package handlers_test

import (
	"regexp"
	"strings"
	"testing"
	"time"

	"sneak.berlin/go/dnswatcher/internal/handlers"
)

func TestRelTime(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name string
		dur  time.Duration
		want string
	}{
		{"zero", 0, "never"},
		{"seconds", 30 * time.Second, "30s ago"},
		{"minutes", 5 * time.Minute, "5m ago"},
		{"hours", 2*time.Hour + 15*time.Minute, "2h 15m ago"},
		{"days", 48*time.Hour + 3*time.Hour, "2d 3h ago"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			var input time.Time
			if tt.dur > 0 {
				input = time.Now().Add(-tt.dur)
			}

			got := handlers.RelTime(input)
			if got != tt.want {
				t.Errorf(
					"RelTime(%v) = %q, want %q",
					tt.dur, got, tt.want,
				)
			}
		})
	}
}

func TestExpiryDays(t *testing.T) {
	t.Parallel()

	// 10 days from now.
	future := time.Now().Add(10 * 24 * time.Hour)

	days := handlers.ExpiryDays(future)
	if days < 9 || days > 10 {
		t.Errorf("expected ~10 days, got %d", days)
	}

	// Already expired.
	past := time.Now().Add(-24 * time.Hour)

	days = handlers.ExpiryDays(past)
	if days != 0 {
		t.Errorf("expected 0 for expired, got %d", days)
	}
}

func TestFormatRecords(t *testing.T) {
	t.Parallel()

	got := handlers.FormatRecords(nil)
	if got != "-" {
		t.Errorf("expected -, got %q", got)
	}

	got = handlers.FormatRecords(map[string][]string{
		"A": {"1.2.3.4"},
	})

	if got != "A: 1.2.3.4" {
		t.Errorf("unexpected format: %q", got)
	}
}

// TestFormatRecordsTypeOrder checks that record types are listed in
// the README's order (A, AAAA, CNAME, MX, TXT, SRV, CAA, NS), with
// any other type after them in alphabetical order.
func TestFormatRecordsTypeOrder(t *testing.T) {
	t.Parallel()

	got := handlers.FormatRecords(map[string][]string{
		"SOA":   {"ns1.example.com. hostmaster.example.com. 1 2 3 4 5"},
		"NS":    {"ns1.example.com.", "ns2.example.com."},
		"CAA":   {`0 issue "letsencrypt.org"`},
		"DNAME": {"example.net."},
		"TXT":   {"v=spf1 -all"},
		"SRV":   {"10 5 443 www.example.com."},
		"MX":    {"10 mail.example.com."},
		"CNAME": {"www.example.com."},
		"AAAA":  {"2001:db8::1"},
		"A":     {"192.0.2.1"},
	})

	want := strings.Join([]string{
		"A: 192.0.2.1",
		"AAAA: 2001:db8::1",
		"CNAME: www.example.com.",
		"MX: 10 mail.example.com.",
		"TXT: v=spf1 -all",
		"SRV: 10 5 443 www.example.com.",
		`CAA: 0 issue "letsencrypt.org"`,
		"NS: ns1.example.com.",
		"NS: ns2.example.com.",
		"DNAME: example.net.",
		"SOA: ns1.example.com. hostmaster.example.com. 1 2 3 4 5",
	}, ", ")

	if got != want {
		t.Errorf("FormatRecords lists types out of order:\n got %q\nwant %q",
			got, want)
	}
}

// dashboardRow returns the table row of page that contains name.
func dashboardRow(t *testing.T, page string, name string) string {
	t.Helper()

	for row := range strings.SplitSeq(page, "<tr") {
		if strings.Contains(row, name) {
			return row
		}
	}

	t.Fatalf("dashboard has no row containing %q", name)

	return ""
}

// TestDashboardShowsFailureReasons checks that the dashboard shows the
// reason in the row of a failed nameserver and of a failed certificate,
// and not in the row of a nameserver that answered.
func TestDashboardShowsFailureReasons(t *testing.T) {
	t.Parallel()

	page := get(t, newHandlersWithFailures(t).HandleDashboard())

	if !strings.Contains(dashboardRow(t, page, failedNS), nsFailureReason) {
		t.Errorf("row of %s does not show %q", failedNS, nsFailureReason)
	}

	if strings.Contains(dashboardRow(t, page, answeringNS), nsFailureReason) {
		t.Errorf("row of %s shows %q", answeringNS, nsFailureReason)
	}

	if !strings.Contains(dashboardRow(t, page, certKey), certFailedReason) {
		t.Errorf("row of %s does not show %q", certKey, certFailedReason)
	}
}

