From 7dcfcb05ecb07f7b4a9aced4bbd48aaefe44fa1d Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Fri, 30 Dec 2016 11:44:01 -0800
Subject: [PATCH] lib: get effective report start/end dates

---
 hledger-lib/Hledger/Reports/ReportOptions.hs | 30 ++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/hledger-lib/Hledger/Reports/ReportOptions.hs b/hledger-lib/Hledger/Reports/ReportOptions.hs
index 8c51f7c0e..de6b10737 100644
--- a/hledger-lib/Hledger/Reports/ReportOptions.hs
+++ b/hledger-lib/Hledger/Reports/ReportOptions.hs
@@ -22,6 +22,9 @@ module Hledger.Reports.ReportOptions (
   queryOptsFromOpts,
   transactionDateFn,
   postingDateFn,
+  reportStartDate,
+  reportEndDate,
+  reportStartEndDates,
 
   tests_Hledger_Reports_ReportOptions
 )
@@ -354,6 +357,33 @@ tests_queryOptsFromOpts = [
                                                              })
  ]
 
+-- | The effective report start date is the one specified by options or queries,
+-- otherwise the earliest transaction or posting date in the journal,
+-- otherwise (for an empty journal) nothing.
+-- Needs IO to parse smart dates in options/queries.
+reportStartDate :: Journal -> ReportOpts -> IO (Maybe Day)
+reportStartDate j ropts = (fst <$>) <$> reportStartEndDates j ropts
+
+-- | The effective report end date is the one specified by options or queries,
+-- otherwise the latest transaction or posting date in the journal,
+-- otherwise (for an empty journal) nothing.
+-- Needs IO to parse smart dates in options/queries.
+reportEndDate :: Journal -> ReportOpts -> IO (Maybe Day)
+reportEndDate j ropts = (fst <$>) <$> reportStartEndDates j ropts
+
+reportStartEndDates :: Journal -> ReportOpts -> IO (Maybe (Day,Day))
+reportStartEndDates j ropts = do
+  today <- getCurrentDay
+  let
+    q = queryFromOpts today ropts
+    mrequestedstartdate = queryStartDate False q
+    mrequestedenddate = queryEndDate False q
+  return $
+    case journalDateSpan False j of  -- don't bother with secondary dates
+      DateSpan (Just journalstartdate) (Just journalenddate) ->
+        Just (fromMaybe journalstartdate mrequestedstartdate, fromMaybe journalenddate mrequestedenddate)
+      _ -> Nothing
+
 
 tests_Hledger_Reports_ReportOptions :: Test
 tests_Hledger_Reports_ReportOptions = TestList $