chore: initialize go-sip repository

2026-09-21 08:56:04 +08:00
commit 643b11b21f
309 changed files with 40521 additions and 0 deletions
@@ -0,0 +1,33 @@
+// Package callwindow enforces the fixed legal window for SIP outbound dialing.
+package callwindow
+
+import (
+	"fmt"
+	"time"
+)
+
+const (
+	LocationName = "Asia/Shanghai"
+	OpenHour     = 9
+	CloseHour    = 20
+)
+
+var shanghai = time.FixedZone(LocationName, 8*60*60)
+
+// Allowed reports whether SIP outbound dialing is permitted at now. The
+// boundary is [09:00, 20:00) in Asia/Shanghai; the input's instant, not its
+// presentation timezone, is authoritative.
+func Allowed(now time.Time) bool {
+	local := now.In(shanghai)
+	minutes := local.Hour()*60 + local.Minute()
+	return minutes >= OpenHour*60 && minutes < CloseHour*60
+}
+
+// Check returns a stable, actionable error when outbound dialing is closed.
+func Check(now time.Time) error {
+	local := now.In(shanghai)
+	if Allowed(now) {
+		return nil
+	}
+	return fmt.Errorf("SIP outbound dialing is closed at %s; allowed window is %02d:00-%02d:00 %s", local.Format("2006-01-02 15:04:05 -0700"), OpenHour, CloseHour, LocationName)
+}