From d9f5c80328b10a4e388a44b6107189795c5951d4 Mon Sep 17 00:00:00 2001
From: David Florness <david@florness.com>
Date: Mon, 15 Feb 2021 10:44:19 -0500
Subject: [PATCH] Properly handle ballot TUI errors

---
 cmd/tallyard/main.go | 11 +++++++++--
 ui/tui.go            | 24 +++++++++++++++++-------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/cmd/tallyard/main.go b/cmd/tallyard/main.go
index 4e6d0a6..3bd810c 100644
--- a/cmd/tallyard/main.go
+++ b/cmd/tallyard/main.go
@@ -129,8 +129,15 @@ func main() {
 	// vote if we need to (user may have voted in previous tallyard
 	// invocation)
 	if el.LocalVoter != nil && el.LocalVoter.Poly == nil {
-		ballot := ui.VoteTUI(el.Candidates)
-		el.LocalVoter.Poly = math.NewRandomPoly(uint(len(*el.FinalJoinIDs)-1), 1024, ballot)
+		ballot, err := ui.VoteTUI(el.Candidates)
+		if err != nil {
+			panic(err)
+		}
+		if ballot == nil {
+			// user likely hit C-c
+			return
+		}
+		el.LocalVoter.Poly = math.NewRandomPoly(uint(len(*el.FinalJoinIDs)-1), 1024, *ballot)
 		el.Save()
 	}
 
diff --git a/ui/tui.go b/ui/tui.go
index f531e99..bb20de8 100644
--- a/ui/tui.go
+++ b/ui/tui.go
@@ -332,8 +332,7 @@ func ElectionWaitTUI(client *mautrix.Client, el *election.Election, eventStore *
 }
 
 // displays a voting UI to the user and returns the encoded ballot
-func VoteTUI(candidates []election.Candidate) []byte {
-	ranks := make([]int, len(candidates))
+func VoteTUI(candidates []election.Candidate) (ballot *[]byte, err error) {
 	app := newTallyardApplication()
 	form := tview.NewForm()
 	form.SetTitle("Vote").SetBorder(true)
@@ -348,31 +347,42 @@ func VoteTUI(candidates []election.Candidate) []byte {
 
 	form.AddButton("Submit", func() {
 		app.Stop()
+		ranks := make([]int, len(candidates))
 		for i := 0; i < len(candidates); i++ {
 			text := form.GetFormItem(i).(*tview.InputField).GetText()
 			if text == "" {
 				ranks[i] = len(candidates)
 				continue
 			}
-			rank, err := strconv.Atoi(text)
+			var rank int
+			rank, err = strconv.Atoi(text)
 			if err != nil {
-				panic(err)
+				err = fmt.Errorf("couldn't parse ballot option %d: %s", i+1, err)
+				return
 			}
 			if rank > len(candidates) {
 				rank = len(candidates)
 			}
 			ranks[i] = rank
 		}
+		b := getBallotFromRankings(ranks)
+		ballot = &b
 	})
 
 	app.SetRoot(form, true)
-	if err := app.Run(); err != nil {
-		panic(err)
+	err2 := app.Run()
+	if err != nil {
+		return nil, err
+	}
+	if err2 != nil {
+		return nil, err2
 	}
 
-	return getBallotFromRankings(ranks)
+	return ballot, nil
 }
 
+// same as tview.Application but includes an "alive" bool that's use by update
+// goroutines
 type tallyardApplication struct {
 	*tview.Application
 	alive bool
-- 
2.38.4