{-# LANGUAGE NoImplicitPrelude   #-}
{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE RecordWildCards     #-}
{-# LANGUAGE ScopedTypeVariables #-}

module Stack.Ls
  ( lsCmd
  , lsParser
  ) where

import Control.Exception (throw)
import Data.Aeson
import Data.Array.IArray ((//), elems)
import Distribution.Package (mkPackageName)
import Stack.Prelude hiding (Snapshot (..), SnapName (..))
import qualified Data.Aeson.Types as A
import qualified Data.List as L
import Data.Text hiding (filter, intercalate, pack, reverse)
import qualified Data.Text as T
import qualified Data.Text.IO as T
import qualified Data.Vector as V
import Network.HTTP.StackClient (httpJSON, addRequestHeader, getResponseBody, parseRequest, hAccept)
import qualified Options.Applicative as OA
import Options.Applicative (idm)
import Options.Applicative.Builder.Extra (boolFlags)
import Path
import RIO.List (sort)
import RIO.PrettyPrint (useColorL)
import RIO.PrettyPrint.DefaultStyles (defaultStyles)
import RIO.PrettyPrint.Types (StyleSpec)
import RIO.PrettyPrint.StylesUpdate (StylesUpdate (..), stylesUpdateL)
import Stack.Constants (osIsWindows)
import Stack.Dot
import Stack.Runners
import Stack.Options.DotParser (listDepsOptsParser)
import Stack.Setup.Installed (Tool (..), filterTools, listInstalled, toolString)
import Stack.Types.Config
import System.Console.ANSI.Codes (SGR (Reset), setSGRCode, sgrToCode)
import System.Process.Pager (pageText)
import System.Directory (listDirectory)
import System.IO (putStrLn)

data LsView
    = Local
    | Remote
    deriving (Show, Eq, Ord)

data SnapshotType
    = Lts
    | Nightly
    deriving (Show, Eq, Ord)

data LsCmds
    = LsSnapshot SnapshotOpts
    | LsDependencies ListDepsOpts
    | LsStyles ListStylesOpts
    | LsTools ListToolsOpts

data SnapshotOpts = SnapshotOpts
    { soptViewType :: LsView
    , soptLtsSnapView :: Bool
    , soptNightlySnapView :: Bool
    } deriving (Eq, Show, Ord)

data ListStylesOpts = ListStylesOpts
    { coptBasic   :: Bool
    , coptSGR     :: Bool
    , coptExample :: Bool
    } deriving (Eq, Ord, Show)

newtype ListToolsOpts = ListToolsOpts
    { toptFilter  :: String
    }

newtype LsCmdOpts = LsCmdOpts
    { lsView :: LsCmds
    }

lsParser :: OA.Parser LsCmdOpts
lsParser = LsCmdOpts
    <$> OA.hsubparser (lsSnapCmd <> lsDepsCmd <> lsStylesCmd <> lsToolsCmd)

lsCmdOptsParser :: OA.Parser LsCmds
lsCmdOptsParser = LsSnapshot <$> lsViewSnapCmd

lsDepOptsParser :: OA.Parser LsCmds
lsDepOptsParser = LsDependencies <$> listDepsOptsParser

lsStylesOptsParser :: OA.Parser LsCmds
lsStylesOptsParser = LsStyles <$> listStylesOptsParser

lsToolsOptsParser :: OA.Parser LsCmds
lsToolsOptsParser = LsTools <$> listToolsOptsParser

listStylesOptsParser :: OA.Parser ListStylesOpts
listStylesOptsParser = ListStylesOpts
    <$> boolFlags False
                  "basic"
                  "a basic report of the styles used. The default is a fuller \
                  \one"
                  idm
    <*> boolFlags True
                  "sgr"
                  "the provision of the equivalent SGR instructions (provided \
                  \by default). Flag ignored for a basic report"
                  idm
    <*> boolFlags True
                  "example"
                  "the provision of an example of the applied style (provided \
                  \by default for colored output). Flag ignored for a basic \
                  \report"
                  idm

listToolsOptsParser :: OA.Parser ListToolsOpts
listToolsOptsParser = ListToolsOpts
    <$> OA.strOption
            ( OA.long "filter"
           <> OA.metavar "TOOL_NAME"
           <> OA.value ""
           <> OA.help "Filter by a tool name (eg 'ghc', 'ghc-git' or 'msys2') \
                      \- case sensitive. The default is no filter"
            )

lsViewSnapCmd :: OA.Parser SnapshotOpts
lsViewSnapCmd =
    SnapshotOpts <$>
    (OA.hsubparser (lsViewRemoteCmd <> lsViewLocalCmd) <|> pure Local) <*>
    OA.switch
        (OA.long "lts" <> OA.short 'l' <> OA.help "Only show lts snapshots") <*>
    OA.switch
        (OA.long "nightly" <> OA.short 'n' <>
         OA.help "Only show nightly snapshots")

