using Newtonsoft.Json.Linq;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using Azure.Identity;
using Azure.Security.KeyVault.Secrets;

namespace CDP
{
    public class Helpers
    {
        public static byte[] GenerateAES256Key()
        {
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.KeySize = 256;
                aesAlg.GenerateKey();
                return aesAlg.Key;
            }
        }

        // hashes a string and removes the dashes (-)
        public static string HashToHex(string str)
        {
            using (SHA256 sha256Hash = SHA256.Create())
            {
                byte[] bytes = sha256Hash.ComputeHash(Encoding.UTF8.GetBytes(str));
                return BitConverter.ToString(bytes).Replace("-", string.Empty).ToLower();
            }
        }

        // takes a short hash and converts it to normal hash.
        // Circle Auth uses hashes stored as hex...use this to convert to that format.
        public static string ConvertShortHashToHex(string shortHash)
        {
            // Add padding characters ('=') to the short hash if needed
            while (shortHash.Length % 4 != 0)
            {
                shortHash += "=";
            }

            // Decode the Base64 short hash to bytes
            byte[] hashBytes = Convert.FromBase64String(shortHash);

            // Convert the bytes to a hexadecimal string
            string hexHash = BitConverter.ToString(hashBytes).Replace("-", "").ToLower();

            return hexHash;
        }


        // Generates an AES Key and converts it to base64
        public static string GenerateAES256KeyToBase64()
        {
            return Convert.ToBase64String(GenerateAES256Key());
        }

        // Generates a guid, removes the - and then converts it to base64
        public static string GenerateShortGuid()
        {
            Guid guid = Guid.NewGuid();
            byte[] bytes = guid.ToByteArray();

            string shortGuid = Convert.ToBase64String(bytes);

            // Remove padding characters from the end of the Base64 string
            shortGuid = shortGuid.TrimEnd('=');

            return shortGuid;
        }
        public static Guid LengthenShortGuid(string shortGuid)
        {
            // Add padding characters to the end of the Base64 string, if needed
            while (shortGuid.Length % 4 != 0)
            {
                shortGuid += "=";
            }

            // Convert the Base64 string back to bytes
            byte[] bytes = Convert.FromBase64String(shortGuid);

            // Create a new GUID from the bytes
            Guid guid = new Guid(bytes);

            return guid;
        }


        public static bool VerifyData(string originalMessage, string signedMessage)
        {
            bool success = false;
            using (var rsa = new RSACryptoServiceProvider())
            {
                var encoder = new UTF8Encoding();
                byte[] bytesToVerify = encoder.GetBytes(originalMessage);
                byte[] signedBytes = Convert.FromBase64String(signedMessage);
                try
                {
                    rsa.FromXmlString(Constants.PublicKey);

                    SHA512Managed Hash = new SHA512Managed();

                    byte[] hashedData = Hash.ComputeHash(signedBytes);

                    success = rsa.VerifyData(bytesToVerify, CryptoConfig.MapNameToOID("SHA512"), signedBytes);
                }
                catch (CryptographicException e)
                {
                    Console.WriteLine(e.Message);
                }
                finally
                {
                    rsa.PersistKeyInCsp = false;
                }
            }
            return success;
        }
        public static string ComputeSignature(string stringToSign, string secret)
        {
            using (var hmacsha256 = new HMACSHA256(System.Text.ASCIIEncoding.UTF8.GetBytes(secret)))
            {
                var bytes = Encoding.ASCII.GetBytes(stringToSign);
                var hashedBytes = hmacsha256.ComputeHash(bytes);
                return Convert.ToBase64String(hashedBytes);
            }
        }

        public static async Task<dynamic> GetSession(string sessionId)
        {
            string toSign = string.Format($"?s={sessionId}");
            string sig = Helpers.ComputeSignature(toSign, Constants.CDPWriteKey);
            string URL = string.Format($"https://circleauth.gocircle.ai/api/session/{toSign}&signature={sig}");

            try
            {
                HttpClient client = new HttpClient();
                client.Timeout = new TimeSpan(0, 1, 0, 0);
                client.DefaultRequestHeaders.Add("x-ua-appKey", Constants.CDPAppKey);
                var response = await client.GetAsync(URL);
                if (response.StatusCode == System.Net.HttpStatusCode.OK)
                {
                    string responseString = await response.Content.ReadAsStringAsync();
                    dynamic obj = JObject.Parse(responseString);
                    dynamic data = obj.data;

                    return data;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }

            return null;
        }

        public static async Task<Boolean> ExpireSession(string sessionId, string userId)
        {
            try
            {
                var dataObj = new { sessionID = sessionId, userID = userId };
                var sig = Helpers.ComputeSignature(JsonConvert.SerializeObject(dataObj), Constants.CDPWriteKey);
                var obj = new { data = dataObj, signature = sig };

