From 3ec432bd53198866b143e0d43ac3624b421d4977 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Thu, 29 Feb 2024 12:31:07 -1000
Subject: [PATCH] dev: rename/improve amountSetFullPrecisionUpTo, add
 mixedAmountSetFullPrecisionUpTo

---
 hledger-lib/Hledger/Data/Amount.hs     | 39 +++++++++++++++++---------
 hledger-lib/Hledger/Data/Valuation.hs  |  4 +--
 hledger/Hledger/Cli/Commands/Prices.hs |  2 +-
 hledger/Hledger/Cli/Commands/Roi.hs    |  2 +-
 4 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/hledger-lib/Hledger/Data/Amount.hs b/hledger-lib/Hledger/Data/Amount.hs
index 2aec34e9d..844ad4431 100644
--- a/hledger-lib/Hledger/Data/Amount.hs
+++ b/hledger-lib/Hledger/Data/Amount.hs
@@ -97,7 +97,7 @@ module Hledger.Data.Amount (
   amountSetPrecisionMax,
   withPrecision,
   amountSetFullPrecision,
-  amountSetFullPrecisionOr,
+  amountSetFullPrecisionUpTo,
   amountInternalPrecision,
   amountDisplayPrecision,
   defaultMaxPrecision,
@@ -159,6 +159,7 @@ module Hledger.Data.Amount (
   wbUnpack,
   mixedAmountSetPrecision,
   mixedAmountSetFullPrecision,
+  mixedAmountSetFullPrecisionUpTo,
   mixedAmountSetPrecisionMin,
   mixedAmountSetPrecisionMax,
 
@@ -453,24 +454,26 @@ amountSetFullPrecision a = amountSetPrecision p a
 
 
 -- | We often want to display "infinite decimal" amounts rounded to some readable
--- number of digits, while still displaying amounts with a large "non infinite" number
--- of decimal digits (eg, 100 or 200 digits) in full.
+-- number of digits, while still displaying amounts with a large but "non infinite"
+-- number of decimal digits (eg 10 or 100 or 200 digits) in full.
 -- This helper is like amountSetFullPrecision, but with some refinements:
--- 1. If the internal precision is the maximum (255), indicating an infinite decimal, 
--- the display precision is set to a smaller hard-coded default (8).
--- 2. A maximum display precision can be specified, setting a hard upper limit.
+--
+-- 1. A maximum display precision can be specified, setting a hard upper limit.
+--
+-- 2. If no limit is specified, and the internal precision is the maximum (255),
+-- indicating an infinite decimal, display precision is set to a smaller default (8).
+--
 -- This function always sets an explicit display precision (ie, Precision n).
-amountSetFullPrecisionOr :: Maybe Word8 -> Amount -> Amount
-amountSetFullPrecisionOr mmaxp a = amountSetPrecision (Precision p2) a
+--
+amountSetFullPrecisionUpTo :: Maybe Word8 -> Amount -> Amount
+amountSetFullPrecisionUpTo mmaxp a = amountSetPrecision (Precision p) a
   where
-    p1 = if -- dbg0 "maxdigits" $
-            amountHasMaxDigits a then defaultMaxPrecision else max disp intp
-      -- & dbg0 "p1"
+    p = case mmaxp of
+      Just maxp -> min maxp $ max disp intp
+      Nothing   -> if amountHasMaxDigits a then defaultMaxPrecision else max disp intp
       where
-        intp = amountInternalPrecision a
         disp = amountDisplayPrecision a
-    p2 = maybe p1 (min p1) mmaxp
-      -- & dbg0 "p2"
+        intp = amountInternalPrecision a
 
 -- | The fallback display precision used when showing amounts
 -- representing an infinite decimal.
@@ -1228,6 +1231,14 @@ mixedAmountSetPrecision p = mapMixedAmountUnsafe (amountSetPrecision p)
 mixedAmountSetFullPrecision :: MixedAmount -> MixedAmount
 mixedAmountSetFullPrecision = mapMixedAmountUnsafe amountSetFullPrecision
 
