package server

import (
	"fmt"
	"net/http"
	"net/http/httptest"
	"net/netip"
	"strings"
	"testing"

	"git.eeqj.de/sneak/routewatch/internal/config"
	"git.eeqj.de/sneak/routewatch/internal/database"
	"git.eeqj.de/sneak/routewatch/internal/logger"
	"git.eeqj.de/sneak/routewatch/internal/metrics"
	"git.eeqj.de/sneak/routewatch/internal/ristypes"
	"git.eeqj.de/sneak/routewatch/internal/routetable"
	"git.eeqj.de/sneak/routewatch/internal/streamer"
)

// testUncarriedASN is an origin AS the prefix page test's routing table does
// not carry for the prefix, so the AS link the page shows comes from the
// origin changes table.
const testUncarriedASN = 64501

// newPrefixDetailServer returns a server whose routing table holds testPrefixV4
// with origin AS 64500, and whose database holds the given origin changes.
func newPrefixDetailServer(
	t *testing.T, changes []routetable.OriginChange,
) *Server {
	t.Helper()

	db, err := database.New(&config.Config{StateDir: t.TempDir()}, logger.New())
	if err != nil {
		t.Fatalf("database.New: %v", err)
	}

	t.Cleanup(func() { _ = db.Close() })

	table := emptyTable()
	announce(table, testPrefixV4, 64500, testPeer(1), testRouteTime(0))

	err = db.WriteOriginChanges(changes)
	if err != nil {
		t.Fatalf("WriteOriginChanges: %v", err)
	}

	return New(db, table, streamer.New(logger.New(), metrics.New()),
		logger.New(), &config.Config{})
}

// TestPrefixDetailShowsOriginChanges checks that the prefix page shows the
// origin changes newest first, with the announced and withdrawn rows and the
// AS link. The rows use an AS the routing table does not carry for the
// prefix, so the link comes from the origin changes table.
func TestPrefixDetailShowsOriginChanges(t *testing.T) {
	t.Parallel()

	prefix := netip.MustParsePrefix(testPrefixV4)

	s := newPrefixDetailServer(t, []routetable.OriginChange{
		{Prefix: prefix, OriginASN: testUncarriedASN, Announced: true,
			PeerCount: 1, Time: testRouteTime(1)},
		{Prefix: prefix, OriginASN: testUncarriedASN, Announced: false,
			PeerCount: 0, Time: testRouteTime(2)},
	})

	rec := httptest.NewRecorder()
	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
		t.Context(), http.MethodGet, "/prefix/"+testPrefixV4, nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
	}

	page := rec.Body.String()

	withdrawn := strings.Index(page, "Withdrawn")
	announced := strings.Index(page, "Announced")

	if withdrawn < 0 || announced < 0 {
		t.Fatalf("page does not show the announced and withdrawn rows")
	}

	// The withdrawn row is newer, so it comes first.
	if withdrawn > announced {
		t.Errorf("the withdrawn row is not shown before the announced row")
	}

	if !strings.Contains(page, `href="/as/64501"`) {
		t.Errorf("page does not link to AS64501")
	}
}

// TestPrefixDetailShowsOriginZeroAsNoKnownOrigin checks that the origin
// changes table shows AS 0 as no known origin, without a link to AS0.
func TestPrefixDetailShowsOriginZeroAsNoKnownOrigin(t *testing.T) {
	t.Parallel()

	prefix := netip.MustParsePrefix(testPrefixV4)

	s := newPrefixDetailServer(t, []routetable.OriginChange{
		{Prefix: prefix, OriginASN: ristypes.NoOrigin, Announced: true,
			PeerCount: 1, Time: testRouteTime(1)},
	})

	rec := httptest.NewRecorder()
	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
		t.Context(), http.MethodGet, "/prefix/"+testPrefixV4, nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
	}

	page := rec.Body.String()

	if !strings.Contains(page, "No known origin") {
		t.Errorf("page does not say the origin change has no known origin")
	}

	if strings.Contains(page, `href="/as/0"`) {
		t.Errorf("page links to AS0")
	}
}

// TestPrefixDetailSaysWhenThereAreMoreChangesThanItShows checks that the
// prefix page says so when a prefix has more origin changes than the page's
// limit.
func TestPrefixDetailSaysWhenThereAreMoreChangesThanItShows(t *testing.T) {
	t.Parallel()

	prefix := netip.MustParsePrefix(testPrefixV4)

	changes := make([]routetable.OriginChange, 0, maxOriginChangesOnPage+1)
	for i := range maxOriginChangesOnPage + 1 {
		changes = append(changes, routetable.OriginChange{
			Prefix: prefix, OriginASN: 64500, Announced: true, PeerCount: 1,
			Time: testRouteTime(i),
		})
	}

	s := newPrefixDetailServer(t, changes)

	rec := httptest.NewRecorder()
	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
		t.Context(), http.MethodGet, "/prefix/"+testPrefixV4, nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
	}

	page := rec.Body.String()

	note := fmt.Sprintf("more than %d changes", maxOriginChangesOnPage)
	if !strings.Contains(page, note) {
		t.Errorf("page does not say there are more than %d changes",
			maxOriginChangesOnPage)
	}

	if got := strings.Count(page, "<td>Announced</td>"); got != maxOriginChangesOnPage {
		t.Errorf("page shows %d change rows, want %d", got,
			maxOriginChangesOnPage)
	}
}

// TestPrefixDetailShowsNoNoteAtTheLimit checks that a prefix with exactly the
// page's limit of origin changes shows all of them and no note.
func TestPrefixDetailShowsNoNoteAtTheLimit(t *testing.T) {
	t.Parallel()

	prefix := netip.MustParsePrefix(testPrefixV4)

	changes := make([]routetable.OriginChange, 0, maxOriginChangesOnPage)
	for i := range maxOriginChangesOnPage {
		changes = append(changes, routetable.OriginChange{
			Prefix: prefix, OriginASN: 64500, Announced: true, PeerCount: 1,
			Time: testRouteTime(i),
		})
	}

	s := newPrefixDetailServer(t, changes)

	rec := httptest.NewRecorder()
	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
		t.Context(), http.MethodGet, "/prefix/"+testPrefixV4, nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
	}

	page := rec.Body.String()

	if strings.Contains(page, "more than") {
		t.Errorf("page says there are more changes, but a prefix has %d",
			maxOriginChangesOnPage)
	}

	if got := strings.Count(page, "<td>Announced</td>"); got != maxOriginChangesOnPage {
		t.Errorf("page shows %d change rows, want %d", got,
			maxOriginChangesOnPage)
	}
}

// TestPrefixDetailShowsOriginChangeTimeAndPeerCount checks that a row shows
// its time and its peer count.
func TestPrefixDetailShowsOriginChangeTimeAndPeerCount(t *testing.T) {
	t.Parallel()

	prefix := netip.MustParsePrefix(testPrefixV4)

	s := newPrefixDetailServer(t, []routetable.OriginChange{
		{Prefix: prefix, OriginASN: 64500, Announced: true, PeerCount: 7,
			Time: testRouteTime(5)},
	})

	rec := httptest.NewRecorder()
	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
		t.Context(), http.MethodGet, "/prefix/"+testPrefixV4, nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
	}

	page := rec.Body.String()

	if !strings.Contains(page, "2026-01-02 03:09:05") {
		t.Errorf("page does not show the origin change's time")
	}

	if !strings.Contains(page, "<td>7</td>") {
		t.Errorf("page does not show the origin change's peer count")
	}
}