phraser: one count helper, so the weather says "1 градус" (V-521)

The weather line spelled "градусов" out in the template, which is the wrong
form for 1-4 and for every number ending in 1-4. Russian inflects the noun
after a numeral, so the count splits into the number and {word}.

hostWord in cmd/mavend/netscan.go already knew the rule for устройство and was
the only place that did. It moves to internal/phraser as CountWord, with
Degrees and Devices over it, and the three call sites that counted devices now
read the same helper the weather line does. Degrees rounds before it counts, so
the noun agrees with the number she is about to say rather than the reading
behind it, and a negative reading counts by its magnitude.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XGTGCWX33aX8SMBSRz9VmS

cmd/mavend/netscan.go

@@ -119,7 +119,7 @@ func (w *netWiring) scanSummary(ctx context.Context) (string, bool) {
 	if len(res.Hosts) == 0 {
 		return phraser.Q(phraser.QueryNetEmpty, map[string]string{"tail": tail}), true
 	}
-	out := fmt.Sprintf("нашла %d %s", len(res.Hosts), hostWord(len(res.Hosts)))
+	out := fmt.Sprintf("нашла %d %s", len(res.Hosts), phraser.Devices(len(res.Hosts)))
 	if shape := scanShape(res.Hosts); shape != "" {
 		out += ", " + shape
 	}
@@ -180,7 +180,7 @@ func (w *netWiring) writeScanRecord(ctx context.Context, res netscan.Result) {
 	if w.api == nil {
 		return
 	}
-	head := fmt.Sprintf("сканирование сети: %d %s", len(res.Hosts), hostWord(len(res.Hosts)))
+	head := fmt.Sprintf("сканирование сети: %d %s", len(res.Hosts), phraser.Devices(len(res.Hosts)))
 	if res.Truncated {
 		head += " (не вся сеть)"
 	}
@@ -211,22 +211,6 @@ func (w *netWiring) writeScanRecord(ctx context.Context, res netscan.Result) {
 	}
 }
 
-// hostWord — Russian counts inflect the noun: 1 устройство, 2-4 устройства,
-// 5+ устройств, and the teens are all the last form.
-func hostWord(n int) string {
-	if n%100 >= 11 && n%100 <= 14 {
-		return "устройств"
-	}
-	switch n % 10 {
-	case 1:
-		return "устройство"
-	case 2, 3, 4:
-		return "устройства"
-	default:
-		return "устройств"
-	}
-}
-
 // isNetworkQuery recognises a question about the LAN, narrowly. It needs a
 // network word AND an ask: "интернет не работает" is a complaint, not a request
 // to scan, and a scan she runs unasked is exactly the noisy behaviour the

cmd/mavend/netscan_test.go

@@ -74,18 +74,6 @@ func TestScanSummaryOnAnEmptyRange(t *testing.T) {
 	}
 }
 
-func TestHostWordAgreesWithTheCount(t *testing.T) {
-	for n, want := range map[int]string{
-		1: "устройство", 2: "устройства", 4: "устройства", 5: "устройств",
-		11: "устройств", 12: "устройств", 21: "устройство", 22: "устройства",
-		25: "устройств", 111: "устройств", 101: "устройство", 0: "устройств",
-	} {
-		if got := hostWord(n); got != want {
-			t.Errorf("hostWord(%d) = %q, want %q", n, got, want)
-		}
-	}
-}
-
 func TestIsNetworkQuery(t *testing.T) {
 	yes := []string{
 		"какие устройства в сети?",

