### Getting Bank Codes Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/configuration.md

Illustrates how to retrieve bank codes using the BankService class.

```csharp
var bankCode = CP.VPOS.Services.BankService.Akbank;           // "0046"
var paymentProvider = CP.VPOS.Services.BankService.Iyzico;    // "9997"
var allBanks = VPOSClient.AllBankList(b => true);
```

--------------------------------

### Additional Installment Query Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Example of how to query additional installment options for a sale.

```csharp
var campaigns = VPOSClient.AdditionalInstallmentQuery(new AdditionalInstallmentQueryRequest
{
    saleInfo = new SaleInfo
    {
        cardNameSurname = "JOHN DOE",
        cardNumber = "4022780520669303",
        cardExpiryDateMonth = 12,
        cardExpiryDateYear = 2025,
        cardCVV = "123",
        amount = 2000m,
        currency = CP.VPOS.Enums.Currency.TRY,
        installment = 1
    }
}, auth);

if (campaigns.confirm)
{
    foreach (var campaign in campaigns.installmentList)
    {
        Console.WriteLine($"Campaign: {campaign.campaignName} ({campaign.campaignCode})");
        Console.WriteLine($"  Description: {campaign.campaignDescription}");
        Console.WriteLine($"  Installments: {campaign.count}");
        Console.WriteLine($"  Required: {campaign.required}");
    }
}
```

--------------------------------

### BIN Installment Query Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Queries available installment options for a specific card BIN.

```csharp
var binQuery = VPOSClient.BINInstallmentQuery(new BINInstallmentQueryRequest
{
    BIN = "402220",
    amount = 1000m,
    currency = CP.VPOS.Enums.Currency.TRY
}, auth);

if (binQuery.confirm)
{
    foreach (var installment in binQuery.installmentList)
    {
        Console.WriteLine($"Installment {installment.count}: Commission {installment.customerCostCommissionRate}%");
    }
}
```

--------------------------------

### All Installment Query Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Queries all available installment options for a given amount across all supported cards and banks.

```csharp
var allInstallments = VPOSClient.AllInstallmentQuery(new AllInstallmentQueryRequest
{
    amount = 5000m,
    currency = CP.VPOS.Enums.Currency.TRY
}, auth);

if (allInstallments.confirm)
{
    var byBankCode = allInstallments.installmentList.GroupBy(x => x.bankCode);
    foreach (var bankGroup in byBankCode)
    {
        Console.WriteLine($"Bank {bankGroup.Key}:");
        foreach (var option in bankGroup)
        {
            Console.WriteLine($"  {option.cardProgram}: {option.count} months @ {option.customerCostCommissionRate}%");
        }
    }
}
```

--------------------------------

### Installation

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Install the CP.VPOS package using the .NET CLI.

```bash
dotnet add package CP.VPOS
```

--------------------------------

### All Credit Card BIN List Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Example of how to retrieve a complete list of all supported credit card BINs.

```csharp
var allBins = VPOSClient.AllCreditCardBinList();
var visaCards = allBins.Where(b => b.cardBrand == CP.VPOS.Enums.CreditCardBrand.Visa);
var commercialCards = allBins.Where(b => b.commercialCard);
```

--------------------------------

### InstallmentCommissionPolicy Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/configuration.md

Demonstrates how to configure installment commission policies using VirtualPOSAuth.

```csharp
var auth = new VirtualPOSAuth
{
    bankCode = CP.VPOS.Services.BankService.Iyzico,
    merchantID = "...",
    merchantUser = "...",
    merchantPassword = "...",
    testPlatform = true,
    installmentCommissionPolicy = InstallmentCommissionPolicy.ChargeToCustomer  // or AbsorbByMerchant
};
```

--------------------------------

### AllBankList Examples

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Examples of how to retrieve lists of banks using different filter criteria.

```csharp
// Get all banks supporting installment API
var installmentBanks = VPOSClient.AllBankList(b => b.InstallmentAPI);
foreach (var bank in installmentBanks)
{
    Console.WriteLine($"{bank.BankCode}: {bank.BankName}");
}

// Get all collective VPOS platforms
var collectivePlatforms = VPOSClient.AllBankList(b => b.CollectiveVPOS);

// Get all banks
var allBanks = VPOSClient.AllBankList(b => true);
```

