pwncash/lib/Internal/Insert.hs

module Internal.Insert
  ( insertStatements
  , insertBudget
  )
where

import Data.Hashable
import Database.Persist.Class
import Database.Persist.Sql hiding (Single, Statement)
import Internal.Statement
import Internal.Types hiding (sign)
import Internal.Utils
import RIO hiding (to)
import qualified RIO.List as L
import qualified RIO.Map as M
import qualified RIO.NonEmpty as NE
import qualified RIO.Text as T
import RIO.Time

--------------------------------------------------------------------------------
-- intervals

expandDatePat :: Bounds -> DatePat -> EitherErrs [Day]
expandDatePat b (Cron cp) = expandCronPat b cp
expandDatePat i (Mod mp) = Right $ expandModPat mp i

expandModPat :: ModPat -> Bounds -> [Day]
expandModPat ModPat {mpStart = s, mpBy = b, mpUnit = u, mpRepeats = r} bs =
  takeWhile (<= upper) $
    (`addFun` start) . (* b')
      <$> maybe id (take . fromIntegral) r [0 ..]
  where
    (lower, upper) = expandBounds bs
    start = maybe lower fromGregorian' s
    b' = fromIntegral b
    addFun = case u of
      Day -> addDays
      Week -> addDays . (* 7)
      Month -> addGregorianMonthsClip
      Year -> addGregorianYearsClip

expandCronPat :: Bounds -> CronPat -> EitherErrs [Day]
expandCronPat b CronPat {cronYear, cronMonth, cronDay, cronWeekly} =
  concatEither3 yRes mRes dRes $ \ys ms ds ->
    filter validWeekday $
      mapMaybe (uncurry3 toDay) $
        takeWhile (\((y, _), m, d) -> (y, m, d) <= (yb1, mb1, db1)) $
          dropWhile (\((y, _), m, d) -> (y, m, d) < (yb0, mb0, db0)) $
            [(y, m, d) | y <- (\y -> (y, isLeapYear y)) <$> ys, m <- ms, d <- ds]
  where
    yRes = case cronYear of
      Nothing -> return [yb0 .. yb1]
      Just pat -> do
        ys <- expandMDYPat (fromIntegral yb0) (fromIntegral yb1) pat
        return $ dropWhile (< yb0) $ fromIntegral <$> ys
    mRes = expandMD 12 cronMonth
    dRes = expandMD 31 cronDay
    (s, e) = expandBounds b
    (yb0, mb0, db0) = toGregorian s
    (yb1, mb1, db1) = toGregorian $ addDays (-1) e
    expandMD lim =
      fmap (fromIntegral <$>)
        . maybe (return [1 .. lim]) (expandMDYPat 1 lim)
    expandW (OnDay x) = [fromEnum x]
    expandW (OnDays xs) = fromEnum <$> xs
    ws = maybe [] expandW cronWeekly
    validWeekday = if null ws then const True else \day -> dayToWeekday day `elem` ws
    toDay (y, leap) m d
      | m == 2 && (not leap && d > 28 || leap && d > 29) = Nothing
      | m `elem` [4, 6, 9, 11] && d > 30 = Nothing
      | otherwise = Just $ fromGregorian y m d

expandMDYPat :: Natural -> Natural -> MDYPat -> EitherErr [Natural]
expandMDYPat lower upper (Single x) = Right [x | lower <= x && x <= upper]
expandMDYPat lower upper (Multi xs) = Right $ dropWhile (<= lower) $ takeWhile (<= upper) xs
expandMDYPat lower upper (After x) = Right [max lower x .. upper]
expandMDYPat lower upper (Before x) = Right [lower .. min upper x]
expandMDYPat lower upper (Between x y) = Right [max lower x .. min upper y]
expandMDYPat lower upper (Repeat RepeatPat {rpStart = s, rpBy = b, rpRepeats = r})
  | b < 1 = Left $ PatternError s b r ZeroLength
  | otherwise = do
      k <- limit r
      return $ dropWhile (<= lower) $ takeWhile (<= k) [s + i * b | i <- [0 ..]]
  where
    limit Nothing = Right upper
    limit (Just n)
      -- this guard not only produces the error for the user but also protects
      -- from an underflow below it
      | n < 1 = Left $ PatternError s b r ZeroRepeats
      | otherwise = Right $ min (s + b * (n - 1)) upper

