using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using TelemetryIO;

namespace DroneClient.Models
{
    public class monitorItem
    {
        public int slotNo = 0;
        public int offset = 0;
        public int len = 0;
        public int id = 0;

        public monitorItem()
        {
            
        }
        public monitorItem(int slotNo, int offset, int len, int id)
        {
            this.slotNo = slotNo;
            this.offset = offset;
            this.len = len;
            this.id = id;
        }
    }

    public class MonitorContainer
    {
        public const int monitorMaxFill = 32;
        public int monitorFillLevel = 0;
        public monitorItem[] monitorItems = new monitorItem[monitorMaxFill];
        public int isMonitor = 0;
        private static volatile MonitorContainer instance;
        private static readonly object _lock = new object();

        public static MonitorContainer Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (_lock)
                    {
                        if (instance == null)
                        {
                            instance = new MonitorContainer();
                        }
                    }
                }
                return instance;
            }

        }

        private MonitorContainer()
        {
            for (int i = 0; i < monitorMaxFill; i++)
            {
                monitorItems[i] = new monitorItem();
            }
        }

        public void resetMonitorContainer()
        {
            for (int i = 0; i < monitorMaxFill; i++)
            {
                monitorItems[i] = new monitorItem();
            }
        }

        public int monitorPut(int slot, int offset, int len)
        {
            int ret_id = 0;
            if (monitorFillLevel < monitorMaxFill)
            {
                monitorItems[monitorFillLevel].slotNo = slot;
                monitorItems[monitorFillLevel].offset = offset;
                monitorItems[monitorFillLevel].len = len;
                monitorItems[monitorFillLevel].id = (slot << 8) + offset;
                ret_id = monitorItems[monitorFillLevel].id;
                monitorFillLevel++;
                isMonitor = 1;
            }

            return ret_id;
        }

        public int monitorRemove(int id)
        {
            int match = 0;
            int ret_id = 0;
            for (int i = 0; i < monitorMaxFill; i++)
            {
                if (monitorItems[i].id == id)
                {
                    match = 1;
                    if (monitorFillLevel > 0) monitorFillLevel--;
                    ret_id = id;
                }

                if (match > 0)
                {
                    if (monitorItems[i].len == 0) return ret_id;
                    if (i < 31)
                    {
                        monitorItems[i].id = monitorItems[i + 1].id;
                        monitorItems[i].offset = monitorItems[i + 1].offset;
                        monitorItems[i].slotNo = monitorItems[i + 1].slotNo;
                        monitorItems[i].len = monitorItems[i + 1].len;
                    }
                    else
                    {
                        monitorItems[i].id = 0;
                        monitorItems[i].offset = 0;
                        monitorItems[i].slotNo = 0;
                        monitorItems[i].len = 0;
                    }
                }
            }
            return ret_id;
        }
    }
}