using System.Globalization;
using System.Numerics;
using System.Security.Cryptography;
using System.Text;

namespace AiQ_GUI
{
    public class Lics
    {
        // Challenge code salts
        const string SAFsalt = "F7W?wbD#'[+:v44]tA<:_iK4hQ}+$R{U";
        const string Streamsalt = "*;5WPsR5i/$8s1I(M)K5=z3fms{_8x4U";
        const string Auditsalt = "4t5e[E06:dXWf:C09Z[h)}V*n>}t0POP";
        const string PasswordSalt = "eP@4^4T2@e@^h12oqf!590";

        // Generates the license response based on the challenge and type of license
        public static string GenerateLicCode(string challenge, string Type)
        {
            string salt; // Different salts for differnet licenses

            if (Type == "Store & Forward")
                salt = SAFsalt;
            else if (Type == "Streaming")
                salt = Streamsalt;
            else if (Type == "Audit")
                salt = Auditsalt;
            else
                return "Unrecognised challenge type: " + Type;

            if (string.IsNullOrEmpty(challenge) || challenge.Length != 6) // Check challenge format
                return "Invalid challenge format. Challenge must be 6 characters.";

            if (string.IsNullOrEmpty(salt) || salt.Length != 32) // Check salt format
                return "Invalid salt format. Salt must be 32 characters.";

            // Hash computation using SHA256 algorithm
            byte[] inputBytes = Encoding.UTF8.GetBytes(challenge + " " + salt); // SHA hash format challenge and salt with space between
            byte[] hashBytes = SHA256.HashData(inputBytes);

            StringBuilder sb = new();
            foreach (byte b in hashBytes)
            {
                sb.Append(b.ToString("x2"));
            }
            string digest = sb.ToString();

            BigInteger BigInt = BigInteger.Parse("0" + digest, NumberStyles.AllowHexSpecifier); // Leading zero is sign for big int.
            return BigInt.ToString().Substring(0, 6);
        }

        public static string GeneratePassword(string mac, string version, int time)
        {
            try
            {
                string timeBlock = (time / 86400).ToString(); // 1-day validity
                string secret = string.Join(" ", mac, version, timeBlock, PasswordSalt);

                byte[] digest = MD5.HashData(Encoding.UTF8.GetBytes(secret));
                return Convert.ToBase64String(digest);
            }
            catch (Exception ex)
            {
                return "Error: Could not generate password " + ex.Message;
            }
        }

        public static void DisplayDevPassword(Versions Vers, Camera CamOnTest)
        {
            CamOnTest.DevPass = FetchDevPassword(Vers);

            if (CamOnTest.DevPass.Contains("Could not"))
            {
                MainForm.Instance.AddToActionsList(CamOnTest.DevPass); // Did not parse, so error.
                return;
            }

            Network.Initialize("developer", CamOnTest.DevPass); // Reinitialise HTTP client with developer password
        }

        public static string FetchDevPassword(Versions Vers)
        {
            try
            {
                return GeneratePassword(Vers.MAC, Vers.version, Vers.timeStamp);
            }
            catch (Exception ex)
            {
                MainForm.Instance.AddToActionsList("Exception in FetchDevPassword: " + ex.Message);
                return null;
            }
        }
    }

    public class Licenses
    {
        public bool saf1 { get; set; }
        public bool saf2 { get; set; }
        public bool saf3 { get; set; }
        public bool saf4 { get; set; }
        public bool audit { get; set; }
        public bool stream { get; set; }
        public string raptorKeyID { get; set; } = string.Empty;
    }

    public class VaxtorLic
    {
        public string protectionKeyId { get; set; } = string.Empty;
        public string error { get; set; } = string.Empty;
    }
}