dayToWeekday :: Day -> Int
dayToWeekday (ModifiedJulianDay d) = mod (fromIntegral d + 2) 7

withDates
  :: MonadFinance m
  => DatePat
  -> (Day -> SqlPersistT m (EitherErrs a))
  -> SqlPersistT m (EitherErrs [a])
withDates dp f = do
  bounds <- lift $ askDBState kmBudgetInterval
  case expandDatePat bounds dp of
    Left es -> return $ Left es
    Right days -> concatEithersL <$> mapM f days

--------------------------------------------------------------------------------
-- budget

-- each budget (designated at the top level by a 'name') is processed in the
-- following steps
-- 1. expand all transactions given the desired date range and date patterns for
--    each directive in the budget
-- 2. sort all transactions by date
-- 3. propagate all balances forward, and while doing so assign values to each
--    transaction (some of which depend on the 'current' balance of the
--    target account)
-- 4. assign shadow transactions (TODO)
-- 5. insert all transactions

insertBudget :: MonadFinance m => Budget -> SqlPersistT m [InsertError]
insertBudget
  b@( Budget
        { budgetLabel
        , incomes
        , transfers
        , shadowTransfers
        , pretax
        , tax
        , posttax
        }
      ) =
    whenHash CTBudget b [] $ \key -> do
      unlessLefts intAllos $ \intAllos_ -> do
        res1 <- mapM (insertIncome key budgetLabel intAllos_) incomes
        res2 <- expandTransfers key budgetLabel transfers
        unlessLefts (concatEithers2 (fmap concat $ concatEithersL res1) res2 (++)) $
          \txs -> do
            unlessLefts (addShadowTransfers shadowTransfers txs) $ \shadow -> do
              let bals = balanceTransfers $ txs ++ shadow
              concat <$> mapM insertBudgetTx bals
    where
      intAllos =
        let pre_ = sortAllos pretax
            tax_ = sortAllos tax
            post_ = sortAllos posttax
         in concatEithers3 pre_ tax_ post_ (,,)
      sortAllos = concatEithersL . fmap sortAllo

type BoundAllocation = Allocation_ (TimeAmount (Day, Day))

type IntAllocations = ([BoundAllocation], [BoundAllocation], [BoundAllocation])

-- TODO this should actually error if there is no ultimate end date
sortAllo :: IntervalAllocation -> EitherErrs BoundAllocation
sortAllo a@Allocation_ {alloAmts = as} = do
  bs <- fmap reverse <$> foldBounds (Right []) $ L.sortOn taWhen as
  return $ a {alloAmts = L.sort bs}
  where
    foldBounds acc [] = acc
    foldBounds acc (x : xs) =
      let res = fmap (fmap expandBounds) $ case xs of
            [] -> mapM resolveBounds x
            (y : _) ->
              let end = intStart $ taWhen y
               in mapM (resolveBounds_ end) x
       in foldBounds (concatEithers2 (plural res) acc (:)) xs

-- TODO this is going to be O(n*m), which might be a problem?
addShadowTransfers :: [ShadowTransfer] -> [BudgetTxType] -> EitherErrs [BudgetTxType]
addShadowTransfers ms txs =
  fmap catMaybes $
    concatEitherL $
      fmap (uncurry fromShadow) $
        [(t, m) | t <- txs, m <- ms]

fromShadow :: BudgetTxType -> ShadowTransfer -> EitherErr (Maybe BudgetTxType)
fromShadow tx t@ShadowTransfer {stFrom, stTo, stDesc, stRatio} = do
  res <- shadowMatches (stMatch t) tx
  return $
    if not res
      then Nothing
      else
        Just $
          BudgetTxType
            { bttTx =
                -- TODO does this actually share the same metadata as the "parent" tx?
                BudgetTx
                  { btMeta = btMeta $ bttTx tx
                  , btWhen = btWhen $ bttTx tx
                  , btFrom = stFrom
                  , btTo = stTo
                  , btValue = dec2Rat stRatio * (btValue $ bttTx tx)
                  , btDesc = stDesc
                  }
            , bttType = FixedAmt
            }