--------------------------------

### Credit Card BIN Query Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Example of how to query credit card BIN information using the VPOS client.

```csharp
var binInfo = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

if (binInfo != null)
{
    Console.WriteLine($"Card: {binInfo.cardBrand} {binInfo.cardType}");
    Console.WriteLine($"Issued by: {binInfo.bankCode}");
    Console.WriteLine($"Program: {binInfo.cardProgram}");
    
    if (binInfo.banksWithInstallments?.Any() == true)
    {
        Console.WriteLine($"Installments available at: {string.Join(", ", binInfo.banksWithInstallments)}");
    }
}
```

--------------------------------

### ToHtmlForm Usage Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Example of how to use the ToHtmlForm extension method.

```csharp
var formFields = new Dictionary<string, string>
{
    { "MdStatus", "1" },
    { "PaReq", "xxxxx" },
    { "TermUrl", "https://yoursite.com/callback" }
};

var html = formFields.ToHtmlForm("https://bank3d.example.com/api");
Response.Write(html);  // Auto-submits form
```

--------------------------------

### Usage Pattern Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/configuration.md

Shows a typical usage pattern for VirtualPOSAuth with VPOSClient operations.

```csharp
var auth = new VirtualPOSAuth
{
    bankCode = CP.VPOS.Services.BankService.QNBpay,
    merchantID = "20158",
    merchantUser = "07fb70f9d8de575f32baa6518e38c5d6",
    merchantPassword = "61d97b2cac247069495be4b16f8604db",
    merchantStorekey = "$2y$10$N9IJkgazXMUwCzpn7NJrZePy3v.dIFOQUyW4yGfT3eWry6m.KxanK",
    testPlatform = true  // Set to false for production
};

// All VPOSClient operations accept this auth object
var saleResponse = VPOSClient.Sale(saleRequest, auth);
var installments = VPOSClient.BINInstallmentQuery(binRequest, auth);
var cancelResponse = VPOSClient.Cancel(cancelRequest, auth);
```

--------------------------------

### String Extensions Usage Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Example demonstrating the usage of string extension methods for sanitization and truncation.

```csharp
var saleRequest = new SaleRequest { /* ... */ };

// Automatic truncation in VPOSClient.Sale()
request.invoiceInfo.cityName = request.invoiceInfo.cityName.clearString().getMaxLength(25);
```

--------------------------------

### Get Card Information

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Shows how to query card details using the BIN number and display the card brand, type, and associated banks for installments.

```csharp
var bin = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

if (bin != null)
{
    Console.WriteLine($"Brand: {bin.cardBrand}");
    Console.WriteLine($"Type: {bin.cardType}");
    Console.WriteLine($"Banks with installments: {string.Join(", ", bin.banksWithInstallments)}");
}
```

--------------------------------

### Bank Code Format Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/errors.md

Example demonstrating the correct format for the bankCode in VirtualPOSAuth.

```csharp
var auth = new VirtualPOSAuth
{
    bankCode = "0046",  // Must be exactly 4 characters
    // ...
};
```

--------------------------------

### Use BIN to Pre-Filter Banks

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Shows how to first get card BIN information and then use the identified banks to pre-filter subsequent installment queries, optimizing the process.

```csharp
// Get card info
var cardBin = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

// Only query installments for banks supporting this card
if (cardBin?.banksWithInstallments?.Any() == true)
{
    foreach (var bankCode in cardBin.banksWithInstallments)
    {
        var auth = new VirtualPOSAuth { bankCode = bankCode, /* ... */ };
        var installments = VPOSClient.BINInstallmentQuery(new BINInstallmentQueryRequest
        {
            BIN = "402220",
            amount = 1000m
        }, auth);
    }
}
```

--------------------------------

### Refund Payment Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Example of how to partially refund a payment.

```csharp
var refundResult = VPOSClient.Refund(new RefundRequest
{
    customerIPAddress = "192.168.1.1",
    orderNumber = "ORD123456",
    transactionId = "123456789",
    refundAmount = 50.00m,
    currency = CP.VPOS.Enums.Currency.TRY
}, auth);

if (refundResult.statu == CP.VPOS.Enums.ResponseStatu.Success)
{
    Console.WriteLine($"Refund successful: {refundResult.refundAmount}");
}
else
{
    Console.WriteLine($"Refund failed: {refundResult.message}");
}
```

