//go:build test && dev

package square

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestDevClient_CreatePayment_ReturnsCompleted(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "test-key-1",
		ReferenceID:    "booking-123",
		Note:           "full",
	}

	result, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "COMPLETED", result.Status)
	assert.Equal(t, int64(5000), result.Amount)
	assert.Equal(t, "VISA", result.CardBrand)
	assert.Equal(t, "4242", result.CardLast4)
	assert.NotZero(t, result.Fees)

	assert.NotEmpty(t, result.CardFingerprint)
	require.NotNil(t, result.ExpMonth)
	assert.Equal(t, 12, *result.ExpMonth)
	require.NotNil(t, result.ExpYear)
	assert.Equal(t, 2030, *result.ExpYear)
	assert.Equal(t, "KEYED", result.EntryMethod)
	assert.Equal(t, "CVV_ACCEPTED", result.CVVStatus)
	assert.Equal(t, "AVS_ACCEPTED", result.AVSStatus)
	assert.NotEmpty(t, result.ReceiptNumber)
	assert.NotEmpty(t, result.CreatedAt)
	assert.NotEmpty(t, result.LocationID)
}

func TestDevClient_CreateCheckout_PendingThenCompleted(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	req := CreateCheckoutReq{
		Amount:         7500,
		Currency:       "GBP",
		IdempotencyKey: "checkout-key-1",
		ReferenceID:    "booking-456",
		AllowTipping:   true,
	}

	result, err := client.CreateCheckout(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "PENDING", result.Status)
	assert.NotEmpty(t, result.ID)

	assert.Equal(t, int64(7500), result.AmountMoney)
	assert.Equal(t, "GBP", result.Currency)
	assert.NotEmpty(t, result.CreatedAt)

	// Poll until the background goroutine completes using assert.Eventually
	var completed *PaymentResult
	assert.Eventually(t, func() bool {
		var getErr error
		completed, getErr = client.GetCheckout(ctx, result.ID)
		return getErr == nil && completed.Status == "COMPLETED"
	}, 5*time.Second, 100*time.Millisecond, "expected checkout to complete")

	assert.Equal(t, int64(8000), completed.Amount, "expected amount 8000 (7500 + 500 tip)")
	assert.Equal(t, int64(500), completed.TipAmount)

	assert.NotEmpty(t, completed.CardFingerprint)
	assert.NotEmpty(t, completed.EntryMethod)
}

func TestDevClient_CreateCheckout_NoTip(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	req := CreateCheckoutReq{
		Amount:         5000,
		Currency:       "GBP",
		IdempotencyKey: "checkout-key-notip",
		ReferenceID:    "booking-789",
		AllowTipping:   false,
	}

	result, err := client.CreateCheckout(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "PENDING", result.Status)
	assert.NotEmpty(t, result.ID)

	assert.Equal(t, int64(5000), result.AmountMoney)
	assert.Equal(t, "GBP", result.Currency)
	assert.NotEmpty(t, result.CreatedAt)

	var completed *PaymentResult
	assert.Eventually(t, func() bool {
		var getErr error
		completed, getErr = client.GetCheckout(ctx, result.ID)
		return getErr == nil && completed.Status == "COMPLETED"
	}, 5*time.Second, 100*time.Millisecond, "expected checkout to complete")

	assert.Equal(t, int64(5000), completed.Amount, "expected amount 5000 (no tip)")
	assert.Equal(t, int64(0), completed.TipAmount)

	assert.NotEmpty(t, completed.CardFingerprint)
	assert.NotEmpty(t, completed.EntryMethod)
}

func TestDevClient_RefundPayment_ReturnsCompleted(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()

	paymentReq := CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-refund",
		ReferenceID:    "booking-refund",
		Note:           "full",
	}

	paymentResult, err := client.CreatePayment(ctx, paymentReq)
	require.NoError(t, err)

	refundReq := RefundPaymentReq{
		PaymentID:      paymentResult.ID,
		Amount:         5000,
		IdempotencyKey: "refund-key-1",
		Reason:         "customer request",
	}

	refundResult, err := client.RefundPayment(ctx, refundReq)
	require.NoError(t, err)
	assert.Equal(t, "COMPLETED", refundResult.Status)
	assert.Equal(t, int64(5000), refundResult.Amount)

	assert.NotEmpty(t, refundResult.PaymentID)
	assert.Equal(t, "customer request", refundResult.Reason)
	assert.NotEmpty(t, refundResult.CreatedAt)
}

