using MQTTnet.Client.ExtendedAuthenticationExchange;
using MQTTnet.Formatter;
using MQTTnet.Packets;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MQTTnet.Client.Options
{
    public class MqttClientOptionsBuilder
    {
        readonly MqttClientOptions _options = new MqttClientOptions();

        MqttClientTcpOptions _tcpOptions;
        MqttClientWebSocketOptions _webSocketOptions;
        MqttClientOptionsBuilderTlsParameters _tlsParameters;
        MqttClientWebSocketProxyOptions _proxyOptions;

        public MqttClientOptionsBuilder WithProtocolVersion(MqttProtocolVersion value)
        {
            if (value == MqttProtocolVersion.Unknown)
            {
                throw new ArgumentException("Protocol version is invalid.");
            }

            _options.ProtocolVersion = value;
            return this;
        }

        public MqttClientOptionsBuilder WithCommunicationTimeout(TimeSpan value)
        {
            _options.CommunicationTimeout = value;
            return this;
        }

        public MqttClientOptionsBuilder WithCleanSession(bool value = true)
        {
            _options.CleanSession = value;
            return this;
        }

        public MqttClientOptionsBuilder WithNoKeepAlive()
        {
            return WithKeepAlivePeriod(TimeSpan.Zero);
        }

        public MqttClientOptionsBuilder WithKeepAlivePeriod(TimeSpan value)
        {
            _options.KeepAlivePeriod = value;
            return this;
        }

        public MqttClientOptionsBuilder WithKeepAliveSendInterval(TimeSpan value)
        {
            _options.KeepAliveSendInterval = value;
            return this;
        }

        public MqttClientOptionsBuilder WithClientId(string value)
        {
            _options.ClientId = value;
            return this;
        }

        public MqttClientOptionsBuilder WithWillMessage(MqttApplicationMessage value)
        {
            _options.WillMessage = value;
            return this;
        }

        public MqttClientOptionsBuilder WithAuthentication(string method, byte[] data)
        {
            _options.AuthenticationMethod = method;
            _options.AuthenticationData = data;
            return this;
        }

        public MqttClientOptionsBuilder WithWillDelayInterval(uint? willDelayInterval)
        {
            _options.WillDelayInterval = willDelayInterval;
            return this;
        }

        public MqttClientOptionsBuilder WithTopicAliasMaximum(ushort? topicAliasMaximum)
        {
            _options.TopicAliasMaximum = topicAliasMaximum;
            return this;
        }

        public MqttClientOptionsBuilder WithMaximumPacketSize(uint? maximumPacketSize)
        {
            _options.MaximumPacketSize = maximumPacketSize;
            return this;
        }

        public MqttClientOptionsBuilder WithReceiveMaximum(ushort? receiveMaximum)
        {
            _options.ReceiveMaximum = receiveMaximum;
            return this;
        }

        public MqttClientOptionsBuilder WithRequestProblemInformation(bool? requestProblemInformation = true)
        {
            _options.RequestProblemInformation = requestProblemInformation;
            return this;
        }

        public MqttClientOptionsBuilder WithRequestResponseInformation(bool? requestResponseInformation = true)
        {
            _options.RequestResponseInformation = requestResponseInformation;
            return this;
        }

        public MqttClientOptionsBuilder WithSessionExpiryInterval(uint? sessionExpiryInterval)
        {
            _options.SessionExpiryInterval = sessionExpiryInterval;
            return this;
        }

        public MqttClientOptionsBuilder WithUserProperty(string name, string value)
        {
            if (name is null) throw new ArgumentNullException(nameof(name));
            if (value is null) throw new ArgumentNullException(nameof(value));

            if (_options.UserProperties == null)
            {
                _options.UserProperties = new List<MqttUserProperty>();
            }

            _options.UserProperties.Add(new MqttUserProperty(name, value));
            return this;
        }

        public MqttClientOptionsBuilder WithCredentials(string username, string password = null)
        {
            byte[] passwordBuffer = null;

            if (password != null)
            {
                passwordBuffer = Encoding.UTF8.GetBytes(password);
            }

            return WithCredentials(username, passwordBuffer);
        }

        public MqttClientOptionsBuilder WithCredentials(string username, byte[] password = null)
        {
            _options.Credentials = new MqttClientCredentials
            {
                Username = username,
                Password = password
            };

            return this;
        }

        public MqttClientOptionsBuilder WithCredentials(IMqttClientCredentials credentials)
        {
            _options.Credentials = credentials;

            return this;
        }

        public MqttClientOptionsBuilder WithExtendedAuthenticationExchangeHandler(IMqttExtendedAuthenticationExchangeHandler handler)
        {
            _options.ExtendedAuthenticationExchangeHandler = handler;
            return this;
        }

        public MqttClientOptionsBuilder WithTcpServer(string server, int? port = null)
        {
            _tcpOptions = new MqttClientTcpOptions
            {
                Server = server,
                Port = port
            };

            return this;
        }

        // TODO: Consider creating _MqttClientTcpOptionsBuilder_ as overload.
        public MqttClientOptionsBuilder WithTcpServer(Action<MqttClientTcpOptions> optionsBuilder)
        {
            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));

