Crussell/backend/internal/square/square_http_client_test.go

//go:build test

package square

import (
	"context"
	"crypto/sha256"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func TestPaymentFromSquare_ElseBranch_SurfacesBrandWithoutCardID(t *testing.T) {
	p := &sqPayment{
		ID:     "pay_1",
		Status: "COMPLETED",
		TotalMoney: sqMoney{Amount: 5000, Currency: "GBP"},
		CardDetails: &sqCardDetails{
			Card: sqCard{
				ID:        "",
				CardBrand: "VISA",
				Last4:     "4242",
			},
		},
	}

	result := paymentFromSquare(p)
	if result.CardBrand != "VISA" {
		t.Errorf("expected CardBrand VISA, got %s", result.CardBrand)
	}
	if result.CardLast4 != "4242" {
		t.Errorf("expected CardLast4 4242, got %s", result.CardLast4)
	}
}

func TestPaymentFromSquare_NilCardDetails(t *testing.T) {
	p := &sqPayment{
		ID:          "pay_2",
		Status:      "COMPLETED",
		TotalMoney:  sqMoney{Amount: 2500, Currency: "GBP"},
		CardDetails: nil,
	}

	result := paymentFromSquare(p)
	if result.CardBrand != "" {
		t.Errorf("expected empty CardBrand when no card details, got %s", result.CardBrand)
	}
	if result.Amount != 2500 {
		t.Errorf("expected amount 2500, got %d", result.Amount)
	}
}

// TestCreateCheckoutHTTP_DeviceOptionsWireShape verifies the terminal checkout
// request puts device_id inside checkout.device_options (Square's required
// shape), not at the top level. A top-level device_id is rejected with 400 by
// Square's real API.
func TestCreateCheckoutHTTP_DeviceOptionsWireShape(t *testing.T) {
	var captured map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/terminals/checkouts" {
			t.Errorf("expected /v2/terminals/checkouts, got %s", r.URL.Path)
		}
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"checkout":{"id":"chk_test","status":"PENDING","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "test-token", http: srv.Client()}

	_, err := createCheckoutHTTPWithClient(context.Background(), CreateCheckoutReq{
		Amount:         5000,
		Currency:       "GBP",
		IdempotencyKey: "ik-1",
		DeviceID:       "dvc_test",
	}, hc)
	if err != nil {
		t.Fatalf("createCheckoutHTTP failed: %v", err)
	}

	checkout, ok := captured["checkout"].(map[string]any)
	if !ok {
		t.Fatalf("expected checkout object in body, got %v", captured)
	}
	// device_id must NOT be at the top level
	if _, hasTopLevel := captured["device_id"]; hasTopLevel {
		t.Errorf("device_id must not be top-level in terminal checkout request: %v", captured)
	}
	// device_id must live under checkout.device_options
	devOpts, ok := checkout["device_options"].(map[string]any)
	if !ok {
		t.Fatalf("expected checkout.device_options in body, got %v", checkout)
	}
	if devOpts["device_id"] != "dvc_test" {
		t.Errorf("expected checkout.device_options.device_id = dvc_test, got %v", devOpts)
	}
}

// TestDoJSON_ErrorParsing covers the doJSON error branches: structured Square
// errors become *squareAPIError (with Code/Detail preserved), while non-JSON
// error bodies fall back to a plain error (so refund classification treats the
// failure as ambiguous).
func TestDoJSON_ErrorParsing(t *testing.T) {
	t.Run("structured_square_error_becomes_squareAPIError", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusBadRequest)
			_, _ = w.Write([]byte(`{"errors":[{"category":"PAYMENT_METHOD_ERROR","code":"REFUND_DECLINED","detail":"The refund was declined","field":"payment_id"}]}`))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "test-token", http: srv.Client()}
		err := hc.doJSON(context.Background(), http.MethodPost, "/v2/refunds", nil, nil)
		if err == nil {
			t.Fatal("expected error")
		}
		var sqErr *squareAPIError
		if !errors.As(err, &sqErr) {
			t.Fatalf("expected *squareAPIError, got %T", err)
		}
		if sqErr.Code != "REFUND_DECLINED" {
			t.Errorf("expected code REFUND_DECLINED, got %s", sqErr.Code)
		}
		if sqErr.Detail != "The refund was declined" {
			t.Errorf("expected detail, got %q", sqErr.Detail)
		}
	})

	t.Run("non_json_error_body_is_plain_error", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "text/plain")
			w.WriteHeader(http.StatusInternalServerError)
			_, _ = w.Write([]byte("upstream blew up"))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "test-token", http: srv.Client()}
		err := hc.doJSON(context.Background(), http.MethodPost, "/v2/refunds", nil, nil)
		if err == nil {
			t.Fatal("expected error")
		}
		var sqErr *squareAPIError
		if errors.As(err, &sqErr) {
			t.Fatalf("expected plain error, got *squareAPIError with code %s", sqErr.Code)
		}
		if !strings.Contains(err.Error(), "HTTP 500") {
			t.Errorf("expected HTTP 500 in error, got %q", err.Error())
		}
	})

	t.Run("http_3xx_is_treated_as_error", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusPermanentRedirect)
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "test-token", http: srv.Client()}
		if err := hc.doJSON(context.Background(), http.MethodPost, "/v2/payments", nil, nil); err == nil {
			t.Fatal("expected error for 3xx status")
		}
	})

	t.Run("empty_token_returns_error_before_http", func(t *testing.T) {
		hc := &httpClient{baseURL: "http://unused", token: "", http: &http.Client{}}
		err := hc.doJSON(context.Background(), http.MethodPost, "/v2/payments", nil, nil)
		if err == nil || !strings.Contains(err.Error(), "SQUARE_ACCESS_TOKEN is not set") {
			t.Fatalf("expected token error, got %v", err)
		}
	})
}

