Added Task number

supabase/migrations/20260221120000_add_task_number.sql

@@ -0,0 +1,66 @@
+-- Add a human‐readable, sequential task number that is shown in the UI
+-- Format: YYYY-MM-##### (resetting each month).
+
+-- 1. Add the column (nullable for now so we can backfill)
+ALTER TABLE tasks
+ADD COLUMN task_number text;
+
+-- 2. Backfill existing rows using created_at as the timestamp basis.
+DO $$
+DECLARE
+    r RECORD;
+    prefix text;
+    cnt int;
+BEGIN
+    FOR r IN
+        SELECT id, created_at
+        FROM tasks
+        WHERE task_number IS NULL
+        ORDER BY created_at
+    LOOP
+        prefix := to_char(r.created_at::timestamp, 'YYYY-MM-');
+        cnt := (SELECT count(*)
+                FROM tasks t
+                WHERE to_char(t.created_at::timestamp, 'YYYY-MM-') = prefix
+                  AND t.created_at <= r.created_at);
+        UPDATE tasks
+        SET task_number = prefix || lpad(cnt::text, 5, '0')
+        WHERE id = r.id;
+    END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+-- 3. Create trigger function to generate numbers on new inserts
+CREATE OR REPLACE FUNCTION tasks_set_task_number()
+RETURNS trigger AS $$
+DECLARE
+    prefix text;
+    seq int;
+BEGIN
+    -- if caller already provided one, do not overwrite
+    IF NEW.task_number IS NOT NULL THEN
+        RETURN NEW;
+    END IF;
+
+    prefix := to_char(now(), 'YYYY-MM-');
+    SELECT COALESCE(MAX((substring(task_number FROM 8))::int), 0) + 1
+      INTO seq
+      FROM tasks
+      WHERE task_number LIKE prefix || '%';
+
+    NEW.task_number := prefix || lpad(seq::text, 5, '0');
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER tasks_set_task_number_before_insert
+BEFORE INSERT ON tasks
+FOR EACH ROW
+EXECUTE FUNCTION tasks_set_task_number();
+
+-- 4. Enforce not-null and uniqueness now that every row has a value
+ALTER TABLE tasks
+    ALTER COLUMN task_number SET NOT NULL;
+
+CREATE UNIQUE INDEX IF NOT EXISTS idx_tasks_task_number
+    ON tasks (task_number);