{-|

A ledger-compatible @register@ command.

-}

{-# LANGUAGE CPP               #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}
{-# LANGUAGE TemplateHaskell   #-}

module Hledger.Cli.Commands.Register (
  registermode
 ,register
 ,postingsReportAsText
 ,postingsReportItemAsText
 -- ,showPostingWithBalanceForVty
 ,tests_Register
) where

import Data.Default (def)
import Data.Maybe (fromMaybe, isJust)
import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Builder as TB
import System.Console.CmdArgs.Explicit (flagNone, flagReq)

import Hledger
import Hledger.Read.CsvReader (CSV, CsvRecord, printCSV)
import Hledger.Cli.CliOptions
import Hledger.Cli.Utils
import Text.Tabular.AsciiWide

registermode = hledgerCommandMode
  $(embedFileRelative "Hledger/Cli/Commands/Register.txt")
  ([flagNone ["cumulative"] (setboolopt "cumulative")
     "show running total from report start date (default)"
  ,flagNone ["historical","H"] (setboolopt "historical")
     "show historical running total/balance (includes postings before report start date)\n "
  ,flagNone ["average","A"] (setboolopt "average")
     "show running average of posting amounts instead of total (implies --empty)"
  ,flagNone ["related","r"] (setboolopt "related") "show postings' siblings instead"
  ,flagNone ["invert"] (setboolopt "invert") "display all amounts with reversed sign"
  ,flagReq  ["width","w"] (\s opts -> Right $ setopt "width" s opts) "N"
     ("set output width (default: " ++
#ifdef mingw32_HOST_OS
      show defaultWidth
#else
      "terminal width"
#endif
      ++ " or $COLUMNS). -wN,M sets description width as well."
     )
  ,outputFormatFlag ["txt","csv","json"]
  ,outputFileFlag
  ])
  [generalflagsgroup1]
  hiddenflags
  ([], Just $ argsFlag "[QUERY]")

-- | Print a (posting) register report.
register :: CliOpts -> Journal -> IO ()
register opts@CliOpts{reportspec_=rspec} j =
    writeOutputLazyText opts . render $ postingsReport rspec j
  where
    fmt = outputFormatFromOpts opts
    render | fmt=="txt"  = postingsReportAsText opts
           | fmt=="csv"  = printCSV . postingsReportAsCsv
           | fmt=="json" = toJsonText
           | otherwise   = error' $ unsupportedOutputFormatError fmt  -- PARTIAL:

postingsReportAsCsv :: PostingsReport -> CSV
postingsReportAsCsv is =
  ["txnidx","date","code","description","account","amount","total"]
  :
  map postingsReportItemAsCsvRecord is

postingsReportItemAsCsvRecord :: PostingsReportItem -> CsvRecord
postingsReportItemAsCsvRecord (_, _, _, p, b) = [idx,date,code,desc,acct,amt,bal]
  where
    idx  = T.pack . show . maybe 0 tindex $ ptransaction p
    date = showDate $ postingDate p -- XXX csv should show date2 with --date2
    code = maybe "" tcode $ ptransaction p
    desc = maybe "" tdescription $ ptransaction p
    acct = bracket $ paccount p
      where
        bracket = case ptype p of
                             BalancedVirtualPosting -> wrap "[" "]"
                             VirtualPosting -> wrap "(" ")"
                             _ -> id
    -- Since postingsReport strips prices from all Amounts when not used, we can display prices.
    amt = wbToText . showMixedAmountB csvDisplay $ pamount p
    bal = wbToText $ showMixedAmountB csvDisplay b

-- | Render a register report as plain text suitable for console output.
postingsReportAsText :: CliOpts -> PostingsReport -> TL.Text
postingsReportAsText opts items = TB.toLazyText lines
  where
    lines = foldMap (postingsReportItemAsText opts amtwidth balwidth) items
    amtwidth = maximumStrict $ 12 : widths (map itemamt items)
    balwidth = maximumStrict $ 12 : widths (map itembal items)
    widths = map wbWidth . concatMap (showMixedAmountLinesB oneLine)
    itemamt (_,_,_,Posting{pamount=a},_) = a
    itembal (_,_,_,_,a) = a