func TestDevClient_CardOnFile_CreateAndGet(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	userID := "user-test-123"

	card, err := client.CreateCardOnFile(ctx, userID, "cnon:test-token", "")
	require.NoError(t, err)

	assert.NotEmpty(t, card.ID)
	assert.Equal(t, "VISA", card.Brand)
	assert.Equal(t, "4242", card.Last4)
	assert.True(t, card.IsDefault)

	assert.True(t, card.Enabled)
	assert.NotEmpty(t, card.CardholderName)
	assert.NotEmpty(t, card.CreatedAt)

	cards, err := client.GetCardsOnFile(ctx, userID)
	require.NoError(t, err)

	require.Len(t, cards, 1)
	assert.Equal(t, card.ID, cards[0].ID)
}

func TestDevClient_CardOnFile_MultipleCards(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	userID := "user-test-multiple"

	card1, err := client.CreateCardOnFile(ctx, userID, "cnon:token-1", "")
	require.NoError(t, err)

	card2, err := client.CreateCardOnFile(ctx, userID, "cnon:token-2", "")
	require.NoError(t, err)

	assert.True(t, card1.Enabled)
	assert.True(t, card2.Enabled)
	assert.NotEmpty(t, card1.CreatedAt)
	assert.NotEmpty(t, card2.CreatedAt)

	cards, err := client.GetCardsOnFile(ctx, userID)
	require.NoError(t, err)

	require.Len(t, cards, 2)
	assert.True(t, card1.IsDefault)
	assert.False(t, card2.IsDefault)
}

func TestDevClient_CardOnFile_Delete(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	userID := "user-test-delete"

	card, err := client.CreateCardOnFile(ctx, userID, "cnon:token-delete", "")
	require.NoError(t, err)

	err = client.DeleteCardOnFile(ctx, card.ID)
	require.NoError(t, err)

	cards, err := client.GetCardsOnFile(ctx, userID)
	require.NoError(t, err)

	require.Len(t, cards, 1)
	assert.False(t, cards[0].Enabled)
}

func TestDevClient_CardOnFile_DeleteNotFound(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()

	err := client.DeleteCardOnFile(ctx, "non-existent-card")
	require.Error(t, err)
}

func TestDevClient_GetCheckout_NotFound(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()

	_, err := client.GetCheckout(ctx, "non-existent-checkout")
	require.Error(t, err)
}

func TestDevClient_CreateCardOnFile_RejectsRawPAN(t *testing.T) {
	// PCI-DSS parity: CreateCardOnFile accepts only token-like source_ids
	// (cnon:xxx / ccof:xxx). Raw PANs are rejected exactly like real Square.
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	tests := []struct {
		name       string
		cardNumber string
	}{
		{"visa", "4111111111111111"},
		{"mastercard", "5555555555554444"},
		{"amex", "378282246310005"},
		{"discover", "6011111111111117"},
		{"too short", "123"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			card, err := client.CreateCardOnFile(ctx, "user-raw-"+tt.name, tt.cardNumber, "")
			require.Error(t, err, "raw PAN must be rejected for production parity")
			assert.Nil(t, card)
			assert.Contains(t, err.Error(), "invalid source_id")
		})
	}
}

func TestCreatePayment_ShouldFail(t *testing.T) {
	client := NewDevClient().(*MockClient)
	client.ShouldFail = true

	ctx := context.Background()
	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "test-key-fail",
		ReferenceID:    "booking-fail",
	}

	result, err := client.CreatePayment(ctx, req)
	require.Error(t, err, "expected error when ShouldFail is true")
	assert.Nil(t, result)
}

func TestRefundPayment_ShouldFail(t *testing.T) {
	client := NewDevClient().(*MockClient)
	client.ShouldFail = true

	ctx := context.Background()
	req := RefundPaymentReq{
		PaymentID:      "pay_mock_fail",
		Amount:         5000,
		IdempotencyKey: "refund-key-fail",
		Reason:         "simulated failure",
	}

	result, err := client.RefundPayment(ctx, req)
	require.Error(t, err, "expected error when ShouldFail is true")
	assert.Nil(t, result)
}

func TestDevClient_RefundPayment_PaymentAlreadyRefunded(t *testing.T) {
	// PAYMENT_ALREADY_REFUNDED means the money already moved at Square, so the
	// mock must return ErrRefundAlreadyProcessed (never ErrRefundDeclined) and
	// must not store a refund — the caller resolves the record to 'completed'.
	client := NewDevClient().(*MockClient)
	client.FailRefundCode = "PAYMENT_ALREADY_REFUNDED"

