Crussell/backend/handlers/webhooks/webhooks_test.go

//go:build test

package webhooks

import (
	"bytes"
	"context"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"crussell/db"
	"github.com/jackc/pgx/v5/pgxpool"
)

// =============================================================================
// Unit tests — verifySquareSignature (pure function)
// =============================================================================

func TestVerifySquareSignature_ValidSignature(t *testing.T) {
	t.Parallel()
	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	key := "test-signing-key"
	notificationURL := "http://localhost:8080/webhooks/square"

	payload := notificationURL + string(body)
	mac := hmac.New(sha256.New, []byte(key))
	mac.Write([]byte(payload))
	expectedSig := base64.StdEncoding.EncodeToString(mac.Sum(nil))

	if !verifySquareSignature(body, expectedSig, key, notificationURL) {
		t.Error("expected valid signature to verify")
	}
}

func TestVerifySquareSignature_InvalidSignature(t *testing.T) {
	t.Parallel()
	body := []byte(`{"type":"payment.updated"}`)
	key := "test-signing-key"
	notificationURL := "http://localhost:8080/webhooks/square"

	if verifySquareSignature(body, "invalid-signature", key, notificationURL) {
		t.Error("expected invalid signature to fail")
	}
}

func TestVerifySquareSignature_WrongKey(t *testing.T) {
	t.Parallel()
	body := []byte(`{"type":"payment.updated"}`)
	notificationURL := "http://localhost:8080/webhooks/square"

	payload := notificationURL + string(body)
	mac := hmac.New(sha256.New, []byte("correct-key"))
	mac.Write([]byte(payload))
	sig := base64.StdEncoding.EncodeToString(mac.Sum(nil))

	// Verify with a different key
	if verifySquareSignature(body, sig, "wrong-key", notificationURL) {
		t.Error("expected wrong key to produce failing verification")
	}
}

func TestVerifySquareSignature_EmptyBody(t *testing.T) {
	t.Parallel()
	key := "test-signing-key"
	notificationURL := "http://localhost:8080/webhooks/square"

	payload := notificationURL + string([]byte{})
	mac := hmac.New(sha256.New, []byte(key))
	mac.Write([]byte(payload))
	expectedSig := base64.StdEncoding.EncodeToString(mac.Sum(nil))

	if !verifySquareSignature([]byte{}, expectedSig, key, notificationURL) {
		t.Error("expected empty body verification to succeed with matching signature")
	}
}

func TestVerifySquareSignature_TamperedBody(t *testing.T) {
	t.Parallel()
	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	key := "test-signing-key"
	notificationURL := "http://localhost:8080/webhooks/square"

	payload := notificationURL + string(body)
	mac := hmac.New(sha256.New, []byte(key))
	mac.Write([]byte(payload))
	sig := base64.StdEncoding.EncodeToString(mac.Sum(nil))

	// Verify with a tampered body
	tamperedBody := []byte(`{"type":"payment.updated","event_id":"evt_2"}`)
	if verifySquareSignature(tamperedBody, sig, key, notificationURL) {
		t.Error("expected tampered body to fail verification")
	}
}

// =============================================================================
// Integration tests — HandleSquareWebhook
// =============================================================================

func makeWebhookRequest(body []byte, signature string, ctx context.Context) *httptest.ResponseRecorder {
	w := httptest.NewRecorder()
	req := httptest.NewRequest("POST", "/webhooks/square", bytes.NewReader(body))
	req = req.WithContext(ctx)
	req.Header.Set("Content-Type", "application/json")
	if signature != "" {
		req.Header.Set("x-square-hmacsha256-signature", signature)
	}
	HandleSquareWebhook(w, req)
	return w
}

// webhookTestEnv sets a signing key and returns a valid signature for the body
// (the fail-closed handler requires a verifiable signature on every request).
func webhookTestEnv(t *testing.T, body []byte) (signature string) {
	t.Helper()
	tKey := "test-signing-key"
	tURL := "http://localhost:8080/webhooks/square"
	mac := hmac.New(sha256.New, []byte(tKey))
	mac.Write([]byte(tURL))
	mac.Write(body)
	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", tKey)
	return base64.StdEncoding.EncodeToString(mac.Sum(nil))
}

// countWebhookEvents returns how many dedup rows exist for an event_id. The
// handler commits its dedup insert to the pool (no per-test transaction), so a
// fresh query sees it.
func countWebhookEvents(t *testing.T, eventID string) int {
	t.Helper()
	var n int
	if err := db.Conn.QueryRow(context.Background(),
		"SELECT COUNT(*) FROM square_webhook_events WHERE event_id = $1", eventID).Scan(&n); err != nil {
		t.Fatalf("failed to count square_webhook_events rows: %v", err)
	}
	return n
}

