module Internal.History
  ( readHistStmt
  , readHistTransfer
  , splitHistory
  )
where

import Control.Monad.Except
import Data.Csv
import Data.Decimal
import Data.Foldable
import Data.Hashable
import GHC.Real
import Internal.Types.Main
import Internal.Utils
import RIO hiding (to)
import qualified RIO.ByteString.Lazy as BL
import RIO.FilePath
import qualified RIO.List as L
import qualified RIO.Map as M
import qualified RIO.Text as T
import RIO.Time
import qualified RIO.Vector as V
import Text.Regex.TDFA hiding (matchAll)
import Text.Regex.TDFA.Text

-- NOTE keep statement and transfer readers separate because the former needs
-- the IO monad, and thus will throw IO errors rather than using the ExceptT
-- thingy
splitHistory :: [History] -> ([PairedTransfer], [Statement])
splitHistory = partitionEithers . fmap go
  where
    go (HistTransfer x) = Left x
    go (HistStatement x) = Right x

--------------------------------------------------------------------------------
-- Transfers

readHistTransfer
  :: (MonadAppError m, MonadFinance m)
  => PairedTransfer
  -> m [Tx CommitR]
readHistTransfer ht = do
  bounds <- asks (unHSpan . csHistoryScope)
  expandTransfer c historyName bounds ht
  where
    c = CommitR (CommitHash $ hash ht) CTHistoryTransfer

--------------------------------------------------------------------------------
-- Statements

readHistStmt
  :: (MonadUnliftIO m, MonadFinance m)
  => FilePath
  -> Statement
  -> m [Tx CommitR]
readHistStmt root i = do
  bs <- readImport root i
  bounds <- asks (unHSpan . csHistoryScope)
  return $ filter (inDaySpan bounds . txDate) $ fmap (\t -> t {txCommit = c}) bs
  where
    c = CommitR (CommitHash $ hash i) CTHistoryStatement

-- TODO this probably won't scale well (pipes?)
readImport :: (MonadUnliftIO m, MonadFinance m) => FilePath -> Statement -> m [Tx ()]
readImport root Statement {stmtTxOpts, stmtParsers, stmtSkipLines, stmtDelim, stmtPaths} = do
  let ores = compileOptions stmtTxOpts
  let cres = combineErrors $ compileMatch <$> stmtParsers
  (compiledOptions, compiledMatches) <- liftIOExcept $ combineError ores cres (,)
  let readStmt = readImport_ stmtSkipLines stmtDelim compiledOptions
  records <- L.sort . concat <$> mapErrorsIO readStmt paths
  fromEither =<< runExceptT (matchRecords compiledMatches records)
  where
    paths = (root </>) <$> stmtPaths

readImport_
  :: MonadUnliftIO m
  => Natural
  -> Word
  -> TxOptsRe
  -> FilePath
  -> m [TxRecord]
readImport_ n delim tns p = do
  res <- tryIO $ BL.readFile p
  bs <- fromEither $ first (AppException . (: []) . StatementIOError . tshow) res
  case decodeByNameWithP (parseTxRecord p tns) opts $ skip bs of
    Left m -> throwIO $ AppException [ParseError $ T.pack m]
    Right (_, v) -> return $ catMaybes $ V.toList v
  where
    opts = defaultDecodeOptions {decDelimiter = fromIntegral delim}
    skip = BL.intercalate "\n" . L.drop (fromIntegral n) . BL.split 10

-- TODO handle this better, this maybe thing is a hack to skip lines with
-- blank dates but will likely want to make this more flexible
parseTxRecord :: FilePath -> TxOptsRe -> NamedRecord -> Parser (Maybe TxRecord)
parseTxRecord p TxOpts {toDate, toAmountFmt, toDesc, toAmount, toOther, toDateFmt} r = do
  d <- r .: T.encodeUtf8 toDate
  if d == ""
    then return Nothing
    else do
      a <- parseDecimal toAmountFmt =<< r .: T.encodeUtf8 toAmount
      e <- r .: T.encodeUtf8 toDesc
      os <- M.fromList <$> mapM (\n -> (n,) <$> r .: T.encodeUtf8 n) toOther
      d' <- parseTimeM True defaultTimeLocale (T.unpack toDateFmt) d
      return $ Just $ TxRecord d' a e os p