lsSnapCmd :: OA.Mod OA.CommandFields LsCmds
lsSnapCmd = OA.command "snapshots" $
  OA.info lsCmdOptsParser $
       OA.progDesc "View snapshots (local by default)"
    <> OA.footer localSnapshotMsg

lsDepsCmd :: OA.Mod OA.CommandFields LsCmds
lsDepsCmd =
    OA.command
        "dependencies"
        (OA.info lsDepOptsParser (OA.progDesc "View the dependencies"))

lsStylesCmd :: OA.Mod OA.CommandFields LsCmds
lsStylesCmd =
    OA.command
        "stack-colors"
        (OA.info lsStylesOptsParser
                 (OA.progDesc "View stack's output styles"))
    <>
    OA.command
        "stack-colours"
        (OA.info lsStylesOptsParser
                 (OA.progDesc "View stack's output styles (alias for \
                              \'stack-colors')"))

lsToolsCmd :: OA.Mod OA.CommandFields LsCmds
lsToolsCmd =
    OA.command
        "tools"
        (OA.info lsToolsOptsParser (OA.progDesc "View stack's installed tools"))

data Snapshot = Snapshot
    { snapId :: Text
    , snapTitle :: Text
    , snapTime :: Text
    } deriving (Show, Eq, Ord)

data SnapshotData = SnapshotData
    { _snapTotalCounts :: Integer
    , snaps :: [[Snapshot]]
    } deriving (Show, Eq, Ord)

instance FromJSON Snapshot where
    parseJSON o@(Array _) = parseSnapshot o
    parseJSON _ = mempty

instance FromJSON SnapshotData where
    parseJSON (Object s) =
        SnapshotData <$> s .: "totalCount" <*> s .: "snapshots"
    parseJSON _ = mempty

toSnapshot :: [Value] -> Snapshot
toSnapshot [String sid, String stitle, String stime] =
    Snapshot
    { snapId = sid
    , snapTitle = stitle
    , snapTime = stime
    }
toSnapshot val = throw $ ParseFailure val

newtype LsException =
    ParseFailure [Value]
    deriving (Show, Typeable)

instance Exception LsException

parseSnapshot :: Value -> A.Parser Snapshot
parseSnapshot = A.withArray "array of snapshot" (return . toSnapshot . V.toList)

displayTime :: Snapshot -> [Text]
displayTime Snapshot {..} = [snapTime]

displaySnap :: Snapshot -> [Text]
displaySnap Snapshot {..} =
    ["Resolver name: " <> snapId, "\n" <> snapTitle <> "\n\n"]

displaySingleSnap :: [Snapshot] -> Text
displaySingleSnap snapshots =
    case snapshots of
        [] -> mempty
        (x:xs) ->
            let snaps =
                    displayTime x <> ["\n\n"] <> displaySnap x <>
                    L.concatMap displaySnap xs
            in T.concat snaps

renderData :: Bool -> Text -> IO ()
renderData True content = pageText content
renderData False content = T.putStr content

displaySnapshotData :: Bool -> SnapshotData -> IO ()
displaySnapshotData term sdata =
    case L.reverse $ snaps sdata of
        [] -> return ()
        xs ->
            let snaps = T.concat $ L.map displaySingleSnap xs
            in renderData term snaps

filterSnapshotData :: SnapshotData -> SnapshotType -> SnapshotData
filterSnapshotData sdata stype =
    sdata
    { snaps = filterSnapData
    }
  where
    snapdata = snaps sdata
    filterSnapData =
        case stype of
            Lts -> L.map (L.filter (\x -> "lts" `isPrefixOf` snapId x)) snapdata
            Nightly ->
                L.map (L.filter (\x -> "nightly" `isPrefixOf` snapId x)) snapdata

displayLocalSnapshot :: Bool -> [String] -> IO ()
displayLocalSnapshot term xs = renderData term (localSnaptoText xs)

localSnaptoText :: [String] -> Text
localSnaptoText xs = T.intercalate "\n" $ L.map T.pack xs

handleLocal :: LsCmdOpts -> RIO Runner ()
handleLocal lsOpts = do
    (instRoot :: Path Abs Dir) <- withConfig YesReexec $ withDefaultEnvConfig installationRootDeps
    isStdoutTerminal <- view terminalL
    let parentInstRoot = parent instRoot
        snapRootDir
          | osIsWindows = parentInstRoot
          | otherwise   = parent parentInstRoot
    snapData' <- liftIO $ listDirectory $ toFilePath snapRootDir
    let snapData = L.sort snapData'
    case lsView lsOpts of
        LsSnapshot SnapshotOpts {..} ->
            case (soptLtsSnapView, soptNightlySnapView) of
                (True, False) ->
                    liftIO $
                    displayLocalSnapshot isStdoutTerminal $
                    L.filter (L.isPrefixOf "lts") snapData
                (False, True) ->
                    liftIO $
                    displayLocalSnapshot isStdoutTerminal $
                    L.filter (L.isPrefixOf "night") snapData
                _ -> liftIO $ displayLocalSnapshot isStdoutTerminal snapData
        LsDependencies _ -> return ()
        LsStyles _ -> return ()
        LsTools _ -> return ()