shadowMatches :: ShadowMatch -> BudgetTxType -> EitherErr Bool
shadowMatches ShadowMatch {smFrom, smTo, smDate, smVal} tx = do
  -- TODO what does the amount do for each of the different types?
  valRes <- valMatches smVal (btValue tx_)
  return $
    memberMaybe (taAcnt $ btFrom tx_) smFrom
      && memberMaybe (taAcnt $ btTo tx_) smTo
      && maybe True (`dateMatches` (btWhen tx_)) smDate
      && valRes
  where
    tx_ = bttTx tx
    memberMaybe x AcntSet {asList, asInclude} =
      (if asInclude then id else not) $ x `elem` asList

balanceTransfers :: [BudgetTxType] -> [BudgetTx]
balanceTransfers ts =
  snd $ L.mapAccumR go initBals $ reverse $ L.sortOn (btWhen . bttTx) ts
  where
    initBals =
      M.fromList $
        fmap (,0) $
          L.nub $
            fmap (btTo . bttTx) ts
              ++ fmap (btFrom . bttTx) ts
    updateBal x = M.update (Just . (+ x))
    lookupBal = M.findWithDefault (error "this should not happen")
    go bals btt =
      let tx = bttTx btt
          from = btFrom tx
          to = btTo tx
          bal = lookupBal to bals
          x = amtToMove bal (bttType btt) (btValue tx)
       in (updateBal x to $ updateBal (-x) from bals, tx {btValue = x})
    -- TODO might need to query signs to make this intuitive; as it is this will
    -- probably work, but for credit accounts I might need to supply a negative
    -- target value
    amtToMove _ FixedAmt x = x
    amtToMove bal Percent x = -(x / 100 * bal)
    amtToMove bal Target x = x - bal

data BudgetMeta = BudgetMeta
  { bmCommit :: !CommitRId
  , bmCur :: !BudgetCurrency
  , bmName :: !T.Text
  }
  deriving (Show)

data BudgetTx = BudgetTx
  { btMeta :: !BudgetMeta
  , btWhen :: !Day
  , btFrom :: !TaggedAcnt
  , btTo :: !TaggedAcnt
  , btValue :: !Rational
  , btDesc :: !T.Text
  }
  deriving (Show)

data BudgetTxType = BudgetTxType
  { bttType :: !AmountType
  , bttTx :: !BudgetTx
  }
  deriving (Show)

insertIncome
  :: MonadFinance m
  => CommitRId
  -> T.Text
  -> IntAllocations
  -> Income
  -> SqlPersistT m (EitherErrs [BudgetTxType])
insertIncome
  key
  name
  (intPre, intTax, intPost)
  i@Income {incWhen, incCurrency, incFrom, incPretax, incPosttax, incTaxes, incToBal} = do
    let meta = BudgetMeta key (NoX incCurrency) name
    let balRes = balanceIncome i
    fromRes <- lift $ checkAcntType IncomeT $ taAcnt incFrom
    case concatEither2 balRes fromRes (,) of
      Left es -> return $ Left es
      -- TODO this hole seems sloppy...
      Right (balance, _) ->
        fmap (fmap (concat . concat)) $
          -- TODO this will scan the interval allocations fully each time
          -- iteration which is a total waste, but the fix requires turning this
          -- loop into a fold which I don't feel like doing now :(
          withDates incWhen $ \day -> do
            let fromAllos = fmap concat . mapM (lift . fromAllo day meta incFrom)
            pre <- fromAllos $ incPretax ++ mapMaybe (selectAllos day) intPre
            -- TODO ensure these are all expense accounts
            tax <- fromAllos $ incTaxes ++ mapMaybe (selectAllos day) intTax
            post <- fromAllos $ incPosttax ++ mapMaybe (selectAllos day) intPost
            let bal =
                  BudgetTxType
                    { bttTx =
                        BudgetTx
                          { btMeta = meta
                          , btWhen = day
                          , btFrom = incFrom
                          , btTo = incToBal
                          , btValue = balance
                          , btDesc = "balance after deductions"
                          }
                    , bttType = FixedAmt
                    }
            return $ concatEithersL [Right [bal], Right tax, Right pre, Right post]