matchRecords :: MonadFinance m => [MatchRe] -> [TxRecord] -> AppExceptT m [Tx ()]
matchRecords ms rs = do
  (matched, unmatched, notfound) <- matchAll (matchPriorities ms) rs
  case (matched, unmatched, notfound) of
    (ms_, [], []) -> return ms_
    (_, us, ns) -> throwError $ AppException [StatementError us ns]

matchPriorities :: [MatchRe] -> [MatchGroup]
matchPriorities =
  fmap matchToGroup
    . L.groupBy (\a b -> spPriority a == spPriority b)
    . L.sortOn (Down . spPriority)

matchToGroup :: [MatchRe] -> MatchGroup
matchToGroup ms =
  uncurry MatchGroup $
    first (L.sortOn spDate) $
      L.partition (isJust . spDate) ms

data MatchGroup = MatchGroup
  { mgDate :: ![MatchRe]
  , mgNoDate :: ![MatchRe]
  }
  deriving (Show)

data Zipped a = Zipped ![a] ![a]

data Unzipped a = Unzipped ![a] ![a] ![a]

initZipper :: [a] -> Zipped a
initZipper = Zipped []

resetZipper :: Zipped a -> Zipped a
resetZipper = initZipper . recoverZipper

recoverZipper :: Zipped a -> [a]
recoverZipper (Zipped as bs) = reverse as ++ bs

zipperSlice
  :: (a -> b -> Ordering)
  -> b
  -> Zipped a
  -> Either (Zipped a) (Unzipped a)
zipperSlice f x = go
  where
    go z@(Zipped _ []) = Left z
    go z@(Zipped bs (a : as)) =
      case f a x of
        GT -> go $ Zipped (a : bs) as
        EQ -> Right $ goEq (Unzipped bs [a] as)
        LT -> Left z
    goEq z@(Unzipped _ _ []) = z
    goEq z@(Unzipped bs cs (a : as)) =
      case f a x of
        GT -> goEq $ Unzipped (a : bs) cs as
        EQ -> goEq $ Unzipped bs (a : cs) as
        LT -> z

zipperMatch
  :: MonadFinance m
  => Unzipped MatchRe
  -> TxRecord
  -> AppExceptT m (Zipped MatchRe, MatchRes (Tx ()))
zipperMatch (Unzipped bs cs as) x = go [] cs
  where
    go _ [] = return (Zipped bs $ cs ++ as, MatchFail)
    go prev (m : ms) = do
      res <- matches m x
      case res of
        MatchFail -> go (m : prev) ms
        skipOrPass ->
          let ps = reverse prev
              ms' = maybe ms (: ms) (matchDec m)
           in return (Zipped bs $ ps ++ ms' ++ as, skipOrPass)

zipperMatch'
  :: MonadFinance m
  => Zipped MatchRe
  -> TxRecord
  -> AppExceptT m (Zipped MatchRe, MatchRes (Tx ()))
zipperMatch' z x = go z
  where
    go (Zipped bs (a : as)) = do
      res <- matches a x
      case res of
        MatchFail -> go (Zipped (a : bs) as)
        skipOrPass ->
          return (Zipped (maybe bs (: bs) $ matchDec a) as, skipOrPass)
    go z' = return (z', MatchFail)

matchDec :: MatchRe -> Maybe MatchRe
matchDec m = case spTimes m of
  Just 1 -> Nothing
  Just n -> Just $ m {spTimes = Just $ n - 1}
  Nothing -> Just m

matchAll
  :: MonadFinance m
  => [MatchGroup]
  -> [TxRecord]
  -> AppExceptT m ([Tx ()], [TxRecord], [MatchRe])
matchAll = go ([], [])
  where
    go (matched, unused) gs rs = case (gs, rs) of
      (_, []) -> return (matched, [], unused)
      ([], _) -> return (matched, rs, unused)
      (g : gs', _) -> do
        (ts, unmatched, us) <- matchGroup g rs
        go (ts ++ matched, us ++ unused) gs' unmatched