	ctx := context.Background()
	req := RefundPaymentReq{
		PaymentID:      "pay_mock_already_refunded",
		Amount:         5000,
		IdempotencyKey: "refund-key-already",
		Reason:         "already refunded",
	}

	result, err := client.RefundPayment(ctx, req)
	require.Error(t, err)
	assert.Nil(t, result)
	assert.True(t, errors.Is(err, ErrRefundAlreadyProcessed), "expected ErrRefundAlreadyProcessed, got: %v", err)
	assert.False(t, errors.Is(err, ErrRefundDeclined), "already-processed refund must not be classified as declined: %v", err)

	client.mu.RLock()
	defer client.mu.RUnlock()
	assert.Len(t, client.refunds, 0, "no refund must be stored when the payment is already refunded")
	assert.Len(t, client.refundByKey, 0, "no refund-by-key entry must be stored when the payment is already refunded")
}

func TestDevClient_RefundPayment_FailRefundCode_OtherCode(t *testing.T) {
	// Any other code configured via FailRefundCode preserves the prior
	// ErrRefundDeclined classification (e.g. REFUND_DECLINED in prod).
	client := NewDevClient().(*MockClient)
	client.FailRefundCode = "REFUND_DECLINED"

	ctx := context.Background()
	req := RefundPaymentReq{
		PaymentID:      "pay_mock_refund_declined",
		Amount:         5000,
		IdempotencyKey: "refund-key-declined",
		Reason:         "declined",
	}

	result, err := client.RefundPayment(ctx, req)
	require.Error(t, err)
	assert.Nil(t, result)
	assert.True(t, errors.Is(err, ErrRefundDeclined), "expected ErrRefundDeclined, got: %v", err)
	assert.False(t, errors.Is(err, ErrRefundAlreadyProcessed), "declined refund must not be classified as already processed: %v", err)
}

func TestDevClient_ConcurrentPayments(t *testing.T) {
	client := NewDevClient().(*MockClient)

	ctx := context.Background()
	var wg sync.WaitGroup
	results := make(chan *PaymentResult, 10)
	errors := make(chan error, 10)

	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func(idx int) {
			defer wg.Done()

			req := CreatePaymentReq{
				Amount:         int64(1000 + idx*100),
				Currency:       "GBP",
				SourceID:       "cnon:test-card",
				IdempotencyKey: fmt.Sprintf("concurrent-key-%d", idx),
				ReferenceID:    "booking-concurrent",
				Note:           "full",
			}

			payResult, payErr := client.CreatePayment(ctx, req)
			if payErr != nil {
				errors <- payErr
				return
			}
			results <- payResult
		}(i)
	}

	wg.Wait()
	close(results)
	close(errors)

	errorCount := 0
	for range errors {
		errorCount++
	}
	assert.Zero(t, errorCount, "expected no concurrent errors")

	resultCount := 0
	for payResult := range results {
		assert.Equal(t, "COMPLETED", payResult.Status)
		assert.NotEmpty(t, payResult.CreatedAt)
		resultCount++
	}
	assert.Equal(t, 10, resultCount)
}

func TestDevClient_CreatePayment_WithTipMoney(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	tip := int64(1000)
	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "test-key-tip",
		ReferenceID:    "booking-tip",
		Note:           "full",
		TipMoney:       &tip,
	}

	result, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "COMPLETED", result.Status)
	assert.Equal(t, int64(6000), result.Amount)
	assert.Equal(t, int64(1000), result.TipAmount)
}

func TestDevClient_CreatePayment_DedupsOnIdempotencyKey(t *testing.T) {
	// Real Square dedups on idempotency key: a same-key retry returns the
	// original payment. The mock must mirror this or dev/testing diverges
	// from production (and the pending-retry logic can't be exercised).
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "dedup-key-1",
		ReferenceID:    "booking-dedup",
	}

	first, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	require.NotEmpty(t, first.ID)

	second, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, first.ID, second.ID, "same-key retry must return the original payment, not a new one")

	// Total stored payments for this key must be one (deduped).
	client.mu.RLock()
	byKey := client.paymentByKey["dedup-key-1"]
	client.mu.RUnlock()
	assert.NotNil(t, byKey)
	assert.Equal(t, first.ID, byKey.ID)
}

func TestDevClient_RefundPayment_DedupsOnIdempotencyKey(t *testing.T) {
	// Real Square dedups on idempotency key: a same-key retry returns the
	// original refund. The mock must mirror this or the pending-refund resume
	// path can't be exercised (and a retry could double-refund the customer).
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	paymentResult, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-refund-dedup",
		ReferenceID:    "booking-refund-dedup",
	})
	require.NoError(t, err)

	req := RefundPaymentReq{
		PaymentID:      paymentResult.ID,
		Amount:         5000,
		IdempotencyKey: "refund-dedup-key-1",
		Reason:         "customer request",
	}

	first, err := client.RefundPayment(ctx, req)
	require.NoError(t, err)
	require.NotEmpty(t, first.ID)

	second, err := client.RefundPayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, first.ID, second.ID, "same-key retry must return the original refund, not a new one")

	// Only one refund stored in the mock's refunds map (deduped).
	client.mu.RLock()
	defer client.mu.RUnlock()
	assert.Len(t, client.refunds, 1, "same-key retry must not store a second refund")
	byKey := client.refundByKey["refund-dedup-key-1"]
	assert.NotNil(t, byKey)
	assert.Equal(t, first.ID, byKey.ID)
}

func TestDevClient_CreatePayment_AutocompleteFalse(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	autocomplete := false
	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "test-key-autocomplete",
		ReferenceID:    "booking-autocomplete",
		Autocomplete:   &autocomplete,
	}

	result, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "APPROVED", result.Status)
	assert.Equal(t, int64(5000), result.Amount)
}

func TestDevClient_CreatePayment_WithBuyerEmail(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	req := CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "test-key-email",
		ReferenceID:    "booking-email",
		BuyerEmail:     "test@example.com",
	}

	result, err := client.CreatePayment(ctx, req)
	require.NoError(t, err)
	assert.Equal(t, "COMPLETED", result.Status)
	assert.Equal(t, "test@example.com", result.BuyerEmail)
}

func TestDevClient_CreateCardOnFile_WithNewFields(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()
	userID := "user-new-fields"

	card, err := client.CreateCardOnFile(ctx, userID, "cnon:test-token", "")
	require.NoError(t, err)

	assert.True(t, card.Enabled)
	assert.NotEmpty(t, card.CardholderName)
	// Local linkage goes in reference_id; the mock does not store the
	// customer_id (prod sends it on card creation when the app has provisioned
	// a Square customer for the user).
	assert.Equal(t, userID, card.ReferenceID)
	assert.Empty(t, card.CustomerID)
	assert.Greater(t, card.Version, int64(0))
	assert.NotEmpty(t, card.CreatedAt)
}

func TestDevClient_DeleteCardOnFile_SoftDelete(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()
	userID := "user-soft-delete"

	card, err := client.CreateCardOnFile(ctx, userID, "cnon:token-soft", "")
	require.NoError(t, err)

	err = client.DeleteCardOnFile(ctx, card.ID)
	require.NoError(t, err)

	cards, err := client.GetCardsOnFile(ctx, userID)
	require.NoError(t, err)
	require.Len(t, cards, 1)
	assert.False(t, cards[0].Enabled)
}

func TestDevClient_GetCardsOnFile_Empty(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	cards, err := client.GetCardsOnFile(ctx, "user-no-cards")
	require.NoError(t, err)
	assert.Empty(t, cards)
}

func TestDevClient_GetCheckout_StillPending(t *testing.T) {
	client := NewDevClient().(*MockClient)
	client.HoldCheckouts = true
	ctx := context.Background()

	result, err := client.CreateCheckout(ctx, CreateCheckoutReq{
		Amount:         5000,
		Currency:       "GBP",
		IdempotencyKey: "pending-checkout",
		ReferenceID:    "pending-ref",
	})
	require.NoError(t, err)
	assert.Equal(t, "PENDING", result.Status)

	_, err = client.GetCheckout(ctx, result.ID)
	require.Error(t, err)
	assert.Contains(t, err.Error(), "pending")
}

func TestDevClient_CreateCheckout_HoldCheckouts(t *testing.T) {
	client := NewDevClient().(*MockClient)
	client.HoldCheckouts = true
	ctx := context.Background()

	result, err := client.CreateCheckout(ctx, CreateCheckoutReq{
		Amount:         2500,
		Currency:       "GBP",
		IdempotencyKey: "hold-checkout",
		ReferenceID:    "hold-ref",
	})
	require.NoError(t, err)
	assert.Equal(t, "PENDING", result.Status)

	_, err = client.GetCheckout(ctx, result.ID)
	require.Error(t, err)
}

func TestDevClient_ListPaymentRefunds_FiltersByPaymentAndTime(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	begin := time.Date(2026, 7, 1, 0, 0, 0, 0, time.UTC)
	client.mu.Lock()
	client.refunds["ref_1"] = &RefundResult{
		ID: "ref_1", Status: "COMPLETED", Amount: 5000, PaymentID: "pay_a",
		LocationID: "L_MOCK", Reason: "customer request", CreatedAt: begin.Add(2 * 24 * time.Hour).Format(time.RFC3339),
	}
	client.refunds["ref_2"] = &RefundResult{
		ID: "ref_2", Status: "COMPLETED", Amount: 2500, PaymentID: "pay_b",
		LocationID: "L_MOCK", Reason: "customer request", CreatedAt: begin.Add(3 * 24 * time.Hour).Format(time.RFC3339),
	}
	client.refunds["ref_3"] = &RefundResult{
		ID: "ref_3", Status: "COMPLETED", Amount: 1000, PaymentID: "pay_a",
		LocationID: "L_MOCK", Reason: "customer request", CreatedAt: begin.Add(-1 * 24 * time.Hour).Format(time.RFC3339),
	}
	client.mu.Unlock()

	results, err := client.ListPaymentRefunds(ctx, "pay_a", begin)
	require.NoError(t, err)
	require.Len(t, results, 1, "only the pay_a refund created after beginTime must be returned")
	assert.Equal(t, "ref_1", results[0].ID)
	assert.Equal(t, int64(5000), results[0].Amount)
	assert.Equal(t, "COMPLETED", results[0].Status)
	assert.Equal(t, "pay_a", results[0].PaymentID)
}

func TestDevClient_ListPaymentRefunds_AfterRefundPayment(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	paymentResult, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-list-refunds",
		ReferenceID:    "booking-list-refunds",
	})
	require.NoError(t, err)

	refundResult, err := client.RefundPayment(ctx, RefundPaymentReq{
		PaymentID:      paymentResult.ID,
		Amount:         5000,
		IdempotencyKey: "refund-for-list",
		Reason:         "customer request",
	})
	require.NoError(t, err)

	results, err := client.ListPaymentRefunds(ctx, paymentResult.ID, time.Now().Add(-24*time.Hour))
	require.NoError(t, err)
	require.Len(t, results, 1, "the refund stored by RefundPayment must be listed")
	assert.Equal(t, refundResult.ID, results[0].ID)
	assert.Equal(t, int64(5000), results[0].Amount)
	assert.Equal(t, "COMPLETED", results[0].Status)
	assert.Equal(t, paymentResult.ID, results[0].PaymentID)
}

func TestDevClient_ListPaymentRefunds_Empty(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	results, err := client.ListPaymentRefunds(ctx, "pay_unknown", time.Now().Add(-24*time.Hour))
	require.NoError(t, err)
	assert.NotNil(t, results, "must return an empty slice, not nil")
	assert.Empty(t, results)
}

func TestDetectCardInfo_Variants(t *testing.T) {
	tests := []struct {
		sourceID  string
		wantBrand string
		wantLast4 string
	}{
		{"cnon:test-card", "VISA", "4242"},
		{"cnon:visa", "VISA", "1111"},
		{"cnon:mastercard", "MASTERCARD", "4444"},
		{"cnon:amex", "AMERICAN_EXPRESS", "0005"},
		{"unknown-source", "VISA", "4242"},
		{"", "VISA", "4242"},
	}

	for _, tt := range tests {
		t.Run(tt.sourceID, func(t *testing.T) {
			brand, last4 := detectCardInfo(tt.sourceID)
			assert.Equal(t, tt.wantBrand, brand)
			assert.Equal(t, tt.wantLast4, last4)
		})
	}
}

func TestDevClient_GetPayment_Found(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	created, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         5000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-get",
		ReferenceID:    "booking-get",
	})
	require.NoError(t, err)

	got, err := client.GetPayment(ctx, created.ID)
	require.NoError(t, err)
	assert.Equal(t, created.ID, got.ID)
	assert.Equal(t, int64(5000), got.Amount)
	assert.Equal(t, "COMPLETED", got.Status)
}

func TestDevClient_GetPayment_NotFound(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	_, err := client.GetPayment(ctx, "pay_does_not_exist")
	require.Error(t, err)
	assert.Contains(t, err.Error(), "not found")
}

func TestDevClient_CreateCustomer_Dedup(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	first, err := client.CreateCustomer(ctx, "Jane Doe", "jane@example.com")
	require.NoError(t, err)
	require.NotEmpty(t, first.ID)
	assert.Equal(t, "jane@example.com", first.Email)
	assert.NotEmpty(t, first.CreatedAt)
	assert.True(t, strings.HasPrefix(first.ID, "cus_mock_"))

	// Same email → same deterministic customer (Square dedups on the
	// email-derived idempotency key; the mock dedups on email).
	second, err := client.CreateCustomer(ctx, "Jane Doe", "jane@example.com")
	require.NoError(t, err)
	assert.Equal(t, first.ID, second.ID, "same-email retry must return the original customer")

	other, err := client.CreateCustomer(ctx, "John Doe", "john@example.com")
	require.NoError(t, err)
	assert.NotEqual(t, first.ID, other.ID)

	client.mu.RLock()
	defer client.mu.RUnlock()
	assert.Len(t, client.customers, 2)
}

func TestDevClient_CreateCustomer_EmptyEmail(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	_, err := client.CreateCustomer(ctx, "Jane Doe", "")
	require.Error(t, err)
	assert.Contains(t, err.Error(), "email")
}

func TestDevClient_CancelCheckout_CancelsPending(t *testing.T) {
	client := NewDevClient().(*MockClient)
	client.HoldCheckouts = true
	ctx := context.Background()

	result, err := client.CreateCheckout(ctx, CreateCheckoutReq{
		Amount:         2500,
		Currency:       "GBP",
		IdempotencyKey: "cancel-checkout",
		ReferenceID:    "cancel-ref",
	})
	require.NoError(t, err)
	assert.Equal(t, "PENDING", result.Status)

	err = client.CancelCheckout(ctx, result.ID)
	require.NoError(t, err)

	client.mu.RLock()
	checkout := client.checkouts[result.ID]
	client.mu.RUnlock()
	require.NotNil(t, checkout)
	assert.Equal(t, "CANCELED", checkout.Status)
}

func TestDevClient_CancelCheckout_UnknownIsNoOp(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	err := client.CancelCheckout(ctx, "chk_does_not_exist")
	require.NoError(t, err)
}

func TestDevClient_CancelCheckout_CompletedIsNoOp(t *testing.T) {
	// Square documents that disabling an already-completed/cancelled checkout
	// has no effect, so the mock must return nil and leave the status alone.
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	result, err := client.CreateCheckout(ctx, CreateCheckoutReq{
		Amount:         2500,
		Currency:       "GBP",
		IdempotencyKey: "cancel-completed",
		ReferenceID:    "cancel-comp-ref",
	})
	require.NoError(t, err)

	assert.Eventually(t, func() bool {
		_, err := client.GetCheckout(ctx, result.ID)
		return err == nil
	}, 5*time.Second, 100*time.Millisecond, "expected checkout to complete")

	err = client.CancelCheckout(ctx, result.ID)
	require.NoError(t, err)

	client.mu.RLock()
	checkout := client.checkouts[result.ID]
	client.mu.RUnlock()
	require.NotNil(t, checkout)
	assert.Equal(t, "COMPLETED", checkout.Status, "cancelling an already-completed checkout must be a no-op")
}

func TestDevClient_CreateCustomer_RedactsEmailInLogs(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	var buf bytes.Buffer
	log.SetOutput(&buf)
	defer log.SetOutput(os.Stderr)

	email := "pii.marker@example.com"
	cust, err := client.CreateCustomer(ctx, "PII Marker", email)
	require.NoError(t, err)
	assert.Equal(t, email, cust.Email, "return value must keep the full email")

	logs := buf.String()
	if strings.Contains(logs, email) {
		t.Errorf("full email %q leaked into mock logs: %q", email, logs)
	}
	if !strings.Contains(logs, "pi***@example.com") {
		t.Errorf("expected redacted email 'pi***@example.com' in logs, got %q", logs)
	}
}

func TestDevClient_CreatePayment_RejectsRawPAN(t *testing.T) {
	// PCI-DSS parity: CreatePayment accepts only token-like source_ids
	// (cnon:xxx / ccof:xxx). Raw PANs are rejected exactly like real Square.
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	tests := []struct {
		name string
		pan  string
	}{
		{"visa", "4111111111111111"},
		{"mastercard", "5555555555554444"},
		{"amex", "378282246310005"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := client.CreatePayment(ctx, CreatePaymentReq{
				Amount:         5000,
				Currency:       "GBP",
				SourceID:       tt.pan,
				IdempotencyKey: "raw-pan-" + tt.name,
				ReferenceID:    "booking-raw",
			})
			require.Error(t, err, "raw PAN must be rejected for production parity")
			assert.Nil(t, result)
			assert.Contains(t, err.Error(), "invalid source_id")
		})
	}
}

func TestDevClient_RefundPayment_ForcePending(t *testing.T) {
	// ForceRefundPending exercises the prod-only PENDING refund branch that
	// is otherwise only reachable against the real Square API.
	client := NewDevClient().(*MockClient)
	client.ForceRefundPending = true
	ctx := context.Background()

	paymentResult, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-pending-refund",
		ReferenceID:    "booking-pending-refund",
	})
	require.NoError(t, err)

	refundResult, err := client.RefundPayment(ctx, RefundPaymentReq{
		PaymentID:      paymentResult.ID,
		Amount:         5000,
		IdempotencyKey: "pending-refund-key",
		Reason:         "customer request",
	})
	require.NoError(t, err)
	assert.Equal(t, "PENDING", refundResult.Status)
	assert.Equal(t, int64(5000), refundResult.Amount)
	assert.Equal(t, paymentResult.ID, refundResult.PaymentID)
}

func TestDevClient_RefundPayment_ZeroAmountUnknownPayment(t *testing.T) {
	// A £0 refund resolves to a full refund only when the payment is known.
	// Against an unknown payment it must fail (the real DB has a CHECK
	// amount > 0) rather than silently record a £0 refund.
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	result, err := client.RefundPayment(ctx, RefundPaymentReq{
		PaymentID:      "pay_unknown_zero",
		Amount:         0,
		IdempotencyKey: "zero-refund-unknown",
	})
	require.Error(t, err)
	assert.Nil(t, result)
	assert.Contains(t, err.Error(), "amount must be positive")
}

func TestDevClient_RefundPayment_ZeroAmountFullRefundWhenPaymentExists(t *testing.T) {
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	paymentResult, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-zero-refund",
		ReferenceID:    "booking-zero-refund",
	})
	require.NoError(t, err)

	refundResult, err := client.RefundPayment(ctx, RefundPaymentReq{
		PaymentID:      paymentResult.ID,
		Amount:         0,
		IdempotencyKey: "zero-refund-known",
	})
	require.NoError(t, err)
	assert.Equal(t, int64(10000), refundResult.Amount, "amount 0 = full refund when the payment exists")
}

func TestDevClient_ListPaymentRefunds_ConcurrentReads(t *testing.T) {
	// Exercises the RLock read path concurrently with writes (Lock) — would
	// deadlock or panic under -race if ListPaymentRefunds wrongly used a
	// write lock.
	client := NewDevClient().(*MockClient)
	ctx := context.Background()

	paymentResult, err := client.CreatePayment(ctx, CreatePaymentReq{
		Amount:         10000,
		Currency:       "GBP",
		SourceID:       "cnon:test-card",
		IdempotencyKey: "payment-for-concurrent-list",
		ReferenceID:    "booking-concurrent-list",
	})
	require.NoError(t, err)

	var wg sync.WaitGroup
	for i := 0; i < 8; i++ {
		wg.Add(2)
		go func(idx int) {
			defer wg.Done()
			_, err := client.RefundPayment(ctx, RefundPaymentReq{
				PaymentID:      paymentResult.ID,
				Amount:         100,
				IdempotencyKey: fmt.Sprintf("refund-concurrent-%d", idx),
				Reason:         "concurrent",
			})
			assert.NoError(t, err)
		}(i)
		go func() {
			defer wg.Done()
			_, err := client.ListPaymentRefunds(ctx, paymentResult.ID, time.Now().Add(-time.Hour))
			assert.NoError(t, err)
		}()
	}
	wg.Wait()

	results, err := client.ListPaymentRefunds(ctx, paymentResult.ID, time.Now().Add(-time.Hour))
	require.NoError(t, err)
	assert.Len(t, results, 8)
}