-- ASSUME allocations are sorted
selectAllos :: Day -> BoundAllocation -> Maybe Allocation
selectAllos day a@Allocation_ {alloAmts = as} = case select [] as of
  [] -> Nothing
  xs -> Just $ a {alloAmts = xs}
  where
    select acc [] = acc
    select acc (x : xs)
      | day < fst (taWhen x) = select acc xs
      | inBounds (taWhen x) day = select (taAmt x : acc) xs
      | otherwise = acc

fromAllo
  :: MonadFinance m
  => Day
  -> BudgetMeta
  -> TaggedAcnt
  -> Allocation
  -> m [BudgetTxType]
fromAllo day meta from Allocation_ {alloTo, alloAmts} = do
  -- TODO this is going to be repeated a zillion times (might matter)
  -- res <- expandTarget alloPath
  return $ fmap toBT alloAmts
  where
    toBT (Amount {amtDesc = desc, amtValue = v}) =
      BudgetTxType
        { bttTx =
            BudgetTx
              { btFrom = from
              , btWhen = day
              , btTo = alloTo
              , btValue = dec2Rat v
              , btDesc = desc
              , btMeta = meta
              }
        , bttType = FixedAmt
        }

-- -- TODO maybe allow tags here?
-- fromTax
--   :: MonadFinance m
--   => Day
--   -> BudgetMeta
--   -> AcntID
--   -> Tax
--   -> m (EitherErr BudgetTxType)
-- fromTax day meta from Tax {taxAcnt = to, taxValue = v} = do
--   res <- checkAcntType ExpenseT to
--   return $ fmap go res
--   where
--     go to_ =
--       BudgetTxType
--         { bttTx =
--             BudgetTx
--               { btFrom = TaggedAcnt from []
--               , btWhen = day
--               , btTo = TaggedAcnt to_ []
--               , btValue = dec2Rat v
--               , btDesc = ""
--               , btMeta = meta
--               }
--         , bttType = FixedAmt
--         }

balanceIncome :: Income -> EitherErr Rational
balanceIncome
  Income
    { incGross = g
    , incWhen = dp
    , incPretax = pre
    , incTaxes = tax
    , incPosttax = post
    }
    | bal < 0 = Left $ IncomeError dp
    | otherwise = Right bal
    where
      bal = dec2Rat g - sum (sumAllocation <$> pre ++ tax ++ post)

sumAllocation :: Allocation -> Rational
sumAllocation = sum . fmap (dec2Rat . amtValue) . alloAmts

-- sumTaxes :: [Tax] -> Rational
-- sumTaxes = sum . fmap (dec2Rat . taxValue)

expandTransfers
  :: MonadFinance m
  => CommitRId
  -> T.Text
  -> [Transfer]
  -> SqlPersistT m (EitherErrs [BudgetTxType])
expandTransfers key name ts = do
  txs <- mapM (expandTransfer key name) ts
  return $ L.sortOn (btWhen . bttTx) . concat <$> concatEithersL txs

expandTransfer :: MonadFinance m => CommitRId -> T.Text -> Transfer -> SqlPersistT m (EitherErrs [BudgetTxType])
expandTransfer key name Transfer {transAmounts, transTo, transCurrency, transFrom} =
  -- whenHash CTExpense t (Right []) $ \key ->
  fmap (fmap concat . concatEithersL) $
    forM transAmounts $ \(TimeAmount {taWhen = pat, taAmt = (Amount {amtDesc = desc, amtValue = v}), taAmtType = atype}) -> do
      withDates pat $ \day ->
        let meta =
              BudgetMeta
                { bmCur = transCurrency
                , bmCommit = key
                , bmName = name
                }
            tx =
              BudgetTxType
                { bttTx =
                    BudgetTx
                      { btMeta = meta
                      , btWhen = day
                      , btFrom = transFrom
                      , btTo = transTo
                      , btValue = dec2Rat v
                      , btDesc = desc
                      }
                , bttType = atype
                }
         in return $ Right tx

