package lookup_test

import (
	"net/netip"
	"slices"
	"testing"
	"testing/synctest"
	"time"

	"sneak.berlin/go/smallwebwaf/internal/lookup"
)

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

	synctest.Test(t, func(t *testing.T) {
		_, clock, g := start()
		placed := netip.MustParsePrefix("203.0.113.9/32")
		notPlaced := netip.MustParsePrefix(unplaced + "/32")
		asked := clock.Now()

		wantCountry(t, g, placed, germany)
		wantCountry(t, g, notPlaced, "")

		clock.advance(time.Hour)
		wantCountry(t, g, placed, germany)

		want := []lookup.Answer{
			{Client: notPlaced, Country: "", Answered: asked, Used: asked},
			{Client: placed, Country: germany, Answered: asked, Used: asked.Add(time.Hour)},
		}
		if got := g.Snapshot(); !slices.Equal(got, want) {
			t.Errorf("snapshot\n%+v\nwant\n%+v", got, want)
		}
	})
}

func TestLoadedAnswersAreKeptFor7DaysFromWhenGeoJSGaveThem(t *testing.T) {
	t.Parallel()

	geojs, clock, g := start()
	now := clock.Now()
	kept := lookup.Answer{
		Client:   netip.MustParsePrefix("203.0.113.9/32"),
		Country:  "FR",
		Answered: now.Add(-week + time.Second),
		Used:     now.Add(-time.Hour),
	}
	stale := lookup.Answer{
		Client:   netip.MustParsePrefix("203.0.113.10/32"),
		Country:  "FR",
		Answered: now.Add(-week),
		Used:     now.Add(-time.Hour),
	}

	g.Load([]lookup.Answer{kept, stale})

	if got := g.Snapshot(); !slices.Equal(got, []lookup.Answer{kept}) {
		t.Errorf("kept %+v, want only the answer GeoJS gave less than 7 days ago", got)
	}

	wantCountry(t, g, kept.Client, "FR")
	wantRequests(t, geojs, 0)
}

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

	const maxAnswers = 100000

	_, clock, g := start()
	now := clock.Now()

	// lookups.json lists the answers by client. Here each was last used a
	// second before the one listed before it, so the last listed is the
	// one used longest ago, and the one dropped.
	answers := make([]lookup.Answer, maxAnswers+1)
	addr := netip.MustParseAddr("10.0.0.0")

	for i := range answers {
		answers[i] = lookup.Answer{
			Client:   netip.PrefixFrom(addr, addr.BitLen()),
			Country:  germany,
			Answered: now,
			Used:     now.Add(-time.Duration(i) * time.Second),
		}
		addr = addr.Next()
	}

	g.Load(answers)

	got := g.Snapshot()
	if len(got) != maxAnswers || got[0] != answers[0] ||
		got[maxAnswers-1] != answers[maxAnswers-1] {
		t.Errorf("%d answers kept, from %s to %s; want %d, from %s to %s",
			len(got), got[0].Client, got[len(got)-1].Client, maxAnswers,
			answers[0].Client, answers[maxAnswers-1].Client)
	}
}