using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Timers;

namespace MotoTrbo_GW
{
    public class SMSConfirm
    {
        private Boolean debug = false;
        private Boolean listFilled = false;
        private Boolean timerInitialized = false;
        private Dictionary<int, SeqAndTime> toBeConfirmed = new Dictionary<int, SeqAndTime>();
        private List<int> availableIDs = new List<int>();
        private int recycleInterval = 60 * 56; //seconds
        private int noACKindex = 1;

        private static Int64 motoSeq = 1;

        public Int32 radioId = 0;

        public SMSConfirm(Int32 radioID)
        {
            this.radioId = radioID;
            fillList();
        }

        private class SeqAndTime
        {
            public String seq_id;
            public double timeStamp;
            public int last_sched_timeGMT = 0;

            public int numberOfRetries = 0;
            public DateTime added = DateTime.Now;


            public SeqAndTime(String seq, double tStamp)
            {
                seq_id = seq;
                timeStamp = tStamp;
                numberOfRetries = 0;
                last_sched_timeGMT = 0;
            }
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public void fillList()
        {
            if (!listFilled)
            {
                for (int i = 1; i < 128; i++)
                {
                    availableIDs.Add(i);
                }
                listFilled = true;
            }
            listFilled = true;
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public void recycleOldConfirmations()
        {
            if (debug)
            {
                SafeMobileLib.Utils.WriteLine("Recycling confirmations at " + DateTime.Now.ToString());
            }
            Dictionary<int, SeqAndTime> tempToBeConfirmed = new Dictionary<int, SeqAndTime>();
            double currentTime = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0)).TotalSeconds;
            foreach (int index in toBeConfirmed.Keys)
            {
                if (toBeConfirmed[index].timeStamp < currentTime - recycleInterval)
                {
                    availableIDs.Add(index);
                    if (debug)
                    {
                        SafeMobileLib.Utils.WriteLine("Removed " + toBeConfirmed[index].seq_id + " from the confirmation requests list");
                    }
                }
                else
                {
                    tempToBeConfirmed.Add(index, toBeConfirmed[index]);
                }
            }
            toBeConfirmed = tempToBeConfirmed;
            if (debug)
            {
                SafeMobileLib.Utils.WriteLine("There are " + toBeConfirmed.Keys.Count + " messages waiting for confirmation,");
                SafeMobileLib.Utils.WriteLine("and " + availableIDs.Count + " available confirmations left");
            }
        }



        [MethodImpl(MethodImplOptions.Synchronized)]
        public int addToConfirmationQueue(String seq_idFromSD)
        {
            //SafeMobileLib.Utils.WriteLine("AVAILABLE " + availableIDs.Count, ConsoleColor.Yellow);
            // remove the oldest message
            if (availableIDs.Count == 0)
            {
                int key = 0;
                DateTime oldest = DateTime.Now;
                KeyValuePair<int, SeqAndTime> toRemove = new KeyValuePair<int, SeqAndTime>();
                foreach (KeyValuePair<int, SeqAndTime> toC in toBeConfirmed)
                {
                    if (toC.Value.added < oldest)
                    {
                        oldest = toC.Value.added;
                        key = toC.Key;
                        toRemove = toC;
                    }
                }

                // trigger event to announce that a message will be removed from the queue
                if (OnRemoveFromQueue != null && toRemove.Value != null)
                    OnRemoveFromQueue(radioId, toRemove.Value.seq_id);

                // remove from the queue
                if (toRemove.Value != null)
                    toBeConfirmed.Remove(toRemove.Key);

                availableIDs.Add(key);
            }

            if (availableIDs.Count > 0)
            {
                double timeStamp = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0)).TotalSeconds;
                SeqAndTime sT = new SeqAndTime(seq_idFromSD, timeStamp);


                int index = (int)availableIDs[0];
                availableIDs.RemoveAt(0);
                if (debug)
                {
                    SafeMobileLib.Utils.WriteLine("Removed from availableIDs, remaining " + availableIDs.Count);
                }

                toBeConfirmed.Add(index, sT);
                return index;
            }
            else
            {
                return -1;
            }
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public String getFromConfirmationQueue(int index)
        {
            String toReturn = "";
            if (toBeConfirmed.ContainsKey(index))
            {
                toReturn = toBeConfirmed[index].seq_id;
                toBeConfirmed.Remove(index);

                availableIDs.Add(index);
                if (debug)
                {
                    SafeMobileLib.Utils.WriteLine("Confirmed message with key " + index + ", removed from hashtable and added to availableIs");
                    SafeMobileLib.Utils.WriteLine("There are " + availableIDs.Count + " available confirmations left");
                }

                return toReturn;
            }
            else
            {
                return "0.0";
            }
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public int getFromConfirmationQueueBySeq(string seqNo)
        {
            foreach (var item in toBeConfirmed)
            {
                if (item.Value.seq_id.Equals(seqNo))
                    return item.Key;
            }

            return 0;
        }

        [MethodImpl(MethodImplOptions.Synchronized)]
        public bool ExistsSequenceInQueue(string seq_no)
        {
            foreach (var item in toBeConfirmed.Values)
            {
                if (item.seq_id.Equals(seq_no))
                    return true;
            }
            return false;
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public int GetNumberOfRetries(string seq_no)
        {
            foreach (var item in toBeConfirmed.Values)
            {
                if (item.seq_id.Equals(seq_no))
                    return item.numberOfRetries;
            }
            return 0;
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public void UpdateNumberOfRetries(string seq_no)
        {
            foreach (var item in toBeConfirmed.Values)
            {
                if (item.seq_id.Equals(seq_no))
                {
                    item.numberOfRetries++;
                }
            }
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public int GetLastSchedTime(string seq_no)
        {
            foreach (var item in toBeConfirmed.Values)
            {
                if (item.seq_id.Equals(seq_no))
                    return item.last_sched_timeGMT;
            }
            return 0;
        }


        [MethodImpl(MethodImplOptions.Synchronized)]
        public void UpdateLastSchedTime(string seq_no, int lastSchedTime)
        {
            foreach (var item in toBeConfirmed.Values)
            {
                if (item.seq_id.Equals(seq_no))
                {
                    item.last_sched_timeGMT = lastSchedTime;
                }
            }
        }


        public delegate void RemoteFromQueue(Int32 radioID, String seqNo);
        public static event RemoteFromQueue OnRemoveFromQueue;

    }
}