-- | Render one register report line item as plain text. Layout is like so:
-- @
-- <---------------- width (specified, terminal width, or 80) -------------------->
-- date (10)  description           account              amount (12)   balance (12)
-- DDDDDDDDDD dddddddddddddddddddd  aaaaaaaaaaaaaaaaaaa  AAAAAAAAAAAA  AAAAAAAAAAAA
-- @
-- If description's width is specified, account will use the remaining space.
-- Otherwise, description and account divide up the space equally.
--
-- With a report interval, the layout is like so:
-- @
-- <---------------- width (specified, terminal width, or 80) -------------------->
-- date (21)              account                        amount (12)   balance (12)
-- DDDDDDDDDDDDDDDDDDDDD  aaaaaaaaaaaaaaaaaaaaaaaaaaaaa  AAAAAAAAAAAA  AAAAAAAAAAAA
-- @
--
-- date and description are shown for the first posting of a transaction only.
--
-- Returns a string which can be multi-line, eg if the running balance
-- has multiple commodities. Does not yet support formatting control
-- like balance reports.
--
-- Also returns the natural width (without padding) of the amount and balance
-- fields.
postingsReportItemAsText :: CliOpts -> Int -> Int -> PostingsReportItem -> TB.Builder
postingsReportItemAsText opts preferredamtwidth preferredbalwidth (mdate, mperiod, mdesc, p, b) =
    table <> TB.singleton '\n'
  where
    table = renderRowB def{tableBorders=False, borderSpaces=False} . Group NoLine $ map Header
      [ textCell TopLeft $ fitText (Just datewidth) (Just datewidth) True True date
      , spacerCell
      , textCell TopLeft $ fitText (Just descwidth) (Just descwidth) True True desc
      , spacerCell2
      , textCell TopLeft $ fitText (Just acctwidth) (Just acctwidth) True True acct
      , spacerCell2
      , Cell TopRight $ map (pad amtwidth) amt
      , spacerCell2
      , Cell BottomRight $ map (pad balwidth) bal
      ]
    spacerCell  = Cell BottomLeft [WideBuilder (TB.singleton ' ') 1]
    spacerCell2 = Cell BottomLeft [WideBuilder (TB.fromString "  ") 2]
    pad fullwidth amt = WideBuilder (TB.fromText $ T.replicate w " ") w <> amt
      where w = fullwidth - wbWidth amt
    -- calculate widths
    (totalwidth,mdescwidth) = registerWidthsFromOpts opts
    datewidth = maybe 10 periodTextWidth mperiod
    date = case mperiod of
             Just period -> if isJust mdate then showPeriod period else ""
             Nothing     -> maybe "" showDate mdate
    (amtwidth, balwidth)
      | shortfall <= 0 = (preferredamtwidth, preferredbalwidth)
      | otherwise      = (adjustedamtwidth, adjustedbalwidth)
      where
        mincolwidth = 2 -- columns always show at least an ellipsis
        maxamtswidth = max 0 (totalwidth - (datewidth + 1 + mincolwidth + 2 + mincolwidth + 2 + 2))
        shortfall = (preferredamtwidth + preferredbalwidth) - maxamtswidth
        amtwidthproportion = fromIntegral preferredamtwidth / fromIntegral (preferredamtwidth + preferredbalwidth)
        adjustedamtwidth = round $ amtwidthproportion * fromIntegral maxamtswidth
        adjustedbalwidth = maxamtswidth - adjustedamtwidth

    remaining = totalwidth - (datewidth + 1 + 2 + amtwidth + 2 + balwidth)
    (descwidth, acctwidth)
      | isJust mperiod = (0, remaining - 2)
      | otherwise      = (w, remaining - 2 - w)
      where
        w = fromMaybe ((remaining - 2) `div` 2) mdescwidth

    -- gather content
    desc = fromMaybe "" mdesc
    acct = parenthesise . elideAccountName awidth $ paccount p
      where
        (parenthesise, awidth) = case ptype p of
            BalancedVirtualPosting -> (wrap "[" "]", acctwidth-2)
            VirtualPosting         -> (wrap "(" ")", acctwidth-2)
            _                      -> (id,acctwidth)
    amt = showamt $ pamount p
    bal = showamt b
    showamt = showMixedAmountLinesB oneLine{displayColour=color_ . _rsReportOpts $ reportspec_ opts}

-- tests

tests_Register = testGroup "Register" [

   testGroup "postingsReportAsText" [
    testCase "unicode in register layout" $ do
      j <- readJournal' "2009/01/01 * медвежья шкура\n  расходы:покупки  100\n  актив:наличные\n"
      let rspec = defreportspec
      (TL.unpack . postingsReportAsText defcliopts $ postingsReport rspec j)
        @?=
        unlines
        ["2009-01-01 медвежья шкура       расходы:покупки                100           100"
        ,"                                актив:наличные                -100             0"]
   ]

 ]