insertBudgetTx :: MonadFinance m => BudgetTx -> SqlPersistT m [InsertError]
insertBudgetTx BudgetTx {btFrom, btTo, btMeta, btValue, btDesc, btWhen} = do
  res <- lift $ splitPair btFrom btTo (bmCur btMeta) btValue
  unlessLefts_ res $ \((sFrom, sTo), exchange) -> do
    insertPair sFrom sTo
    forM_ exchange $ \(xFrom, xTo) -> insertPair xFrom xTo
  where
    insertPair from to = do
      k <- insert $ TransactionR (bmCommit btMeta) btWhen btDesc
      insertBudgetLabel k from
      insertBudgetLabel k to
    insertBudgetLabel k split = do
      sk <- insertSplit k split
      insert_ $ BudgetLabelR sk $ bmName btMeta

type SplitPair = (KeySplit, KeySplit)

splitPair
  :: MonadFinance m
  => TaggedAcnt
  -> TaggedAcnt
  -> BudgetCurrency
  -> Rational
  -> m (EitherErrs (SplitPair, Maybe SplitPair))
splitPair from to cur val = case cur of
  NoX curid -> fmap (fmap (,Nothing)) $ pair curid from to val
  X (Exchange {xFromCur, xToCur, xAcnt, xRate}) -> do
    let middle = TaggedAcnt xAcnt []
    res1 <- pair xFromCur from middle val
    res2 <- pair xToCur middle to (val * dec2Rat xRate)
    return $ concatEithers2 res1 res2 $ \a b -> (a, Just b)
  where
    pair curid from_ to_ v = do
      s1 <- split curid from_ (-v)
      s2 <- split curid to_ v
      return $ concatEithers2 s1 s2 (,)
    split c TaggedAcnt {taAcnt, taTags} v =
      resolveSplit $
        Split
          { sAcnt = taAcnt
          , sValue = v
          , sComment = ""
          , sCurrency = c
          , sTags = taTags
          }

checkAcntType
  :: MonadFinance m
  => AcntType
  -> AcntID
  -> m (EitherErr AcntID)
checkAcntType t = checkAcntTypes (t :| [])

checkAcntTypes
  :: MonadFinance m
  => NE.NonEmpty AcntType
  -> AcntID
  -> m (EitherErr AcntID)
checkAcntTypes ts i = (go =<<) <$> lookupAccountType i
  where
    go t
      | t `L.elem` ts = Right i
      | otherwise = Left $ AccountError i ts

--------------------------------------------------------------------------------
-- statements

insertStatements :: MonadFinance m => Config -> SqlPersistT m [InsertError]
insertStatements conf = concat <$> mapM insertStatement (statements conf)

insertStatement :: MonadFinance m => Statement -> SqlPersistT m [InsertError]
insertStatement (StmtManual m) = insertManual m
insertStatement (StmtImport i) = insertImport i

insertManual :: MonadFinance m => Manual -> SqlPersistT m [InsertError]
insertManual
  m@Manual
    { manualDate = dp
    , manualFrom = from
    , manualTo = to
    , manualValue = v
    , manualCurrency = u
    , manualDesc = e
    } = do
    whenHash CTManual m [] $ \c -> do
      bounds <- lift $ askDBState kmStatementInterval
      -- let days = expandDatePat bounds dp
      let dayRes = expandDatePat bounds dp
      unlessLefts dayRes $ \days -> do
        txRes <- mapM (lift . tx) days
        unlessLefts_ (concatEithersL txRes) $ mapM_ (insertTx c)
    where
      tx day = txPair day from to u (dec2Rat v) e

insertImport :: MonadFinance m => Import -> SqlPersistT m [InsertError]
insertImport i = whenHash CTImport i [] $ \c -> do
  -- TODO this isn't efficient, the whole file will be read and maybe no
  -- transactions will be desired
  recoverIO (lift $ readImport i) $ \r -> unlessLefts r $ \bs -> do
    bounds <- expandBounds <$> lift (askDBState kmStatementInterval)
    res <- mapM (lift . resolveTx) $ filter (inBounds bounds . txDate) bs
    unlessLefts_ (concatEithersL res) $ mapM_ (insertTx c)
  where
    recoverIO x rest = do
      res <- tryIO x
      case res of
        Right r -> rest r
        -- If file is not found (or something else happens) then collect the
        -- error try the remaining imports
        Left e -> return [InsertIOError $ showT e]