matchGroup
  :: MonadFinance m
  => MatchGroup
  -> [TxRecord]
  -> AppExceptT m ([Tx ()], [TxRecord], [MatchRe])
matchGroup MatchGroup {mgDate = ds, mgNoDate = ns} rs = do
  (md, rest, ud) <- matchDates ds rs
  (mn, unmatched, un) <- matchNonDates ns rest
  return (md ++ mn, unmatched, filter ((/= Nothing) . spTimes) $ ud ++ un)

matchDates
  :: MonadFinance m
  => [MatchRe]
  -> [TxRecord]
  -> AppExceptT m ([Tx ()], [TxRecord], [MatchRe])
matchDates ms = go ([], [], initZipper ms)
  where
    go (matched, unmatched, z) [] =
      return
        ( catMaybes matched
        , reverse unmatched
        , recoverZipper z
        )
    go (matched, unmatched, z) (r : rs) =
      case zipperSlice findDate r z of
        Left zipped -> go (matched, r : unmatched, zipped) rs
        Right unzipped -> do
          (z', res) <- zipperMatch unzipped r
          let (m, u) = case res of
                (MatchPass p) -> (Just p : matched, unmatched)
                MatchSkip -> (Nothing : matched, unmatched)
                MatchFail -> (matched, r : unmatched)
          go (m, u, z') rs
    findDate m r = maybe EQ (`compareDate` trDate r) $ spDate m

matchNonDates
  :: MonadFinance m
  => [MatchRe]
  -> [TxRecord]
  -> AppExceptT m ([Tx ()], [TxRecord], [MatchRe])
matchNonDates ms = go ([], [], initZipper ms)
  where
    go (matched, unmatched, z) [] =
      return
        ( catMaybes matched
        , reverse unmatched
        , recoverZipper z
        )
    go (matched, unmatched, z) (r : rs) = do
      (z', res) <- zipperMatch' z r
      let (m, u) = case res of
            MatchPass p -> (Just p : matched, unmatched)
            MatchSkip -> (Nothing : matched, unmatched)
            MatchFail -> (matched, r : unmatched)
       in go (m, u, resetZipper z') rs

matches :: MonadFinance m => MatchRe -> TxRecord -> AppExceptT m (MatchRes (Tx ()))
matches
  StatementParser {spTx, spOther, spVal, spDate, spDesc, spPriority}
  r@TxRecord {trDate, trAmount, trDesc, trOther} = do
    res <- liftInner $
      combineError3 val other desc $
        \x y z -> x && y && z && date
    if res
      then maybe (return MatchSkip) convert spTx
      else return MatchFail
    where
      val = valMatches spVal $ toRational trAmount
      date = maybe True (`dateMatches` trDate) spDate
      other = foldM (\a o -> (a &&) <$> otherMatches trOther o) True spOther
      desc = maybe (return True) (matchMaybe (unTxDesc trDesc) . snd) spDesc
      convert tg = MatchPass <$> toTx (fromIntegral spPriority) tg r

toTx :: MonadFinance m => Int -> TxGetter -> TxRecord -> AppExceptT m (Tx ())
toTx
  priority
  TxGetter
    { tgFrom
    , tgTo
    , tgCurrency
    , tgOtherEntries
    , tgScale
    }
  r@TxRecord {trAmount, trDate, trDesc} = do
    combineError curRes subRes $ \(cur, f, t) ss ->
      Tx
        { txDate = trDate
        , txDescr = trDesc
        , txCommit = ()
        , txPrimary =
            Left $
              EntrySet
                { esTotalValue = roundToP (cpPrec cur) trAmount *. tgScale
                , esCurrency = cpID cur
                , esFrom = f
                , esTo = t
                }
        , txOther = Left <$> ss
        , txBudget = historyName
        , txPriority = priority
        }
    where
      curRes = do
        m <- asks csCurrencyMap
        cur <- liftInner $ resolveCurrency m r tgCurrency
        let prec = cpPrec cur
        let fromRes = liftInner $ resolveHalfEntry resolveFromValue prec r () tgFrom
        let toRes = liftInner $ resolveHalfEntry resolveToValue prec r () tgTo
        combineError fromRes toRes (cur,,)
      subRes = mapErrors (resolveSubGetter r) tgOtherEntries