--------------------------------

### Usage Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Example of how to use the BankService constants in VirtualPOSAuth.

```csharp
var auth = new VirtualPOSAuth
{
    bankCode = CP.VPOS.Services.BankService.QNBpay,  // Use constant instead of "9990"
    merchantID = "...",
    merchantUser = "...",
    merchantPassword = "...",
    testPlatform = true
};
```

--------------------------------

### Query Installments

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Illustrates how to query available installment options for a given amount and currency, then group and display them by bank code.

```csharp
var result = VPOSClient.AllInstallmentQuery(new AllInstallmentQueryRequest
{
    amount = 5000m,
    currency = Currency.TRY
}, auth);

if (result.confirm)
{
    foreach (var option in result.installmentList.GroupBy(x => x.bankCode))
    {
        Console.WriteLine($"\nBank {option.Key}:");
        foreach (var installment in option)
            Console.WriteLine($"  {installment.count} months @ {installment.customerCostCommissionRate}%");
    }
}
```

--------------------------------

### Example: 3D Secure Sale - Step 1

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Initiates a payment transaction with 3D Secure authentication enabled, returning a redirect URL or HTML for user authentication.

```csharp
var saleRequest = new SaleRequest
{
    invoiceInfo = customerInfo,
    shippingInfo = customerInfo,
    saleInfo = new SaleInfo
    {
        cardNameSurname = "JOHN DOE",
        cardNumber = "4022780520669303",
        cardExpiryDateMonth = 1,
        cardExpiryDateYear = 2050,
        cardCVV = "988",
        amount = 100.50m,
        currency = CP.VPOS.Enums.Currency.TRY,
        installment = 1
    },
    payment3D = new Payment3D 
    {
        confirm = true,
        returnURL = "https://yoursite.com/payment/complete"
    },
    customerIPAddress = "192.168.1.1",
    orderNumber = "ORD123456"
};

var response = VPOSClient.Sale(saleRequest, auth);

if (response.statu == CP.VPOS.Enums.SaleResponseStatu.RedirectURL)
{
    // Redirect user to response.message URL for 3D authentication
    Response.Redirect(response.message);
}
else if (response.statu == CP.VPOS.Enums.SaleResponseStatu.RedirectHTML)
{
    // Output HTML form that auto-submits to 3D provider
    Response.Write(response.message);
}
```

--------------------------------

### Get Banks Supporting Card

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Retrieves BIN information and then lists the issuing bank and other banks that support installments for the given card.

```csharp
var cardBin = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

if (cardBin?.banksWithInstallments?.Any() == true)
{
    // Issuing bank is first
    var issuingBank = cardBin.banksWithInstallments[0];
    Console.WriteLine($"Issued by: {issuingBank}");
    
    // Other banks that support installments
    var otherBanks = cardBin.banksWithInstallments.Skip(1);
    Console.WriteLine($"Also offers installments at: {string.Join(", ", otherBanks)}");
}
```

--------------------------------

### ToHtmlForm Output Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Example of the generated HTML form for 3D Secure redirection.

```html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "...">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>Sanal Pos</title></head>
<body>
    <form action="{link}" name="3DFormPost" id="3DFormPost" method="post">
    <input type="hidden" name="..." value="..." />
    ...
    </form>
    <script type="text/javascript">
        document.getElementById('3DFormPost').submit();
    </script>
</body>
</html>
```

--------------------------------

### AllInstallmentQueryRequest

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Request to query all available installment options across banks/cards.

```csharp
public class AllInstallmentQueryRequest : ModelValidation
{
    [Required]
    [Range(0.0001, 10000000.00)]
    public decimal amount { get; set; }
    
    public Currency? currency { get; set; }
}
```

--------------------------------

### BINInstallmentQueryResponse

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Response with installment options for a card BIN.

```csharp
public class BINInstallmentQueryResponse
{
    public bool confirm { get; set; }
    public List<installment> installmentList { get; set; }
}

public class installment
{
    public int count { get; set; }
    public float customerCostCommissionRate { get; set; }
}
```

