using System;
using System.IO;
using System.Net;
using Interop.Clickatell;

namespace Neo.Afx.WinService.Messages
{
    /// <summary>
    /// A wrapper class for sending SMS's using the Clickatell (Vodazone) API.
    /// </summary>
    public class SmsVodazone : ISmsSender
    {
        private string ApiID { get; set; }
        private string UserName { get; set; }
        private string Password { get; set; }

        #region Initialization

        /// <summary>
        /// Initializes a new instance of the <see cref="SmsVodazone"/> class
        /// by using the given values.
        /// </summary>
        /// <param name="apiID">The API ID to be queried.</param>
        /// <param name="userName">The user name to be queried.</param>
        /// <param name="password">The password to be queried.</param>
        public SmsVodazone(string apiID, string userName, string password)
        {
            try
            {
                ApiID = apiID;
                UserName = userName;
                Password = password;
                
                var reply = Authenticate();
                
                string replyText;
                if (!ReplyOk(reply, "OK: ", out replyText))
                {
                    throw new Exception(replyText);
                }                
            }
            catch (Exception ex)
            {
                throw new Exception(GetInnermostMessage(ex));
            }            
        }
        
        #endregion

        #region Credits

        /// <summary>
        /// Gets the number of credits left.
        /// </summary>
        public int Credits
        {
            get
            {
                var balance = QueryBalance();
                string credits;
                if(ReplyOk(balance, "Credit: ", out credits))
                {
                    if (credits.Contains("."))
                    {
                        credits = credits.Substring(0, credits.IndexOf("."));
                    }

                    return (int)float.Parse(credits);
                }
                return 0;
            }
        }

        #endregion

        #region Send

        /// <summary>
        /// Sends the given message to the given cell number.
        /// </summary>
        /// <param name="message">The message to be sent.</param>
        /// <param name="cellNumber">The cell number to which the message is sent.</param>
        /// <param name="error">When this method returns, contains the error message if
        /// the SMS was not sent successfully; otherwise contains a null references.</param>
        /// <returns>
        /// 	<code>true</code> if successful; <code>false</code> otherwise.
        /// </returns>
        public bool Send(string message, string cellNumber, out string error)
        {
            var successful = true;
            try
            {
                string replyText;
                var reply = SendMsg(message, cellNumber);
                if(ReplyOk(reply, "ID: ", out replyText))
                {
                    #region Check if successful
                    reply = QueryMsg(replyText);
                    if(ReplyOk(reply, "Status: ", out replyText))
                    {
                        var messageStatus = (eSMSMsgStatus)Int32.Parse(replyText);
                        error = messageStatus.ToString();

                        #region Set successful based on message status

                        switch(messageStatus)
                        {
                            case eSMSMsgStatus.SMS_MSG_CANCELLED:
                                successful = false;
                                break;
                            case eSMSMsgStatus.SMS_MSG_DELIVERED:
                                break;
                            case eSMSMsgStatus.SMS_MSG_ERR_DELIVERING_MSG:
                                successful = false;
                                break;
                            case eSMSMsgStatus.SMS_MSG_ERR_WITH_MSG:
                                successful = false;
                                break;
                            case eSMSMsgStatus.SMS_MSG_EXPIRED:
                                successful = false;
                                break;
                            case eSMSMsgStatus.SMS_MSG_OK:
                                break;
                            case eSMSMsgStatus.SMS_MSG_QUEUED:
                                break;
                            case eSMSMsgStatus.SMS_MSG_QUEUED_LATER_DELIV:
                                break;
                            case eSMSMsgStatus.SMS_MSG_RECEIVED:
                                break;
                            case eSMSMsgStatus.SMS_MSG_ROUTING_ERROR:
                                successful = false;
                                break;
                            case eSMSMsgStatus.SMS_MSG_UNKNOWN:
                                break;
                        }

                        #endregion
                    }
                    else
                    {
                        error = replyText;
                        successful = false;
                    }

                    #endregion
                }
                else
                {
                    error = replyText;
                    successful = false;
                }
            }
            catch(Exception ex)
            {
                error = GetInnermostMessage(ex);
                successful = false;
            }
            return successful;
        }

        #endregion

        #region ReplyOk

        static bool ReplyOk(string reply, string tag, out string message)
        {
            const string Marker = "ERR: ";

            message = null;
            if(!String.IsNullOrEmpty(reply))
            {
                var p1 = reply.IndexOf(Marker);
                if(p1 == -1)
                {
                    p1 = reply.IndexOf(tag);
                    message = p1 == -1 ? reply : reply.Substring(p1 + tag.Length);
                    return true;
                }

                // An error occurred so get error message
                message = reply.Substring(p1 + Marker.Length);
            }
            return false;
        }

        #endregion

        #region GetInnermostMessage
        public string GetInnermostMessage(Exception ex)
        {
            if (ex.InnerException == null)
            {
                return ex.Message;
            }
            else
            {
                return GetInnermostMessage(ex.InnerException);
            }
        }
        #endregion

        #region Helper Methods
        private string Authenticate()
        {
            return RequestGET("auth","");
        }

        private string QueryBalance()
        {
            return RequestGET("getbalance", "");
        }

        private string SendMsg(string message, string cellNumber)
        {
            return RequestGET("sendmsg", "to=" + cellNumber + "&text=" + message);
        }

        private string QueryMsg(string replyText)
        {
            return RequestGET("querymsg", "apimsgid=" + replyText);
        }


        public string RequestGET(string action, string queryString)
        {
            try
            {
                var baseUri = String.Format("https://api.clickatell.com/http/{0}?user={1}&password={2}&api_id={3}", action ,UserName, Password, ApiID);
                baseUri += "&" + queryString;

                HttpWebRequest request = (HttpWebRequest)
                WebRequest.Create(baseUri); 
                request.KeepAlive = false;

                request.ProtocolVersion = HttpVersion.Version10;
                request.Method = "GET";

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                string result = "";
                using (StreamReader rdr = new StreamReader(response.GetResponseStream()))
                {
                    result = rdr.ReadToEnd();
                }

                return result;
            }
            catch (Exception ex)
            {
                return "ERROR: " + GetInnermostMessage(ex);
            }
        }

        #endregion


    }

}