+-- | In each component amount, increase the display precision sufficiently
+-- to render it exactly if possible, but not more than the given max precision,
+-- and if no max precision is given and the amount has infinite decimals,
+-- limit display precision to a hard-coded smaller number (8).
+-- See amountSetFullPrecisionUpTo.
+mixedAmountSetFullPrecisionUpTo :: Maybe Word8 -> MixedAmount -> MixedAmount
+mixedAmountSetFullPrecisionUpTo mmaxp = mapMixedAmountUnsafe (amountSetFullPrecisionUpTo mmaxp)
+
 -- | In each component amount, ensure the display precision is at least the given value.
 -- Makes all amounts have an explicit Precision.
 mixedAmountSetPrecisionMin :: Word8 -> MixedAmount -> MixedAmount
diff --git a/hledger-lib/Hledger/Data/Valuation.hs b/hledger-lib/Hledger/Data/Valuation.hs
index 7e174e347..614f59a4d 100644
--- a/hledger-lib/Hledger/Data/Valuation.hs
+++ b/hledger-lib/Hledger/Data/Valuation.hs
@@ -115,7 +115,7 @@ amountPriceDirectiveFromCost :: Day -> Amount -> Maybe PriceDirective
 amountPriceDirectiveFromCost d amt@Amount{acommodity=fromcomm, aquantity=n} = case acost amt of
     Just (UnitCost u)           -> Just $ pd{pdamount=u}
     Just (TotalCost t) | n /= 0 -> Just $ pd{pdamount=u}
-      where u = amountSetFullPrecisionOr Nothing $ divideAmount n t
+      where u = amountSetFullPrecisionUpTo Nothing $ divideAmount n t
     _                            -> Nothing
   where
     pd = PriceDirective{pddate = d, pdcommodity = fromcomm, pdamount = nullamt}
@@ -209,7 +209,7 @@ amountValueAtDate priceoracle styles mto d a =
       -- set the display precision to match the internal precision (showing all digits),
       -- unnormalised (don't strip trailing zeros);
       -- but if it looks like an infinite decimal, limit the precision to 8.
-      & amountSetFullPrecisionOr Nothing
+      & amountSetFullPrecisionUpTo Nothing
       & dbg9With (lbl "calculated value".showAmount)
 
 -- | Calculate the gain of each component amount, that is the difference
diff --git a/hledger/Hledger/Cli/Commands/Prices.hs b/hledger/Hledger/Cli/Commands/Prices.hs
index 0d46899d9..65ac476f1 100644
--- a/hledger/Hledger/Cli/Commands/Prices.hs
+++ b/hledger/Hledger/Cli/Commands/Prices.hs
@@ -107,7 +107,7 @@ reversePriceDirective pd@PriceDirective{pdcommodity=c, pdamount=a}
     where
       lbl = lbl_ "reversePriceDirective"
       a' =
-        amountSetFullPrecisionOr (Just defaultMaxPrecision) $
+        amountSetFullPrecisionUpTo (Just defaultMaxPrecision) $
         invertAmount a{acommodity=c}
         & dbg9With (lbl "calculated reverse price".showAmount)
         -- & dbg9With (lbl "precision of reverse price".show.amountDisplayPrecision)
diff --git a/hledger/Hledger/Cli/Commands/Roi.hs b/hledger/Hledger/Cli/Commands/Roi.hs
index 0ec91c5a4..28c1bb9a3 100644
--- a/hledger/Hledger/Cli/Commands/Roi.hs
+++ b/hledger/Hledger/Cli/Commands/Roi.hs
@@ -147,7 +147,7 @@ roi CliOpts{rawopts_=rawopts, reportspec_=rspec@ReportSpec{_rsReportOpts=ReportO
                , T.pack $ showMixedAmount $ styleAmounts styles $ cashFlowAmt
                -- , T.pack $ showMixedAmount $
                --   -- dbg0With (lbl "cashflow after styling".showMixedAmountOneLine) $
-               --   mapMixedAmount (amountSetFullPrecisionOr (Just defaultMaxPrecision)) $
+               --   mapMixedAmount (amountSetFullPrecisionUpTo (Just defaultMaxPrecision)) $
                --   styleAmounts (styles
                --                 -- & dbg0With (lbl "styles".show))
                --   cashFlowAmt