resolveSubGetter
  :: MonadFinance m
  => TxRecord
  -> TxSubGetter
  -> AppExceptT m SecondayEntrySet
resolveSubGetter r TxSubGetter {tsgFrom, tsgTo, tsgValue, tsgCurrency} = do
  m <- asks csCurrencyMap
  cur <- liftInner $ resolveCurrency m r tsgCurrency
  let prec = cpPrec cur
  let toRes = resolveHalfEntry resolveToValue prec r () tsgTo
  let valRes = liftInner $ resolveValue prec r tsgValue
  liftInner $ combineErrorM toRes valRes $ \t v -> do
    f <- resolveHalfEntry resolveFromValue prec r v tsgFrom
    return $
      EntrySet
        { esTotalValue = ()
        , esCurrency = cpID cur
        , esFrom = f
        , esTo = t
        }

resolveHalfEntry
  :: (Precision -> TxRecord -> n -> AppExcept v')
  -> Precision
  -> TxRecord
  -> v
  -> TxHalfGetter (EntryGetter n)
  -> AppExcept (HalfEntrySet v v')
resolveHalfEntry f prec r v TxHalfGetter {thgAcnt, thgComment, thgTags, thgEntries} =
  combineError acntRes esRes $ \a es ->
    HalfEntrySet
      { hesPrimary =
          Entry
            { eAcnt = a
            , eValue = v
            , eComment = thgComment
            , eTags = thgTags
            }
      , hesOther = es
      }
  where
    acntRes = resolveAcnt r thgAcnt
    esRes = mapErrors (resolveEntry f prec r) thgEntries

otherMatches :: M.Map T.Text T.Text -> FieldMatcherRe -> AppExcept Bool
otherMatches dict m = case m of
  Val (Field n mv) -> valMatches mv =<< (readRational =<< lookup_ MatchNumeric n)
  Desc (Field n (_, md)) -> (`matchMaybe` md) =<< lookup_ MatchText n
  where
    lookup_ t n = lookupErr (MatchField t) n dict

resolveEntry
  :: (Precision -> TxRecord -> n -> AppExcept v)
  -> Precision
  -> TxRecord
  -> EntryGetter n
  -> AppExcept (Entry AcntID v TagID)
resolveEntry f prec r s@Entry {eAcnt, eValue} =
  combineError acntRes valRes $ \a v -> s {eAcnt = a, eValue = v}
  where
    acntRes = resolveAcnt r eAcnt
    valRes = f prec r eValue

resolveFromValue :: Precision -> TxRecord -> EntryNumGetter -> AppExcept EntryValue
resolveFromValue = resolveValue

resolveToValue :: Precision -> TxRecord -> LinkedEntryNumGetter -> AppExcept EntryLink
resolveToValue _ _ (Linked l) = return $ LinkIndex l
resolveToValue prec r (Getter g) = LinkValue <$> resolveValue prec r g

resolveValue :: Precision -> TxRecord -> EntryNumGetter -> AppExcept EntryValue
resolveValue prec TxRecord {trOther, trAmount} s = case s of
  (LookupN t) -> EntryFixed . go <$> (readDouble =<< lookupErr EntryValField t trOther)
  (ConstN c) -> return $ EntryFixed $ go c
  AmountN m -> return $ EntryFixed $ trAmount *. m
  BalanceN x -> return $ EntryBalance $ go x
  PercentN x -> return $ EntryPercent x
  where
    go = realFracToDecimalP prec

resolveAcnt :: TxRecord -> EntryAcnt -> AppExcept AcntID
resolveAcnt r e = AcntID <$> resolveEntryField AcntField r (unAcntID <$> e)

resolveCurrency :: CurrencyMap -> TxRecord -> EntryCur -> AppExcept CurrencyPrec
resolveCurrency m r c = do
  i <- resolveEntryField CurField r (unCurID <$> c)
  case M.lookup (CurID i) m of
    Just k -> return k
    Nothing -> throwError $ AppException [LookupError (DBKey CurField) i]