// testDBHost mirrors testdb.dbHost so the broken-pool test can reach the same
// Postgres instance without importing testdb internals.
func testDBHost() string {
	if h := os.Getenv("TEST_DB_HOST"); h != "" {
		return h
	}
	if h := os.Getenv("POSTGRES_HOST"); h != "" {
		return h
	}
	return "localhost"
}

func TestHandleSquareWebhook_PaymentUpdated(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_payment_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Errorf("expected 200, got %d. body: %s", w.Code, w.Body.String())
	}
	if w.Body.String() != "ok" {
		t.Errorf("expected body 'ok', got %q", w.Body.String())
	}
}

func TestHandleSquareWebhook_RefundUpdated(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "refund.updated",
		EventID:   "evt_refund_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"refund_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Errorf("expected 200, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_DisputeCreated(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "dispute.created",
		EventID:   "evt_dispute_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"dispute_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Errorf("expected 200 for dispute.created, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_UnknownEventType(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "invoice.created",
		EventID:   "evt_unknown_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"inv_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Errorf("expected 200 for unknown event type, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_InvalidJSON(t *testing.T) {
	body := []byte(`{invalid json}`)
	sig := webhookTestEnv(t, body)
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusBadRequest {
		t.Errorf("expected 400 for invalid JSON, got %d. body: %s", w.Code, w.Body.String())
	}
}

// TestHandleSquareWebhook_EmptyEventID_Rejected verifies a signed event with an
// empty event_id is rejected with 400 — fail-safe: no dispatch, no dedup row.
// Square's retry policy treats 4xx as non-retryable, so the malformed event is
// dropped without side effects.
func TestHandleSquareWebhook_EmptyEventID_Rejected(t *testing.T) {
	body := []byte(`{"type":"payment.updated","event_id":"","data":{"id":"payment_empty_id"}}`)
	sig := webhookTestEnv(t, body)

	var buf bytes.Buffer
	oldOutput := log.Writer()
	log.SetOutput(&buf)
	defer log.SetOutput(oldOutput)

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusBadRequest {
		t.Fatalf("expected 400 for empty event_id, got %d. body: %s", w.Code, w.Body.String())
	}

	out := buf.String()
	if !strings.Contains(out, "Rejecting event with empty event_id (400)") {
		t.Errorf("expected empty event_id rejection log, got:\n%s", out)
	}
	if strings.Contains(out, "Received event: payment.updated") {
		t.Errorf("expected empty event_id to skip dispatch, got:\n%s", out)
	}

	// No dedup row may be written for an empty event_id.
	if n := countWebhookEvents(t, ""); n != 0 {
		t.Errorf("expected no dedup row for empty event_id, got %d", n)
	}
}

func TestHandleSquareWebhook_BodyTooLarge(t *testing.T) {
	// 600KB body exceeds the 512KB limit
	largeBody := []byte(strings.Repeat("a", 600*1024))
	sig := webhookTestEnv(t, largeBody)
	w := makeWebhookRequest(largeBody, sig, context.Background())
	if w.Code != http.StatusRequestEntityTooLarge {
		t.Errorf("expected 413 for oversized body, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_ValidSignatureWithEnvKey(t *testing.T) {

	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	key := "env-signing-key"
	notificationURL := "http://localhost:8080/webhooks/square"

	payload := notificationURL + string(body)
	mac := hmac.New(sha256.New, []byte(key))
	mac.Write([]byte(payload))
	sig := base64.StdEncoding.EncodeToString(mac.Sum(nil))

	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", key)

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Errorf("expected 200 with valid signature, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_InvalidSignatureWithEnvKey(t *testing.T) {

	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)

	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "env-signing-key")

	w := makeWebhookRequest(body, "bad-signature", context.Background())
	if w.Code != http.StatusForbidden {
		t.Errorf("expected 403 with invalid signature, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_NoSignatureWhenKeySet(t *testing.T) {

	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)

	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "env-signing-key")

	// No x-square-signature header at all
	w := makeWebhookRequest(body, "", context.Background())
	if w.Code != http.StatusForbidden {
		t.Errorf("expected 403 when signature key is set but header missing, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_RejectedWhenKeyEmpty(t *testing.T) {

	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "")

