Parsers for standard ledger and timelog files.


module Ledger.Parse
import Control.Monad
import Control.Monad.Error
import Text.ParserCombinators.Parsec
import Text.ParserCombinators.Parsec.Char
import Text.ParserCombinators.Parsec.Language
import Text.ParserCombinators.Parsec.Combinator
import qualified Text.ParserCombinators.Parsec.Token as P
import System.Directory
import System.IO
import qualified Data.Map as Map
import Data.Time.LocalTime
import Data.Time.Calendar
import Ledger.Utils
import Ledger.Types
import Ledger.Dates
import Ledger.Amount
import Ledger.Entry
import Ledger.Commodity
import Ledger.TimeLog
import Ledger.RawLedger
import System.FilePath(takeDirectory,combine)

-- utils

-- | Some context kept during parsing.
data LedgerFileCtx = Ctx {
      ctxYear     :: !(Maybe Integer)  -- ^ the default year most recently specified with Y
    , ctxCommod   :: !(Maybe String)   -- ^ I don't know
    , ctxAccount  :: ![String]         -- ^ the current stack of "container" accounts specified by !account
    } deriving (Read, Show)

emptyCtx :: LedgerFileCtx
emptyCtx = Ctx { ctxYear = Nothing, ctxCommod = Nothing, ctxAccount = [] }

-- containing accounts "nest" hierarchically

pushParentAccount :: String -> GenParser tok LedgerFileCtx ()
pushParentAccount parent = updateState addParentAccount
    where addParentAccount ctx0 = ctx0 { ctxAccount = normalize parent : ctxAccount ctx0 }
          normalize = (++ ":") 

popParentAccount :: GenParser tok LedgerFileCtx ()
popParentAccount = do ctx0 <- getState
                      case ctxAccount ctx0 of
                        [] -> unexpected "End of account block with no beginning"
                        (_:rest) -> setState $ ctx0 { ctxAccount = rest }

getParentAccount :: GenParser tok LedgerFileCtx String
getParentAccount = liftM (concat . reverse . ctxAccount) getState

setYear :: Integer -> GenParser tok LedgerFileCtx ()
setYear y = updateState (\ctx -> ctx{ctxYear=Just y})

getYear :: GenParser tok LedgerFileCtx (Maybe Integer)
getYear = liftM ctxYear getState

printParseError :: (Show a) => a -> IO ()
printParseError e = do putStr "ledger parse error at "; print e

-- let's get to it

parseLedgerFile :: LocalTime -> FilePath -> ErrorT String IO RawLedger
parseLedgerFile t "-" = liftIO (hGetContents stdin) >>= parseLedger t "-"
parseLedgerFile t f   = liftIO (readFile f)         >>= parseLedger t f

-- | Parses the contents of a ledger file, or gives an error.  Requires
-- the current (local) time to calculate any unfinished timelog sessions,
-- we pass it in for repeatability.
parseLedger :: LocalTime -> FilePath -> String -> ErrorT String IO RawLedger
parseLedger reftime inname intxt = do
  case runParser ledgerFile emptyCtx inname intxt of
    Right m  -> liftM (rawLedgerConvertTimeLog reftime) $ m `ap` (return rawLedgerEmpty)
    Left err -> throwError $ show err

-- As all ledger line types can be distinguished by the first
-- character, excepting transactions versus empty (blank or
-- comment-only) lines, can use choice w/o try

ledgerFile :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerFile = do entries <- many1 ledgerAnyEntry 
                return $ liftM (foldr1 (.)) $ sequence entries
    where ledgerAnyEntry = choice [ ledgerDirective
                                  , liftM (return . addEntry)         ledgerEntry
                                  , liftM (return . addModifierEntry) ledgerModifierEntry
                                  , liftM (return . addPeriodicEntry) ledgerPeriodicEntry
                                  , liftM (return . addHistoricalPrice) ledgerHistoricalPrice
                                  , ledgerDefaultYear
                                  , emptyLine >> return (return id)
                                  , liftM (return . addTimeLogEntry)  timelogentry

ledgerDirective :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerDirective = do char '!'
                     directive <- many nonspace
                     case directive of
                       "include" -> ledgerInclude
                       "account" -> ledgerAccountBegin
                       "end"     -> ledgerAccountEnd