--------------------------------------------------------------------------------
-- low-level transaction stuff

-- TODO tags here?
txPair
  :: MonadFinance m
  => Day
  -> AcntID
  -> AcntID
  -> CurID
  -> Rational
  -> T.Text
  -> m (EitherErrs KeyTx)
txPair day from to cur val desc = resolveTx tx
  where
    split a v = Split {sAcnt = a, sValue = v, sComment = "", sCurrency = cur, sTags = []}
    tx =
      Tx
        { txDescr = desc
        , txDate = day
        , txSplits = [split from (-val), split to val]
        }

resolveTx :: MonadFinance m => BalTx -> m (EitherErrs KeyTx)
resolveTx t@Tx {txSplits = ss} = do
  res <- concatEithersL <$> mapM resolveSplit ss
  return $ fmap (\kss -> t {txSplits = kss}) res

resolveSplit :: MonadFinance m => BalSplit -> m (EitherErrs KeySplit)
resolveSplit s@Split {sAcnt, sCurrency, sValue, sTags} = do
  aid <- lookupAccountKey sAcnt
  cid <- lookupCurrency sCurrency
  sign <- lookupAccountSign sAcnt
  tags <- mapM lookupTag sTags
  -- TODO correct sign here?
  -- TODO lenses would be nice here
  return $
    (concatEithers2 (concatEither3 aid cid sign (,,)) $ concatEitherL tags) $
      \(aid_, cid_, sign_) tags_ ->
        s
          { sAcnt = aid_
          , sCurrency = cid_
          , sValue = sValue * fromIntegral (sign2Int sign_)
          , sTags = tags_
          }

insertTx :: MonadUnliftIO m => Key CommitR -> KeyTx -> SqlPersistT m ()
insertTx c Tx {txDate = d, txDescr = e, txSplits = ss} = do
  k <- insert $ TransactionR c d e
  mapM_ (insertSplit k) ss

insertSplit :: MonadUnliftIO m => Key TransactionR -> KeySplit -> SqlPersistT m (Key SplitR)
insertSplit t Split {sAcnt, sCurrency, sValue, sComment, sTags} = do
  k <- insert $ SplitR t sCurrency sAcnt sComment sValue
  mapM_ (insert_ . TagRelationR k) sTags
  return k

lookupAccount :: MonadFinance m => AcntID -> m (EitherErr (Key AccountR, AcntSign, AcntType))
lookupAccount p = lookupErr (DBKey AcntField) p <$> (askDBState kmAccount)

lookupAccountKey :: MonadFinance m => AcntID -> m (EitherErr (Key AccountR))
lookupAccountKey = (fmap (fmap fstOf3)) . lookupAccount

lookupAccountSign :: MonadFinance m => AcntID -> m (EitherErr AcntSign)
lookupAccountSign = fmap (fmap sndOf3) . lookupAccount

lookupAccountType :: MonadFinance m => AcntID -> m (EitherErr AcntType)
lookupAccountType = fmap (fmap thdOf3) . lookupAccount

lookupCurrency :: MonadFinance m => T.Text -> m (EitherErr (Key CurrencyR))
lookupCurrency c = lookupErr (DBKey CurField) c <$> (askDBState kmCurrency)

lookupTag :: MonadFinance m => TagID -> m (EitherErr (Key TagR))
lookupTag c = lookupErr (DBKey TagField) c <$> (askDBState kmTag)

-- TODO this hashes twice (not that it really matters)
whenHash
  :: (Hashable a, MonadFinance m)
  => ConfigType
  -> a
  -> b
  -> (Key CommitR -> SqlPersistT m b)
  -> SqlPersistT m b
whenHash t o def f = do
  let h = hash o
  hs <- lift $ askDBState kmNewCommits
  if h `elem` hs then f =<< insert (CommitR h t) else return def