            _tcpOptions = new MqttClientTcpOptions();
            optionsBuilder.Invoke(_tcpOptions);

            return this;
        }

        public MqttClientOptionsBuilder WithProxy(string address, string username = null, string password = null, string domain = null, bool bypassOnLocal = false, string[] bypassList = null)
        {
            _proxyOptions = new MqttClientWebSocketProxyOptions
            {
                Address = address,
                Username = username,
                Password = password,
                Domain = domain,
                BypassOnLocal = bypassOnLocal,
                BypassList = bypassList
            };

            return this;
        }

        public MqttClientOptionsBuilder WithProxy(Action<MqttClientWebSocketProxyOptions> optionsBuilder)
        {
            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));

            _proxyOptions = new MqttClientWebSocketProxyOptions();
            optionsBuilder(_proxyOptions);
            return this;
        }

        public MqttClientOptionsBuilder WithWebSocketServer(string uri, MqttClientOptionsBuilderWebSocketParameters parameters = null)
        {
            _webSocketOptions = new MqttClientWebSocketOptions
            {
                Uri = uri,
                RequestHeaders = parameters?.RequestHeaders,
                CookieContainer = parameters?.CookieContainer
            };

            return this;
        }

        public MqttClientOptionsBuilder WithWebSocketServer(Action<MqttClientWebSocketOptions> optionsBuilder)
        {
            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));

            _webSocketOptions = new MqttClientWebSocketOptions();
            optionsBuilder.Invoke(_webSocketOptions);

            return this;
        }

        public MqttClientOptionsBuilder WithTls(MqttClientOptionsBuilderTlsParameters parameters)
        {
            _tlsParameters = parameters;
            return this;
        }

        public MqttClientOptionsBuilder WithTls()
        {
            return WithTls(new MqttClientOptionsBuilderTlsParameters { UseTls = true });
        }

        public MqttClientOptionsBuilder WithTls(Action<MqttClientOptionsBuilderTlsParameters> optionsBuilder)
        {
            if (optionsBuilder == null) throw new ArgumentNullException(nameof(optionsBuilder));

            _tlsParameters = new MqttClientOptionsBuilderTlsParameters();
            optionsBuilder(_tlsParameters);
            return this;
        }

        public IMqttClientOptions Build()
        {
            if (_tcpOptions == null && _webSocketOptions == null)
            {
                throw new InvalidOperationException("A channel must be set.");
            }

            if (_tlsParameters != null)
            {
                if (_tlsParameters?.UseTls == true)
                {
                    var tlsOptions = new MqttClientTlsOptions
                    {
                        UseTls = true,
                        SslProtocol = _tlsParameters.SslProtocol,
                        AllowUntrustedCertificates = _tlsParameters.AllowUntrustedCertificates,
#if WINDOWS_UWP
                        Certificates = _tlsParameters.Certificates?.Select(c => c.ToArray()).ToList(),
#else
                        Certificates = _tlsParameters.Certificates?.ToList(),
#endif
                        CertificateValidationCallback = _tlsParameters.CertificateValidationCallback,
                        CertificateValidationHandler = _tlsParameters.CertificateValidationHandler,
                        IgnoreCertificateChainErrors = _tlsParameters.IgnoreCertificateChainErrors,
                        IgnoreCertificateRevocationErrors = _tlsParameters.IgnoreCertificateRevocationErrors
                    };

                    if (_tcpOptions != null)
                    {
                        _tcpOptions.TlsOptions = tlsOptions;
                    }
                    else if (_webSocketOptions != null)
                    {
                        _webSocketOptions.TlsOptions = tlsOptions;
                    }
                }
            }

            if (_proxyOptions != null)
            {
                if (_webSocketOptions == null)
                {
                    throw new InvalidOperationException("Proxies are only supported for WebSocket connections.");
                }

                _webSocketOptions.ProxyOptions = _proxyOptions;
            }

            _options.ChannelOptions = (IMqttClientChannelOptions)_tcpOptions ?? _webSocketOptions;

            return _options;
        }
    }
}