ledgerInclude :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerInclude = do many1 spacenonewline
                   filename <- restofline
                   outerState <- getState
                   outerPos <- getPosition
                   let inIncluded = show outerPos ++ " in included file " ++ show filename ++ ":\n"
                   return $ do contents <- expandPath outerPos filename >>= readFileE outerPos
                               case runParser ledgerFile outerState filename contents of
                                 Right l   -> l `catchError` (\err -> throwError $ inIncluded ++ err)
                                 Left perr -> throwError $ inIncluded ++ show perr
    where readFileE outerPos filename = ErrorT $ do (liftM Right $ readFile filename) `catch` leftError
              where leftError err = return $ Left $ currentPos ++ whileReading ++ show err
                    currentPos = show outerPos
                    whileReading = " reading " ++ show filename ++ ":\n"

expandPath :: (MonadIO m) => SourcePos -> FilePath -> m FilePath
expandPath pos fp = liftM mkRelative (expandHome fp)
    mkRelative = combine (takeDirectory (sourceName pos))
    expandHome inname | "~/" `isPrefixOf` inname = do homedir <- liftIO getHomeDirectory
                                                      return $ homedir ++ drop 1 inname
                      | otherwise                = return inname

ledgerAccountBegin :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerAccountBegin = do many1 spacenonewline
                        parent <- ledgeraccountname
                        pushParentAccount parent
                        return $ return id

ledgerAccountEnd :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerAccountEnd = popParentAccount >> return (return id)

-- parsers

-- | Parse a RawLedger from either a ledger file or a timelog file.
-- It tries first the timelog parser then the ledger parser; this means
-- parse errors for ledgers are useful while those for timelogs are not.

{-| Parse a ledger file. Here is the ledger grammar from the ledger 2.5 manual:

The ledger file format is quite simple, but also very flexible. It supports
many options, though typically the user can ignore most of them. They are
summarized below.  The initial character of each line determines what the
line means, and how it should be interpreted. Allowable initial characters

NUMBER      A line beginning with a number denotes an entry. It may be followed by any
            number of lines, each beginning with whitespace, to denote the entry’s account
            transactions. The format of the first line is:

                    DATE[=EDATE] [*|!] [(CODE)] DESC

            If ‘*’ appears after the date (with optional effective date), it indicates the entry
            is “cleared”, which can mean whatever the user wants it t omean. If ‘!’ appears
            after the date, it indicates d the entry is “pending”; i.e., tentatively cleared from
            the user’s point of view, but not yet actually cleared. If a ‘CODE’ appears in
            parentheses, it may be used to indicate a check number, or the type of the
            transaction. Following these is the payee, or a description of the transaction.
            The format of each following transaction is:

                      ACCOUNT     AMOUNT    [; NOTE]

            The ‘ACCOUNT’ may be surrounded by parentheses if it is a virtual
            transactions, or square brackets if it is a virtual transactions that must
            balance. The ‘AMOUNT’ can be followed by a per-unit transaction cost,
            by specifying ‘ AMOUNT’, or a complete transaction cost with ‘\@ AMOUNT’.
            Lastly, the ‘NOTE’ may specify an actual and/or effective date for the
            transaction by using the syntax ‘[ACTUAL_DATE]’ or ‘[=EFFECTIVE_DATE]’ or

=           An automated entry. A value expression must appear after the equal sign.
            After this initial line there should be a set of one or more transactions, just as
            if it were normal entry. If the amounts of the transactions have no commodity,
            they will be applied as modifiers to whichever real transaction is matched by
            the value expression.
~           A period entry. A period expression must appear after the tilde.
            After this initial line there should be a set of one or more transactions, just as
            if it were normal entry.

!           A line beginning with an exclamation mark denotes a command directive. It
            must be immediately followed by the command word. The supported commands

                        Include the stated ledger file.
                        The account name is given is taken to be the parent of all transac-
                        tions that follow, until ‘!end’ is seen.
           ‘!end’       Ends an account block.
;          A line beginning with a colon indicates a comment, and is ignored.
Y          If a line begins with a capital Y, it denotes the year used for all subsequent
           entries that give a date without a year. The year should appear immediately
           after the Y, for example: ‘Y2004’. This is useful at the beginning of a file, to
           specify the year for that file. If all entries specify a year, however, this command
           has no effect.
P          Specifies a historical price for a commodity. These are usually found in a pricing
           history file (see the ‘-Q’ option). The syntax is:

                  P DATE SYMBOL PRICE

N SYMBOL   Indicates that pricing information is to be ignored for a given symbol, nor will
           quotes ever be downloaded for that symbol. Useful with a home currency, such
           as the dollar ($). It is recommended that these pricing options be set in the price
           database file, which defaults to ‘~/.pricedb’. The syntax for this command is:

                  N SYMBOL

D AMOUNT   Specifies the default commodity to use, by specifying an amount in the expected
           format. The entry command will use this commodity as the default when none
           other can be determined. This command may be used multiple times, to set
           the default flags for different commodities; whichever is seen last is used as the
           default commodity. For example, to set US dollars as the default commodity,
           while also setting the thousands flag and decimal flag for that commodity, use:

                  D $1,000.00

           Specifies a commodity conversion, where the first amount is given to be equiv-
           alent to the second amount. The first amount should use the decimal precision
           desired during reporting:

                  C 1.00 Kb = 1024 bytes

i, o, b, h
           These four relate to timeclock support, which permits ledger to read timelog
           files. See the timeclock’s documentation for more info on the syntax of its
           timelog files.

See "Tests" for sample data.

emptyLine :: GenParser Char st ()
emptyLine = do many spacenonewline
               optional $ char ';' >> many (noneOf "\n")
               return ()

ledgercomment :: GenParser Char st String
ledgercomment = 
    try (do
          char ';'
          many spacenonewline
          many (noneOf "\n")
    <|> return "" <?> "comment"

ledgerModifierEntry :: GenParser Char LedgerFileCtx ModifierEntry
ledgerModifierEntry = do
  char '=' <?> "modifier entry"
  many spacenonewline
  valueexpr <- restofline
  transactions <- ledgertransactions
  return $ ModifierEntry valueexpr transactions

ledgerPeriodicEntry :: GenParser Char LedgerFileCtx PeriodicEntry
ledgerPeriodicEntry = do
  char '~' <?> "entry"
  many spacenonewline
  periodexpr <- restofline
  transactions <- ledgertransactions
  return $ PeriodicEntry periodexpr transactions

ledgerHistoricalPrice :: GenParser Char LedgerFileCtx HistoricalPrice
ledgerHistoricalPrice = do
  char 'P' <?> "hprice"
  many spacenonewline
  date <- ledgerdate
  many spacenonewline
  symbol1 <- commoditysymbol
  many spacenonewline
  (Mixed [Amount c price pri]) <- someamount
  return $ HistoricalPrice date symbol1 (symbol c) price

-- like ledgerAccountBegin, updates the LedgerFileCtx
ledgerDefaultYear :: GenParser Char LedgerFileCtx (ErrorT String IO (RawLedger -> RawLedger))
ledgerDefaultYear = do
  char 'Y' <?> "default year"
  many spacenonewline
  y <- many1 digit
  let y' = read y
  guard (y' >= 1000)
  setYear y'
  return $ return id

-- | Try to parse a ledger entry. If we successfully parse an entry, ensure it is balanced,
-- and if we cannot, raise an error.
ledgerEntry :: GenParser Char LedgerFileCtx Entry
ledgerEntry = do
  date <- ledgerdate <?> "entry"
  status <- ledgerstatus
  code <- ledgercode
-- ledger treats entry comments as part of the description, we will too
--   desc <- many (noneOf ";\n") <?> "description"
--   let description = reverse $ dropWhile (==' ') $ reverse desc
  description <- many (noneOf "\n") <?> "description"
  comment <- ledgercomment
  transactions <- ledgertransactions
  let e = Entry date status code description comment transactions ""
  case balanceEntry e of
    Right e' -> return e'
    Left err -> error err

ledgerdate :: GenParser Char LedgerFileCtx Day
ledgerdate = try ledgerfulldate <|> ledgerpartialdate

ledgerfulldate :: GenParser Char LedgerFileCtx Day
ledgerfulldate = do
  (y,m,d) <- ymd
  many spacenonewline
  return $ fromGregorian (read y) (read m) (read d)