--------------------------------

### Example: Direct Sale (3D Disabled)

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Demonstrates how to perform a direct payment transaction without 3D Secure authentication using the VPOSClient.Sale method.

```csharp
var auth = new VirtualPOSAuth
{
    bankCode = CP.VPOS.Services.BankService.QNBpay,
    merchantID = "20158",
    merchantUser = "07fb70f9d8de575f32baa6518e38c5d6",
    merchantPassword = "61d97b2cac247069495be4b16f8604db",
    merchantStorekey = "$2y$10$N9IJkgazXMUwCzpn7NJrZePy3v.dIFOQUyW4yGfT3eWry6m.KxanK",
    testPlatform = true
};

var customerInfo = new CustomerInfo
{
    taxNumber = "1111111111",
    emailAddress = "test@test.com",
    name = "John",
    surname = "Doe",
    phoneNumber = "5555555555",
    addressDesc = "123 Main St",
    cityName = "Istanbul",
    country = CP.VPOS.Enums.Country.TUR,
    postCode = "34000",
    taxOffice = "Maltepe",
    townName = "Maltepe"
};

var saleRequest = new SaleRequest
{
    invoiceInfo = customerInfo,
    shippingInfo = customerInfo,
    saleInfo = new SaleInfo
    {
        cardNameSurname = "JOHN DOE",
        cardNumber = "4022780520669303",
        cardExpiryDateMonth = 1,
        cardExpiryDateYear = 2050,
        cardCVV = "988",
        amount = 100.50m,
        currency = CP.VPOS.Enums.Currency.TRY,
        installment = 1
    },
    payment3D = new Payment3D { confirm = false },
    customerIPAddress = "192.168.1.1",
    orderNumber = "ORD123456"
};

var response = VPOSClient.Sale(saleRequest, auth);

if (response.statu == CP.VPOS.Enums.SaleResponseStatu.Success)
{
    Console.WriteLine($"Payment successful. Transaction ID: {response.transactionId}");
}
else
{
    Console.WriteLine($"Payment failed: {response.message}");
}
```

--------------------------------

### Cancel Payment Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Example of how to cancel a same-day payment transaction.

```csharp
var cancelResult = VPOSClient.Cancel(new CancelRequest
{
    customerIPAddress = "192.168.1.1",
    orderNumber = "ORD123456",
    transactionId = "123456789",
    currency = CP.VPOS.Enums.Currency.TRY
}, auth);

if (cancelResult.statu == CP.VPOS.Enums.ResponseStatu.Success)
{
    Console.WriteLine($"Payment cancelled. Refunded: {cancelResult.refundAmount}");
}
else
{
    Console.WriteLine($"Cancellation failed: {cancelResult.message}");
}
```

--------------------------------

### BINInstallmentQueryRequest

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Request to query installment options for a specific card BIN.

```csharp
public class BINInstallmentQueryRequest : ModelValidation
{
    [Required]
    [StringLength(8, MinimumLength = 6)]
    [RegularExpression("[0-9]+")]
    public string BIN { get; set; }
    
    [Required]
    [Range(0.0001, 10000000.00)]
    public decimal amount { get; set; }
    
    public Currency? currency { get; set; }
}
```

--------------------------------

### ModelValidation Usage Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Example of how to use the Validate() method from the ModelValidation base class.

```csharp
request.Validate();  // Throws ValidationException if invalid
```

--------------------------------

### AdditionalInstallmentQueryRequest

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Request to query promotional installment campaigns for a card.

```csharp
public class AdditionalInstallmentQueryRequest : ModelValidation
{
    [Required]
    public SaleInfo saleInfo { get; set; }
}
```

--------------------------------

### Basic Payment

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Example of performing a basic payment transaction using CP.VPOS.

```csharp
using CP.VPOS;
using CP.VPOS.Models;
using CP.VPOS.Enums;

var auth = new VirtualPOSAuth
{
    bankCode = CP.VPOS.Services.BankService.QNBpay,
    merchantID = "your-merchant-id",
    merchantUser = "your-api-user",
    merchantPassword = "your-api-password",
    merchantStorekey = "your-3d-key",
    testPlatform = true
};

var saleRequest = new SaleRequest
{
    orderNumber = "ORDER123",
    customerIPAddress = "192.168.1.1",
    saleInfo = new SaleInfo
    {
        cardNameSurname = "JOHN DOE",
        cardNumber = "4022780520669303",
        cardExpiryDateMonth = 12,
        cardExpiryDateYear = 2025,
        cardCVV = "123",
        amount = 100.50m,
        currency = Currency.TRY,
        installment = 1
    },
    invoiceInfo = new CustomerInfo
    {
        name = "John",
        surname = "Doe",
        emailAddress = "john@example.com",
        phoneNumber = "5551234567",
        taxNumber = "12345678901"
    },
    shippingInfo = new CustomerInfo
    {
        name = "John",
        surname = "Doe",
        emailAddress = "john@example.com",
        phoneNumber = "5551234567",
        taxNumber = "12345678901"
    },
    payment3D = new Payment3D { confirm = false }
};

var response = VPOSClient.Sale(saleRequest, auth);

if (response.statu == SaleResponseStatu.Success)
{
    Console.WriteLine($"Payment successful: {response.transactionId}");
}
else
{
    Console.WriteLine($"Payment failed: {response.message}");
}
```