handleRemote
    :: HasRunner env
    => LsCmdOpts -> RIO env ()
handleRemote lsOpts = do
    req <- liftIO $ parseRequest urlInfo
    isStdoutTerminal <- view terminalL
    let req' = addRequestHeader hAccept "application/json" req
    result <- httpJSON req'
    let snapData = getResponseBody result
    case lsView lsOpts of
        LsSnapshot SnapshotOpts {..} ->
            case (soptLtsSnapView, soptNightlySnapView) of
                (True, False) ->
                    liftIO $
                    displaySnapshotData isStdoutTerminal $
                    filterSnapshotData snapData Lts
                (False, True) ->
                    liftIO $
                    displaySnapshotData isStdoutTerminal $
                    filterSnapshotData snapData Nightly
                _ -> liftIO $ displaySnapshotData isStdoutTerminal snapData
        LsDependencies _ -> return ()
        LsStyles _ -> return ()
        LsTools _ -> return ()
  where
    urlInfo = "https://www.stackage.org/snapshots"

lsCmd :: LsCmdOpts -> RIO Runner ()
lsCmd lsOpts =
    case lsView lsOpts of
        LsSnapshot SnapshotOpts {..} ->
            case soptViewType of
                Local -> handleLocal lsOpts
                Remote -> handleRemote lsOpts
        LsDependencies depOpts -> listDependencies depOpts
        LsStyles stylesOpts -> withConfig NoReexec $ listStylesCmd stylesOpts
        LsTools toolsOpts -> withConfig NoReexec $ listToolsCmd toolsOpts

lsViewLocalCmd :: OA.Mod OA.CommandFields LsView
lsViewLocalCmd = OA.command "local" $
  OA.info (pure Local) $
       OA.progDesc "View local snapshots"
    <> OA.footer localSnapshotMsg

lsViewRemoteCmd :: OA.Mod OA.CommandFields LsView
lsViewRemoteCmd = OA.command "remote" $
  OA.info (pure Remote) $
       OA.progDesc "View remote snapshots"
    <> OA.footer pagerMsg

pagerMsg :: String
pagerMsg =
  "On a terminal, uses a pager, if one is available. Respects the PAGER \
  \environment variable (subject to that, prefers pager 'less' to 'more')."

localSnapshotMsg :: String
localSnapshotMsg =
  "A local snapshot is identified by a hash code. " <> pagerMsg

-- | List stack's output styles
listStylesCmd :: ListStylesOpts -> RIO Config ()
listStylesCmd opts = do
    lc <- ask
    -- This is the same test as is used in Stack.Types.Runner.withRunner
    let useColor = view useColorL lc
        styles = elems $ defaultStyles // stylesUpdate (view stylesUpdateL lc)
        isComplex = not (coptBasic opts)
        showSGR = isComplex && coptSGR opts
        showExample = isComplex && coptExample opts && useColor
        styleReports = L.map (styleReport showSGR showExample) styles
    liftIO $ T.putStrLn $ T.intercalate (if isComplex then "\n" else ":") styleReports
  where
    styleReport :: Bool -> Bool -> StyleSpec -> Text
    styleReport showSGR showExample (k, sgrs) = k <> "=" <> codes
        <> (if showSGR then sgrsList else mempty)
        <> (if showExample then example else mempty)
      where
        codes = T.intercalate ";" (L.map (fromString . show) $
                    L.concatMap sgrToCode sgrs)
        sgrsList = " [" <> T.intercalate ", " (L.map (fromString . show) sgrs)
                   <> "]"
        example = " " <> ansi <> "Example" <> reset
        ansi = fromString $ setSGRCode sgrs
        reset = fromString $ setSGRCode [Reset]

-- | List stack's installed tools, sorted (see instance of 'Ord' for 'Tool').
listToolsCmd :: ListToolsOpts -> RIO Config ()
listToolsCmd opts = do
    localPrograms <- view $ configL.to configLocalPrograms
    installed <- sort <$> listInstalled localPrograms
    let wanted = case toptFilter opts of
            [] -> installed
            "ghc-git" -> [t | t@(ToolGhcGit _ _) <- installed]
            pkgName -> filtered pkgName installed
    liftIO $ mapM_ (putStrLn . toolString) wanted
  where
    filtered pkgName installed = Tool <$>
        filterTools (mkPackageName pkgName) (const True) installed