Add Omni/Fact.hs core module with CRUD operations

The Omni/Fact.hs module is complete with CRUD operations:

- **createFact**: Create a new fact with project, content, related
files - **getFact**: Retrieve a fact by ID - **getAllFacts**: Get all
facts from the database - **getFactsByProject**: Get facts filtered by
project - **getFactsByFile**: Get facts related to a specific file -
**updateFact**: Update an existing fact's content, related files,
and - **deleteFact**: Delete a fact by ID

The module properly re-exports the `Fact` data type from
`Omni.Task.Core

Task-Id: t-158.2

1 files changed, 81 insertions, 0 deletions

diff --git a/Omni/Fact.hs b/Omni/Fact.hs
new file mode 100644
index 0000000..57db7fc
--- /dev/null
+++ b/Omni/Fact.hs
@@ -0,0 +1,81 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+-- | Fact module for the Jr knowledge base.
+--
+-- Facts are pieces of knowledge learned during task execution that can
+-- inform future work on similar tasks or files.
+module Omni.Fact
+  ( Fact (..),
+    createFact,
+    getFact,
+    getAllFacts,
+    getFactsByProject,
+    getFactsByFile,
+    updateFact,
+    deleteFact,
+  )
+where
+
+import Alpha
+import Data.Aeson (encode)
+import qualified Data.ByteString.Lazy.Char8 as BLC
+import qualified Data.Text as Text
+import Data.Time (getCurrentTime)
+import qualified Database.SQLite.Simple as SQL
+import Omni.Task.Core
+  ( Fact (..),
+    getFactsForFile,
+    getFactsForProject,
+    loadFacts,
+    saveFact,
+    withDb,
+  )
+import qualified Omni.Task.Core as TaskCore
+
+-- | Create a new fact and return its ID.
+createFact :: Text -> Text -> [Text] -> Maybe Text -> Double -> IO Int
+createFact project content relatedFiles sourceTask confidence = do
+  now <- getCurrentTime
+  let fact =
+        Fact
+          { factId = Nothing,
+            factProject = project,
+            factContent = content,
+            factRelatedFiles = relatedFiles,
+            factSourceTask = sourceTask,
+            factConfidence = confidence,
+            factCreatedAt = now
+          }
+  saveFact fact
+
+-- | Get a fact by its ID.
+getFact :: Int -> IO (Maybe Fact)
+getFact fid = do
+  facts <- getAllFacts
+  pure <| find (\f -> factId f == Just fid) facts
+
+-- | Get all facts from the database.
+getAllFacts :: IO [Fact]
+getAllFacts = loadFacts
+
+-- | Get facts for a specific project.
+getFactsByProject :: Text -> IO [Fact]
+getFactsByProject = getFactsForProject
+
+-- | Get facts related to a specific file.
+getFactsByFile :: Text -> IO [Fact]
+getFactsByFile = getFactsForFile
+
+-- | Update an existing fact.
+updateFact :: Int -> Text -> [Text] -> Double -> IO ()
+updateFact fid content relatedFiles confidence =
+  withDb <| \conn ->
+    SQL.execute
+      conn
+      "UPDATE facts SET fact = ?, related_files = ?, confidence = ? WHERE id = ?"
+      (content, Text.pack (BLC.unpack (encode relatedFiles)), confidence, fid)
+
+-- | Delete a fact by ID.
+deleteFact :: Int -> IO ()
+deleteFact = TaskCore.deleteFact