--------------------------------

### NuGet Package Manager

Source: https://github.com/cempehlivan/cp.vpos/blob/master/README.md

Install the CP.VPOS library using the NuGet Package Manager.

```powershell
Install-Package CP.VPOS
```

--------------------------------

### AdditionalInstallmentQueryResponse

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Response with promotional/campaign installment options.

```csharp
public class AdditionalInstallmentQueryResponse
{
    public bool confirm { get; set; }
    public List<AdditionalInstallment> installmentList { get; set; }
}

public class AdditionalInstallment
{
    public int count { get; set; }
    public string campaignCode { get; set; }
    public string campaignName { get; set; }
    public string campaignDescription { get; set; }
    public bool required { get; set; }
}
```

--------------------------------

### AllInstallmentQueryResponse

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Response with installment options across all banks and card programs.

```csharp
public class AllInstallmentQueryResponse
{
    public bool confirm { get; set; }
    public List<AllInstallment> installmentList { get; set; }
}

public class AllInstallment
{
    public string bankCode { get; set; }
    public CreditCardProgram cardProgram { get; set; }
    public int count { get; set; }
    public float customerCostCommissionRate { get; set; }
}
```

--------------------------------

### 3D Secure Response Handling

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Example of handling the 3D Secure response callback from the bank.

```csharp
var result = VPOSClient.Sale3DResponse(new Sale3DResponseRequest
{
    responseArray = formData  // Form/query data from bank
}, auth);
```

--------------------------------

### Check Bank Support

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Demonstrates how to retrieve a list of banks that support the installment API and print their codes and names.

```csharp
var banks = VPOSClient.AllBankList(b => b.InstallmentAPI);
foreach (var bank in banks)
    Console.WriteLine($"{bank.BankCode}: {bank.BankName}");
```

--------------------------------

### BIN Database Structure

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Example JSON entry for the BIN database.

```json
{
  "binNumber": "402220",
  "bankCode": "0111",
  "cardType": 1,
  "cardBrand": 0,
  "commercialCard": false,
  "cardProgram": 4
}
```

--------------------------------

### Payment Callback Example

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/vpos-client.md

Handles incoming payment callback notifications from the bank, processing the response and updating payment status.

```csharp
[HttpPost]
public IActionResult PaymentCallback()
{
    // Extract form data from bank
    Dictionary<string, object> responseData = new Dictionary<string, object>();
    
    if (Request.Method == "GET")
    {
        foreach (var key in Request.Query.Keys)
            responseData[key] = (object)Request.Query[key];
    }
    else
    {
        foreach (var key in Request.Form.Keys)
            responseData[key] = (object)Request.Form[key];
    }

    var result = VPOSClient.Sale3DResponse(new Sale3DResponseRequest
    {
        responseArray = responseData
    }, auth);

    if (result.statu == CP.VPOS.Enums.SaleResponseStatu.Success)
    {
        // Payment completed successfully
        return Ok("Payment successful");
    }
    else
    {
        // Payment failed
        return BadRequest("Payment failed: " + result.message);
    }
}
```

--------------------------------

### Public API Usage

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Demonstrates how to query single BIN information, retrieve all BINs, and check for installment support from banks.

```csharp
// Query single BIN
var binInfo = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

// Get all BINs
var allBins = VPOSClient.AllCreditCardBinList();

// Query and find installment banks
if (binInfo?.banksWithInstallments?.Any() == true)
{
    foreach (var bankCode in binInfo.banksWithInstallments)
    {
        Console.WriteLine($"Bank {bankCode} supports installments for this card");
    }
}
```

