feat: add schemaOrgToCooklang conversion function

src/Roux/SchemaOrg.hs

@@ -17,7 +17,8 @@ import Data.Aeson (FromJSON (..), (.!=), (.:), (.:?))
 import qualified Data.Aeson as A
 import qualified Data.Aeson.KeyMap as KM
 import Data.Aeson.Types (parseMaybe)
-import Data.Maybe (fromMaybe, mapMaybe)
+import Data.List.NonEmpty (NonEmpty ((:|)), fromList)
+import Data.Maybe (catMaybes, fromMaybe, mapMaybe)
 import Data.Text (Text)
 import qualified Data.Text as T
 
@@ -213,12 +214,71 @@ parseSchemaOrgRecipe val = do
         _ -> Nothing
 
 -- ---------------------------------------------------------------------------
--- Stubs for future tasks
+-- Conversion to Cooklang Recipe
 -- ---------------------------------------------------------------------------
 
--- | Convert a SchemaOrgRecipe to a Cooklang Recipe. (Stub — will be implemented in Task 3)
+-- | Convert a SchemaOrgRecipe to a Cooklang Recipe.
 schemaOrgToCooklang :: SchemaOrgRecipe -> Either String Recipe
-schemaOrgToCooklang _ = Left "Not yet implemented"
+schemaOrgToCooklang r =
+    Right
+        Recipe
+            { recipeMetadata = buildMetadata r
+            , recipeSections = buildSections r
+            }
+
+buildMetadata :: SchemaOrgRecipe -> Metadata
+buildMetadata r =
+    emptyMetadata
+        { metaTitle = Just (soName r)
+        , metaDescription = soDescription r
+        , metaSource = soUrl r
+        , metaTotalTime = soTotalTime r >>= parseISODuration
+        , metaPrepTime = soPrepTime r >>= parseISODuration
+        , metaCookTime = soCookTime r >>= parseISODuration
+        , metaServings = parseServings =<< soRecipeYield r
+        , metaAuthor = soPersonName <$> soAuthor r
+        , metaCourse = soRecipeCategory r
+        , metaCuisine = soRecipeCuisine r
+        , metaTags = soKeywords r
+        , metaImage = case soImage r of
+            (img : _) -> Just (soImageObjectUrl img)
+            [] -> Nothing
+        }
+
+buildSections :: SchemaOrgRecipe -> NonEmpty Section
+buildSections r =
+    let ingSection = buildIngredientSection (soRecipeIngredient r)
+        methodSection = buildMethodSection (soRecipeInstructions r)
+        sections = catMaybes [Just ingSection, methodSection]
+     in case sections of
+            (s : ss) -> s :| ss
+            [] -> Section Nothing (SecStep (Step []) :| []) :| []
+
+buildIngredientSection :: [Text] -> Section
+buildIngredientSection ings
+    | null ings = Section Nothing (SecStep (Step []) :| [])
+    | otherwise =
+        let items = concatMap (\t -> [StepText (", "), StepText t]) ings
+            step = Step items
+         in Section (Just "Ingredients") (SecStep step :| [])
+
+buildMethodSection :: [SchemaOrgHowToStep] -> Maybe Section
+buildMethodSection [] = Nothing
+buildMethodSection steps =
+    let stepItems = map (\s -> SecStep (Step [StepText (sohsText s)])) steps
+     in Just (Section (Just "Method") (fromList stepItems))
+
+-- | Parse a servings string like "4 to 6 servings".
+parseServings :: Text -> Maybe (Int, Maybe Text)
+parseServings t =
+    case T.words t of
+        (numStr : rest) -> do
+            n <- readMaybe (T.unpack numStr)
+            let unit = case rest of
+                    (_ : _) -> Just (T.intercalate " " rest)
+                    [] -> Nothing
+            Just (n, unit)
+        _ -> Nothing
 
 {- | Parse an ISO 8601 duration string into a Cooklang Duration.
 Supports formats like PT20M, PT1H30M, P1DT2H, P1D.