From 192e5b097308fbad27930cc519c07236bde71224 Mon Sep 17 00:00:00 2001
From: Marty Sluijtman <marty.wanderer@disroot.org>
Date: Tue, 19 Nov 2024 10:41:25 +0100
Subject: [PATCH] Some utility functions

---
 lib/DND/Sheet/Parser.hs | 55 ++++++++++++++++++++++++++++++++---------
 sheet-parser-hs.cabal   |  1 +
 2 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/lib/DND/Sheet/Parser.hs b/lib/DND/Sheet/Parser.hs
index 29a0620..877cbd3 100644
--- a/lib/DND/Sheet/Parser.hs
+++ b/lib/DND/Sheet/Parser.hs
@@ -1,11 +1,13 @@
 module DND.Sheet.Parser
 ( parseSheet
---, getSheet
-, listSkills
 , createExample
 , getName
 , getStat
-, listSkillNames
+, getSkill
+, getSkillNames
+, getStatNames
+, getSkillScore
+, getProficiency
 ) where
 
 import           Control.Monad
@@ -15,21 +17,13 @@ import qualified Data.ByteString.Lazy.UTF8 as BSU
 import           Data.Maybe                (fromJust)
 import           DND.Bob                   (bob)
 import           DND.Sheet.Content
-
---getSheet :: FilePath -> IO B.ByteString
---getSheet = B.readFile
+import qualified Data.Map as Map
 
 parseSheet :: FilePath -> IO Character
 parseSheet x = unwrap . decode =<< B.readFile x
     where unwrap (Just y) = return y
           unwrap Nothing  = error $ "Failed to parse character sheet: " ++ x
 
-listSkills :: Character -> [Skill]
-listSkills = join . map skills . stats
-
-listSkillNames :: Character -> IO ()
-listSkillNames = mapM_ (putStrLn . skillName) . listSkills
-
 createExample :: FilePath -> IO ()
 createExample = flip encodeFile bob
 
@@ -38,3 +32,40 @@ getName = charName . preamble
 
 getStat :: Character -> String -> Stat
 getStat char s = head . filter (\a -> statName a == s) . stats $ char
+
+getSkill :: Character -> String -> Skill
+getSkill char s = head . filter (\a -> skillName a == s) . skills $ char
+
+getSkillNames :: Character -> [String]
+getSkillNames = map skillStat . skills
+
+getStatNames :: Character -> [String]
+getStatNames = map statName . stats
+
+getProficiency :: Character -> Int
+getProficiency = fromJust . flip Map.lookup profTable . charLevel . preamble
+    -- https://www.nerdsandscoundrels.com/how-to-calculate-proficiency-bonus-5e/
+    -- for some fucking reason there appears to be no simple mathematical way to get a character's proficiency bonus
+    where profTable = Map.fromList
+            [ (1,2),  (2,2),  (3,2),  (4,2)
+            , (5,3),  (6,3),  (7,3),  (8,3)
+            , (9,4),  (10,4), (11,4), (12,4)
+            , (13,5), (14,5), (15,5), (16,5)
+            , (17,6), (18,6), (19,6), (20,6)
+            ]
+
+-- https://worldbuildersjunction.com/dungeon-and-dragons-ability-scores-explained-for-beginners/
+-- from the Go implementation
+-- return (stat.Score - 10) / 2
+
+getSkillScore :: Character -> String -> Int
+getSkillScore char skillString = let
+    skill = getSkill char skillString
+    stat = getStat char $ skillStat skill
+    prof = getProficiency char
+    modifier = case skillMod skill of
+                        Proficient -> prof
+                        Expertise  -> prof * 2
+                        Half       -> div prof 2
+                        None       -> 0
+    in (modifier +) . (`div` 2) $ statScore stat - 10
diff --git a/sheet-parser-hs.cabal b/sheet-parser-hs.cabal
index b03ea5f..3666132 100644
--- a/sheet-parser-hs.cabal
+++ b/sheet-parser-hs.cabal
@@ -68,6 +68,7 @@ library
                     , bytestring
                     , utf8-string
                     , random
+                    , containers
 
     hs-source-dirs:   lib