[PM-20087] [PM-21104] Preview tax amount for organization trial initiation (#5787)

* [NO LOGIC] [PM-21104] Organize Core.Billing tax code

* Add PreviewTaxAmountCommand and expose through TaxController

* Add PreviewTaxAmountCommandTests

* Run dotnet format

src/Core/Billing/Tax/Commands/PreviewTaxAmountCommand.cs

@@ -0,0 +1,147 @@
+#nullable enable
+using Bit.Core.Billing.Constants;
+using Bit.Core.Billing.Enums;
+using Bit.Core.Billing.Extensions;
+using Bit.Core.Billing.Models;
+using Bit.Core.Billing.Pricing;
+using Bit.Core.Billing.Tax.Services;
+using Bit.Core.Services;
+using Microsoft.Extensions.Logging;
+using Stripe;
+
+namespace Bit.Core.Billing.Tax.Commands;
+
+public interface IPreviewTaxAmountCommand
+{
+    Task<BillingCommandResult<decimal>> Run(OrganizationTrialParameters parameters);
+}
+
+public class PreviewTaxAmountCommand(
+    ILogger<PreviewTaxAmountCommand> logger,
+    IPricingClient pricingClient,
+    IStripeAdapter stripeAdapter,
+    ITaxService taxService) : IPreviewTaxAmountCommand
+{
+    public async Task<BillingCommandResult<decimal>> Run(OrganizationTrialParameters parameters)
+    {
+        var (planType, productType, taxInformation) = parameters;
+
+        var plan = await pricingClient.GetPlanOrThrow(planType);
+
+        var options = new InvoiceCreatePreviewOptions
+        {
+            Currency = "usd",
+            CustomerDetails = new InvoiceCustomerDetailsOptions
+            {
+                Address = new AddressOptions
+                {
+                    Country = taxInformation.Country,
+                    PostalCode = taxInformation.PostalCode
+                }
+            },
+            SubscriptionDetails = new InvoiceSubscriptionDetailsOptions
+            {
+                Items = [
+                    new InvoiceSubscriptionDetailsItemOptions
+                    {
+                        Price = plan.HasNonSeatBasedPasswordManagerPlan() ? plan.PasswordManager.StripePlanId : plan.PasswordManager.StripeSeatPlanId,
+                        Quantity = 1
+                    }
+                ]
+            }
+        };
+
+        if (productType == ProductType.SecretsManager)
+        {
+            options.SubscriptionDetails.Items.Add(new InvoiceSubscriptionDetailsItemOptions
+            {
+                Price = plan.SecretsManager.StripeSeatPlanId,
+                Quantity = 1
+            });
+
+            options.Coupon = StripeConstants.CouponIDs.SecretsManagerStandalone;
+        }
+
+        if (!string.IsNullOrEmpty(taxInformation.TaxId))
+        {
+            var taxIdType = taxService.GetStripeTaxCode(
+                taxInformation.Country,
+                taxInformation.TaxId);
+
+            if (string.IsNullOrEmpty(taxIdType))
+            {
+                return BadRequest.UnknownTaxIdType;
+            }
+
+            options.CustomerDetails.TaxIds = [
+                new InvoiceCustomerDetailsTaxIdOptions
+                {
+                    Type = taxIdType,
+                    Value = taxInformation.TaxId
+                }
+            ];
+        }
+
+        if (planType.GetProductTier() == ProductTierType.Families)
+        {
+            options.AutomaticTax = new InvoiceAutomaticTaxOptions { Enabled = true };
+        }
+        else
+        {
+            options.AutomaticTax = new InvoiceAutomaticTaxOptions
+            {
+                Enabled = options.CustomerDetails.Address.Country == "US" ||
+                          options.CustomerDetails.TaxIds is [_, ..]
+            };
+        }
+
+        try
+        {
+            var invoice = await stripeAdapter.InvoiceCreatePreviewAsync(options);
+            return Convert.ToDecimal(invoice.Tax) / 100;
+        }
+        catch (StripeException stripeException) when (stripeException.StripeError.Code ==
+                                                      StripeConstants.ErrorCodes.CustomerTaxLocationInvalid)
+        {
+            return BadRequest.TaxLocationInvalid;
+        }
+        catch (StripeException stripeException) when (stripeException.StripeError.Code ==
+                                                      StripeConstants.ErrorCodes.TaxIdInvalid)
+        {
+            return BadRequest.TaxIdNumberInvalid;
+        }
+        catch (StripeException stripeException)
+        {
+            logger.LogError(stripeException, "Stripe responded with an error during {Operation}. Code: {Code}", nameof(PreviewTaxAmountCommand), stripeException.StripeError.Code);
+            return new Unhandled();
+        }
+    }
+}
+
+#region Command Parameters
+
+public record OrganizationTrialParameters
+{
+    public required PlanType PlanType { get; set; }
+    public required ProductType ProductType { get; set; }
+    public required TaxInformationDTO TaxInformation { get; set; }
+
+    public void Deconstruct(
+        out PlanType planType,
+        out ProductType productType,
+        out TaxInformationDTO taxInformation)
+    {
+        planType = PlanType;
+        productType = ProductType;
+        taxInformation = TaxInformation;
+    }
+
+    public record TaxInformationDTO
+    {
+        public required string Country { get; set; }
+        public required string PostalCode { get; set; }
+        public string? TaxId { get; set; }
+    }
+}
+
+#endregion