package watcher_test

import (
	"maps"
	"strings"
	"testing"

	"sneak.berlin/go/dnswatcher/internal/config"
	"sneak.berlin/go/dnswatcher/internal/state"
	"sneak.berlin/go/dnswatcher/internal/watcher"
)

// When one nameserver's A record changes and its TXT record does not,
// the record change and the inconsistency it starts name the A record
// alone, with its values written as plain text.
func TestChangeMessagesNameTheChangedType(t *testing.T) {
	t.Parallel()

	// A nameserver's records: this A address and the same TXT record.
	records := func(address string) map[string][]string {
		return map[string][]string{
			"A":   {address},
			"TXT": {"v=spf1 -all"},
		}
	}

	before := hostnameState(map[string]map[string][]string{
		nsA: records(ip1),
		nsB: records(ip1),
	})
	after := hostnameState(map[string]map[string][]string{
		nsA: records(ip1),
		nsB: records(ip2),
	})

	// The hostname change detection uses only the notifier.
	notifier := &mockNotifier{}
	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)

	w.DetectHostnameChanges(t.Context(), host, before, after)

	want := map[string]string{
		"Record Change: " + host: `Hostname: www.example.net
Nameserver: b.ns.example.net.
Type: A
Old: 192.0.2.1
New: 192.0.2.2`,
		"Inconsistency: " + host: `Hostname: www.example.net
Type: A
a.ns.example.net.: 192.0.2.1
b.ns.example.net.: 192.0.2.2`,
	}

	notifications := notifier.getNotifications()
	if len(notifications) != len(want) {
		t.Fatalf(
			"sent %d notifications, want %d: %v",
			len(notifications), len(want), notifications,
		)
	}

	for _, n := range notifications {
		if n.Message != want[n.Title] {
			t.Errorf(
				"%s message:\n%s\nwant:\n%s",
				n.Title, n.Message, want[n.Title],
			)
		}
	}
}

// Every kind of notification about a configured apex domain's own
// records names it as a domain.
func TestDomainRecordNotificationsNameTheDomain(t *testing.T) {
	t.Parallel()

	notifier := &mockNotifier{}
	w := watcher.NewForTest(
		&config.Config{Domains: []string{domain}},
		nil, nil, nil, nil, notifier,
	)

	// nsA's address changes, which also makes it differ from nsC; nsB
	// fails; nsC answers again; nsD is gone.
	nsD := "d.ns.example.net."
	w.DetectHostnameChanges(t.Context(), domain,
		saved(map[string]*state.NameserverRecordState{
			nsA: answered(map[string][]string{"A": {ip1}}),
			nsB: answered(map[string][]string{"A": {ip1}}),
			nsC: failed(),
			nsD: answered(map[string][]string{"A": {ip1}}),
		}),
		saved(map[string]*state.NameserverRecordState{
			nsA: answered(map[string][]string{"A": {ip2}}),
			nsB: failed(),
			nsC: answered(map[string][]string{"A": {ip1}}),
		}),
	)

	// The address at the end of its CNAME chain changes.
	w.DetectHostnameChanges(
		t.Context(), domain, cnameState(ip1), cnameState(ip2),
	)

	// NS Failure is sent for nsB failing and for nsD being gone.
	want := map[string]int{
		"Record Change":        1,
		"Inconsistency":        1,
		"NS Failure":           2,
		"NS Recovery":          1,
		"CNAME Address Change": 1,
	}

	sent := make(map[string]int)

	for _, n := range notifier.getNotifications() {
		kind, _, _ := strings.Cut(n.Title, ":")
		sent[kind]++

		if !strings.HasPrefix(n.Message, "Domain: "+domain+"\n") {
			t.Errorf("%s message does not name the domain:\n%s",
				n.Title, n.Message)
		}
	}

	if !maps.Equal(sent, want) {
		t.Errorf("sent %v, want %v", sent, want)
	}
}

// The startup notification counts the configured domains and hostnames,
// although the state's hostnames also hold the apex domain's own
// records. Nothing is looked up: the watcher has no resolver.
func TestStartupNotificationCountsConfiguredNames(t *testing.T) {
	t.Parallel()

	cfg := defaultTestConfig(t)
	cfg.SendTestNotification = true
	cfg.Domains = []string{domain}
	cfg.Hostnames = []string{host}

	deps := newTestDeps(t, cfg)
	w := watcher.NewForTest(cfg, deps.state, nil, nil, nil, deps.notifier)

	// The state a check of both names saves.
	deps.state.SetDomainState(domain, &state.DomainState{
		Nameservers: []string{nsA},
	})

	for _, name := range []string{domain, host} {
		deps.state.SetHostnameState(name, saved(
			map[string]*state.NameserverRecordState{
				nsA: answered(map[string][]string{"A": {ip1}}),
			},
		))
	}

	w.MaybeSendTestNotification(t.Context())

	notifications := deps.notifier.getNotifications()

	counts := "\nMonitoring 1 domain(s) and 1 hostname(s).\n"
	if len(notifications) != 1 ||
		!strings.Contains(notifications[0].Message, counts) {
		t.Errorf("sent %v, want one message with %q", notifications, counts)
	}
}