	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	// Fail-closed: an unset signing key means the webhook cannot be verified,
	// so the request is rejected rather than accepted with a bad signature.
	w := makeWebhookRequest(body, "some-signature", context.Background())
	if w.Code != http.StatusServiceUnavailable {
		t.Errorf("expected 503 when no key configured (fail-closed), got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_NoRawPayloadInLogs(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_pii_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data: json.RawMessage(`{"id":"payment_pii_1","buyer_email_address":"secret@example.com",
			"card_details":{"card":{"brand":"VISA","last_4":"1234","cardholder_name":"Jane Doe"}}}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	var buf bytes.Buffer
	oldOutput := log.Writer()
	log.SetOutput(&buf)
	defer log.SetOutput(oldOutput)

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d. body: %s", w.Code, w.Body.String())
	}

	out := buf.String()
	for _, pii := range []string{"secret@example.com", "VISA", "1234", "Jane Doe", "payment_pii_1_full"} {
		if strings.Contains(out, pii) {
			t.Errorf("log output leaked PII %q:\n%s", pii, out)
		}
	}
	if !strings.Contains(out, "data.id=payment_pii_1") {
		t.Errorf("expected log to include object id, got:\n%s", out)
	}
	if !strings.Contains(out, "Received event: payment.updated") {
		t.Errorf("expected log to reference event type, got:\n%s", out)
	}
}

// =============================================================================
// Dedup — event_id replay protection
// =============================================================================

func TestHandleSquareWebhook_DuplicateEventID(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_http_dup_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_dup_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	// First delivery processes the event.
	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Fatalf("expected first delivery 200, got %d. body: %s", w.Code, w.Body.String())
	}

	// Replay of the same signed event returns 200 but skips dispatch.
	w2 := makeWebhookRequest(body, sig, context.Background())
	if w2.Code != http.StatusOK {
		t.Fatalf("expected replay 200, got %d. body: %s", w2.Code, w2.Body.String())
	}
	if w2.Body.String() != "ok" {
		t.Errorf("expected replay body 'ok', got %q", w2.Body.String())
	}

	// The persistent dedup row is written exactly once despite both deliveries.
	if n := countWebhookEvents(t, event.EventID); n != 1 {
		t.Errorf("expected exactly 1 persisted dedup row, got %d", n)
	}
}

func TestHandleSquareWebhook_DistinctEventIDs(t *testing.T) {
	for _, id := range []string{"evt_distinct_1", "evt_distinct_2"} {
		event := SquareWebhookEvent{
			Type:      "payment.updated",
			EventID:   id,
			CreatedAt: "2025-01-01T00:00:00Z",
			Data:      json.RawMessage(`{"id":"p"}`),
		}
		body, _ := json.Marshal(event)
		sig := webhookTestEnv(t, body)
		w := makeWebhookRequest(body, sig, context.Background())
		if w.Code != http.StatusOK {
			t.Fatalf("expected 200 for %s, got %d. body: %s", id, w.Code, w.Body.String())
		}
	}
}

func TestSquareWebhookDedup_FirstThenDuplicate(t *testing.T) {
	d := newSquareWebhookDedup(1000)
	if d.register("evt_dedup_1") {
		t.Error("expected first occurrence to register as new")
	}
	if !d.register("evt_dedup_1") {
		t.Error("expected second occurrence to register as duplicate")
	}
}

func TestSquareWebhookDedup_CapEvictsOldest(t *testing.T) {
	d := newSquareWebhookDedup(3)
	for i := 0; i < 3; i++ {
		if d.register(fmt.Sprintf("evt_cap_%d", i)) {
			t.Errorf("expected evt_cap_%d to register as new", i)
		}
	}
	// The 4th distinct ID pushes out the oldest (evt_cap_0).
	if d.register("evt_cap_3") {
		t.Errorf("expected evt_cap_3 to register as new")
	}
	// Survivors still dedupe (register returns true without mutating the set).
	for _, id := range []string{"evt_cap_1", "evt_cap_2", "evt_cap_3"} {
		if !d.register(id) {
			t.Errorf("expected %s to still be a duplicate", id)
		}
	}
	// The evicted ID is treated as new again.
	if d.register("evt_cap_0") {
		t.Errorf("expected evt_cap_0 to be evicted and treated as new")
	}
}

func TestSquareWebhookDedup_HasDoesNotRecord(t *testing.T) {
	d := newSquareWebhookDedup(3)
	if d.has("evt_has_1") {
		t.Error("expected has() on empty set to return false")
	}
	if d.register("evt_has_1") {
		t.Error("expected first register to report new")
	}
	if !d.has("evt_has_1") {
		t.Error("expected has() to observe a registered id")
	}
}