// TestCreatePaymentHTTP_WireShape verifies the exact request body and headers
// sent to POST /v2/payments: source_id, idempotency_key, amount_money,
// location_id fallback, tip_money, and the auth/Square-Version headers.
func TestCreatePaymentHTTP_WireShape(t *testing.T) {
	var captured map[string]any
	var gotAuth, gotVersion, gotContentType string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/payments" {
			t.Errorf("expected /v2/payments, got %s", r.URL.Path)
		}
		gotAuth = r.Header.Get("Authorization")
		gotVersion = r.Header.Get("Square-Version")
		gotContentType = r.Header.Get("Content-Type")
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"payment":{"id":"pay_1","status":"COMPLETED","total_money":{"amount":5000,"currency":"GBP"},"source_type":"CARD","card_details":{"card":{"id":"ccof_x","card_brand":"VISA","last_4":"4242"},"entry_method":"ON_FILE"},"location_id":"loc_env","created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "secret-token", locationID: "loc_env", http: srv.Client()}
	tip := int64(500)
	res, err := createPaymentHTTPWithClient(context.Background(), CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "ik-payment-1",
		ReferenceID:    "bk_123",
		Note:           "deposit",
		TipMoney:       &tip,
		BuyerEmail:     "buyer@example.com",
	}, hc)
	if err != nil {
		t.Fatalf("createPaymentHTTP failed: %v", err)
	}

	if gotAuth != "Bearer secret-token" {
		t.Errorf("expected Authorization 'Bearer secret-token', got %q", gotAuth)
	}
	if gotVersion != squareAPIVersion {
		t.Errorf("expected Square-Version %q, got %q", squareAPIVersion, gotVersion)
	}
	if gotContentType != "application/json" {
		t.Errorf("expected Content-Type application/json, got %q", gotContentType)
	}

	if captured["source_id"] != "cnon:test-card" {
		t.Errorf("expected source_id cnon:test-card, got %v", captured["source_id"])
	}
	if captured["idempotency_key"] != "ik-payment-1" {
		t.Errorf("expected idempotency_key ik-payment-1, got %v", captured["idempotency_key"])
	}
	if captured["location_id"] != "loc_env" {
		t.Errorf("expected location_id loc_env (env fallback), got %v", captured["location_id"])
	}
	amt, ok := captured["amount_money"].(map[string]any)
	if !ok {
		t.Fatalf("expected amount_money object, got %v", captured["amount_money"])
	}
	if amt["amount"] != float64(5000) || amt["currency"] != "GBP" {
		t.Errorf("expected amount_money {5000 GBP}, got %v", amt)
	}
	tipMoney, ok := captured["tip_money"].(map[string]any)
	if !ok {
		t.Fatalf("expected tip_money object, got %v", captured["tip_money"])
	}
	if tipMoney["amount"] != float64(500) {
		t.Errorf("expected tip_money amount 500, got %v", tipMoney["amount"])
	}

	if res.ID != "pay_1" || res.Amount != 5000 || res.CardBrand != "VISA" || res.CardLast4 != "4242" {
		t.Errorf("unexpected payment result: %+v", res)
	}
}

// TestCreatePaymentHTTP_TipMoneyAbsentWhenNil verifies tip_money is omitted
// when not set (it's omitempty in the wire struct).
func TestCreatePaymentHTTP_TipMoneyAbsentWhenNil(t *testing.T) {
	var captured map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"payment":{"id":"pay_2","status":"COMPLETED","total_money":{"amount":1000,"currency":"GBP"},"source_type":"CARD","card_details":{"card":{"id":"ccof_x","card_brand":"MASTERCARD","last_4":"4444"},"entry_method":"ON_FILE"},"location_id":"loc","created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	_, err := createPaymentHTTPWithClient(context.Background(), CreatePaymentReq{
		Amount: 1000, Currency: "GBP", SourceID: "ccof:existing", IdempotencyKey: "ik-2",
	}, hc)
	if err != nil {
		t.Fatalf("createPaymentHTTP failed: %v", err)
	}
	if _, present := captured["tip_money"]; present {
		t.Errorf("expected tip_money to be absent when nil, got %v", captured["tip_money"])
	}
}

