package notify

import (
	"context"
	"encoding/json"
	"errors"
	"net"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/vasyakrg/dns-autoresolver/internal/store"
)

func TestTelegramSendSuccess(t *testing.T) {
	var gotPath string
	var gotBody map[string]string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotPath = r.URL.Path
		_ = json.NewDecoder(r.Body).Decode(&gotBody)
		w.WriteHeader(http.StatusOK)
	}))
	defer srv.Close()

	tg := &Telegram{BaseURL: srv.URL, HTTP: srv.Client()}
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "A record changed", At: time.Now()}

	err := tg.Send(context.Background(), json.RawMessage(`{"chat_id":"12345"}`), "sekret-token", ev)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if gotPath != "/botsekret-token/sendMessage" {
		t.Fatalf("unexpected path: %s", gotPath)
	}
	if gotBody["chat_id"] != "12345" {
		t.Fatalf("unexpected chat_id: %+v", gotBody)
	}
	if !strings.Contains(gotBody["text"], "example.com") || !strings.Contains(gotBody["text"], "drift") {
		t.Fatalf("unexpected text: %+v", gotBody)
	}
}

func TestTelegramSendServerError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusInternalServerError)
	}))
	defer srv.Close()

	tg := &Telegram{BaseURL: srv.URL, HTTP: srv.Client()}
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "x", At: time.Now()}

	if err := tg.Send(context.Background(), json.RawMessage(`{"chat_id":"1"}`), "tok", ev); err == nil {
		t.Fatal("expected error on 500 response")
	}
}

func TestTelegramSendTransportErrorDoesNotLeakSecret(t *testing.T) {
	// Bind and immediately close a server: its address is now unreachable
	// (connection refused), which makes http.Client.Do return a *url.Error
	// whose Error() embeds the full request URL — including /bot<secret>/.
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
	deadURL := srv.URL
	srv.Close()

	tg := &Telegram{BaseURL: deadURL, HTTP: srv.Client()}
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "x", At: time.Now()}

	const secret = "super-secret-bot-token"
	err := tg.Send(context.Background(), json.RawMessage(`{"chat_id":"1"}`), secret, ev)
	if err == nil {
		t.Fatal("expected error for unreachable host")
	}
	if strings.Contains(err.Error(), secret) {
		t.Fatalf("error leaks secret: %v", err)
	}
	if strings.Contains(err.Error(), deadURL) {
		t.Fatalf("error leaks request URL: %v", err)
	}
}

func TestWebhookSendSuccess(t *testing.T) {
	var gotEvent Event
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("unexpected method: %s", r.Method)
		}
		_ = json.NewDecoder(r.Body).Decode(&gotEvent)
		w.WriteHeader(http.StatusOK)
	}))
	defer srv.Close()

	// allowPrivate: true — httptest.Server listens on 127.0.0.1, which the
	// SSRF guard would otherwise reject; production dispatchers never set
	// this (see TestIsAllowedURL / TestNewDispatcherDoesNotAllowPrivate).
	wh := &Webhook{HTTP: srv.Client(), allowPrivate: true}
	ev := Event{Project: "proj", Domain: "example.com", Status: "in_sync", Summary: "resolved", At: time.Now()}

	cfg, _ := json.Marshal(map[string]string{"url": srv.URL})
	if err := wh.Send(context.Background(), cfg, "", ev); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if gotEvent.Domain != "example.com" || gotEvent.Status != "in_sync" {
		t.Fatalf("unexpected event delivered: %+v", gotEvent)
	}
}

func TestWebhookSendNonSuccessStatus(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusBadRequest)
	}))
	defer srv.Close()

	wh := &Webhook{HTTP: srv.Client(), allowPrivate: true}
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "x", At: time.Now()}
	cfg, _ := json.Marshal(map[string]string{"url": srv.URL})

	if err := wh.Send(context.Background(), cfg, "", ev); err == nil {
		t.Fatal("expected error on 400 response")
	}
}

func TestWebhookSendRejectsPrivateDestinationByDefault(t *testing.T) {
	wh := &Webhook{HTTP: http.DefaultClient} // allowPrivate not set: SSRF guard active
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "x", At: time.Now()}
	cfg, _ := json.Marshal(map[string]string{"url": "http://127.0.0.1:1/hook"})

