package payment

import (
	"context"
	"errors"
	"log/slog"
	"net"
	"time"
)

// PaymentLogger isolates payment audit logging from the payment workflow and
// lets an application replace slog with its own structured logger.
type PaymentLogger interface {
	Info(context.Context, string, ...any)
	Error(context.Context, string, ...any)
}

type slogPaymentLogger struct {
	logger *slog.Logger
}

func NewPaymentLogger(logger *slog.Logger) PaymentLogger {
	if logger == nil {
		logger = slog.Default()
	}
	return &slogPaymentLogger{logger: logger.With("mod", "payment")}
}

func (l *slogPaymentLogger) Info(ctx context.Context, message string, args ...any) {
	l.logger.InfoContext(ctx, message, args...)
}

func (l *slogPaymentLogger) Error(ctx context.Context, message string, args ...any) {
	for i := 0; i+1 < len(args); i += 2 {
		if key, ok := args[i].(string); ok && (key == "error" || key == "err") {
			args[i] = "error_code"
			if err, ok := args[i+1].(error); ok {
				args[i+1] = paymentErrorCode(err)
			} else {
				args[i+1] = "redacted"
			}
		}
	}
	l.logger.ErrorContext(ctx, message, args...)
}

func paymentErrorCode(err error) string {
	switch {
	case errors.Is(err, ErrPaymentOrderNotFound):
		return "order_not_found"
	case errors.Is(err, ErrPaymentProviderNotFound):
		return "provider_not_configured"
	case errors.Is(err, ErrPaymentOrderConflict):
		return "order_conflict"
	case errors.Is(err, ErrPaymentProviderConflict):
		return "provider_conflict"
	case errors.Is(err, ErrPaymentOrderBusy):
		return "order_busy"
	case errors.Is(err, ErrPaymentOrderState):
		return "invalid_order_state"
	case errors.Is(err, ErrPaymentOperationRejected):
		return "provider_rejected"
	case errors.Is(err, context.Canceled):
		return "cancelled"
	case errors.Is(err, context.DeadlineExceeded):
		return "timeout"
	default:
		var networkError net.Error
		if errors.As(err, &networkError) && networkError.Timeout() {
			return "timeout"
		}
		return "operation_failed"
	}
}

func (uc *PaymentUsecase) logPaymentOperation(ctx context.Context, operation string, started time.Time, provider, tradeNo string, result *PaymentResult, err error) {
	attrs := []any{"provider", provider, "trade_no", tradeNo, "duration_ms", time.Since(started).Milliseconds()}
	if result != nil {
		attrs = append(attrs, "provider_trade_no", result.ProviderTradeNo, "provider_status", result.Status,
			"order_status", result.OrderStatus, "fulfillment_status", result.FulfillmentStatus,
			"refund_status", result.RefundStatus, "duplicate", result.Duplicate)
	}
	if err != nil {
		uc.logger.Error(ctx, "payment."+operation+".failed", append(attrs, "error_code", paymentErrorCode(err))...)
		return
	}
	uc.logger.Info(ctx, "payment."+operation+".completed", attrs...)
}