using System.Security.Cryptography;
using System.Text;
using Galaeth.Services.Configuration;
using Galaeth.Services.Interfaces;
using Injectio.Attributes;
using Konscious.Security.Cryptography;
using Microsoft.Extensions.Options;

namespace Galaeth.Services.Services;

/// <inheritdoc />
[RegisterSingleton]
public class CryptographyService : ICryptographyService
{
    private readonly PwdHashConfiguration _configuration;

    /// <summary>
    /// Initializes a new instance of the <see cref="CryptographyService"/> class.
    /// </summary>
    /// <param name="pwdHashSettings">Instance of <see cref="IOptions{PwdHashConfiguration}"/>.</param>
    public CryptographyService(IOptions<PwdHashConfiguration> pwdHashSettings)
    {
        _configuration = pwdHashSettings.Value;
    }

    /// <inheritdoc/>
    public byte[] GenerateSalt(int? size = null)
    {
        var result = RandomNumberGenerator.GetBytes(size ?? _configuration.SaltSize);
        return result;
    }

    /// <inheritdoc/>
    public byte[] HashPassword(string password, byte[] salt)
    {
        var argon2Id = new Argon2id(Encoding.UTF8.GetBytes(password));
        argon2Id.Salt = salt;
        argon2Id.DegreeOfParallelism = _configuration.DegreeOfParallelism;
        argon2Id.Iterations = _configuration.NumberOfIterations;
        argon2Id.MemorySize = _configuration.MemoryToUseKb;
        var bytes = argon2Id.GetBytes(_configuration.HashSize);
        GC.Collect();
        return bytes;
    }

    /// <inheritdoc/>
    public bool VerifyPassword(string password, byte[] salt, byte[] passwordHash)
    {
        var checkHash = HashPassword(password, salt);
        return passwordHash.SequenceEqual(checkHash);
    }

    /// <inheritdoc/>
    public bool VerifyPassword(string password, string salt, string passwordHash)
    {
        var checkHash = HashPassword(password, Convert.FromBase64String(salt));
        return Convert.FromBase64String(passwordHash).SequenceEqual(checkHash);
    }

    /// <inheritdoc/>
    public string GenerateRandomString(int length)
    {
        const string availableChars = "ABCDEFGHIJKLMONOPQRSTUVWXYZabcdefghijklmonopqrstuvwxyz0123456789";
        return RandomNumberGenerator.GetString(availableChars, length);
    }
}