feat: add CookLog module with types and DB operations

src/Roux/CookLog.hs

@@ -0,0 +1,116 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+{- | Cook log: track which recipes were cooked when, with optional notes.
+
+Uses sqlite-simple for persistence.  The database file lives alongside the
+recipe directory as @cook-log.db@.
+-}
+module Roux.CookLog (
+    CookEntry (..),
+    initDb,
+    insertEntry,
+    fetchEntries,
+    fetchAllEntries,
+) where
+
+import Data.Aeson (FromJSON, ToJSON)
+import qualified Data.Aeson as A
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Time.Calendar (Day, fromGregorianValid)
+import Data.Time.Clock (UTCTime, getCurrentTime)
+import qualified Data.Time.Format as Time
+import Database.SQLite.Simple (Connection, FromRow (..), Only (..), Query)
+import qualified Database.SQLite.Simple as SQL
+
+-- | A single cooking log entry.
+data CookEntry = CookEntry
+    { ceId             :: !Int
+    , ceRecipeFilename :: !Text
+    , ceCookedDate     :: !Day
+    , ceComment        :: !Text
+    , ceCreatedAt      :: !UTCTime
+    }
+    deriving stock (Eq, Show)
+
+instance FromRow CookEntry where
+    fromRow = CookEntry <$> SQL.field <*> SQL.field <*> SQL.field <*> SQL.field <*> SQL.field
+
+instance ToJSON CookEntry where
+    toJSON e = A.object
+        [ "id"              A..= A.toJSON (ceId e)
+        , "recipe_filename" A..= A.toJSON (ceRecipeFilename e)
+        , "cooked_date"     A..= A.toJSON (show (ceCookedDate e))
+        , "comment"         A..= A.toJSON (ceComment e)
+        , "created_at"      A..= A.toJSON (show (ceCreatedAt e))
+        ]
+
+instance FromJSON CookEntry where
+    parseJSON = A.withObject "CookEntry" $ \o ->
+        CookEntry
+            <$> o A..: "id"
+            <*> o A..: "recipe_filename"
+            <*> (parseDate =<< o A..: "cooked_date")
+            <*> o A..: "comment"
+            <*> (parseUTC =<< o A..: "created_at")
+        where
+        parseDate t = case T.splitOn "-" t of
+            [y, m, d] -> case fromGregorianValid
+                (read (T.unpack y)) (read (T.unpack m)) (read (T.unpack d)) of
+                Just day -> pure day
+                Nothing -> fail "invalid date"
+            _ -> fail "expected YYYY-MM-DD"
+        parseUTC t = case T.unpack t of
+            "" -> fail "empty datetime"
+            s -> case Time.parseTimeM True Time.defaultTimeLocale "%Y-%m-%d %H:%M:%S" s of
+                Just ut -> pure ut
+                Nothing -> fail "invalid datetime"
+
+-- | Open or create the DB, ensuring the table exists.
+initDb :: FilePath -> IO Connection
+initDb dbPath = do
+    conn <- SQL.open dbPath
+    SQL.execute_ conn createTableSQL
+    pure conn
+  where
+    createTableSQL :: Query
+    createTableSQL =
+        "CREATE TABLE IF NOT EXISTS cook_log ( \
+        \    id INTEGER PRIMARY KEY AUTOINCREMENT, \
+        \    recipe_filename TEXT NOT NULL, \
+        \    cooked_date TEXT NOT NULL, \
+        \    comment TEXT NOT NULL DEFAULT '', \
+        \    created_at TEXT NOT NULL \
+        \)"
+
+-- | Insert a new cook log entry. Returns the new row id.
+insertEntry :: Connection -> Text -> Day -> Maybe Text -> IO Int
+insertEntry conn filename day mComment = do
+    now <- getCurrentTime
+    SQL.withTransaction conn $ do
+        SQL.execute
+            conn
+            "INSERT INTO cook_log (recipe_filename, cooked_date, comment, created_at) VALUES (?, ?, ?, ?)"
+            (filename, show day, T.strip (fromMaybe "" mComment), show now)
+        rows <- SQL.query conn "SELECT last_insert_rowid()" ()
+        case rows of
+            [Only i] -> pure i
+            _ -> fail "expected last_insert_rowid() to return a row"
+  where
+    fromMaybe d Nothing = d
+    fromMaybe _ (Just x) = x
+
+-- | Fetch all entries for a given recipe, newest first.
+fetchEntries :: Connection -> Text -> IO [CookEntry]
+fetchEntries conn filename =
+    SQL.query conn
+        "SELECT id, recipe_filename, cooked_date, comment, created_at \
+        \ FROM cook_log WHERE recipe_filename = ? ORDER BY cooked_date DESC, id DESC"
+        (Only filename)
+
+-- | Fetch all entries across all recipes, newest first.
+fetchAllEntries :: Connection -> IO [CookEntry]
+fetchAllEntries conn =
+    SQL.query_ conn
+        "SELECT id, recipe_filename, cooked_date, comment, created_at \
+        \ FROM cook_log ORDER BY cooked_date DESC, id DESC"