	err := wh.Send(context.Background(), cfg, "", ev)
	if err == nil {
		t.Fatal("expected error for loopback destination")
	}
	if !strings.Contains(err.Error(), "destination not allowed") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestIsAllowedURL(t *testing.T) {
	cases := []struct {
		name    string
		rawurl  string
		allowed bool
	}{
		{"localhost hostname", "http://localhost/hook", false},
		{"loopback ip", "http://127.0.0.1/hook", false},
		{"loopback ipv6", "http://[::1]/hook", false},
		{"link-local metadata", "http://169.254.169.254/latest/meta-data", false},
		{"private class a", "http://10.0.0.1/hook", false},
		{"private class c", "http://192.168.1.1/hook", false},
		{"private class b", "http://172.16.0.1/hook", false},
		{"unspecified", "http://0.0.0.0/hook", false},
		{"multicast", "http://224.0.0.1/hook", false},
		{"non-http scheme", "ftp://example.com/hook", false},
		{"public ip", "http://93.184.216.34/hook", true},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			err := isAllowedURL(tc.rawurl)
			if tc.allowed && err != nil {
				t.Fatalf("expected %q to be allowed, got error: %v", tc.rawurl, err)
			}
			if !tc.allowed && err == nil {
				t.Fatalf("expected %q to be rejected, got nil error", tc.rawurl)
			}
		})
	}
}

func TestDialControlBlocksActualConnectingAddress(t *testing.T) {
	cases := []struct {
		name    string
		address string
		blocked bool
	}{
		{"loopback v4", "127.0.0.1:80", true},
		{"loopback v6", "[::1]:80", true},
		{"metadata link-local", "169.254.169.254:80", true},
		{"private class a", "10.0.0.1:80", true},
		{"private class b", "172.16.0.1:80", true},
		{"private class c", "192.168.1.1:80", true},
		{"unspecified", "0.0.0.0:80", true},
		{"multicast", "224.0.0.1:80", true},
		{"public ip", "93.184.216.34:443", false},
	}
	control := dialControl(false)
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			err := control("tcp", tc.address, nil)
			if tc.blocked && err == nil {
				t.Fatalf("expected %q to be blocked", tc.address)
			}
			if !tc.blocked && err != nil {
				t.Fatalf("expected %q to be allowed, got: %v", tc.address, err)
			}
		})
	}
}

func TestIsBlockedIPCGNATRange(t *testing.T) {
	cases := []struct {
		name    string
		ip      string
		blocked bool
	}{
		{"cgnat start", "100.64.0.1", true},
		{"cgnat end", "100.127.255.255", true},
		{"just below cgnat", "100.63.255.255", false},
		{"just above cgnat", "100.128.0.0", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			ip := net.ParseIP(tc.ip)
			if ip == nil {
				t.Fatalf("failed to parse %q", tc.ip)
			}
			got := isBlockedIP(ip)
			if got != tc.blocked {
				t.Fatalf("isBlockedIP(%q) = %v, want %v", tc.ip, got, tc.blocked)
			}
		})
	}
}

func TestDialControlAllowsEverythingWhenAllowPrivate(t *testing.T) {
	control := dialControl(true)
	if err := control("tcp", "127.0.0.1:80", nil); err != nil {
		t.Fatalf("expected allowPrivate to skip the dial guard, got: %v", err)
	}
}

// TestWebhookControlBlocksConnectionEvenWhenPreCheckPasses simulates the
// DNS-rebinding TOCTOU: allowPrivate=true skips the pre-request isAllowedURL
// check (standing in for a rebinding attacker answering a public IP to that
// lookup), but the Transport's Control func — wired independently of
// Webhook.allowPrivate — still inspects the literal address the dialer
// connects to and must still reject it. If Control did not exist, this
// request would reach the httptest handler; it must not.
func TestWebhookControlBlocksConnectionEvenWhenPreCheckPasses(t *testing.T) {
	var handlerCalled bool
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		handlerCalled = true
		w.WriteHeader(http.StatusOK)
	}))
	defer srv.Close()

	wh := &Webhook{
		HTTP:         &http.Client{Transport: newWebhookTransport(false)},
		allowPrivate: true, // pre-check bypassed on purpose; Control is not
	}
	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "x", At: time.Now()}
	cfg, _ := json.Marshal(map[string]string{"url": srv.URL})

	err := wh.Send(context.Background(), cfg, "", ev)
	if err == nil {
		t.Fatal("expected error: Control should have blocked the loopback connection")
	}
	if !strings.Contains(err.Error(), "destination not allowed") {
		t.Fatalf("unexpected error: %v", err)
	}
	if handlerCalled {
		t.Fatal("Control should have rejected the dial before the handler ran")
	}
}