// TestRefundPaymentHTTP_CodeClassification verifies definitive refund rejection
// codes (Square's documented list: REFUND_DECLINED, REFUND_AMOUNT_INVALID,
// PAYMENT_NOT_REFUNDABLE) map to ErrRefundDeclined, the money-in-flight codes
// (PAYMENT_ALREADY_REFUNDED, REFUND_ALREADY_PENDING) map to
// ErrRefundAlreadyProcessed, and ambiguous errors pass through unwrapped.
func TestRefundPaymentHTTP_CodeClassification(t *testing.T) {
	cases := []struct {
		name       string
		code       string
		wantErrIs  error // nil = no sentinel expected
		wantErrNil bool
	}{
		{name: "refund_declined", code: "REFUND_DECLINED", wantErrIs: ErrRefundDeclined},
		{name: "amount_invalid", code: "REFUND_AMOUNT_INVALID", wantErrIs: ErrRefundDeclined},
		{name: "payment_not_refundable", code: "PAYMENT_NOT_REFUNDABLE", wantErrIs: ErrRefundDeclined},
		{name: "already_refunded", code: "PAYMENT_ALREADY_REFUNDED", wantErrIs: ErrRefundAlreadyProcessed},
		{name: "already_pending", code: "REFUND_ALREADY_PENDING", wantErrIs: ErrRefundAlreadyProcessed},
		{name: "ambiguous_code", code: "INTERNAL_SERVER_ERROR", wantErrIs: nil},
		{name: "ambiguous_non_json", code: "", wantErrIs: nil}, // raw text body
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.Header().Set("Content-Type", "application/json")
				w.WriteHeader(http.StatusBadRequest)
				if tc.code == "" {
					_, _ = w.Write([]byte("plain text failure"))
				} else {
					_, _ = w.Write([]byte(fmt.Sprintf(`{"errors":[{"category":"PAYMENT_METHOD_ERROR","code":%q,"detail":"boom"}]}`, tc.code)))
				}
			}))
			defer srv.Close()

			hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
			_, err := refundPaymentHTTPWithClient(context.Background(), RefundPaymentReq{
				PaymentID: "pay_1", Amount: 1000, IdempotencyKey: "ik-refund",
			}, hc)
			if tc.wantErrNil {
				if err != nil {
					t.Fatalf("expected nil error, got %v", err)
				}
				return
			}
			if err == nil {
				t.Fatal("expected error")
			}
			if tc.wantErrIs == nil {
				if errors.Is(err, ErrRefundDeclined) || errors.Is(err, ErrRefundAlreadyProcessed) {
					t.Fatalf("expected NO sentinel for ambiguous error, got %v", err)
				}
				return
			}
			if !errors.Is(err, tc.wantErrIs) {
				t.Errorf("expected errors.Is(%v), got %v", tc.wantErrIs, err)
			}
		})
	}
}

// TestRefundPaymentHTTP_WireShape verifies the refund request body and success
// response parsing.
func TestRefundPaymentHTTP_WireShape(t *testing.T) {
	var captured map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/refunds" {
			t.Errorf("expected /v2/refunds, got %s", r.URL.Path)
		}
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"refund":{"id":"ref_1","status":"COMPLETED","amount_money":{"amount":1000,"currency":"GBP"},"payment_id":"pay_1","location_id":"loc","reason":"cancellation","created_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	res, err := refundPaymentHTTPWithClient(context.Background(), RefundPaymentReq{
		PaymentID: "pay_1", Amount: 1000, IdempotencyKey: "ik-refund", Reason: "cancellation",
	}, hc)
	if err != nil {
		t.Fatalf("refundPaymentHTTP failed: %v", err)
	}
	if captured["payment_id"] != "pay_1" {
		t.Errorf("expected payment_id pay_1, got %v", captured["payment_id"])
	}
	if captured["idempotency_key"] != "ik-refund" {
		t.Errorf("expected idempotency_key ik-refund, got %v", captured["idempotency_key"])
	}
	if res.ID != "ref_1" || res.Status != "COMPLETED" || res.Amount != 1000 || res.PaymentID != "pay_1" {
		t.Errorf("unexpected refund result: %+v", res)
	}
}

// TestGetCheckoutHTTP_StatusBranches covers the checkout polling state machine:
// PENDING and IN_PROGRESS → ErrCheckoutPending, CANCELED → generic error,
// COMPLETED without payment IDs → generic error, COMPLETED with payment IDs →
// fetches the payment.
func TestGetCheckoutHTTP_StatusBranches(t *testing.T) {
	t.Run("pending_returns_ErrCheckoutPending", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_1","status":"PENDING","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := getCheckoutHTTPWithClient(context.Background(), "chk_1", hc)
		if !errors.Is(err, ErrCheckoutPending) {
			t.Fatalf("expected ErrCheckoutPending, got %v", err)
		}
	})

	t.Run("in_progress_returns_ErrCheckoutPending", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_2","status":"IN_PROGRESS","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := getCheckoutHTTPWithClient(context.Background(), "chk_2", hc)
		if !errors.Is(err, ErrCheckoutPending) {
			t.Fatalf("expected ErrCheckoutPending, got %v", err)
		}
	})

	t.Run("cancelled_is_generic_error", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_3","status":"CANCELED","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := getCheckoutHTTPWithClient(context.Background(), "chk_3", hc)
		if err == nil || errors.Is(err, ErrCheckoutPending) {
			t.Fatalf("expected generic non-pending error, got %v", err)
		}
		if !strings.Contains(err.Error(), "CANCELED") {
			t.Errorf("expected status in error, got %q", err.Error())
		}
	})

	t.Run("completed_without_payment_ids_is_error", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_4","status":"COMPLETED","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := getCheckoutHTTPWithClient(context.Background(), "chk_4", hc)
		if err == nil || !strings.Contains(err.Error(), "no payment IDs") {
			t.Fatalf("expected 'no payment IDs' error, got %v", err)
		}
	})

