
            if signature'
            then mainCommitArguments <> ["-S"]
            else mainCommitArguments

    (checkoutExitCode, _, _) <- liftIO
        $ withFile "/dev/null" WriteMode
        $ testCheckout repository' branch'
 
    unless (checkoutExitCode == ExitSuccess)
        $ liftIO
        $ callProcess "git" ["-C", repository', "checkout", "-b", branch', "master"]
    liftIO
        $ callProcess "git" ["-C", repository', "add", Text.unpack packagePath]
        >> callProcess "git" commitArguments
  where
    testCheckout repository' branch' nullHandle =
        let createCheckoutProcess = (proc "git" ["-C", repository', "checkout", branch'])
                { std_in = NoStream
                , std_err = UseHandle nullHandle
                }
         in readCreateProcessWithExitCode createCheckoutProcess ""

hostedSources :: Text -> SlackBuilderT URI
hostedSources absoluteURL = SlackBuilderT (asks downloadURL)
    >>= liftIO . mkURI . (<> absoluteURL)

remoteFileExists :: Text -> SlackBuilderT Bool
remoteFileExists url = hostedSources url
    >>= traverse (runReq httpConfig . go . fst) . useHttpsURI
    <&> maybe False ((== 200) . responseStatusCode)
  where
    httpConfig = defaultHttpConfig
        { httpConfigCheckResponse = const $ const $ const Nothing
        }
    go uri = req HEAD uri NoReqBody ignoreResponse mempty

uploadCommand :: Text -> Text -> SlackBuilderT ()
uploadCommand localPath remotePath' = do
    remoteRoot <- SlackBuilderT $ asks remotePath
    repository' <- SlackBuilderT $ asks repository

    liftIO $ callProcess "scp"
        [ repository' </> Text.unpack localPath
        , Text.unpack $ remoteRoot <> remotePath'
        ]

cloneAndArchive :: Text -> Text -> FilePath -> Text -> SlackBuilderT ()
cloneAndArchive repo nameVersion tarball tagPrefix = do
    let (_, version) = Text.breakOnEnd "-" nameVersion
        nameVersion' = Text.unpack nameVersion

    repository' <- SlackBuilderT $ asks repository
    liftIO $ callProcess "rm" ["-rf", nameVersion']

    liftIO $ callProcess "git" ["clone", Text.unpack repo, nameVersion']
    liftIO $ callProcess "git"
        [ "-C"
        , nameVersion'
        , "checkout"
        , Text.unpack $ tagPrefix <> version
        ]
    liftIO $ callProcess "git"
        [ "-C"
        , nameVersion'
        , "submodule"
        , "update"
        , "--init"
        , "--recursive"
        ]

    liftIO $ callProcess "tar"
        [ "Jcvf"
        , repository' </> tarball
        , nameVersion'
        ]
    liftIO $ callProcess "rm" ["-rf", nameVersion']

responseBodySource :: MonadIO m => Response BodyReader -> ConduitT i ByteString m ()
responseBodySource = bodyReaderSource . responseBody
  where
    bodyReaderSource br = liftIO (brRead br) >>= go br
    go br bs = unless (ByteString.null bs) $ yield bs >> bodyReaderSource br

sinkHash :: Monad m => ConduitT ByteString Void m (Digest MD5)
sinkHash = sink hashInit
  where
    sink ctx = await
        >>= maybe (pure $ hashFinalize ctx) (sink . hashUpdate ctx)

download :: URI -> FilePath -> SlackBuilderT (Maybe (Digest MD5))
download uri target = traverse (runReq defaultHttpConfig . go . fst)
    $ useHttpsURI uri
  where
    go uri' = reqBr GET uri' NoReqBody mempty readResponse
    readResponse :: Response BodyReader -> IO (Digest MD5)
    readResponse response = runConduitRes
        $ responseBodySource response
        .| getZipSink (ZipSink (sinkFile target) *> ZipSink sinkHash)

clone :: Text -> Text -> Text -> SlackBuilderT (Maybe (Digest MD5))
clone repo tarball tagPrefix = do
    repository' <- SlackBuilderT $ asks repository
    let tarballPath = Text.unpack tarball
        nameVersion = Text.pack $ takeBaseName tarballPath
        remotePath = Text.pack $ joinPath $ ("/" :) $ drop 1 $ splitPath tarballPath
        localPath = repository' </> tarballPath
    remoteFileExists' <- remoteFileExists remotePath

    if remoteFileExists'
    then
        hostedSources remotePath >>= flip download localPath
    else
        let go = sourceFile localPath .| sinkHash
         in cloneAndArchive repo nameVersion tarballPath tagPrefix
            >> uploadCommand tarball remotePath
            >> liftIO (runConduitRes go) <&> Just