1 files changed, 36 insertions, 7 deletions
diff --git a/Omni/Task/Core.hs b/Omni/Task/Core.hs
index f7b7915..98ef6f9 100644
--- a/Omni/Task/Core.hs
+++ b/Omni/Task/Core.hs
@@ -13,7 +13,8 @@ import qualified Data.ByteString.Lazy.Char8 as BLC
 import qualified Data.List as List
 import qualified Data.Text as T
 import qualified Data.Text.IO as TIO
-import Data.Time (UTCTime, diffTimeToPicoseconds, getCurrentTime, utctDayTime)
+import Data.Time (UTCTime, diffTimeToPicoseconds, getCurrentTime, utctDayTime, utctDay)
+import Data.Time.Calendar (toModifiedJulianDay)
 import GHC.Generics ()
 import System.Directory (createDirectoryIfMissing, doesFileExist)
 import System.Environment (lookupEnv)
@@ -104,13 +105,41 @@ initTaskDb = do
 generateId :: IO Text
 generateId = do
   now <- getCurrentTime
-  -- Convert current time to microseconds since midnight
-  let dayTime = utctDayTime now
-      microseconds = diffTimeToPicoseconds dayTime `div` 1000000
-      -- Convert to base62 for shorter IDs
-      encoded = toBase62 (fromIntegral microseconds)
+  -- Convert current time to microseconds since epoch (using MJD)
+  let day = utctDay now
+      dayTime = utctDayTime now
+      mjd = toModifiedJulianDay day
+      micros = diffTimeToPicoseconds dayTime `div` 1000000
+      -- Combine MJD and micros to ensure uniqueness across days.
+      -- Multiplier 10^11 (100,000 seconds) is safe for any day length.
+      totalMicros = (mjd * 100000000000) + micros
+      encoded = toBase62 totalMicros
   pure <| "t-" <> T.pack encoded
 
+-- Generate a child ID based on parent ID (e.g. "t-abc.1", "t-abc.1.2")
+-- Finds the next available sequential suffix among existing children.
+generateChildId :: Text -> IO Text
+generateChildId parentId = do
+  tasks <- loadTasks
+  -- Find the max suffix among ALL tasks that look like children (to avoid ID collisions)
+  -- We check all tasks, not just those with taskParent set, because we want to ensure
+  -- ID uniqueness even if the parent link is missing.
+  let suffixes = mapMaybe (getSuffix parentId <. taskId) tasks
+      nextSuffix = case suffixes of
+        [] -> 1
+        s -> maximum s + 1
+  pure <| parentId <> "." <> T.pack (show nextSuffix)
+
+getSuffix :: Text -> Text -> Maybe Int
+getSuffix parent childId =
+  if parent `T.isPrefixOf` childId && T.length childId > T.length parent
+    then
+      let rest = T.drop (T.length parent) childId
+       in if T.head rest == '.'
+            then readMaybe (T.unpack (T.tail rest))
+            else Nothing
+    else Nothing
+
 -- Convert number to base62 (0-9, a-z, A-Z)
 toBase62 :: Integer -> String
 toBase62 0 = "0"
@@ -192,7 +221,7 @@ saveTask task = do
 -- Create a new task
 createTask :: Text -> TaskType -> Maybe Text -> Maybe Text -> Priority -> [Dependency] -> IO Task
 createTask title taskType parent namespace priority deps = do
-  tid <- generateId
+  tid <- maybe generateId generateChildId parent
   now <- getCurrentTime
   let task =
         Task