	t.Run("completed_fetches_payment", func(t *testing.T) {
		var checkoutPath, paymentPath string
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			switch {
			case r.URL.Path == "/v2/terminals/checkouts/chk_5":
				checkoutPath = r.URL.Path
				_, _ = w.Write([]byte(`{"checkout":{"id":"chk_5","status":"COMPLETED","amount_money":{"amount":5000,"currency":"GBP"},"payment_ids":["pay_5"],"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
			case r.URL.Path == "/v2/payments/pay_5":
				paymentPath = r.URL.Path
				_, _ = w.Write([]byte(`{"payment":{"id":"pay_5","status":"COMPLETED","total_money":{"amount":5000,"currency":"GBP"},"source_type":"CARD","card_details":{"card":{"id":"ccof_x","card_brand":"VISA","last_4":"4242"},"entry_method":"EMV"},"location_id":"loc","created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
			default:
				t.Errorf("unexpected path %s", r.URL.Path)
			}
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		res, err := getCheckoutHTTPWithClient(context.Background(), "chk_5", hc)
		if err != nil {
			t.Fatalf("getCheckoutHTTP failed: %v", err)
		}
		if checkoutPath == "" || paymentPath == "" {
			t.Fatal("expected both checkout and payment fetches")
		}
		if res.ID != "pay_5" || res.Amount != 5000 || res.EntryMethod != "EMV" {
			t.Errorf("unexpected payment result: %+v", res)
		}
	})
}

// TestListRefundsHTTP_Pagination verifies cursor-based pagination: multiple
// pages are fetched, filtered by paymentID, and the 20-page guard triggers.
func TestListRefundsHTTP_Pagination(t *testing.T) {
	t.Run("two_pages_combined_and_filtered", func(t *testing.T) {
		var paths []string
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			paths = append(paths, r.URL.String())
			w.Header().Set("Content-Type", "application/json")
			if strings.Contains(r.URL.RawQuery, "cursor=page2") {
				_, _ = w.Write([]byte(`{"refunds":[{"id":"ref_3","status":"COMPLETED","amount_money":{"amount":1000,"currency":"GBP"},"payment_id":"pay_target","created_at":"2026-07-31T00:00:00Z"},{"id":"ref_4","status":"COMPLETED","amount_money":{"amount":2000,"currency":"GBP"},"payment_id":"pay_other","created_at":"2026-07-31T00:00:00Z"}],"cursor":""}`))
				return
			}
			_, _ = w.Write([]byte(`{"refunds":[{"id":"ref_1","status":"COMPLETED","amount_money":{"amount":500,"currency":"GBP"},"payment_id":"pay_target","created_at":"2026-07-31T00:00:00Z"},{"id":"ref_2","status":"COMPLETED","amount_money":{"amount":900,"currency":"GBP"},"payment_id":"pay_other","created_at":"2026-07-31T00:00:00Z"}],"cursor":"page2"}`))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		begin := time.Date(2026, 7, 1, 0, 0, 0, 0, time.UTC)
		refunds, err := listRefundsHTTPWithClient(context.Background(), "pay_target", begin, hc)
		if err != nil {
			t.Fatalf("listRefundsHTTP failed: %v", err)
		}
		if len(paths) != 2 {
			t.Fatalf("expected 2 pages, got %d: %v", len(paths), paths)
		}
		if !strings.Contains(paths[0], "begin_time=") {
			t.Errorf("expected begin_time in first request, got %q", paths[0])
		}
		if !strings.Contains(paths[0], "limit=100") {
			t.Errorf("expected limit=100 in first request, got %q", paths[0])
		}
		// Only pay_target refunds survive the client-side filter.
		if len(refunds) != 2 {
			t.Fatalf("expected 2 filtered refunds (ref_1 + ref_3), got %d: %+v", len(refunds), refunds)
		}
	})

	t.Run("page_guard_returns_partial_results", func(t *testing.T) {
		// The 20-page guard must not discard what was already collected: it
		// logs a truncation warning and returns the partial results instead
		// of failing the reconcile with an error.
		calls := 0
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			calls++
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"refunds":[{"id":"ref_x","status":"COMPLETED","amount_money":{"amount":100,"currency":"GBP"},"payment_id":"pay_partial","created_at":"2026-07-31T00:00:00Z"}],"cursor":"next"}`))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		refunds, err := listRefundsHTTPWithClient(context.Background(), "pay_partial", time.Now(), hc)
		if err != nil {
			t.Fatalf("expected partial results (nil error), got %v", err)
		}
		if calls != 20 {
			t.Errorf("expected exactly 20 HTTP calls before guard, got %d", calls)
		}
		if len(refunds) != 20 {
			t.Errorf("expected 20 refunds collected across pages (one per page), got %d", len(refunds))
		}
	})
}