// --- Dispatcher ---

type mockChannelStore struct {
	channels []store.Channel
	err      error
}

func (m *mockChannelStore) ListEnabledChannels(ctx context.Context, projectID uuid.UUID) ([]store.Channel, error) {
	return m.channels, m.err
}

type mockDecryptor struct {
	fail bool
}

func (m *mockDecryptor) Decrypt(enc string) ([]byte, error) {
	if m.fail {
		return nil, errBoom
	}
	return []byte("decrypted-" + enc), nil
}

var errBoom = &boomErr{}

type boomErr struct{}

func (*boomErr) Error() string { return "decrypt boom" }

func TestDispatcherSendsToAllChannelsAndAggregatesErrors(t *testing.T) {
	var tgCalled, whCalled bool
	var tgSecret string

	tgSrv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tgCalled = true
		w.WriteHeader(http.StatusOK)
	}))
	defer tgSrv.Close()

	whSrv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		whCalled = true
		w.WriteHeader(http.StatusInternalServerError) // webhook fails
	}))
	defer whSrv.Close()

	projectID := uuid.New()
	channels := []store.Channel{
		{
			ID: uuid.New(), ProjectID: projectID, Type: "telegram",
			Config: json.RawMessage(`{"chat_id":"1"}`), SecretEnc: "enc-token", Enabled: true,
		},
		{
			ID: uuid.New(), ProjectID: projectID, Type: "webhook",
			Config: json.RawMessage(`{"url":"` + whSrv.URL + `"}`), SecretEnc: "", Enabled: true,
		},
	}

	d := NewDispatcher(&mockChannelStore{channels: channels}, &mockDecryptor{})
	// Redirect telegram to the httptest server and capture the decrypted secret.
	d.byType["telegram"] = notifierFunc(func(ctx context.Context, cfg json.RawMessage, secret string, ev Event) error {
		tgSecret = secret
		tg := &Telegram{BaseURL: tgSrv.URL, HTTP: tgSrv.Client()}
		return tg.Send(ctx, cfg, secret, ev)
	})
	// httptest servers listen on loopback, which the SSRF guard rejects by
	// default; swap in an allowPrivate webhook so this test can still hit it.
	d.byType["webhook"] = &Webhook{HTTP: whSrv.Client(), allowPrivate: true}

	ev := Event{Project: "proj", Domain: "example.com", Status: "drift", Summary: "changed", At: time.Now()}
	results, err := d.Send(context.Background(), projectID, ev)

	if !tgCalled {
		t.Error("expected telegram notifier to be called")
	}
	if !whCalled {
		t.Error("expected webhook notifier to be called")
	}
	if err == nil {
		t.Fatal("expected aggregated error because webhook failed")
	}
	if tgSecret != "decrypted-enc-token" {
		t.Fatalf("expected decrypted secret to be passed to telegram, got %q", tgSecret)
	}

	if len(results) != 2 {
		t.Fatalf("results = %d, want 2", len(results))
	}
	byType := make(map[string]ChannelResult, len(results))
	for _, r := range results {
		byType[r.Type] = r
	}
	if tg, ok := byType["telegram"]; !ok || tg.Err != nil {
		t.Fatalf("telegram result = %+v, want ok result", tg)
	}
	if wh, ok := byType["webhook"]; !ok || wh.Err == nil {
		t.Fatalf("webhook result = %+v, want error result", wh)
	}
}

