Phase 5: Extract functions to reduce complexity

- Create atoms.go with BuildUnifiedAtomList, SortAtomsByUrgency, PartitionAtomsByTime
- Create helpers.go with parseFormOr400, requireFormValue
- Refactor HandleTabTasks from 95 lines to 25 lines using extracted functions
- Remove duplicate atomUrgencyTier function
- Update handlers to use parseFormOr400 helper

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/internal/handlers/helpers.go b/internal/handlers/helpers.go
new file mode 100644
index 0000000..e67eea7
--- /dev/null
+++ b/internal/handlers/helpers.go
@@ -0,0 +1,26 @@
+package handlers
+
+import (
+	"net/http"
+)
+
+// parseFormOr400 parses the request form and returns false if parsing fails
+// (after writing a 400 error response). Returns true if parsing succeeds.
+func parseFormOr400(w http.ResponseWriter, r *http.Request) bool {
+	if err := r.ParseForm(); err != nil {
+		JSONError(w, http.StatusBadRequest, "Failed to parse form", err)
+		return false
+	}
+	return true
+}
+
+// requireFormValue returns the form value for the given key, or writes a 400 error
+// and returns empty string if the value is missing.
+func requireFormValue(w http.ResponseWriter, r *http.Request, key string) (string, bool) {
+	value := r.FormValue(key)
+	if value == "" {
+		JSONError(w, http.StatusBadRequest, "Missing required field: "+key, nil)
+		return "", false
+	}
+	return value, true
+}