// TestCreateCardOnFileHTTP_IdempotencyKey verifies the deterministic SHA-256
// idempotency key derivation and the request wire shape (source_id + card).
func TestCreateCardOnFileHTTP_IdempotencyKey(t *testing.T) {
	var captured map[string]any
	var gotAuth string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/cards" {
			t.Errorf("expected /v2/cards, got %s", r.URL.Path)
		}
		gotAuth = r.Header.Get("Authorization")
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"card":{"id":"ccof_x","card_brand":"VISA","last_4":"4242","exp_month":12,"exp_year":2030,"fingerprint":"fp1","customer_id":"","reference_id":"user_1","enabled":true,"version":1,"created_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "secret", http: srv.Client()}
	res, err := createCardOnFileHTTPWithClient(context.Background(), "user_1", "cnon:test-card", "", hc)
	if err != nil {
		t.Fatalf("createCardOnFileHTTP failed: %v", err)
	}

	sum := sha256.Sum256([]byte("user_1|cnon:test-card"))
	wantIK := "card-" + fmt.Sprintf("%x", sum)[:38]
	if captured["idempotency_key"] != wantIK {
		t.Errorf("expected idempotency_key %q, got %v", wantIK, captured["idempotency_key"])
	}
	// Square's documented idempotency-key limit for /v2/cards is 45 chars —
	// the truncated key must never exceed it (C-1 regression guard).
	if len(wantIK) > 45 {
		t.Errorf("idempotency_key %q is %d chars, exceeds Square's 45-char limit", wantIK, len(wantIK))
	}
	if captured["source_id"] != "cnon:test-card" {
		t.Errorf("expected source_id cnon:test-card, got %v", captured["source_id"])
	}
	card, ok := captured["card"].(map[string]any)
	if !ok {
		t.Fatalf("expected card object, got %v", captured["card"])
	}
	// The local user ID goes in reference_id (free-form); customer_id is
	// emitted only when the app has provisioned a Square customer for the user
	// (empty customerID → omitted via omitempty).
	if card["reference_id"] != "user_1" {
		t.Errorf("expected card.reference_id user_1, got %v", card["reference_id"])
	}
	if _, present := card["customer_id"]; present {
		t.Errorf("expected card.customer_id to be ABSENT when customerID is empty, got %v", card["customer_id"])
	}
	if gotAuth != "Bearer secret" {
		t.Errorf("expected Authorization 'Bearer secret', got %q", gotAuth)
	}
	if res.CardID != "ccof_x" || res.Brand != "VISA" || res.Last4 != "4242" {
		t.Errorf("unexpected card result: %+v", res)
	}
}

// TestCreateCardOnFileHTTP_CustomerIDEmitted verifies card.customer_id is sent
// when the app has provisioned a Square customer for the user (Square marks
// customer_id Required on the Card object for saved-card flows).
func TestCreateCardOnFileHTTP_CustomerIDEmitted(t *testing.T) {
	var captured map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/cards" {
			t.Errorf("expected /v2/cards, got %s", r.URL.Path)
		}
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"card":{"id":"ccof_x","card_brand":"VISA","last_4":"4242","exp_month":12,"exp_year":2030,"fingerprint":"fp1","customer_id":"cus_1","reference_id":"user_1","enabled":true,"version":1,"created_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "secret", http: srv.Client()}
	_, err := createCardOnFileHTTPWithClient(context.Background(), "user_1", "cnon:test-card", "cus_1", hc)
	if err != nil {
		t.Fatalf("createCardOnFileHTTP failed: %v", err)
	}

	card, ok := captured["card"].(map[string]any)
	if !ok {
		t.Fatalf("expected card object, got %v", captured["card"])
	}
	if card["customer_id"] != "cus_1" {
		t.Errorf("expected card.customer_id cus_1, got %v", card["customer_id"])
	}
	// The idempotency key is derived solely from user|card, so it is identical
	// whether or not a customer_id accompanies the request.
	sum := sha256.Sum256([]byte("user_1|cnon:test-card"))
	wantIK := "card-" + fmt.Sprintf("%x", sum)[:38]
	if captured["idempotency_key"] != wantIK {
		t.Errorf("expected idempotency_key %q, got %v", wantIK, captured["idempotency_key"])
	}
}

// TestGetCardsOnFileHTTP_ReferenceIDFilter verifies the List Cards request uses
// the native reference_id filter (the local user ID) — not the invalid
// customer_id — and that cards are returned unfiltered server-side.
func TestGetCardsOnFileHTTP_ReferenceIDFilter(t *testing.T) {
	var gotRawQuery string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			t.Errorf("expected GET, got %s", r.Method)
		}
		if r.URL.Path != "/v2/cards" {
			t.Errorf("expected /v2/cards, got %s", r.URL.Path)
		}
		gotRawQuery = r.URL.RawQuery
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"cards":[{"id":"ccof_1","card_brand":"VISA","last_4":"4242","exp_month":12,"exp_year":2030,"fingerprint":"fp1","reference_id":"user_1","enabled":true,"version":1,"created_at":"2026-07-31T00:00:00Z"},{"id":"ccof_2","card_brand":"MASTERCARD","last_4":"1111","exp_month":6,"exp_year":2029,"fingerprint":"fp2","reference_id":"user_other","enabled":true,"version":1,"created_at":"2026-07-31T00:00:00Z"}]}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	cards, err := getCardsOnFileHTTPWithClient(context.Background(), "user_1", hc)
	if err != nil {
		t.Fatalf("getCardsOnFileHTTP failed: %v", err)
	}