resolveEntryField :: EntryIDType -> TxRecord -> EntryTextGetter T.Text -> AppExcept T.Text
resolveEntryField t TxRecord {trOther = o} s = case s of
  ConstT p -> return p
  LookupT f -> lookup_ f o
  MapT (Field f m) -> do
    k <- lookup_ f o
    lookup_ k m
  Map2T (Field (f1, f2) m) -> do
    (k1, k2) <- combineError (lookup_ f1 o) (lookup_ f2 o) (,)
    lookup_ (k1, k2) m
  where
    lookup_ :: (Ord k, Show k) => k -> M.Map k v -> AppExcept v
    lookup_ = lookupErr (EntryIDField t)

readDouble :: T.Text -> AppExcept Double
readDouble s = case readMaybe $ T.unpack s of
  Just x -> return x
  Nothing -> throwError $ AppException [ConversionError s True]

readRational :: T.Text -> AppExcept Rational
readRational s = case T.split (== '.') s of
  [x] -> maybe err (return . fromInteger) $ readT x
  [x, y] -> case (readT x, readT y) of
    (Just x', Just y') ->
      let p = 10 ^ T.length y
          k = if x' >= 0 then 1 else -1
       in return $ fromInteger x' + k * y' % p
    _ -> err
  _ -> err
  where
    readT = readMaybe . T.unpack
    err = throwError $ AppException [ConversionError s False]

compileOptions :: TxOpts T.Text -> AppExcept TxOptsRe
compileOptions o@TxOpts {toAmountFmt = pat} = do
  re <- compileRegex True pat
  return $ o {toAmountFmt = re}

compileMatch :: StatementParser T.Text -> AppExcept MatchRe
compileMatch m@StatementParser {spDesc, spOther} = do
  combineError dres ores $ \d os -> m {spDesc = d, spOther = os}
  where
    go = compileRegex False
    dres = mapM go spDesc
    ores = combineErrors $ fmap (mapM go) spOther

compileRegex :: Bool -> T.Text -> AppExcept (Text, Regex)
compileRegex groups pat = case res of
  Right re -> return (pat, re)
  Left _ -> throwError $ AppException [RegexError pat]
  where
    res =
      compile
        (blankCompOpt {newSyntax = True})
        (blankExecOpt {captureGroups = groups})
        pat

matchMaybe :: T.Text -> Regex -> AppExcept Bool
matchMaybe q re = case execute re q of
  Right res -> return $ isJust res
  Left _ -> throwError $ AppException [RegexError "this should not happen"]

matchGroupsMaybe :: T.Text -> Regex -> [T.Text]
matchGroupsMaybe q re = case regexec re q of
  Right Nothing -> []
  Right (Just (_, _, _, xs)) -> xs
  -- this should never fail as regexec always returns Right
  Left _ -> []

parseDecimal :: MonadFail m => (T.Text, Regex) -> T.Text -> m Decimal
parseDecimal (pat, re) s = case matchGroupsMaybe s re of
  [sign, x, ""] -> Decimal 0 . uncurry (*) <$> readWhole sign x
  [sign, x, y] -> do
    d <- readT "decimal" y
    let p = T.length y
    (k, w) <- readWhole sign x
    return $ Decimal (fromIntegral p) (k * (w * (10 ^ p) + d))
  _ -> msg "malformed decimal"
  where
    readT what t = case readMaybe $ T.unpack t of
      Just d -> return $ fromInteger d
      _ -> msg $ T.unwords ["could not parse", what, singleQuote t]
    msg :: MonadFail m => T.Text -> m a
    msg m =
      fail $
        T.unpack $
          T.unwords [m, "-", keyVals [("pattern", pat), ("query", s)]]
    readSign x
      | x == "-" = return (-1)
      | x == "+" || x == "" = return 1
      | otherwise = msg $ T.append "invalid sign: " x
    readWhole sign x = do
      w <- readT "whole number" x
      k <- readSign sign
      return (k, w)

historyName :: BudgetName
historyName = BudgetName "history"