--------------------------------

### Find Card Type and Brand

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Example of querying BIN information to determine the card type (Credit/Debit), brand (Visa, MasterCard), program, issuing bank, and if it's a commercial card.

```csharp
var cardBin = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest
{
    binNumber = "402220"
});

if (cardBin != null)
{
    Console.WriteLine($"Card Type: {cardBin.cardType}");         // Credit or Debit
    Console.WriteLine($"Brand: {cardBin.cardBrand}");            // Visa, MasterCard, etc.
    Console.WriteLine($"Program: {cardBin.cardProgram}");        // Bonus, Axess, etc.
    Console.WriteLine($"Issuing Bank: {cardBin.bankCode}");      // Bank code
    Console.WriteLine($"Commercial: {cardBin.commercialCard}");  // Corporate card
}
```

--------------------------------

### Query Card Info

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/INDEX.md

Shows how to query card information using the CreditCardBinQuery method.

```csharp
var bin = VPOSClient.CreditCardBinQuery(new CreditCardBinQueryRequest 
    { binNumber = "402220" });
```

--------------------------------

### 3D Secure Payment

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/INDEX.md

Illustrates how to initiate a 3D Secure payment, including handling the redirect URL.

```csharp
var response = VPOSClient.Sale(saleRequest with { 
    payment3D = new Payment3D { confirm = true, returnURL = callbackUrl }
}, auth);

if (response.statu == SaleResponseStatu.RedirectURL)
    Response.Redirect(response.message);
```

--------------------------------

### Refund Payment

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/INDEX.md

Demonstrates how to process a refund for a previous payment.

```csharp
var result = VPOSClient.Refund(new RefundRequest
{
    transactionId = savedTxId,
    orderNumber = orderId,
    refundAmount = amount,
    currency = Currency.TRY,
    customerIPAddress = ip
}, auth);
```

--------------------------------

### Minimal Payment

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/INDEX.md

Demonstrates a basic payment transaction using the VPOSClient.Sale method.

```csharp
var response = VPOSClient.Sale(saleRequest, auth);
if (response.statu == SaleResponseStatu.Success)
    Console.WriteLine($"Paid: {response.transactionId}");
```

--------------------------------

### InstallmentCommissionPolicy Enum

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Controls how installment commissions are applied in collective VPOS platforms.

```csharp
public enum InstallmentCommissionPolicy
{
    Default = 0,              // Preserves backward-compatible behavior
    ChargeToCustomer = 1,     // Commission charged to customer
    AbsorbByMerchant = 2      // Merchant absorbs commission
}
```

--------------------------------

### ToHtmlForm Method

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Generates an HTML form for 3D Secure redirection.

```csharp
internal static string ToHtmlForm(this Dictionary<string, string> keyValuePairs, string link)
```

--------------------------------

### 3D Secure Payment Configuration

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/README.md

Configuration for enabling 3D Secure authentication in payment requests.

```csharp
payment3D = new Payment3D 
{
    confirm = true,
    returnURL = "https://yoursite.com/payment/callback"
}
```

--------------------------------

### CalculateCustomerCommissionRate

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Calculates the customer-facing commission rate from the seller commission rate.

```csharp
internal static float CalculateCustomerCommissionRate(float sellerCommissionRate)
```

--------------------------------

### toXml

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Converts a Dictionary to an XML string for bank requests.

```csharp
internal static string toXml(this Dictionary<string, object> valuePairs, 
    string rootTag = "CC5Request", 
    string charset = "ISO-8859-9")
```

```csharp
var data = new Dictionary<string, object>
{
    { "OrderId", "12345" },
    { "Amount", "100.50" },
    { "Card", new Dictionary<string, object>
    {
        { "Number", "4022780520669303" },
        { "CVV", "123" }
    }}
};

var xml = data.toXml();
// Result:
// <?xml version="1.0" encoding="ISO-8859-9" standalone="yes"?>
// <CC5Request>
//   <OrderId>12345</OrderId>
//   <Amount>100.50</Amount>
//   <Card>
//     <Number>4022780520669303</Number>
//     <CVV>123</CVV>
//   </Card>
// </CC5Request>
```

