//go:build test
// +build test

package webhooks

import (
	"bytes"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

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

func TestVerifySquareSignature_ValidSignature(t *testing.T) {
	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	key := "test-signing-key"

	mac := hmac.New(sha256.New, []byte(key))
	mac.Write(body)
	expectedSig := hex.EncodeToString(mac.Sum(nil))

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

func TestVerifySquareSignature_InvalidSignature(t *testing.T) {
	body := []byte(`{"type":"payment.updated"}`)
	key := "test-signing-key"

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

func TestVerifySquareSignature_WrongKey(t *testing.T) {
	body := []byte(`{"type":"payment.updated"}`)

	mac := hmac.New(sha256.New, []byte("correct-key"))
	mac.Write(body)
	sig := hex.EncodeToString(mac.Sum(nil))

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

func TestVerifySquareSignature_EmptyBody(t *testing.T) {
	key := "test-signing-key"

	mac := hmac.New(sha256.New, []byte(key))
	mac.Write([]byte{})
	expectedSig := hex.EncodeToString(mac.Sum(nil))

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

func TestVerifySquareSignature_TamperedBody(t *testing.T) {
	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	key := "test-signing-key"

	mac := hmac.New(sha256.New, []byte(key))
	mac.Write(body)
	sig := hex.EncodeToString(mac.Sum(nil))

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

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

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

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)
	w := makeWebhookRequest(body, "")
	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)
	w := makeWebhookRequest(body, "")
	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)
	w := makeWebhookRequest(body, "")
	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)
	w := makeWebhookRequest(body, "")
	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) {
	w := makeWebhookRequest([]byte(`{invalid json}`), "")
	if w.Code != http.StatusBadRequest {
		t.Errorf("expected 400 for invalid JSON, got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_BodyTooLarge(t *testing.T) {
	// 600KB body exceeds the 512KB limit
	largeBody := []byte(strings.Repeat("a", 600*1024))
	w := makeWebhookRequest(largeBody, "")
	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"

	mac := hmac.New(sha256.New, []byte(key))
	mac.Write(body)
	sig := hex.EncodeToString(mac.Sum(nil))

	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", key)

	w := makeWebhookRequest(body, sig)
	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")
	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, "")
	if w.Code != http.StatusOK {
		t.Errorf("expected 200 when no signature provided (dev stub), got %d. body: %s", w.Code, w.Body.String())
	}
}

func TestHandleSquareWebhook_SignatureSkippedWhenKeyEmpty(t *testing.T) {
	t.Setenv("SQUARE_WEBHOOK_SIGNATURE_KEY", "")

	body := []byte(`{"type":"payment.updated","event_id":"evt_1"}`)
	// Bad signature but key is empty, so verification should be skipped
	w := makeWebhookRequest(body, "some-signature")
	if w.Code != http.StatusOK {
		t.Errorf("expected 200 when no key configured (dev stub), got %d. body: %s", w.Code, w.Body.String())
	}
}