cmd/streamdata: retry metadata entry

This enables fixing metadata when a mistake is made.

Signed-off-by: Yonah <contrib@gensokyo.uk>

cmd/streamdata/main.go

@@ -130,11 +130,12 @@ func main() {
 				defer toErr(&err)
 				isattyStd()
 				br := bufio.NewReader(os.Stdin)
+				now := time.Now()
 
+			retry:
 				v.Title = require(promptTrimNoEmpty(br, "Title: "))
 				v.Category = require(prompt(br, "Category: "))
 
-				now := time.Now()
 				year := require(promptUintFallbackBounds(
 					br, "Year: ",
 					1970, uint64(now.Year()),
@@ -161,6 +162,11 @@ func main() {
 					time.UTC,
 				)
 
+				printVOD(v)
+				if !require(promptBool(br, "Proceed? ", true)) {
+					goto retry
+				}
+
 				var resp *http.Response
 				if resp, err = http.DefaultClient.Do(req); err != nil {
 					return

cmd/streamdata/prompt.go

@@ -126,6 +126,40 @@ invalid:
 	return v, true
 }
 
+// promptBool prompts the user for a y/n response until a valid response or a
+// single newline character is read.
+func promptBool(
+	br *bufio.Reader,
+	p string,
+	fallback bool,
+) (bool, bool) {
+	if fallback {
+		p += "[Y/n] "
+	} else {
+		p += "[y/N] "
+	}
+
+invalid:
+	s, ok := prompt(br, p)
+	if !ok {
+		return false, false
+	}
+
+	switch strings.ToLower(strings.TrimSpace(s)) {
+	default:
+		goto invalid
+
+	case "":
+		return fallback, true
+
+	case "y":
+		return true, true
+
+	case "n":
+		return false, true
+	}
+}
+
 // require panics with an error if ok is false, and returns v otherwise.
 func require[T any](v T, ok bool) T {
 	if !ok {