Global code ovehaul - remove CAS and other, add 15 minute greet check

- Remove CAS, as it no longer works for us
- Remove other checks
- Implement 15 minute greet timeout check
- Fix chat logos
- Ditch thirdparty logger, use stdlib log facility wrapper for logging

internal/elog/status.go

@@ -0,0 +1,63 @@
+package elog
+
+import (
+	"strings"
+
+	"github.com/NicoNex/echotron/v3"
+)
+
+// LogUserStatus records a change to a chat member's status — join, leave, ban,
+// promote, demote, restrict — as carried by Update.ChatMember.
+func LogUserStatus(ev *echotron.ChatMemberUpdated) {
+	if _, on := chatLogRoot(); !on || ev == nil {
+		return
+	}
+
+	who := ev.NewChatMember.User
+	if who == nil {
+		who = ev.OldChatMember.User
+	}
+
+	var b strings.Builder
+
+	// The subject is already rendered by renderLine's "user <id> (<desc>)"
+	// prefix, so the body starts at the transition itself.
+	b.WriteString("status ")
+	b.WriteString(orUnknown(ev.OldChatMember.Status))
+	b.WriteString(" -> ")
+	b.WriteString(orUnknown(ev.NewChatMember.Status))
+
+	if ev.NewChatMember.CustomTitle != "" {
+		b.WriteString(" custom_title=")
+		b.WriteString(ev.NewChatMember.CustomTitle)
+	}
+
+	b.WriteString(" by ")
+	b.WriteString(describeUserRef(&ev.From))
+
+	appendLine(ev.Chat.ID, renderLine(ev.Chat, who, b.String()))
+}
+
+// describeUserRef renders a value-type User reference.
+func describeUserRef(u *echotron.User) string {
+	if u == nil {
+		return "user unknown"
+	}
+
+	if desc := describeUser(u); desc != "" {
+		return "user " + itoa(u.ID) + " (" + desc + ")"
+	}
+
+	return "user " + itoa(u.ID)
+}
+
+// orUnknown renders a status, or a placeholder when Telegram sent none.
+func orUnknown(status string) string {
+	if status == "" {
+		return "unknown"
+	}
+
+	return status
+}
+
+/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */