//go:build dev

package square

import (
	"context"
	"crussell/clock"
	"fmt"
	"log"
	"os"
	"strings"
	"sync"
	"time"
)

var Client SquareClient

var isTesting = os.Getenv("GO_TESTING") == "1"

func mockSleep(d time.Duration) {
	if !isTesting {
		time.Sleep(d)
	}
}

type MockClient struct {
	mu            sync.RWMutex
	cards         map[string]map[string]*CardOnFile
	checkouts     map[string]*CheckoutResult
	payments      map[string]*PaymentResult
	paymentByKey  map[string]*PaymentResult
	refunds       map[string]*RefundResult
	completed     map[string]*PaymentResult
	HoldCheckouts bool
	ShouldFail    bool // if true, CreatePayment/RefundPayment return errors for testing error paths
}

type devProdClient struct{}

func (d *devProdClient) CreatePayment(ctx context.Context, req CreatePaymentReq) (*PaymentResult, error) {
	return createPaymentHTTP(ctx, req)
}
func (d *devProdClient) CreateCheckout(ctx context.Context, req CreateCheckoutReq) (*CheckoutResult, error) {
	return createCheckoutHTTP(ctx, req)
}
func (d *devProdClient) GetCheckout(ctx context.Context, checkoutID string) (*PaymentResult, error) {
	return getCheckoutHTTP(ctx, checkoutID)
}
func (d *devProdClient) RefundPayment(ctx context.Context, req RefundPaymentReq) (*RefundResult, error) {
	return refundPaymentHTTP(ctx, req)
}
func (d *devProdClient) CreateCardOnFile(ctx context.Context, userID, cardToken string) (*CardOnFile, error) {
	return createCardOnFileHTTP(ctx, userID, cardToken)
}
func (d *devProdClient) CreateCardOnFileRaw(ctx context.Context, userID, cardNumber string, expMonth, expYear int, cvc string) (*CardOnFile, error) {
	return nil, fmt.Errorf("square: raw card number input is not supported in production — use CreateCardOnFile with a card nonce")
}
func (d *devProdClient) GetCardsOnFile(ctx context.Context, userID string) ([]CardOnFile, error) {
	return getCardsOnFileHTTP(ctx, userID)
}
func (d *devProdClient) DeleteCardOnFile(ctx context.Context, cardID string) error {
	return deleteCardOnFileHTTP(ctx, cardID)
}

func NewClient() SquareClient {
	return NewDevClient()
}

func NewDevClient() SquareClient {
	env := os.Getenv("SQUARE_ENVIRONMENT")
	if env == "sandbox" || env == "production" {
		log.Printf("[SQUARE-PROD] SQUARE_ENVIRONMENT=%s — making real API calls to %s", env, realBaseURL(env))
		return &devProdClient{}
	}
	log.Println("[SQUARE-MOCK] Using in-memory mock client")
	return &MockClient{
		cards:        make(map[string]map[string]*CardOnFile),
		checkouts:    make(map[string]*CheckoutResult),
		payments:     make(map[string]*PaymentResult),
		paymentByKey: make(map[string]*PaymentResult),
		refunds:      make(map[string]*RefundResult),
		completed:    make(map[string]*PaymentResult),
	}
}

func detectCardInfo(sourceID string) (brand, last4 string) {
	switch sourceID {
	case "cnon:test-card":
		return "VISA", "4242"
	case "cnon:visa":
		return "VISA", "1111"
	case "cnon:mastercard":
		return "MASTERCARD", "4444"
	case "cnon:amex":
		return "AMERICAN_EXPRESS", "0005"
	default:
		return "VISA", "4242"
	}
}

func (m *MockClient) CreatePayment(ctx context.Context, req CreatePaymentReq) (*PaymentResult, error) {
	if m.ShouldFail {
		return nil, fmt.Errorf("mock: payment declined (simulated failure)")
	}
	log.Printf("[SQUARE-MOCK] CreatePayment: amount=%d, reference=%s, source=%s", req.Amount, req.ReferenceID, req.SourceID)
	mockSleep(1 * time.Second)

	m.mu.Lock()
	defer m.mu.Unlock()

	// Real Square dedups on idempotency key: a retry with the same key returns
	// the original payment rather than creating a second charge. The mock
	// mirrors this so dev/testing behaves like production (also why the tip
	// retry regression test can rely on the mock).
	if req.IdempotencyKey != "" {
		if existing, ok := m.paymentByKey[req.IdempotencyKey]; ok {
			log.Printf("[SQUARE-MOCK] CreatePayment dedup hit: key=%s → id=%s", req.IdempotencyKey, existing.ID)
			return existing, nil
		}
	}

	now := clock.Now().UTC()

	status := "COMPLETED"
	if req.Autocomplete != nil && !*req.Autocomplete {
		status = "APPROVED"
	}

	amount := req.Amount
	tipAmount := int64(0)
	if req.TipMoney != nil {
		tipAmount = *req.TipMoney
		amount += tipAmount
	}

	cardBrand, cardLast4 := detectCardInfo(req.SourceID)

	// Entry method: ON_FILE for card-on-file tokens, KEYED for nonces
	entryMethod := "KEYED"
	if len(req.SourceID) >= 5 && req.SourceID[:5] == "ccof:" {
		entryMethod = "ON_FILE"
	}

	paymentID := fmt.Sprintf("pay_mock_%d", now.UnixNano())
	fees := amount*14/1000 + 25 // online rate: 1.4% + 25p

	locationID := req.LocationID
	if locationID == "" {
		locationID = "L_MOCK"
	}

	result := &PaymentResult{
		ID:              paymentID,
		Status:          status,
		Amount:          amount,
		CardBrand:       cardBrand,
		CardLast4:       cardLast4,
		CardFingerprint: fmt.Sprintf("sqfp_mock_%d", now.UnixNano()),
		ExpMonth:        12,
		ExpYear:         2030,
		EntryMethod:     entryMethod,
		CVVStatus:       "CVV_ACCEPTED",
		AVSStatus:       "AVS_ACCEPTED",
		TipAmount:       tipAmount,
		ReceiptURL:      "https://squareup.com/receipt/" + paymentID,
		ReceiptNumber:   fmt.Sprintf("RCPT_mock_%d", now.UnixNano()),
		SquarePayID:     "sqp_" + paymentID,
		Fees:            fees,
		BuyerEmail:      req.BuyerEmail,
		CustomerID:      req.CustomerID,
		LocationID:      locationID,
		CreatedAt:       now.Format(time.RFC3339),
		UpdatedAt:       now.Format(time.RFC3339),
		ReferenceID:     req.ReferenceID,
	}
	m.payments[paymentID] = result
	m.payments[result.SquarePayID] = result
	if req.IdempotencyKey != "" {
		m.paymentByKey[req.IdempotencyKey] = result
	}
	log.Printf("[SQUARE-MOCK] Payment created: id=%s, status=%s, amount=%d, fees=%d", paymentID, status, amount, fees)
	return result, nil
}

func (m *MockClient) CreateCheckout(ctx context.Context, req CreateCheckoutReq) (*CheckoutResult, error) {
	log.Printf("[SQUARE-MOCK] CreateCheckout: amount=%d, tipEnabled=%v, reference=%s", req.Amount, req.TipEnabled, req.ReferenceID)

	now := clock.Now().UTC()
	checkoutID := fmt.Sprintf("chk_mock_%d", now.UnixNano())

	result := &CheckoutResult{
		ID:          checkoutID,
		Status:      "PENDING",
		AmountMoney: req.Amount,
		Currency:    req.Currency,
		DeviceID:    req.DeviceID,
		ReferenceID: req.ReferenceID,
		Note:        req.Note,
		CreatedAt:   now.Format(time.RFC3339),
		UpdatedAt:   now.Format(time.RFC3339),
		Deadline:    now.Add(5 * time.Minute).Format(time.RFC3339),
	}

	m.mu.Lock()
	m.checkouts[checkoutID] = result
	m.mu.Unlock()

	// Copy the result before spawning the goroutine to avoid data races.
	// The caller gets this copy; the goroutine modifies the map-stored original.
	resultCopy := *result

	if !m.HoldCheckouts {
		go func() {
			defer func() {
				if r := recover(); r != nil {
					log.Printf("Panic recovered in Square mock payment processing: %v", r)
				}
			}()
			mockSleep(3 * time.Second)

			m.mu.Lock()
			defer m.mu.Unlock()

			payNow := clock.Now().UTC()
			paymentID := fmt.Sprintf("pay_mock_%d", payNow.UnixNano())
			amount := req.Amount
			tipAmount := int64(0)
			if req.TipEnabled {
				tipAmount = 500
				amount += tipAmount
			}
			fees := amount * 175 / 10000 // in-person rate: 1.75%

			paymentResult := &PaymentResult{
				ID:              paymentID,
				Status:          "COMPLETED",
				Amount:          amount,
				CardBrand:       "VISA",
				CardLast4:       "4242",
				CardFingerprint: fmt.Sprintf("sqfp_mock_%d", payNow.UnixNano()),
				ExpMonth:        12,
				ExpYear:         2030,
				EntryMethod:     "EMV",
				CVVStatus:       "CVV_ACCEPTED",
				AVSStatus:       "AVS_ACCEPTED",
				TipAmount:       tipAmount,
				ReceiptURL:      "https://squareup.com/receipt/" + paymentID,
				ReceiptNumber:   fmt.Sprintf("RCPT_mock_%d", payNow.UnixNano()),
				SquarePayID:     "sqp_" + paymentID,
				Fees:            fees,
				CustomerID:      req.CustomerID,
				LocationID:      "L_MOCK",
				CreatedAt:       payNow.Format(time.RFC3339),
				UpdatedAt:       payNow.Format(time.RFC3339),
				ReferenceID:     req.ReferenceID,
			}
			m.completed[checkoutID] = paymentResult
			m.checkouts[checkoutID].Status = "COMPLETED"
			m.checkouts[checkoutID].UpdatedAt = payNow.Format(time.RFC3339)
			m.checkouts[checkoutID].PaymentIDs = []string{paymentID}
			log.Printf("[SQUARE-MOCK] Checkout completed: id=%s, amount=%d, tip=%d", checkoutID, amount, tipAmount)
		}()
	}

	return &resultCopy, nil
}

func (m *MockClient) GetCheckout(ctx context.Context, checkoutID string) (*PaymentResult, error) {
	log.Printf("[SQUARE-MOCK] GetCheckout: id=%s", checkoutID)

	m.mu.RLock()
	defer m.mu.RUnlock()

	checkout, ok := m.checkouts[checkoutID]
	if !ok {
		return nil, fmt.Errorf("checkout not found: %s", checkoutID)
	}

	if checkout.Status == "PENDING" {
		return nil, ErrCheckoutPending
	}

	result, ok := m.completed[checkoutID]
	if !ok {
		return nil, fmt.Errorf("checkout result not found: %s", checkoutID)
	}

	return result, nil
}

func (m *MockClient) RefundPayment(ctx context.Context, req RefundPaymentReq) (*RefundResult, error) {
	if m.ShouldFail {
		return nil, fmt.Errorf("mock: refund declined (simulated failure)")
	}
	log.Printf("[SQUARE-MOCK] RefundPayment: payment=%s, amount=%d", req.PaymentID, req.Amount)
	mockSleep(1 * time.Second)

	m.mu.Lock()
	defer m.mu.Unlock()

	now := clock.Now().UTC()
	refundID := fmt.Sprintf("ref_mock_%d", now.UnixNano())

	payment, ok := m.payments[req.PaymentID]
	if !ok {
		// Payment not in mock map — this happens when integration tests
		// create payments via DB fixture with a square_payment_id, bypassing
		// the mock. Process the refund without full payment data.
		log.Printf("[SQUARE-MOCK] RefundPayment: payment %s not in mock map — proceeding without full payment data", req.PaymentID)
	}

