Harden NWS key message parsing

internal/providers/nws/forecast_discussion.go

@@ -594,6 +594,18 @@ func parseForecastDiscussionKeyMessages(body []string) []string {
 	if len(body) == 0 {
 		return nil
 	}
+	hasMarkers := false
+	for _, raw := range body {
+		line := strings.TrimSpace(raw)
+		if line == "" {
+			continue
+		}
+		if _, ok := stripForecastDiscussionKeyMessageMarker(line); ok {
+			hasMarkers = true
+			break
+		}
+	}
+
 	var messages []string
 	var current strings.Builder
 
@@ -605,15 +617,21 @@ func parseForecastDiscussionKeyMessages(body []string) []string {
 		current.Reset()
 	}
 
+	seenMarker := false
 	for _, raw := range body {
 		line := strings.TrimSpace(raw)
 		if line == "" {
+			if !hasMarkers || !seenMarker {
+				flush()
+			}
 			continue
 		}
-		if strings.HasPrefix(line, "-") {
+		if stripped, ok := stripForecastDiscussionKeyMessageMarker(line); ok {
 			flush()
-			line = strings.TrimSpace(strings.TrimPrefix(line, "-"))
-			current.WriteString(line)
+			seenMarker = true
+			line = stripped
+		}
+		if line == "" {
 			continue
 		}
 		if current.Len() > 0 {
@@ -690,11 +708,75 @@ func isForecastDiscussionIssuedAtLine(line string) bool {
 
 func isForecastDiscussionKeyMessageMetadataLine(line string) bool {
 	line = strings.TrimSpace(line)
-	return hasForecastDiscussionASCIIPrefix(line, "Issued at") || hasForecastDiscussionASCIIPrefix(line, "Updated at")
+	for _, label := range []string{"Issued at", "Updated at"} {
+		if !hasForecastDiscussionASCIIPrefix(line, label) || len(line) == len(label) || !isForecastDiscussionHorizontalWhitespace(line[len(label)]) {
+			continue
+		}
+		if _, err := parseForecastDiscussionIssueTime(strings.TrimSpace(line[len(label):])); err == nil {
+			return true
+		}
+	}
+	return false
+}
+
+func stripForecastDiscussionKeyMessageMarker(line string) (string, bool) {
+	if line == "" {
+		return "", false
+	}
+
+	if line[0] == '-' || line[0] == '*' {
+		content := line[1:]
+		hadWhitespace := len(content) > 0 && isForecastDiscussionHorizontalWhitespace(content[0])
+		content = strings.TrimLeft(content, " \t")
+		if hadWhitespace {
+			if stripped, ok := stripForecastDiscussionKeyMessageNumericMarker(content); ok {
+				content = stripped
+			}
+		}
+		return content, true
+	}
+
+	return stripForecastDiscussionKeyMessageNumericMarker(line)
+}
+
+func stripForecastDiscussionKeyMessageNumericMarker(line string) (string, bool) {
+	digitEnd := 0
+	for digitEnd < len(line) && line[digitEnd] >= '0' && line[digitEnd] <= '9' {
+		digitEnd++
+	}
+	if digitEnd == 0 || digitEnd == len(line) || (line[digitEnd] != ')' && line[digitEnd] != '.') {
+		return "", false
+	}
+
+	markerEnd := digitEnd + 1
+	if markerEnd < len(line) && !isForecastDiscussionHorizontalWhitespace(line[markerEnd]) {
+		return "", false
+	}
+	value, err := strconv.ParseUint(line[:digitEnd], 10, 0)
+	if err != nil || value == 0 {
+		return "", false
+	}
+	return strings.TrimLeft(line[markerEnd:], " \t"), true
 }
 
 func hasForecastDiscussionASCIIPrefix(line, prefix string) bool {
-	return len(line) >= len(prefix) && strings.EqualFold(line[:len(prefix)], prefix)
+	if len(line) < len(prefix) {
+		return false
+	}
+	for i := range prefix {
+		actual := line[i]
+		if actual >= 'A' && actual <= 'Z' {
+			actual += 'a' - 'A'
+		}
+		expected := prefix[i]
+		if expected >= 'A' && expected <= 'Z' {
+			expected += 'a' - 'A'
+		}
+		if actual != expected {
+			return false
+		}
+	}
+	return true
 }
 
 func trimBlankLines(lines []string) []string {