// TestHandleSquareWebhook_DedupDispatchOnce verifies the handler body runs
// exactly once across a delivery + replay, with a single persisted dedup row.
func TestHandleSquareWebhook_DedupDispatchOnce(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_dispatch_once_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_dispatch_once_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	var buf bytes.Buffer
	oldOutput := log.Writer()
	log.SetOutput(&buf)
	defer log.SetOutput(oldOutput)

	w1 := makeWebhookRequest(body, sig, context.Background())
	if w1.Code != http.StatusOK {
		t.Fatalf("expected first delivery 200, got %d. body: %s", w1.Code, w1.Body.String())
	}
	w2 := makeWebhookRequest(body, sig, context.Background())
	if w2.Code != http.StatusOK {
		t.Fatalf("expected replay 200, got %d. body: %s", w2.Code, w2.Body.String())
	}
	if w2.Body.String() != "ok" {
		t.Errorf("expected replay body 'ok', got %q", w2.Body.String())
	}

	out := buf.String()
	if got := strings.Count(out, "Received event: payment.updated"); got != 1 {
		t.Errorf("expected dispatch to run exactly once, saw %d 'Received event' log lines:\n%s", got, out)
	}
	if n := countWebhookEvents(t, event.EventID); n != 1 {
		t.Errorf("expected exactly 1 persisted dedup row, got %d", n)
	}
}

// TestHandleSquareWebhook_DedupPersistsAcrossRestart simulates a restart: the
// event was handled by a previous process whose in-memory cache is gone, but
// the dedup row survived in the DB. The dedup row now commits AFTER dispatch
// (at-least-once delivery), so a replayed delivery is re-dispatched — the
// idempotent status-guarded handlers are a no-op the second time — and is
// acknowledged 200 without duplicating the persisted dedup row.
func TestHandleSquareWebhook_DedupPersistsAcrossRestart(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_restart_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_restart_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	if _, err := db.Conn.Exec(context.Background(),
		"INSERT INTO square_webhook_events (event_id) VALUES ($1) ON CONFLICT (event_id) DO NOTHING", event.EventID); err != nil {
		t.Fatalf("failed to seed dedup row: %v", err)
	}

	var buf bytes.Buffer
	oldOutput := log.Writer()
	log.SetOutput(&buf)
	defer log.SetOutput(oldOutput)

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200 for replayed event, got %d. body: %s", w.Code, w.Body.String())
	}
	if w.Body.String() != "ok" {
		t.Errorf("expected body 'ok', got %q", w.Body.String())
	}
	if out := buf.String(); !strings.Contains(out, "Received event: payment.updated") {
		t.Errorf("expected replayed event to be re-dispatched (at-least-once), got:\n%s", out)
	}
	if n := countWebhookEvents(t, event.EventID); n != 1 {
		t.Errorf("expected still exactly 1 dedup row, got %d", n)
	}
}

// TestHandleSquareWebhook_DedupInsertFails_FailsClosed verifies the handler
// rejects (503) when the dedup INSERT cannot be persisted, so Square retries.
func TestHandleSquareWebhook_DedupInsertFails_FailsClosed(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_db_down_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_db_down_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	orig := db.Conn
	defer func() { db.Conn = orig }()
	// A pool whose database does not exist fails every Exec — simulating a DB
	// that is unreachable or down.
	badDSN := fmt.Sprintf("postgres://myuser:mypassword@%s:5432/crussell_test_webhooks_nonexistent?sslmode=disable", testDBHost())
	badPool, err := pgxpool.New(context.Background(), badDSN)
	if err != nil {
		t.Fatalf("failed to create broken pool: %v", err)
	}
	defer badPool.Close()
	db.Conn = db.NewPoolProxy(badPool)

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusServiceUnavailable {
		t.Fatalf("expected 503 when dedup write fails, got %d. body: %s", w.Code, w.Body.String())
	}
}

// TestHandleSquareWebhook_DedupNilConn_FailsClosed verifies the handler also
// rejects (503) when the DB was never wired at all (defensive fail-closed).
func TestHandleSquareWebhook_DedupNilConn_FailsClosed(t *testing.T) {
	event := SquareWebhookEvent{
		Type:      "payment.updated",
		EventID:   "evt_nil_conn_1",
		CreatedAt: "2025-01-01T00:00:00Z",
		Data:      json.RawMessage(`{"id":"payment_nil_conn_1"}`),
	}
	body, _ := json.Marshal(event)
	sig := webhookTestEnv(t, body)

	orig := db.Conn
	db.Conn = nil
	defer func() { db.Conn = orig }()

	w := makeWebhookRequest(body, sig, context.Background())
	if w.Code != http.StatusServiceUnavailable {
		t.Fatalf("expected 503 when DB is not wired, got %d. body: %s", w.Code, w.Body.String())
	}
}