package blocker

import (
	"context"
	"encoding/json"
	"net/netip"
	"strings"
	"testing"
	"time"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes/fake"

	"git.tornberg.me/go-otel/internal/honeypot"
)

type feed []honeypot.IP

func (f feed) PromotedIPs() []honeypot.IP { return f }

func setup(t *testing.T, cfg Config, data map[string]string, src Source) (*Blocker, *fake.Clientset, *time.Time) {
	t.Helper()
	client := fake.NewSimpleClientset(&corev1.ConfigMap{
		ObjectMeta: metav1.ObjectMeta{Namespace: "ingress-nginx", Name: "ingress-nginx-controller"},
		Data:       data,
	})
	b := New(cfg, client, src)
	clock := time.Date(2026, 9, 19, 12, 0, 0, 0, time.UTC)
	b.now = func() time.Time { return clock }
	return b, client, &clock
}

func current(t *testing.T, c *fake.Clientset) *corev1.ConfigMap {
	t.Helper()
	cm, err := c.CoreV1().ConfigMaps("ingress-nginx").Get(context.Background(), "ingress-nginx-controller", metav1.GetOptions{})
	if err != nil {
		t.Fatal(err)
	}
	return cm
}

func scanner(ip string) honeypot.IP { return honeypot.IP{Address: ip, Count: 40, Paths: 12} }

func liveConfig() Config {
	c := DefaultConfig()
	c.DryRun = false
	return c
}

func TestDryRunWritesNothing(t *testing.T) {
	b, client, _ := setup(t, DefaultConfig(), map[string]string{"use-gzip": "true"}, feed{scanner("203.0.113.5")})
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	cm := current(t, client)
	if _, ok := cm.Data["block-cidrs"]; ok || cm.Annotations[AnnotationManaged] != "" {
		t.Fatalf("dry run wrote to the configmap: %+v %+v", cm.Data, cm.Annotations)
	}
	if len(b.last.Candidates) != 1 {
		t.Fatalf("dry run should still report candidates: %+v", b.last)
	}
}

func TestBlocksScannerAndPreservesManualEntries(t *testing.T) {
	b, client, _ := setup(t, liveConfig(), map[string]string{"block-cidrs": "198.51.100.0/24", "use-gzip": "true"}, feed{scanner("203.0.113.5")})
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	cm := current(t, client)
	if got := cm.Data["block-cidrs"]; got != "198.51.100.0/24,203.0.113.5" {
		t.Fatalf("block-cidrs = %q", got)
	}
	if cm.Data["use-gzip"] != "true" {
		t.Fatal("unrelated keys must be untouched")
	}
	var state map[string]int64
	if err := json.Unmarshal([]byte(cm.Annotations[AnnotationManaged]), &state); err != nil || len(state) != 1 {
		t.Fatalf("annotation = %q (%v)", cm.Annotations[AnnotationManaged], err)
	}
}

func TestNeverBlocksInternalOrAllowlisted(t *testing.T) {
	cfg := liveConfig()
	cfg.Allow = []netip.Prefix{netip.MustParsePrefix("203.0.113.0/24")}
	b, client, _ := setup(t, cfg, nil, feed{scanner("127.0.0.1"), scanner("10.244.4.1"), scanner("192.168.1.9"), scanner("203.0.113.77")})
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if v := current(t, client).Data["block-cidrs"]; v != "" {
		t.Fatalf("blocked %q", v)
	}
}

func TestThresholdsKeepOutOccasionalVisitors(t *testing.T) {
	b, client, _ := setup(t, liveConfig(), nil, feed{
		{Address: "203.0.113.1", Count: 4, Paths: 4},    // too few hits
		{Address: "203.0.113.2", Count: 500, Paths: 1},  // one path hammered
		{Address: "203.0.113.3", Count: 200, Paths: 60}, // broad scanner
	})
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if v := current(t, client).Data["block-cidrs"]; v != "203.0.113.3" {
		t.Fatalf("block-cidrs = %q", v)
	}
}

func TestExpiryRemovesOnlyManagedEntries(t *testing.T) {
	src := feed{scanner("203.0.113.5")}
	b, client, clock := setup(t, liveConfig(), map[string]string{"block-cidrs": "198.51.100.7"}, src)
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	b.source = feed{} // scanner goes quiet
	*clock = clock.Add(25 * time.Hour)
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if v := current(t, client).Data["block-cidrs"]; v != "198.51.100.7" {
		t.Fatalf("after expiry block-cidrs = %q, want only the manual entry", v)
	}
}

func TestWritesAreRateLimitedAndNewPerTickCapped(t *testing.T) {
	cfg := liveConfig()
	cfg.MaxNewPerTick = 2
	var many feed
	for _, ip := range []string{"203.0.113.1", "203.0.113.2", "203.0.113.3", "203.0.113.4"} {
		many = append(many, scanner(ip))
	}
	b, client, clock := setup(t, cfg, nil, many)
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if n := len(strings.Split(current(t, client).Data["block-cidrs"], ",")); n != 2 {
		t.Fatalf("first tick added %d, want 2", n)
	}
	*clock = clock.Add(time.Minute) // inside MinWrite
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if n := len(strings.Split(current(t, client).Data["block-cidrs"], ",")); n != 2 {
		t.Fatalf("write was not rate limited: %d entries", n)
	}
	*clock = clock.Add(10 * time.Minute)
	if err := b.Tick(context.Background()); err != nil {
		t.Fatal(err)
	}
	if n := len(strings.Split(current(t, client).Data["block-cidrs"], ",")); n != 4 {
		t.Fatalf("after the interval got %d entries, want 4", n)
	}
}