// dashboardSection returns the section of page under heading.
func dashboardSection(t *testing.T, page string, heading string) string {
	t.Helper()

	for section := range strings.SplitSeq(page, "<section") {
		words := strings.Join(strings.Fields(section), " ")
		if strings.Contains(words, "> "+heading+" </h2>") {
			return section
		}
	}

	t.Fatalf("dashboard has no section headed %q", heading)

	return ""
}

// TestDashboardShowsDomainRecordsUnderDomains checks that the dashboard
// shows an apex domain's own records in the Domains section, and
// neither lists nor counts the domain as a hostname.
func TestDashboardShowsDomainRecordsUnderDomains(t *testing.T) {
	t.Parallel()

	page := get(t, newHandlersWithFailures(t).HandleDashboard())

	domains := dashboardSection(t, page, "Domains")
	if !strings.Contains(dashboardRow(t, domains, domainAddress), testDomain) {
		t.Errorf("row of %s does not name %s", domainAddress, testDomain)
	}

	if strings.Contains(dashboardSection(t, page, "Hostnames"), testDomain) {
		t.Errorf("Hostnames section lists the domain %s", testDomain)
	}

	words := strings.Join(strings.Fields(page), " ")

	footer := "monitoring 2 domains + 1 hostnames"
	if !strings.Contains(words, footer) {
		t.Errorf("dashboard does not say %q", footer)
	}

	// With the tags taken out, the summary bar starts "Domains 2
	// Hostnames 1".
	text := regexp.MustCompile(`<[^>]*>`).ReplaceAllString(page, " ")
	summary := "Domains 2 Hostnames 1"

	if !strings.Contains(strings.Join(strings.Fields(text), " "), summary) {
		t.Errorf("summary bar does not say %q", summary)
	}
}

// TestDashboardMarksDomainThatDoesNotExist checks that the Domains
// section says a domain that does not exist does not exist, and does
// not say so of a domain that exists.
func TestDashboardMarksDomainThatDoesNotExist(t *testing.T) {
	t.Parallel()

	page := get(t, newHandlersWithFailures(t).HandleDashboard())
	domains := dashboardSection(t, page, "Domains")

	if !strings.Contains(dashboardRow(t, domains, missingDomain), "does not exist") {
		t.Errorf("row of %s does not say it does not exist", missingDomain)
	}

	if strings.Contains(dashboardRow(t, domains, testDomain), "does not exist") {
		t.Errorf("row of %s says it does not exist", testDomain)
	}
}

// rowCells returns the text of each cell of a dashboard table row
// whose cells start with tag, "<th" or "<td".
func rowCells(row string, tag string) []string {
	tags := regexp.MustCompile(`<[^>]*>`)
	parts := strings.Split(row, tag)[1:]
	cells := make([]string, 0, len(parts))

	for _, cell := range parts {
		text := tags.ReplaceAllString(tag+cell, " ")
		cells = append(cells, strings.Join(strings.Fields(text), " "))
	}

	return cells
}

// TestDashboardPortsTellDomainsFromHostnames checks that the Ports
// table lists an apex domain under Domains and a hostname under
// Hostnames when both resolve to the port's address.
func TestDashboardPortsTellDomainsFromHostnames(t *testing.T) {
	t.Parallel()

	page := get(t, newHandlersWithFailures(t).HandleDashboard())
	ports := dashboardSection(t, page, "Ports")

	headings := rowCells(dashboardRow(t, ports, "Address</th>"), "<th")
	cells := rowCells(dashboardRow(t, ports, sharedPort), "<td")

	if len(cells) != len(headings) {
		t.Fatalf("row of %s has cells %q under headings %q",
			sharedPort, cells, headings)
	}

	under := make(map[string]string)
	for i, heading := range headings {
		under[heading] = cells[i]
	}

	if under["Domains"] != testDomain {
		t.Errorf("row of %s lists %q under Domains, want %q",
			sharedPort, under["Domains"], testDomain)
	}

	if under["Hostnames"] != testHostname {
		t.Errorf("row of %s lists %q under Hostnames, want %q",
			sharedPort, under["Hostnames"], testHostname)
	}
}