Show functional Updates page when checks are disabled

Ref T572

admin.go

@@ -583,6 +583,7 @@ func handleViewAdminUpdates(app *App, u *User, w http.ResponseWriter, r *http.Re
 
 	p := struct {
 		*UserPage
+		CurReleaseNotesURL    string
 		LastChecked           string
 		LastChecked8601       string
 		LatestVersion         string
@@ -592,6 +593,7 @@ func handleViewAdminUpdates(app *App, u *User, w http.ResponseWriter, r *http.Re
 	}{
 		UserPage: NewUserPage(app, r, u, "Updates", nil),
 	}
+	p.CurReleaseNotesURL = wfReleaseNotesURL(p.Version)
 	if app.cfg.App.UpdateChecks {
 		p.LastChecked = app.updates.lastCheck.Format("January 2, 2006, 3:04 PM")
 		p.LastChecked8601 = app.updates.lastCheck.Format("2006-01-02T15:04:05Z")

templates/user/admin/app-updates.tmpl

@@ -5,11 +5,16 @@
 	p.intro {
 		text-align: left;
 	}
+	p.disabled {
+		font-style: italic;
+		color: #999;
+	}
 </style>
 
 <div class="content-container snug">
 	{{template "admin-header" .}}
 
+{{ if .UpdateChecks }}
 	{{if not .UpdateAvailable}}
 		<p class="intro"><span class="check">&check;</span> WriteFreely is <strong>up to date</strong>.</p>
 		<p>Installed version: <strong>{{.Version}}</strong> (<a href="{{.LatestReleaseNotesURL}}" target="changelog-wf">release notes</a>).</p>
@@ -27,6 +32,11 @@
 	var d = new Date(displayEl.getAttribute("datetime"));
 	displayEl.textContent = d.toLocaleDateString(navigator.language || "en-US", { dateStyle: 'long', timeStyle: 'short' });
 	</script>
+{{ else }}
+	<p class="intro disabled">Automated update checks are disabled.</p>
+	<p>Installed version: <strong>{{.Version}}</strong> (<a href="{{.CurReleaseNotesURL}}" target="changelog-wf">release notes</a>).</p>
+	<p>Learn about latest releases on the <a href="https://blog.writefreely.org/tag:release" target="changelog-wf">WriteFreely blog</a> or <a href="https://discuss.write.as/c/writefreely/updates" target="forum-wf">forum</a>.</p>
+{{ end }}
 
 {{template "footer" .}}
 

updates.go

@@ -70,7 +70,11 @@ func (uc updatesCache) ReleaseURL() string {
 // ReleaseNotesURL returns the full URL to the blog.writefreely.org release notes
 // for the latest version as stored in the cache.
 func (uc updatesCache) ReleaseNotesURL() string {
-	ver := strings.TrimPrefix(uc.latestVersion, "v")
+	return wfReleaseNotesURL(uc.latestVersion)
+}
+
+func wfReleaseNotesURL(v string) string {
+	ver := strings.TrimPrefix(v, "v")
 	ver = strings.TrimSuffix(ver, ".0")
 	// hack until go 1.12 in build/travis
 	seg := strings.Split(ver, ".")