From 46fdce52e857fb25ef9d2c2229a58a6f878ece73 Mon Sep 17 00:00:00 2001
From: Charles Le Maux <charles.le-maux@epitech.eu>
Date: Tue, 8 Oct 2024 13:33:09 +0200
Subject: [PATCH] [~] REFACTOR : Middlewares and Utilities

---
 Middlewares.cs | 126 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 Middlewares.cs

diff --git a/Middlewares.cs b/Middlewares.cs
new file mode 100644
index 0000000..73d7087
--- /dev/null
+++ b/Middlewares.cs
@@ -0,0 +1,126 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
+
+namespace Simple_API;
+
+public static class Middlewares
+{
+    public class ClaimsValidationMiddleware (RequestDelegate next)
+    {
+        public async Task InvokeAsync(HttpContext context)
+        {
+            if (context.User.Identity?.IsAuthenticated == true)
+            {
+                var userId = context.User.FindFirst(ClaimTypes.GivenName)?.Value;
+                var role = context.User.FindFirst(ClaimTypes.Role)?.Value;
+
+                if (string.IsNullOrEmpty(userId) || string.IsNullOrEmpty(role))
+                {
+                    Console.WriteLine(context.Connection.RemoteIpAddress?.ToString());
+                    context.Response.StatusCode = StatusCodes.Status400BadRequest;
+                    await context.Response.WriteAsync("Reported detected spoofed JWT in request header to admins.");
+                    return;
+                }
+            }
+            await next(context);
+        }
+    }
+}
+
+public static class LightCrypto
+{
+    private const string IdCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+    private const int IdLength = 28;
+    
+    public static string GenerateRandomId()
+    {
+        byte[] randomBytes = new byte[IdLength];
+        using (RandomNumberGenerator rng = RandomNumberGenerator.Create())
+        {
+            rng.GetBytes(randomBytes);
+        }
+
+        char[] idChars = new char[IdLength];
+
+        for (int i = 0; i < IdLength; i++)
+        {
+            idChars[i] = IdCharacters[randomBytes[i] % IdCharacters.Length];
+        }
+
+        return new string(idChars);
+    }
+    
+    public static string GenerateJwtToken(string email, string role, string userId, IConfiguration configuration)
+    {
+        var claims = new[]
+        {
+            new Claim(ClaimTypes.Email, email),
+            new Claim(ClaimTypes.Role, role),
+            new Claim(ClaimTypes.GivenName, userId),
+        };
+
+        var configKey = configuration["Jwt:Key"];
+
+        if (string.IsNullOrEmpty(configKey))
+        {
+            return string.Empty;
+        }
+
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(configKey));
+        var credentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+        var token = new JwtSecurityToken(
+            issuer: configuration["Jwt:Issuer"],
+            audience: configuration["Jwt:Audience"],
+            claims: claims,
+            expires: DateTime.Now.AddMinutes(190),
+            signingCredentials: credentials);
+
+        return new JwtSecurityTokenHandler().WriteToken(token);
+    }
+    
+    public static string HashPassword(string password)
+    {
+        using var hmac = new HMACSHA256();
+        var salt = hmac.Key;
+        var hash = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
+        
+        return Convert.ToBase64String(salt) + ":" + Convert.ToBase64String(hash);
+    }
+
+    public static bool VerifyPassword(string hashedPassword, string password)
+    {
+        var parts = hashedPassword.Split(':');
+        var salt = Convert.FromBase64String(parts[0]);
+        var hash = Convert.FromBase64String(parts[1]);
+
+        using var hmac = new HMACSHA256(salt);
+        var computedHash = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
+
+        return computedHash.SequenceEqual(hash);
+    }
+}
+
+public static class DatabaseUtils
+{ 
+    public static async Task<string> GenerateUniqueIdAsync(Database.Database context)
+    {
+        string uniqueId;
+
+        do
+        {
+            uniqueId = LightCrypto.GenerateRandomId();
+        } while (await IdExistsInDatabase(context, uniqueId));
+
+        return uniqueId;
+    }
+        
+    private static async Task<bool> IdExistsInDatabase(Database.Database context, string id)
+    {
+        return await context.Users.AnyAsync(user => user.Id == id);
+    }
+}
\ No newline at end of file