// TestDispatcherSendReturnsPerChannelResults exercises the exact scenario
// from the plan: one telegram channel succeeding, one webhook channel
// failing at the Notifier — the metric consumer (scheduler) needs a result
// per channel, not one aggregate blob, to record accurate per-channel/status
// metrics.
func TestDispatcherSendReturnsPerChannelResults(t *testing.T) {
	projectID := uuid.New()
	channels := []store.Channel{
		{ID: uuid.New(), ProjectID: projectID, Type: "telegram", Config: json.RawMessage(`{"chat_id":"1"}`), Enabled: true},
		{ID: uuid.New(), ProjectID: projectID, Type: "webhook", Config: json.RawMessage(`{"url":"http://x"}`), Enabled: true},
	}
	d := NewDispatcher(&mockChannelStore{channels: channels}, &mockDecryptor{})
	d.byType["telegram"] = notifierFunc(func(ctx context.Context, cfg json.RawMessage, secret string, ev Event) error {
		return nil
	})
	d.byType["webhook"] = notifierFunc(func(ctx context.Context, cfg json.RawMessage, secret string, ev Event) error {
		return errBoom
	})

	results, err := d.Send(context.Background(), projectID, Event{Project: "p", Domain: "d", Status: "drift"})
	if err == nil {
		t.Fatal("expected aggregated error because webhook failed")
	}
	if len(results) != 2 {
		t.Fatalf("results = %d, want 2", len(results))
	}
	if results[0].Type != "telegram" || results[0].Err != nil {
		t.Fatalf("results[0] = %+v, want telegram/nil", results[0])
	}
	if results[1].Type != "webhook" || results[1].Err == nil {
		t.Fatalf("results[1] = %+v, want webhook/error", results[1])
	}
}

func TestDispatcherSkipsUnknownChannelType(t *testing.T) {
	projectID := uuid.New()
	channels := []store.Channel{
		{ID: uuid.New(), ProjectID: projectID, Type: "carrier-pigeon", Config: json.RawMessage(`{}`), Enabled: true},
	}
	d := NewDispatcher(&mockChannelStore{channels: channels}, &mockDecryptor{})
	results, err := d.Send(context.Background(), projectID, Event{Project: "p", Domain: "d", Status: "drift"})
	if err != nil {
		t.Fatalf("unexpected error for unknown channel type: %v", err)
	}
	if len(results) != 0 {
		t.Fatalf("results = %d, want 0: unknown channel type must not produce a result", len(results))
	}
}

func TestDispatcherDecryptFailureIsAggregatedNotFatal(t *testing.T) {
	var whCalled bool
	whSrv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		whCalled = true
		w.WriteHeader(http.StatusOK)
	}))
	defer whSrv.Close()

	projectID := uuid.New()
	channels := []store.Channel{
		{ID: uuid.New(), ProjectID: projectID, Type: "telegram", Config: json.RawMessage(`{"chat_id":"1"}`), SecretEnc: "enc", Enabled: true},
		{ID: uuid.New(), ProjectID: projectID, Type: "webhook", Config: json.RawMessage(`{"url":"` + whSrv.URL + `"}`), Enabled: true},
	}
	d := NewDispatcher(&mockChannelStore{channels: channels}, &mockDecryptor{fail: true})
	// httptest servers listen on loopback, which the SSRF guard rejects by
	// default; swap in an allowPrivate webhook so this test can still hit it.
	d.byType["webhook"] = &Webhook{HTTP: whSrv.Client(), allowPrivate: true}

	results, err := d.Send(context.Background(), projectID, Event{Project: "p", Domain: "d", Status: "drift"})
	if err == nil {
		t.Fatal("expected error due to decrypt failure")
	}
	if !whCalled {
		t.Error("expected webhook channel to still be attempted after telegram decrypt failure")
	}

	if len(results) != 2 {
		t.Fatalf("results = %d, want 2", len(results))
	}
	byType := make(map[string]ChannelResult, len(results))
	for _, r := range results {
		byType[r.Type] = r
	}
	tg, ok := byType["telegram"]
	if !ok {
		t.Fatal("expected a telegram result")
	}
	if tg.Err == nil {
		t.Fatalf("telegram result = %+v, want decrypt error", tg)
	}
	if !errors.Is(tg.Err, errBoom) {
		t.Fatalf("telegram result err = %v, want errBoom", tg.Err)
	}
	wh, ok := byType["webhook"]
	if !ok {
		t.Fatal("expected a webhook result")
	}
	if wh.Err != nil {
		t.Fatalf("webhook result = %+v, want ok result (decrypt failure on telegram must not fail webhook)", wh)
	}
}

// notifierFunc adapts a function to the Notifier interface for tests.
type notifierFunc func(ctx context.Context, cfg json.RawMessage, secret string, ev Event) error

func (f notifierFunc) Send(ctx context.Context, cfg json.RawMessage, secret string, ev Event) error {
	return f(ctx, cfg, secret, ev)
}