// SPDX-FileCopyrightText: 2026 Echolot contributors
// SPDX-License-Identifier: GPL-3.0-or-later

package config

import "testing"

// The fixture is fmr's real UDP listen spec, because the point of deriving these from the bound
// listeners is that they cannot disagree with what the server actually answers on.
const fmrUDP = "89.185.109.150:8442,89.185.109.151:8442," +
	"[2001:1ad0:c4fe:6767::150]:8442,[2001:1ad0:c4fe:6767::151]:8442"

func TestMeasurementAddrsSplitsPrimaryFromReserved(t *testing.T) {
	c := &Config{
		UDPListen:     fmrUDP,
		ReservedAddrs: "89.185.109.151,2001:1ad0:c4fe:6767::151",
	}
	ip4, ip6, ip4Alt, ip6Alt := c.MeasurementAddrs()
	for _, tc := range []struct{ got, want, name string }{
		{ip4, "89.185.109.150", "ip4"},
		{ip6, "2001:1ad0:c4fe:6767::150", "ip6"},
		{ip4Alt, "89.185.109.151", "ip4_alt"},
		{ip6Alt, "2001:1ad0:c4fe:6767::151", "ip6_alt"},
	} {
		if tc.got != tc.want {
			t.Errorf("%s = %q, want %q", tc.name, tc.got, tc.want)
		}
	}
}

func TestMeasurementAddrsWithNothingReserved(t *testing.T) {
	// No reservation means no alternate: reporting a second address as the RFC 5780 alternate
	// when it was never set aside for that would tell a client to expect a redirect that the
	// server has no intention of sending.
	c := &Config{UDPListen: fmrUDP}
	ip4, ip6, ip4Alt, ip6Alt := c.MeasurementAddrs()
	if ip4 == "" || ip6 == "" {
		t.Fatalf("primaries should still be found: ip4=%q ip6=%q", ip4, ip6)
	}
	if ip4Alt != "" || ip6Alt != "" {
		t.Errorf("no address is reserved, so there is no alternate; got %q / %q", ip4Alt, ip6Alt)
	}
}

func TestMeasurementAddrsIgnoresWhatItCannotRead(t *testing.T) {
	// A wildcard bind names no address, and a hostname is not resolved here. Either would be a
	// guess presented to clients as fact.
	c := &Config{UDPListen: ":8442,probe.example.net:8442,89.185.109.150:8442"}
	ip4, ip6, _, _ := c.MeasurementAddrs()
	if ip4 != "89.185.109.150" {
		t.Errorf("ip4 = %q, want the one address that was actually spelled out", ip4)
	}
	if ip6 != "" {
		t.Errorf("ip6 = %q, want empty — none was configured", ip6)
	}
}