	// Native reference_id filter — never the invalid customer_id, never a
	// limit that Square's List Cards API doesn't support.
	if !strings.Contains(gotRawQuery, "reference_id=user_1") {
		t.Errorf("expected reference_id=user_1 in query, got %q", gotRawQuery)
	}
	if strings.Contains(gotRawQuery, "customer_id") {
		t.Errorf("expected NO customer_id in query (local IDs are not Square customers), got %q", gotRawQuery)
	}
	if strings.Contains(gotRawQuery, "limit") {
		t.Errorf("expected NO limit param (List Cards has no limit; server filters by reference_id), got %q", gotRawQuery)
	}

	if len(cards) != 2 {
		t.Fatalf("expected 2 cards returned, got %d", len(cards))
	}
	if cards[0].ReferenceID != "user_1" || cards[1].ReferenceID != "user_other" {
		t.Errorf("unexpected cards: %+v %+v", cards[0], cards[1])
	}
}

// TestCreateCheckoutHTTP_TipSettings verifies AllowTipping is emitted as
// checkout.device_options.tip_settings.allow_tipping (Square's wire shape for
// enabling terminal tips) and omitted entirely when not set.
func TestCreateCheckoutHTTP_TipSettings(t *testing.T) {
	t.Run("allow_tipping_true_emits_tip_settings", func(t *testing.T) {
		var captured map[string]any
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
				t.Errorf("failed to decode request body: %v", err)
			}
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_tip","status":"PENDING","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := createCheckoutHTTPWithClient(context.Background(), CreateCheckoutReq{
			Amount: 5000, Currency: "GBP", IdempotencyKey: "ik-tip", DeviceID: "dvc_1", AllowTipping: true,
		}, hc)
		if err != nil {
			t.Fatalf("createCheckoutHTTP failed: %v", err)
		}
		checkout, ok := captured["checkout"].(map[string]any)
		if !ok {
			t.Fatalf("expected checkout object, got %v", captured)
		}
		// tip_settings must NOT be at the checkout top level — a top-level
		// tip_settings is silently ignored by Square (terminal tip loss).
		if _, hasTopLevel := checkout["tip_settings"]; hasTopLevel {
			t.Errorf("tip_settings must not be top-level in terminal checkout request: %v", checkout)
		}
		// tip_settings must live under checkout.device_options
		devOpts, ok := checkout["device_options"].(map[string]any)
		if !ok {
			t.Fatalf("expected checkout.device_options in body, got %v", checkout)
		}
		tipSettings, ok := devOpts["tip_settings"].(map[string]any)
		if !ok {
			t.Fatalf("expected device_options.tip_settings when AllowTipping is true, got %v", devOpts)
		}
		if tipSettings["allow_tipping"] != true {
			t.Errorf("expected tip_settings.allow_tipping=true, got %v", tipSettings)
		}
	})

	t.Run("allow_tipping_false_omits_tip_settings", func(t *testing.T) {
		var captured map[string]any
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
				t.Errorf("failed to decode request body: %v", err)
			}
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_notip","status":"PENDING","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()

		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		_, err := createCheckoutHTTPWithClient(context.Background(), CreateCheckoutReq{
			Amount: 5000, Currency: "GBP", IdempotencyKey: "ik-notip", DeviceID: "dvc_1", AllowTipping: false,
		}, hc)
		if err != nil {
			t.Fatalf("createCheckoutHTTP failed: %v", err)
		}
		checkout, ok := captured["checkout"].(map[string]any)
		if !ok {
			t.Fatalf("expected checkout object, got %v", captured)
		}
		// device_options is always present (device_id is required); only the
		// tip_settings sub-object must be absent.
		devOpts, ok := checkout["device_options"].(map[string]any)
		if !ok {
			t.Fatalf("expected checkout.device_options in body, got %v", checkout)
		}
		if _, present := devOpts["tip_settings"]; present {
			t.Errorf("expected device_options.tip_settings ABSENT when AllowTipping is false, got %v", devOpts["tip_settings"])
		}
	})
}

// TestGetPaymentHTTP verifies GET /v2/payments/{id} maps via paymentFromSquare
// and that an empty payment ID errors before any HTTP call.
func TestGetPaymentHTTP_WireShape(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			t.Errorf("expected GET, got %s", r.Method)
		}
		if r.URL.Path != "/v2/payments/pay_1" {
			t.Errorf("expected /v2/payments/pay_1, got %s", r.URL.Path)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"payment":{"id":"pay_1","status":"COMPLETED","total_money":{"amount":5000,"currency":"GBP"},"source_type":"CARD","card_details":{"card":{"id":"ccof_x","card_brand":"VISA","last_4":"4242"},"entry_method":"EMV"},"location_id":"loc","created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	res, err := getPaymentHTTPWithClient(context.Background(), "pay_1", hc)
	if err != nil {
		t.Fatalf("getPaymentHTTP failed: %v", err)
	}
	if res.ID != "pay_1" || res.Amount != 5000 || res.EntryMethod != "EMV" {
		t.Errorf("unexpected payment result: %+v", res)
	}

	_, err = getPaymentHTTPWithClient(context.Background(), "", hc)
	if err == nil || !strings.Contains(err.Error(), "invalid payment id") {
		t.Fatalf("expected empty-ID error, got %v", err)
	}
}

func TestGetPaymentHTTP_NotFound(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusNotFound)
		_, _ = w.Write([]byte(`{"errors":[{"category":"INVALID_REQUEST_ERROR","code":"NOT_FOUND","detail":"Payment not found"}]}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	_, err := getPaymentHTTPWithClient(context.Background(), "pay_missing", hc)
	if err == nil {
		t.Fatal("expected error for not-found payment")
	}
}