                HttpClient client = new HttpClient();
                client.Timeout = new TimeSpan(0, 1, 0, 0);
                client.DefaultRequestHeaders.Add("x-ua-appKey", Constants.CDPAppKey);
                var content = new StringContent(JsonConvert.SerializeObject(obj), Encoding.UTF8, "application/json");

                var r = client.PostAsync("https://circleaccess.circlesecurity.ai/api/user/session/expire", content).Result;
                return r.StatusCode == HttpStatusCode.OK;
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
            return false;
        }


        /// <summary>
        /// this is the HASH that Circle Auth likes, it's just a SHA265 in hex.
        /// </summary>
        public static string HashText(string rawData)
        {
            try
            {
                // Create a SHA256   
                using SHA256 sha256Hash = SHA256.Create();
                byte[] bytes = sha256Hash.ComputeHash(Encoding.UTF8.GetBytes(rawData));
                StringBuilder builder = new();
                for (int i = 0; i < bytes.Length; i++)
                {
                    builder.Append(bytes[i].ToString("x2"));
                }
                return builder.ToString();
            }
            catch (Exception ex)
            {
                return null;
            }
        }
        public static string HashAndShortenText(string text)
        {
            // Hash the email address using SHA-256
            using (SHA256 sha256 = SHA256.Create())
            {
                byte[] hashBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(text));

                string shortHash = Convert.ToBase64String(hashBytes);

                // make the short hash URL friendly
                shortHash = shortHash.Replace("+", "-").Replace("/", "_");

                // Remove padding characters from the end of the Base64 string
                shortHash = shortHash.TrimEnd('=');

                return shortHash;
            }
        }
        public static async Task<SingleLogin> CreateSession(string customerAppKey, string returnURL, string payloadJson, string webHook = "")
        {
            var client = new HttpClient();

            // wacky hack since I can't declare anonymous variables without initializing them
            var payloadObject = new
            {
                Test = "123"
            };

            var dataObj = new
            {
                payload = payloadJson,
                customerAppKey = customerAppKey,
                customID = "blahORama",
                returnUrl = returnURL,
                mobileUrl = returnURL,
                webhookUrl = webHook
            };

            var sig = Helpers.ComputeSignature(JsonConvert.SerializeObject(dataObj), Constants.CDPWriteKey);
            var obj = new { data = dataObj, signature = sig };
            string json = JsonConvert.SerializeObject(obj);

            client.DefaultRequestHeaders.Add("x-ua-appKey", Constants.CDPAppKey);
            HttpContent c = new StringContent(json, Encoding.UTF8, "application/json");
            var response = await client.PostAsync(new Uri("https://circleaccess.circlesecurity.ai/api/single/create"), c);

            SingleLogin sl = new SingleLogin();
            if (response.StatusCode == System.Net.HttpStatusCode.OK)
            {
                string body = response.Content.ReadAsStringAsync().Result; //right!
                dynamic stuff = JObject.Parse(body);
                sl.QRCodeUrl = stuff.data.qrcode.ToString();
                sl.LoginId = stuff.data.singleLoginID.ToString();
                return sl;
            }

            return null;
        }
    }

    public class KeyVaultService
    {
        private readonly string _keyVaultUrl;

        public KeyVaultService(string keyVaultUrl)
        {
            _keyVaultUrl = keyVaultUrl;
        }

        public async Task SetSecretAsync(string secretName, string secretValue)
        {
#if DEBUG
            var client = new SecretClient(new Uri(_keyVaultUrl), new VisualStudioCredential());
#else
            var client = new SecretClient(new Uri(_keyVaultUrl), new DefaultAzureCredential());
#endif

            // Set the secret in the Key Vault
            await client.SetSecretAsync(secretName, secretValue);
        }
        public async Task<string> GetSecretAsync(string secretName)
        {
#if DEBUG
            var client = new SecretClient(new Uri(_keyVaultUrl), new VisualStudioCredential());
#else
            var client = new SecretClient(new Uri(_keyVaultUrl), new DefaultAzureCredential());
#endif

            // Set the secret in the Key Vault
            KeyVaultSecret kvs = await client.GetSecretAsync(secretName);
            return kvs.Value;
        }
    }


    public class SingleLogin
    {
        public string QRCodeUrl { get; set; }
        public string LoginId { get; set; }
        public SingleLogin()
        {
        }

        public override string ToString()
        {
            return QRCodeUrl;
        }
    }

}