Began adding transactions on the quote database : getters and locks management.

Hsbot/Plugin/Quote.hs

@@ -3,7 +3,11 @@
 module Hsbot.Plugin.Quote
     () where
 
+import Control.Monad.Reader
+import Control.Monad.State
+import Data.Acid
 import qualified Data.Map as M
+import System.Random
 import Data.SafeCopy
 import Data.Typeable
 import System.Time
@@ -45,3 +49,37 @@ $(deriveSafeCopy 0 'base ''QuoteElt)
 $(deriveSafeCopy 0 'base ''Quote)
 $(deriveSafeCopy 0 'base ''QuoteDB)
 
+-- | Quote database transactions
+getQuote :: Int -> Query QuoteDB (Maybe Quote)
+getQuote quoteId = asks quoteBotDB >>= return . M.lookup quoteId
+
+getQuoteDB :: Query QuoteDB (M.Map Int Quote)
+getQuoteDB = asks quoteBotDB
+
+isQuoteLockedFor :: Int -> String -> ClockTime -> Query QuoteDB (Either String Bool)
+isQuoteLockedFor quoteId requestor now = do
+    theQuote <- asks quoteBotDB >>= return . M.lookup quoteId
+    case theQuote of
+        Just quote -> do
+            currentLock <- asks lockedQuotes >>= return . M.lookup quoteId
+            case currentLock of
+                Just (owner, lockStamp) ->
+                  if owner == requestor
+                    then return $ Right True
+                    else return . Right $ (addToClockTime (TimeDiff 0 0 0 0 5 0 0) lockStamp > now)     -- Is the entry older than 5 min?
+                Nothing -> return $ Right True
+        Nothing -> return $ Left "QuoteId not found"
+
+lockQuoteIdFor :: Int -> String -> ClockTime -> Update QuoteDB ()
+lockQuoteIdFor quoteId requestor now = get >>= \db -> put db { lockedQuotes = M.insert quoteId (requestor, now) (lockedQuotes db) }
+
+$(makeAcidic ''QuoteDB ['getQuote, 'getQuoteDB, 'isQuoteLockedFor, 'lockQuoteIdFor])
+
+-- | gets a random quote from the database
+getRandomQuote :: AcidState QuoteDB -> IO (Maybe Quote)
+getRandomQuote quoteDB = do
+    db <- query' quoteDB GetQuoteDB
+    if M.size db > 0
+      then getStdRandom (randomR (0, M.size db - 1)) >>= \rInt -> return . Just . snd $ M.elemAt rInt db
+      else return Nothing
+