// TestCreateCustomerHTTP_WireShape verifies the CreateCustomer request body:
// deterministic "customer-" + sha256(email) idempotency key (≤45 chars),
// email_address, and given_name.
func TestCreateCustomerHTTP_WireShape(t *testing.T) {
	var captured map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Errorf("expected POST, got %s", r.Method)
		}
		if r.URL.Path != "/v2/customers" {
			t.Errorf("expected /v2/customers, got %s", r.URL.Path)
		}
		if err := json.NewDecoder(r.Body).Decode(&captured); err != nil {
			t.Errorf("failed to decode request body: %v", err)
		}
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"customer":{"id":"cus_1","email_address":"jane@example.com","given_name":"Jane","created_at":"2026-07-31T00:00:00Z"}}`))
	}))
	defer srv.Close()

	hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
	res, err := createCustomerHTTPWithClient(context.Background(), "Jane", "jane@example.com", hc)
	if err != nil {
		t.Fatalf("createCustomerHTTP failed: %v", err)
	}

	sum := sha256.Sum256([]byte("jane@example.com"))
	wantIK := "customer-" + fmt.Sprintf("%x", sum)[:35]
	if captured["idempotency_key"] != wantIK {
		t.Errorf("expected idempotency_key %q, got %v", wantIK, captured["idempotency_key"])
	}
	// Square's documented idempotency-key limit is 45 chars — the truncated
	// key must never exceed it.
	if len(wantIK) > 45 {
		t.Errorf("idempotency_key %q is %d chars, exceeds Square's 45-char limit", wantIK, len(wantIK))
	}
	if captured["email_address"] != "jane@example.com" {
		t.Errorf("expected email_address jane@example.com, got %v", captured["email_address"])
	}
	if captured["given_name"] != "Jane" {
		t.Errorf("expected given_name Jane, got %v", captured["given_name"])
	}
	if res.ID != "cus_1" || res.Email != "jane@example.com" || res.CreatedAt == "" {
		t.Errorf("unexpected customer result: %+v", res)
	}
}

// TestCancelCheckoutHTTP_NonFatalErrors verifies CancelCheckout treats
// already-completed/unknown checkouts as a no-op: structured NOT_FOUND, plain
// HTTP 404, and success all return nil. Genuine failures propagate.
func TestCancelCheckoutHTTP_NonFatalErrors(t *testing.T) {
	t.Run("success_is_nil", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.Method != http.MethodPost {
				t.Errorf("expected POST, got %s", r.Method)
			}
			if r.URL.Path != "/v2/terminals/checkouts/chk_1/cancel" {
				t.Errorf("expected cancel path, got %s", r.URL.Path)
			}
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"checkout":{"id":"chk_1","status":"CANCELED","amount_money":{"amount":5000,"currency":"GBP"},"created_at":"2026-07-31T00:00:00Z","updated_at":"2026-07-31T00:00:00Z"}}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		if err := cancelCheckoutHTTPWithClient(context.Background(), "chk_1", hc); err != nil {
			t.Fatalf("expected nil for successful cancel, got %v", err)
		}
	})

	t.Run("structured_not_found_is_nil", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusNotFound)
			_, _ = w.Write([]byte(`{"errors":[{"category":"INVALID_REQUEST_ERROR","code":"NOT_FOUND","detail":"Checkout not found or already completed"}]}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		if err := cancelCheckoutHTTPWithClient(context.Background(), "chk_missing", hc); err != nil {
			t.Fatalf("expected nil for NOT_FOUND (already completed is a no-op), got %v", err)
		}
	})

	t.Run("plain_404_is_nil", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusNotFound)
			_, _ = w.Write([]byte("checkout not found"))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		if err := cancelCheckoutHTTPWithClient(context.Background(), "chk_404", hc); err != nil {
			t.Fatalf("expected nil for plain HTTP 404, got %v", err)
		}
	})

	t.Run("other_error_propagates", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusBadRequest)
			_, _ = w.Write([]byte(`{"errors":[{"category":"INVALID_REQUEST_ERROR","code":"INVALID_VALUE","detail":"bad"}]}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		if err := cancelCheckoutHTTPWithClient(context.Background(), "chk_bad", hc); err == nil {
			t.Fatal("expected non-nil error for genuine failure")
		}
	})

	t.Run("noop_code_is_error", func(t *testing.T) {
		// "NOOP" is NOT a confirmed Square error code, so it must propagate as
		// an error — only NOT_FOUND is treated as an idempotent no-op.
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusBadRequest)
			_, _ = w.Write([]byte(`{"errors":[{"category":"INVALID_REQUEST_ERROR","code":"NOOP","detail":"nothing to cancel"}]}`))
		}))
		defer srv.Close()
		hc := &httpClient{baseURL: srv.URL, token: "t", http: srv.Client()}
		err := cancelCheckoutHTTPWithClient(context.Background(), "chk_noop", hc)
		if err == nil {
			t.Fatal("expected NOOP code to propagate as an error (NOOP is not a confirmed Square code)")
		}
		if code := ErrorCode(err); code != "NOOP" {
			t.Errorf("expected NOOP code on error, got %q", code)
		}
	})
}

