using System;
using System.Collections.Generic;

namespace Unosquare.Swan.Networking {
  /// <summary>
  /// Represents the state of an SMTP session associated with a client.
  /// </summary>
  public class SmtpSessionState {
    #region Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="SmtpSessionState"/> class.
    /// </summary>
    public SmtpSessionState() {
      this.DataBuffer = new List<Byte>();
      this.Reset(true);
      this.ResetAuthentication();
    }

    #endregion

    #region Properties

    /// <summary>
    /// Gets the contents of the data buffer.
    /// </summary>
    public List<Byte> DataBuffer {
      get; protected set;
    }

    /// <summary>
    /// Gets or sets a value indicating whether this instance has initiated.
    /// </summary>
    public Boolean HasInitiated {
      get; set;
    }

    /// <summary>
    /// Gets or sets a value indicating whether the current session supports extensions.
    /// </summary>
    public Boolean SupportsExtensions {
      get; set;
    }

    /// <summary>
    /// Gets or sets the client hostname.
    /// </summary>
    public String ClientHostname {
      get; set;
    }

    /// <summary>
    /// Gets or sets a value indicating whether the session is currently receiving DATA.
    /// </summary>
    public Boolean IsInDataMode {
      get; set;
    }

    /// <summary>
    /// Gets or sets the sender address.
    /// </summary>
    public String SenderAddress {
      get; set;
    }

    /// <summary>
    /// Gets the recipients.
    /// </summary>
    public List<String> Recipients { get; } = new List<String>();

    /// <summary>
    /// Gets or sets the extended data supporting any additional field for storage by a responder implementation.
    /// </summary>
    public Object ExtendedData {
      get; set;
    }

    #endregion

    #region AUTH State

    /// <summary>
    /// Gets or sets a value indicating whether this instance is in authentication mode.
    /// </summary>
    public Boolean IsInAuthMode {
      get; set;
    }

    /// <summary>
    /// Gets or sets the username.
    /// </summary>
    public String Username {
      get; set;
    }

    /// <summary>
    /// Gets or sets the password.
    /// </summary>
    public String Password {
      get; set;
    }

    /// <summary>
    /// Gets a value indicating whether this instance has provided username.
    /// </summary>
    public Boolean HasProvidedUsername => String.IsNullOrWhiteSpace(this.Username) == false;

    /// <summary>
    /// Gets or sets a value indicating whether this instance is authenticated.
    /// </summary>
    public Boolean IsAuthenticated {
      get; set;
    }

    /// <summary>
    /// Gets or sets the authentication mode.
    /// </summary>
    public String AuthMode {
      get; set;
    }

    /// <summary>
    /// Gets or sets a value indicating whether this instance is channel secure.
    /// </summary>
    public Boolean IsChannelSecure {
      get; set;
    }

    /// <summary>
    /// Resets the authentication state.
    /// </summary>
    public void ResetAuthentication() {
      this.Username = String.Empty;
      this.Password = String.Empty;
      this.AuthMode = String.Empty;
      this.IsInAuthMode = false;
      this.IsAuthenticated = false;
    }

    #endregion

    #region Methods

    /// <summary>
    /// Resets the data mode to false, clears the recipients, the sender address and the data buffer.
    /// </summary>
    public void ResetEmail() {
      this.IsInDataMode = false;
      this.Recipients.Clear();
      this.SenderAddress = String.Empty;
      this.DataBuffer.Clear();
    }

    /// <summary>
    /// Resets the state table entirely.
    /// </summary>
    /// <param name="clearExtensionData">if set to <c>true</c> [clear extension data].</param>
    public void Reset(Boolean clearExtensionData) {
      this.HasInitiated = false;
      this.SupportsExtensions = false;
      this.ClientHostname = String.Empty;
      this.ResetEmail();

      if(clearExtensionData) {
        this.ExtendedData = null;
      }
    }

    /// <summary>
    /// Creates a new object that is a copy of the current instance.
    /// </summary>
    /// <returns>A clone.</returns>
    public virtual SmtpSessionState Clone() {
      SmtpSessionState clonedState = this.CopyPropertiesToNew<SmtpSessionState>(new[] { nameof(this.DataBuffer) });
      clonedState.DataBuffer.AddRange(this.DataBuffer);
      clonedState.Recipients.AddRange(this.Recipients);

      return clonedState;
    }

    #endregion
  }
}