-- | Match a partial M/D date in a ledger. Warning, this terminates the
-- program if it finds a match when there is no default year specified.
ledgerpartialdate :: GenParser Char LedgerFileCtx Day
ledgerpartialdate = do
  (_,m,d) <- md
  many spacenonewline
  y <- getYear
  when (y==Nothing) $ error "partial date found, but no default year specified"
  return $ fromGregorian (fromJust y) (read m) (read d)

ledgerdatetime :: GenParser Char LedgerFileCtx LocalTime
ledgerdatetime = do 
  day <- ledgerdate
  h <- many1 digit
  char ':'
  m <- many1 digit
  s <- optionMaybe $ do
      char ':'
      many1 digit
  many spacenonewline
  let tod = TimeOfDay (read h) (read m) (maybe 0 (fromIntegral.read) s)
  return $ LocalTime day tod

ledgerstatus :: GenParser Char st Bool
ledgerstatus = try (do { char '*'; many1 spacenonewline; return True } ) <|> return False

ledgercode :: GenParser Char st String
ledgercode = try (do { char '('; code <- anyChar `manyTill` char ')'; many1 spacenonewline; return code } ) <|> return ""

ledgertransactions :: GenParser Char LedgerFileCtx [RawTransaction]
ledgertransactions = many $ try ledgertransaction

ledgertransaction :: GenParser Char LedgerFileCtx RawTransaction
ledgertransaction = many1 spacenonewline >> choice [ normaltransaction, virtualtransaction, balancedvirtualtransaction ]

normaltransaction :: GenParser Char LedgerFileCtx RawTransaction
normaltransaction = do
  status <- ledgerstatus
  account <- transactionaccountname
  amount <- transactionamount
  many spacenonewline
  comment <- ledgercomment
  parent <- getParentAccount
  return (RawTransaction status account amount comment RegularTransaction)

virtualtransaction :: GenParser Char LedgerFileCtx RawTransaction
virtualtransaction = do
  status <- ledgerstatus
  char '('
  account <- transactionaccountname
  char ')'
  amount <- transactionamount
  many spacenonewline
  comment <- ledgercomment
  parent <- getParentAccount
  return (RawTransaction status account amount comment VirtualTransaction)

balancedvirtualtransaction :: GenParser Char LedgerFileCtx RawTransaction
balancedvirtualtransaction = do
  status <- ledgerstatus
  char '['
  account <- transactionaccountname
  char ']'
  amount <- transactionamount
  many spacenonewline
  comment <- ledgercomment
  return (RawTransaction status account amount comment BalancedVirtualTransaction)

-- Qualify with the parent account from parsing context
transactionaccountname :: GenParser Char LedgerFileCtx AccountName
transactionaccountname = liftM2 (++) getParentAccount ledgeraccountname

-- | account names may have single spaces inside them, and are terminated by two or more spaces
ledgeraccountname :: GenParser Char st String
ledgeraccountname = do
    accountname <- many1 (accountnamechar <|> singlespace)
    return $ striptrailingspace accountname
      singlespace = try (do {spacenonewline; do {notFollowedBy spacenonewline; return ' '}})
      -- couldn't avoid consuming a final space sometimes, harmless
      striptrailingspace s = if last s == ' ' then init s else s

accountnamechar = notFollowedBy (oneOf "()[]") >> nonspace
    <?> "account name character (non-bracket, non-parenthesis, non-whitespace)"

transactionamount :: GenParser Char st MixedAmount
transactionamount =
  try (do
        many1 spacenonewline
        a <- someamount <|> return missingamt
        return a
      ) <|> return missingamt

someamount = try leftsymbolamount <|> try rightsymbolamount <|> nosymbolamount 

leftsymbolamount :: GenParser Char st MixedAmount
leftsymbolamount = do
  sym <- commoditysymbol 
  sp <- many spacenonewline
  (q,p,comma) <- amountquantity
  pri <- priceamount
  let c = Commodity {symbol=sym,side=L,spaced=not $ null sp,comma=comma,precision=p}
  return $ Mixed [Amount c q pri]
  <?> "left-symbol amount"

rightsymbolamount :: GenParser Char st MixedAmount
rightsymbolamount = do
  (q,p,comma) <- amountquantity
  sp <- many spacenonewline
  sym <- commoditysymbol
  pri <- priceamount
  let c = Commodity {symbol=sym,side=R,spaced=not $ null sp,comma=comma,precision=p}
  return $ Mixed [Amount c q pri]
  <?> "right-symbol amount"

nosymbolamount :: GenParser Char st MixedAmount
nosymbolamount = do
  (q,p,comma) <- amountquantity
  pri <- priceamount
  let c = Commodity {symbol="",side=L,spaced=False,comma=comma,precision=p}
  return $ Mixed [Amount c q pri]
  <?> "no-symbol amount"

commoditysymbol :: GenParser Char st String
commoditysymbol = many1 (noneOf "-.0123456789;\n ") <?> "commodity symbol"

priceamount :: GenParser Char st (Maybe MixedAmount)
priceamount =
    try (do
          many spacenonewline
          char '@'
          many spacenonewline
          a <- someamount
          return $ Just a
          ) <|> return Nothing

