components/LiteCharms.Features/Extensions/Hash.cs

using LiteCharms.Features.Hasher;
using LiteCharms.Features.Hasher.Configuration;
using LiteCharms.Features.Models;

namespace LiteCharms.Features.Extensions;

public static class Hash
{
    public const string HasherConfigSectionName = "HasherSettings";

    public static IServiceCollection AddHashServices(this IServiceCollection services, IConfiguration configuration)
    {
        services.Configure<HasherSettings>(configuration.GetSection(HasherConfigSectionName));

        var settings = configuration.GetSection(HasherConfigSectionName).Get<HasherSettings>();

        services.AddSingleton<IHashids>(_ =>
            new Hashids(settings!.Salt, minHashLength: settings.MinHashLength));

        services.AddSingleton<HashService>();

        return services;
    }

    public static string ToRawPayfastPayload(this PayfastWebhookPayload input, string passphrase)
    {
        var parameters = new List<string>();

        if (!string.IsNullOrWhiteSpace(input.Amount))
            parameters.Add($"amount={WebUtility.UrlEncode(input.Amount)}");

        if (!string.IsNullOrWhiteSpace(input.ItemName))
            parameters.Add($"item_name={WebUtility.UrlEncode(input.ItemName)}");

        if (!string.IsNullOrWhiteSpace(input.MPaymentId))
            parameters.Add($"m_payment_id={WebUtility.UrlEncode(input.MPaymentId)}");

        string payload = string.Join("&", parameters);

        if (!string.IsNullOrWhiteSpace(passphrase))
            payload += $"&passphrase={WebUtility.UrlEncode(passphrase)}";

        return payload;
    }

    public static (PayfastWebhookPayload Payload, string Passphrase) FromRawPayfastPayload(this string rawPayload)
    {
        string passphrase = string.Empty;
        var payload = new PayfastWebhookPayload();

        if (string.IsNullOrWhiteSpace(rawPayload)) return (payload, passphrase);

        var segments = rawPayload.Split('&', StringSplitOptions.RemoveEmptyEntries);

        foreach (var segment in segments)
        {
            int delimiterIndex = segment.IndexOf('=');
            if (delimiterIndex == -1)
                continue;

            string key = segment[..delimiterIndex].Trim();
            string rawValue = segment[(delimiterIndex + 1)..];

            string decodedValue = WebUtility.UrlDecode(rawValue);

            switch (key.ToLowerInvariant())
            {
                case "amount":
                    payload.Amount = decodedValue;
                    break;
                case "item_name":
                    payload.ItemName = decodedValue;
                    break;
                case "m_payment_id":
                    payload.MPaymentId = decodedValue;
                    break;
                case "passphrase":
                    passphrase = decodedValue;
                    break;
            }
        }

        return (payload, passphrase);
    }

    public static (PayfastWebhookPayload Payload, string Passphrase) FromRawPayfastPayload(this IFormCollection form)
    {
        string passphrase = string.Empty;
        var payload = new PayfastWebhookPayload();

        if (form.IsNullOrEmpty()) return (payload, passphrase);

        payload = new PayfastWebhookPayload
        {
            Amount = form.TryGetValue("amount", out var amountValues) ? amountValues.ToString() : null,
            ItemName = form.TryGetValue("item_name", out var itemValues) ? itemValues.ToString() : null,
            MPaymentId = form.TryGetValue("m_payment_id", out var paymentIdValues) ? paymentIdValues.ToString() : null,
        };

        return (payload, passphrase);
    }
}