// TestPaymentFromSquare_ExpiryPointers verifies exp_month/exp_year are set as
// pointers when card details are present and left nil when absent.
func TestPaymentFromSquare_ExpiryPointers(t *testing.T) {
	t.Run("card_details_sets_pointers", func(t *testing.T) {
		p := &sqPayment{
			ID: "pay_exp", Status: "COMPLETED", TotalMoney: sqMoney{Amount: 5000, Currency: "GBP"},
			CardDetails: &sqCardDetails{
				Card: sqCard{ID: "ccof_x", CardBrand: "VISA", Last4: "4242", ExpMonth: 12, ExpYear: 2030},
			},
		}
		result := paymentFromSquare(p)
		if result.ExpMonth == nil || result.ExpYear == nil {
			t.Fatalf("expected non-nil expiry pointers, got %v/%v", result.ExpMonth, result.ExpYear)
		}
		if *result.ExpMonth != 12 || *result.ExpYear != 2030 {
			t.Errorf("expected exp 12/2030, got %d/%d", *result.ExpMonth, *result.ExpYear)
		}
	})

	t.Run("no_card_details_leaves_nil", func(t *testing.T) {
		p := &sqPayment{ID: "pay_noexp", Status: "COMPLETED", TotalMoney: sqMoney{Amount: 2500, Currency: "GBP"}}
		result := paymentFromSquare(p)
		if result.ExpMonth != nil || result.ExpYear != nil {
			t.Errorf("expected nil expiry without card details, got %v/%v", result.ExpMonth, result.ExpYear)
		}
	})
}

// TestValidSquareID covers the URL path-segment safety check: Square IDs are
// alphanumeric plus '_' and '-' and at most 64 chars. Empty, over-long, and
// any character outside that set is rejected before it can reach a URL path.
func TestValidSquareID(t *testing.T) {
	valid := []string{
		"pay_123",
		"P1-abc",
		"chk_1",
		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-", // exactly 64 chars
	}
	invalid := []string{
		"",
		"has space",
		"bad/char",
		"bad.char",
		"traversal/../..",
		strings.Repeat("a", 65),
	}
	for _, id := range valid {
		if !validSquareID(id) {
			t.Errorf("expected %q to be a valid Square ID", id)
		}
	}
	for _, id := range invalid {
		if validSquareID(id) {
			t.Errorf("expected %q to be rejected", id)
		}
	}
}

// TestIDValidation_RejectsBeforeHTTP verifies getPayment/getCheckout/cancelCheckout
// reject malformed IDs before building the request URL. The client points at an
// unused host: a request that slipped past validation would fail with a network
// error instead of an "invalid ... id" error, so the assertion is meaningful.
func TestIDValidation_RejectsBeforeHTTP(t *testing.T) {
	hc := &httpClient{baseURL: "http://unused", token: "t", http: &http.Client{}}
	ctx := context.Background()

	_, err := getPaymentHTTPWithClient(ctx, "bad/id", hc)
	if err == nil || !strings.Contains(err.Error(), "invalid payment id") {
		t.Fatalf("expected invalid payment id error, got %v", err)
	}

	_, err = getCheckoutHTTPWithClient(ctx, "bad/id", hc)
	if err == nil || !strings.Contains(err.Error(), "invalid checkout id") {
		t.Fatalf("expected invalid checkout id error, got %v", err)
	}

	err = cancelCheckoutHTTPWithClient(ctx, "bad/id", hc)
	if err == nil || !strings.Contains(err.Error(), "invalid checkout id") {
		t.Fatalf("expected invalid checkout id error, got %v", err)
	}
}

// TestErrorCode_ErrorDetail verifies the exported accessors surface the
// structured Square error Code/Detail for direct and wrapped *squareAPIError
// values, and return "" for non-Square errors (so handlers can classify charge
// failures structurally instead of substring-matching).
func TestErrorCode_ErrorDetail(t *testing.T) {
	t.Run("direct", func(t *testing.T) {
		base := &squareAPIError{Code: "INVALID_VALUE", Detail: "bad thing", err: errors.New("square: boom")}
		if got := ErrorCode(base); got != "INVALID_VALUE" {
			t.Errorf("expected INVALID_VALUE, got %q", got)
		}
		if got := ErrorDetail(base); got != "bad thing" {
			t.Errorf("expected detail 'bad thing', got %q", got)
		}
	})

	t.Run("wrapped", func(t *testing.T) {
		base := &squareAPIError{Code: "CARD_DECLINED", Detail: "card declined", err: errors.New("square: boom")}
		wrapped := fmt.Errorf("wrap: %w", base)
		if got := ErrorCode(wrapped); got != "CARD_DECLINED" {
			t.Errorf("expected CARD_DECLINED through wrap, got %q", got)
		}
		if got := ErrorDetail(wrapped); got != "card declined" {
			t.Errorf("expected detail through wrap, got %q", got)
		}
	})

	t.Run("non_square_error", func(t *testing.T) {
		if got := ErrorCode(errors.New("plain")); got != "" {
			t.Errorf("expected \"\", got %q", got)
		}
		if got := ErrorDetail(errors.New("plain")); got != "" {
			t.Errorf("expected \"\", got %q", got)
		}
		if got := ErrorCode(nil); got != "" {
			t.Errorf("expected \"\" for nil, got %q", got)
		}
		if got := ErrorDetail(nil); got != "" {
			t.Errorf("expected \"\" for nil, got %q", got)
		}
	})
}