--------------------------------

### Filter BIN Database

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/bank-utilities.md

Demonstrates how to filter the entire BIN database based on various criteria such as card brand, commercial status, card type, bank code, and card program.

```csharp
var allBins = VPOSClient.AllCreditCardBinList();

// All Visa cards
var visaCards = allBins.Where(b => b.cardBrand == CP.VPOS.Enums.CreditCardBrand.Visa).ToList();

// Commercial cards only
var commercialCards = allBins.Where(b => b.commercialCard).ToList();

// All credit cards (not debit)
var creditCards = allBins.Where(b => b.cardType == CP.VPOS.Enums.CreditCardType.Credit).ToList();

// Cards from specific bank
var akbankCards = allBins.Where(b => b.bankCode == CP.VPOS.Services.BankService.Akbank).ToList();

// Cards with specific program
var axessCards = allBins.Where(b => b.cardProgram == CP.VPOS.Enums.CreditCardProgram.Axess).ToList();
```

--------------------------------

### CreditCardBinQueryResponse

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Response with detailed card BIN information.

```csharp
public class CreditCardBinQueryResponse
{
    public string binNumber { get; set; }
    public string bankCode { get; set; }
    public CreditCardType cardType { get; set; }
    public CreditCardBrand cardBrand { get; set; }
    public bool commercialCard { get; set; }
    public CreditCardProgram cardProgram { get; set; }
    public List<string> banksWithInstallments { get; set; }
}
```

--------------------------------

### Basic ValidationException Handling

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/errors.md

Demonstrates catching a general ValidationException during a sale operation.

```csharp
using System.ComponentModel.DataAnnotations;

try
{
    var response = VPOSClient.Sale(saleRequest, auth);
}
catch (ValidationException ex)
{
    Console.WriteLine($"Validation Error: {ex.Message}");
}
```

--------------------------------

### CustomerInfo

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Address and contact information for customer.

```csharp
public class CustomerInfo : ModelValidation
{
    [Required]
    public string name { get; set; }
    
    [Required]
    public string surname { get; set; }
    
    [Required]
    public string emailAddress { get; set; }
    
    [Required]
    public string phoneNumber { get; set; }
    
    [Required]
    public string taxNumber { get; set; }
    
    public string taxOffice { get; set; }
    public Country country { get; set; }
    public string cityName { get; set; }
    public string townName { get; set; }
    public string addressDesc { get; set; }
    public string postCode { get; set; }
}
```

--------------------------------

### time Method

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Returns the current UTC time in milliseconds since the epoch.

```csharp
internal static long time()
```

--------------------------------

### CreditCardBinQueryRequest

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/types.md

Request to query card BIN information.

```csharp
public class CreditCardBinQueryRequest : ModelValidation
{
    [Required]
    [StringLength(8, MinimumLength = 6)]
    [RegularExpression("[0-9]+")]
    public string binNumber { get; set; }
}
```

--------------------------------

### XmltoDictionary

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/api-reference/helpers.md

Converts an XML response string to a Dictionary.

```csharp
internal static Dictionary<string, object> XmltoDictionary(string xml, string xpath = "CC5Response")
```

```csharp
var xml = @"<?xml version='1.0' encoding='ISO-8859-9'?>
<CC5Response>
  <OrderId>12345</OrderId>
  <Status>0</Status>
</CC5Response>";

var dict = FoundationHelper.XmltoDictionary(xml);
// Result: { {"OrderId", "12345"}, {"Status", "0"} }
```

--------------------------------

### SaleResponseStatu Enum and Checking Status

Source: https://github.com/cempehlivan/cp.vpos/blob/master/_autodocs/errors.md

Defines the SaleResponseStatu enum for sale operations and demonstrates how to check its values.

```csharp
public enum SaleResponseStatu
{
    Error = 0,           // Transaction failed
    Success = 1,         // Transaction completed successfully
    RedirectURL = 2,     // User must be redirected to URL for 3D
    RedirectHTML = 3     // HTML form must be submitted for 3D
}

// Checking Status:
var response = VPOSClient.Sale(saleRequest, auth);

if (response.statu == SaleResponseStatu.Success)
{
    Console.WriteLine($"Payment successful. ID: {response.transactionId}");
}
else if (response.statu == SaleResponseStatu.Error)
{
    Console.WriteLine($"Payment failed: {response.message}");
}
else if (response.statu == SaleResponseStatu.RedirectURL)
{
    // Redirect user to 3D page
    Response.Redirect(response.message);
}
else if (response.statu == SaleResponseStatu.RedirectHTML)
{
    // Output HTML form that auto-submits
    Response.Write(response.message);
}
```