Integration-TransactionImporter-SimmonsBank/AAIntegration.SimmonsBank.API/Services/UserService.cs

namespace AAIntegration.SimmonsBank.API.Services;

using AAIntegration.SimmonsBank.API.Entities;
using AAIntegration.SimmonsBank.API.Config;
using AAIntegration.SimmonsBank.API.Models.Users;
using System;
using System.Collections.Generic;
using System.Security.Cryptography;

public interface IUserService
{
    string Create(UserCreateRequest model);
    void Update(string apiKey, UserUpdateRequest model);
    void Delete(string apiKey);
    Dictionary<string, int> GetAllApiKeys();
    User GetUser(string ApiKey);
    IEnumerable<User> GetAll();
}

public class UserService : IUserService
{
    private DataContext _context;

    public UserService(
        DataContext context)
    {
        _context = context;
    }

    public string Create(UserCreateRequest model)
    {
        User user = new User();
        user.SimmonsBankUsername = model.Username;
        user.SimmonsBankPassword = model.Password;
        user.MFAKey = model.MFAKey;

        // Generate API Key
        user.ApiKey = generateApiKey();

        // save user
        _context.Users.Add(user);
        _context.SaveChanges();

        // Return API Key
        return user.ApiKey;
    }

    public void Update(string apiKey, UserUpdateRequest model)
    {
        var user = this.GetUser(apiKey);

        // User.Username
        if (model.Username != null)
            user.SimmonsBankUsername = model.Username;

        // User.Password
        if (model.Password != null)
            user.SimmonsBankPassword = model.Password;

        // User.MFAKey
        if (model.MFAKey != null)
            user.MFAKey = model.MFAKey;

        _context.Users.Update(user);
        _context.SaveChanges();
    }

    public void Delete(string apiKey)
    {
        var user = this.GetUser(apiKey);
        _context.Users.Remove(user);
        _context.SaveChanges();
    }

    public Dictionary<string, int> GetAllApiKeys()
    {
        return _context.Users
            .Where(u => u.ApiKey != null)
            .ToDictionary(u => u.ApiKey, u => u.Id);
    }

    public User GetUser(string ApiKey)
    {
        var user = _context.Users
            .Where(u => u.ApiKey == ApiKey)
            .FirstOrDefault() ?? throw new KeyNotFoundException("User not found");

        return user;
    }

    public IEnumerable<User> GetAll()
    {
        return _context.Users;
    }

    // helper methods

    private User getUser(int id)
    {
        var user = _context.Users.Find(id) ?? throw new KeyNotFoundException("User not found");
        return user;
    }

    private const string _prefix = "SB-";
    private const int _numberOfSecureBytesToGenerate = 32;
    private const int _lengthOfKey = 32;

    private string generateApiKey()
    {
        var bytes = RandomNumberGenerator.GetBytes(_numberOfSecureBytesToGenerate);

        string base64String = Convert.ToBase64String(bytes)
            .Replace("+", "-")
            .Replace("/", "_");
        
        var keyLength = _lengthOfKey - _prefix.Length; 

        return _prefix + base64String[..keyLength];
    }

}