	amount := req.Amount
	if amount == 0 && ok {
		amount = payment.Amount
	}

	locationID := req.LocationID
	if locationID == "" {
		locationID = "L_MOCK"
	}

	result := &RefundResult{
		ID:         refundID,
		Status:     "COMPLETED",
		Amount:     amount,
		PaymentID:  req.PaymentID,
		LocationID: locationID,
		Reason:     req.Reason,
		CreatedAt:  now.Format(time.RFC3339),
	}
	m.refunds[refundID] = result
	log.Printf("[SQUARE-MOCK] Refund completed: id=%s, payment=%s, amount=%d", refundID, req.PaymentID, amount)
	return result, nil
}

func (m *MockClient) CreateCardOnFile(ctx context.Context, userID, cardToken string) (*CardOnFile, error) {
	log.Printf("[SQUARE-MOCK] CreateCardOnFile: user=%s", userID)

	// Match the real Square API: source_id must be a token (cnon:xxx nonce or
	// ccof:xxx card ID). Raw PANs are rejected exactly as Square would, so the
	// mock behaves identically to production.
	if !isTokenLike(cardToken) {
		return nil, fmt.Errorf("invalid source_id: %q — use a card nonce (cnon:xxx) or card ID (ccof:xxx)", cardToken)
	}

	m.mu.Lock()
	defer m.mu.Unlock()

	if m.cards[userID] == nil {
		m.cards[userID] = make(map[string]*CardOnFile)
	}

	now := clock.Now().UTC()
	cardID := fmt.Sprintf("mock_card_%d", now.UnixNano())
	brand, last4 := detectCardInfo(cardToken)
	card := &CardOnFile{
		ID:             cardID,
		CardID:         fmt.Sprintf("ccof_mock_%d", now.UnixNano()),
		Brand:          brand,
		Last4:          last4,
		ExpMonth:       12,
		ExpYear:        2030,
		Fingerprint:    fmt.Sprintf("sqfp_mock_%d", now.UnixNano()),
		CardholderName: "John Doe",
		CustomerID:     userID,
		Enabled:        true,
		IsDefault:      len(m.cards[userID]) == 0,
		Version:        1,
		CreatedAt:      now.Format(time.RFC3339),
	}
	m.cards[userID][cardID] = card
	log.Printf("[SQUARE-MOCK] Card created: id=%s, brand=%s, last4=%s", cardID, card.Brand, card.Last4)
	return card, nil
}

func (m *MockClient) CreateCardOnFileRaw(ctx context.Context, userID, cardNumber string, expMonth, expYear int, cvc string) (*CardOnFile, error) {
	// PCI-DSS parity with production: raw card numbers are never accepted.
	// The mock must behave identically to the ProdClient so dev testing does
	// not mask a production failure.
	return nil, fmt.Errorf("square: raw card number input is not supported in production — use CreateCardOnFile with a card nonce")
}

func (m *MockClient) GetCardsOnFile(ctx context.Context, userID string) ([]CardOnFile, error) {
	log.Printf("[SQUARE-MOCK] GetCardsOnFile: user=%s", userID)

	m.mu.RLock()
	defer m.mu.RUnlock()

	userCards, ok := m.cards[userID]
	if !ok {
		return []CardOnFile{}, nil
	}

	var cards []CardOnFile
	for _, card := range userCards {
		cards = append(cards, *card)
	}
	return cards, nil
}

func (m *MockClient) DeleteCardOnFile(ctx context.Context, cardID string) error {
	log.Printf("[SQUARE-MOCK] DeleteCardOnFile: id=%s", cardID)

	m.mu.Lock()
	defer m.mu.Unlock()

	for userID, cards := range m.cards {
		if card, ok := cards[cardID]; ok {
			card.Enabled = false
			log.Printf("[SQUARE-MOCK] Card disabled: id=%s (user=%s)", cardID, userID)
			return nil
		}
	}
	return fmt.Errorf("card not found: %s", cardID)
}

// isTokenLike returns true for Square source_id tokens: cnon:xxx nonces and
// ccof:xxx card IDs. Raw PANs (all digits) are NOT token-like and are rejected.
func isTokenLike(s string) bool {
	return strings.HasPrefix(s, "cnon:") || strings.HasPrefix(s, "ccof:")
}

func realBaseURL(env string) string {
	if env == "production" {
		return squareProductionURL
	}
	return squareSandboxURL
}