feat: Move mail system to shared

shared/mail/licence.go

@@ -0,0 +1,81 @@
+package mail
+
+import (
+	"fmt"
+	"time"
+)
+
+// SendLicense delivers the blob inline. It is signed public data, not a secret —
+// it is useless on any instance other than the one it names.
+func (s Sender) SendLicense(to, instanceName, blob string) error {
+	return s.sendTemplate(to, "", "license", struct {
+		InstanceName string
+		Blob         string
+	}{instanceName, blob})
+}
+
+// SendInstanceReady tells a customer their cloud instance exists, where it is,
+// and when its licence runs out.
+//
+// The expiry is stated here rather than only in a later reminder: a Free licence
+// that quietly expires in a month is a surprise, and the first email is the one
+// people keep.
+func (s Sender) SendInstanceReady(to, instanceName, loginURL string, expires time.Time) error {
+	return s.sendTemplate(to, "", "instanceready", struct {
+		InstanceName string
+		LoginURL     string
+		Expires      time.Time
+	}{instanceName, loginURL, expires})
+}
+
+// SendRenewed confirms a renewal and states the new date.
+func (s Sender) SendRenewed(to, instanceName string, expires time.Time) error {
+	return s.sendTemplate(to, "", "renewed", struct {
+		InstanceName string
+		Expires      time.Time
+	}{instanceName, expires})
+}
+
+// SendExpiring is the renew-now nudge, seven days out.
+func (s Sender) SendExpiring(to, instanceName, portalURL string, expires time.Time) error {
+	return s.sendTemplate(to, "", "expiring", struct {
+		InstanceName string
+		PortalURL    string
+		Expires      time.Time
+	}{instanceName, portalURL, expires})
+}
+
+// SendExpired states plainly what has stopped and what happens next.
+//
+// It names the deletion date rather than a vague warning: the whole point of the
+// sequence is that nobody loses an instance without having been told a date. A
+// zero deleteOn means the reaper is disabled, and then no date is claimed.
+func (s Sender) SendExpired(to, instanceName, portalURL string, deleteOn time.Time) error {
+	return s.sendTemplate(to, "", "expired", struct {
+		InstanceName string
+		PortalURL    string
+		DeleteOn     time.Time
+	}{instanceName, portalURL, deleteOn})
+}
+
+// SendDeletionWarning is the final countdown, sent at seven days and one day.
+func (s Sender) SendDeletionWarning(to, instanceName, portalURL string, deleteOn time.Time, daysLeft int) error {
+	when := fmt.Sprintf("in %d days", daysLeft)
+	if daysLeft <= 1 {
+		when = "tomorrow"
+	}
+	return s.sendTemplate(to, "", "deletionwarning", struct {
+		InstanceName string
+		PortalURL    string
+		When         string
+		DeleteOn     time.Time
+	}{instanceName, portalURL, when, deleteOn})
+}
+
+// SendLinkReminder chases a self-hosted customer who paid but never linked.
+func (s Sender) SendLinkReminder(to, instanceName string) error {
+	return s.sendTemplate(to, "", "linkreminder", struct {
+		InstanceName string
+		PortalURL    string
+	}{instanceName, s.PublicURL})
+}