cmd/mavend/smarthome.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/kami/maven/internal/config"
+	"github.com/kami/maven/internal/phraser"
 	"github.com/kami/maven/internal/smarthome"
 	"github.com/kami/maven/internal/store"
 )
@@ -185,7 +186,7 @@ func (w *homeWiring) homeSummary(ctx context.Context) (string, bool) {
 	case dark > 0 && len(sensors) == 0:
 		// Nothing is on and everything she can see is unreachable. "всё
 		// выключено" would be a claim about the house she cannot make.
-		return fmt.Sprintf("дом молчит: %d %s не отвечают.", dark, hostWord(dark)), true
+		return fmt.Sprintf("дом молчит: %d %s не отвечают.", dark, phraser.Devices(dark)), true
 	default:
 		parts = append(parts, "всё выключено")
 	}
@@ -193,7 +194,7 @@ func (w *homeWiring) homeSummary(ctx context.Context) (string, bool) {
 		parts = append(parts, strings.Join(sensors, ", "))
 	}
 	if dark > 0 {
-		parts = append(parts, fmt.Sprintf("%d %s не отвечают", dark, hostWord(dark)))
+		parts = append(parts, fmt.Sprintf("%d %s не отвечают", dark, phraser.Devices(dark)))
 	}
 	return strings.Join(parts, "; ") + ".", true
 }

internal/phraser/plural.go

@@ -0,0 +1,47 @@
+package phraser
+
+// The counted noun, in the form the number in front of it demands.
+//
+// Russian inflects a noun after a numeral, and the form depends on the last two
+// digits: 1 градус, 2 градуса, 5 градусов, 11 градусов, 21 градус, 22 градуса.
+// A line file cannot spell that out, so a count in a template splits into two
+// placeholders — the number, and {word} filled from here.
+//
+// The rule lived once as hostWord in cmd/mavend/netscan.go, which meant the
+// weather line said "градусов" for every temperature and was wrong for 1-4 and
+// for every number ending in 1-4. One helper, every count site (Vikunja #521).
+
+import "math"
+
+// CountWord picks between the three forms n needs: one for 1, few for 2-4, many
+// for 0, 5-20 and anything ending in those. A negative count reads its own
+// magnitude, since minus does not change the noun: -2 градуса.
+func CountWord(n int, one, few, many string) string {
+	if n < 0 {
+		n = -n
+	}
+	if n%100 >= 11 && n%100 <= 14 {
+		return many
+	}
+	switch n % 10 {
+	case 1:
+		return one
+	case 2, 3, 4:
+		return few
+	default:
+		return many
+	}
+}
+
+// Degrees — the noun for a temperature. Takes the reading as it arrives from a
+// weather provider and counts by the whole degrees she is about to say, so the
+// noun agrees with the number in the same sentence rather than with the reading
+// behind it.
+func Degrees(temp float64) string {
+	return CountWord(int(math.Round(temp)), "градус", "градуса", "градусов")
+}
+
+// Devices — the noun for a count of hosts on the LAN or of smart-home devices.
+func Devices(n int) string {
+	return CountWord(n, "устройство", "устройства", "устройств")
+}

internal/phraser/plural_test.go

@@ -0,0 +1,32 @@
+package phraser
+
+import "testing"
+
+// The bug the helper exists for: the weather line said "градусов" for every
+// reading, which is wrong for 1-4 and for every number ending in 1-4.
+func TestDegreesAgreeWithTheReading(t *testing.T) {
+	for temp, want := range map[float64]string{
+		1: "градус", 1.4: "градус", 2: "градуса", 4: "градуса", 5: "градусов",
+		0: "градусов", 11: "градусов", 14: "градусов", 21: "градус",
+		22: "градуса", 25: "градусов", 101: "градус",
+		// Minus does not change the noun, and a reading rounds to the number
+		// she is about to say: -2.4° is "-2 градуса", not "-2 градусов".
+		-1: "градус", -2.4: "градуса", -5: "градусов", -11: "градусов",
+	} {
+		if got := Degrees(temp); got != want {
+			t.Errorf("Degrees(%v) = %q, want %q", temp, got, want)
+		}
+	}
+}
+
+func TestDevicesAgreeWithTheCount(t *testing.T) {
+	for n, want := range map[int]string{
+		1: "устройство", 2: "устройства", 4: "устройства", 5: "устройств",
+		11: "устройств", 12: "устройств", 21: "устройство", 22: "устройства",
+		25: "устройств", 111: "устройств", 101: "устройство", 0: "устройств",
+	} {
+		if got := Devices(n); got != want {
+			t.Errorf("Devices(%d) = %q, want %q", n, got, want)
+		}
+	}
+}