-- gawd.. trying to parse a ledger number without error:

-- | parse a ledger-style numeric quantity and also return the number of
-- digits to the right of the decimal point and whether thousands are
-- separated by comma.
amountquantity :: GenParser Char st (Double, Int, Bool)
amountquantity = do
  sign <- optionMaybe $ string "-"
  (intwithcommas,frac) <- numberparts
  let comma = ',' `elem` intwithcommas
  let precision = length frac
  -- read the actual value. We expect this read to never fail.
  let int = filter (/= ',') intwithcommas
  let int' = if null int then "0" else int
  let frac' = if null frac then "0" else frac
  let sign' = fromMaybe "" sign
  let quantity = read $ sign'++int'++"."++frac'
  return (quantity, precision, comma)
  <?> "commodity quantity"

-- | parse the two strings of digits before and after a possible decimal
-- point.  The integer part may contain commas, or either part may be
-- empty, or there may be no point.
numberparts :: GenParser Char st (String,String)
numberparts = numberpartsstartingwithdigit <|> numberpartsstartingwithpoint

numberpartsstartingwithdigit :: GenParser Char st (String,String)
numberpartsstartingwithdigit = do
  let digitorcomma = digit <|> char ','
  first <- digit
  rest <- many digitorcomma
  frac <- try (do {char '.'; many digit >>= return}) <|> return ""
  return (first:rest,frac)
numberpartsstartingwithpoint :: GenParser Char st (String,String)
numberpartsstartingwithpoint = do
  char '.'
  frac <- many1 digit
  return ("",frac)

{-| Parse a timelog file. Here is the timelog grammar, from timeclock.el 2.6:

A timelog contains data in the form of a single entry per line.
Each entry has the form:


CODE is one of: b, h, i, o or O.  COMMENT is optional when the code is
i, o or O.  The meanings of the codes are:

  b  Set the current time balance, or \"time debt\".  Useful when
     archiving old log data, when a debt must be carried forward.
     The COMMENT here is the number of seconds of debt.

  h  Set the required working time for the given day.  This must
     be the first entry for that day.  The COMMENT in this case is
     the number of hours in this workday.  Floating point amounts
     are allowed.

  i  Clock in.  The COMMENT in this case should be the name of the
     project worked on.

  o  Clock out.  COMMENT is unnecessary, but can be used to provide
     a description of how the period went, for example.

  O  Final clock out.  Whatever project was being worked on, it is
     now finished.  Useful for creating summary reports.


i 2007/03/10 12:26:00 hledger
o 2007/03/10 17:26:02

timelog :: GenParser Char LedgerFileCtx TimeLog
timelog = do
  entries <- many timelogentry <?> "timelog entry"
  return $ TimeLog entries

timelogentry :: GenParser Char LedgerFileCtx TimeLogEntry
timelogentry = do
  code <- oneOf "bhioO"
  many1 spacenonewline
  datetime <- ledgerdatetime
  comment <- liftM2 (++) getParentAccount restofline
  return $ TimeLogEntry code datetime comment

-- misc parsing

-- | Parse a --display expression which is a simple date predicate, like
-- "d>[DATE]" or "d<=[DATE]", and return a transaction-matching predicate.
datedisplayexpr :: GenParser Char st (Transaction -> Bool)
datedisplayexpr = do
  char 'd'
  op <- compareop
  char '['
  (y,m,d) <- smartdate
  char ']'
  let edate = parsedate $ printf "%04s/%02s/%02s" y m d
  let matcher = \(Transaction{date=tdate}) -> 
                  case op of
                    "<"  -> tdate <  edate
                    "<=" -> tdate <= edate
                    "="  -> tdate == edate
                    "==" -> tdate == edate -- just in case
                    ">=" -> tdate >= edate
                    ">"  -> tdate >  edate
  return matcher              

compareop = choice $ map (try . string) ["<=",">=","==","<","=",">"]