using DSInternals.Common.Cryptography;
using DSInternals.Common.Exceptions;
using DSInternals.Common.Interop;
using DSInternals.Common.Properties;
using System;
using System.ComponentModel;
using System.DirectoryServices.ActiveDirectory;
using System.IO;
using System.Security;
using System.Text.RegularExpressions;

namespace DSInternals.Common
{
    public static class Validator
    {
        private const string hexPattern = "^([0-9a-fA-F][0-9a-fA-F])+$";

        public static void AssertSuccess(NtStatus status)
        {
            Win32ErrorCode code = NativeMethods.RtlNtStatusToDosError(status);
            AssertSuccess(code);
        }
        public static void AssertSuccess(Win32ErrorCode code)
        {
            switch(code)
            {
                case Win32ErrorCode.Success:
                case Win32ErrorCode.MORE_DATA:
                    // No error occured, so exit gracefully.
                    return;
            }

            var genericException = new Win32Exception((int)code);
            Exception exceptionToThrow;
            // We will try to translate the generic Win32 exception to a more specific built-in exception.
            switch(code)
            {
                case Win32ErrorCode.DS_INVALID_DN_SYNTAX:
                    exceptionToThrow = new ArgumentException(genericException.Message, genericException);
                    break;
                case Win32ErrorCode.ACCESS_DENIED:
                case Win32ErrorCode.DS_DRA_ACCESS_DENIED:
                case Win32ErrorCode.WRONG_PASSWORD:
                case Win32ErrorCode.PASSWORD_EXPIRED:
                    exceptionToThrow = new UnauthorizedAccessException(genericException.Message, genericException);
                    break;
                case Win32ErrorCode.NOT_ENOUGH_MEMORY:
                case Win32ErrorCode.OUTOFMEMORY:
                case Win32ErrorCode.DS_DRA_OUT_OF_MEM:
                case Win32ErrorCode.RPC_S_OUT_OF_RESOURCES:
                    exceptionToThrow = new OutOfMemoryException(genericException.Message, genericException);
                    break;
                case Win32ErrorCode.NO_LOGON_SERVERS:
                case Win32ErrorCode.NO_SUCH_DOMAIN:
                case Win32ErrorCode.RPC_S_SERVER_UNAVAILABLE:
                case Win32ErrorCode.RPC_S_CALL_FAILED:
                    exceptionToThrow = new ActiveDirectoryServerDownException(genericException.Message, genericException);
                    break;
                case Win32ErrorCode.DS_OBJ_NOT_FOUND:
                // This error code means either a non-existing DN or Access Denied.
                case Win32ErrorCode.DS_DRA_BAD_DN:
                    exceptionToThrow = new DirectoryObjectNotFoundException(null, genericException);
                    break;
                // TODO: Add translation for ActiveDirectoryOperationException and for other exception types.
                default:
                    // We were not able to translate the Win32Exception to a more specific type.
                    exceptionToThrow = genericException;
                    break;
            }
            throw exceptionToThrow;
        }

        public static void AssertIsHex(string value, string paramName)
        {
            bool isHexString = Regex.IsMatch(value, hexPattern);
            if (!isHexString)
            {
                var exception = new ArgumentException(Resources.NotHexStringMessage, paramName);
                exception.Data.Add("Value", value);
                throw exception;
            }
        }

        public static void AssertNotNull(object value, string paramName)
        {
            if(value == null)
            {
                throw new ArgumentNullException(paramName);
            }
        }
        public static void AssertNotNullOrWhiteSpace(string value, string paramName)
        {
            if(string.IsNullOrWhiteSpace(value))
            {
                throw new ArgumentNullException(paramName);
            }
        }
        public static void AssertLength(string value, int length, string paramName)
        {
            AssertNotNull(value, paramName);
            if(value.Length != length)
            {
                throw new ArgumentOutOfRangeException(paramName, value.Length, Resources.UnexpectedLengthMessage);
            }
        }

        public static void AssertMaxLength(SecureString password, int maxLength, string paramName)
        {
            AssertNotNull(password, paramName);
            if (password.Length > maxLength)
            {
                throw new ArgumentOutOfRangeException(paramName, password.Length, Resources.InputLongerThanMaxMessage);
            }
        }

        public static void AssertMaxLength(string input, int maxLength, string paramName)
        {
            AssertNotNull(input, paramName);
            if (input.Length > maxLength)
            {
                throw new ArgumentOutOfRangeException(paramName, input.Length, Resources.InputLongerThanMaxMessage);
            }
        }

        public static void AssertMinLength(byte[] data, int minLength, string paramName)
        {
            AssertNotNull(data, paramName);
            if (data.Length < minLength)
            {
                var exception = new ArgumentOutOfRangeException(paramName, data.Length, Resources.InputShorterThanMinMessage);
                // DEBUG: exception.Data.Add("BinaryBlob", data.ToHex());
                throw exception;
            }
        }

        public static void AssertLength(byte[] value, long length, string paramName)
        {
            AssertNotNull(value, paramName);
            if (value.Length != length)
            {
                throw new ArgumentOutOfRangeException(paramName, value.Length, Resources.UnexpectedLengthMessage);
            }
        }

        public static void AssertFileExists(string filePath)
        {
            bool exists = File.Exists(filePath);
            if(!exists)
            {
                throw new FileNotFoundException(Resources.PathNotFoundMessage, filePath);
            }
        }

        public static void AssertDirectoryExists(string directoryPath)
        {
            bool exists = Directory.Exists(directoryPath);
            if (!exists)
            {
                throw new DirectoryNotFoundException(Resources.PathNotFoundMessage);
            }
        }

        public static void AssertCrcMatches(byte[] buffer, uint expectedCrc)
        {
            uint actualCrc = Crc32.Calculate(buffer);
            if(actualCrc != expectedCrc)
            {
                throw new Exception(Resources.InvalidCRCMessage);
            }
        }
    }
}