hledger/hledger-lib/Hledger/Data/TransactionModifier.hs

151 lines
6.8 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE CPP #-}
{-|
A 'TransactionModifier' is a rule that modifies certain 'Transaction's,
typically adding automated postings to them.
-}
module Hledger.Data.TransactionModifier (
modifyTransactions
)
where
import Control.Applicative ((<|>))
import Data.Maybe
#if !(MIN_VERSION_base(4,11,0))
import Data.Monoid ((<>))
#endif
import qualified Data.Text as T
import Data.Time.Calendar
import Hledger.Data.Types
import Hledger.Data.Dates
import Hledger.Data.Amount
import Hledger.Data.Transaction
import Hledger.Query
import Hledger.Data.Posting (commentJoin, commentAddTag)
import Hledger.Utils.UTF8IOCompat (error')
import Hledger.Utils.Debug
-- $setup
-- >>> :set -XOverloadedStrings
-- >>> import Hledger.Data.Posting
-- >>> import Hledger.Data.Transaction
-- >>> import Hledger.Data.Journal
-- | Apply all the given transaction modifiers, in turn, to each transaction.
modifyTransactions :: [TransactionModifier] -> [Transaction] -> [Transaction]
modifyTransactions tmods = map applymods
where
applymods t = taggedt'
where
t' = foldr (flip (.) . transactionModifierToFunction) id tmods t
taggedt'
-- PERF: compares txns to see if any modifier had an effect, inefficient ?
| t' /= t = t'{tcomment = tcomment t' `commentAddTag` ("modified","")
,ttags = ("modified","") : ttags t'
}
| otherwise = t'
-- | Converts a 'TransactionModifier' to a 'Transaction'-transforming function,
-- which applies the modification(s) specified by the TransactionModifier.
-- Currently this means adding automated postings when certain other postings are present.
-- The postings of the transformed transaction will reference it in the usual
-- way (ie, 'txnTieKnot' is called).
--
-- >>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "" ["pong" `post` usd 2]) nulltransaction{tpostings=["ping" `post` usd 1]}
-- 0000-01-01
-- ping $1.00
-- pong $2.00 ; generated-posting: =
-- <BLANKLINE>
-- >>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "miss" ["pong" `post` usd 2]) nulltransaction{tpostings=["ping" `post` usd 1]}
-- 0000-01-01
-- ping $1.00
-- <BLANKLINE>
-- >>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "ping" ["pong" `post` amount{aismultiplier=True, aquantity=3}]) nulltransaction{tpostings=["ping" `post` usd 2]}
-- 0000-01-01
-- ping $2.00
-- pong $6.00 ; generated-posting: = ping
-- <BLANKLINE>
--
transactionModifierToFunction :: TransactionModifier -> (Transaction -> Transaction)
transactionModifierToFunction mt =
\t@(tpostings -> ps) -> txnTieKnot t{ tpostings=generatePostings ps }
where
q = simplifyQuery $ tmParseQuery mt (error' "a transaction modifier's query cannot depend on current date")
mods = map (tmPostingRuleToFunction (tmquerytxt mt)) $ tmpostingrules mt
generatePostings ps = [p' | p <- ps
, p' <- if q `matchesPosting` p then p:[ m p | m <- mods] else [p]]
-- | Parse the 'Query' from a 'TransactionModifier's 'tmquerytxt',
-- and return it as a function requiring the current date.
--
-- >>> tmParseQuery (TransactionModifier "" []) undefined
-- Any
-- >>> tmParseQuery (TransactionModifier "ping" []) undefined
-- Acct "ping"
-- >>> tmParseQuery (TransactionModifier "date:2016" []) undefined
-- Date (DateSpan 2016)
-- >>> tmParseQuery (TransactionModifier "date:today" []) (read "2017-01-01")
-- Date (DateSpan 2017-01-01)
-- >>> tmParseQuery (TransactionModifier "date:today" []) (read "2017-01-01")
-- Date (DateSpan 2017-01-01)
tmParseQuery :: TransactionModifier -> (Day -> Query)
tmParseQuery mt = fst . flip parseQuery (tmquerytxt mt)
-- | Converts a 'TransactionModifier''s posting rule to a 'Posting'-generating function,
-- which will be used to make a new posting based on the old one (an "automated posting").
-- The new posting's amount can optionally be the old posting's amount multiplied by a constant.
-- If the old posting had a total-priced amount, the new posting's multiplied amount will be unit-priced.
-- The new posting will have two tags added: a normal generated-posting: tag which also appears in the comment,
-- and a hidden _generated-posting: tag which does not.
-- The TransactionModifier's query text is also provided, and saved
-- as the tags' value.
tmPostingRuleToFunction :: T.Text -> TMPostingRule -> (Posting -> Posting)
tmPostingRuleToFunction querytxt pr =
\p -> renderPostingCommentDates $ pr
{ pdate = pdate pr <|> pdate p
, pdate2 = pdate2 pr <|> pdate2 p
, pamount = amount' p
, pcomment = pcomment pr `commentAddTag` ("generated-posting",qry)
, ptags = ("generated-posting", qry) :
("_generated-posting",qry) :
ptags pr
}
where
qry = "= " <> querytxt
amount' = case postingRuleMultiplier pr of
Nothing -> const $ pamount pr
Just n -> \p ->
-- Multiply the old posting's amount by the posting rule's multiplier.
let
pramount = dbg7 "pramount" $ head $ amounts $ pamount pr
matchedamount = dbg7 "matchedamount" $ pamount p
-- Handle a matched amount with a total price carefully so as to keep the transaction balanced (#928).
-- Approach 1: convert to a unit price and increase the display precision slightly
-- Mixed as = dbg7 "multipliedamount" $ n `multiplyMixedAmount` mixedAmountTotalPriceToUnitPrice matchedamount
-- Approach 2: multiply the total price (keeping it positive) as well as the quantity
Mixed as = dbg7 "multipliedamount" $ n `multiplyMixedAmountAndPrice` matchedamount
in
case acommodity pramount of
"" -> Mixed as
-- TODO multipliers with commodity symbols are not yet a documented feature.
-- For now: in addition to multiplying the quantity, it also replaces the
-- matched amount's commodity, display style, and price with those of the posting rule.
c -> Mixed [a{acommodity = c, astyle = astyle pramount, aprice = aprice pramount} | a <- as]
postingRuleMultiplier :: TMPostingRule -> Maybe Quantity
postingRuleMultiplier p =
case amounts $ pamount p of
[a] | aismultiplier a -> Just $ aquantity a
_ -> Nothing
renderPostingCommentDates :: Posting -> Posting
renderPostingCommentDates p = p { pcomment = comment' }
where
dates = T.concat $ catMaybes [T.pack . showDate <$> pdate p, ("=" <>) . T.pack . showDate <$> pdate2 p]
comment'
| T.null dates = pcomment p
| otherwise = ("[" <> dates <> "]") `commentJoin` pcomment p