using Edge.Core.Processor;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Text.Json;
using System.Threading.Tasks;
using GasConcentrations_Yt95h.MessageEntity;
using GasConcentrations_Yt95h.MessageEntity.Incoming;
using GasConcentrations_Yt95h.MessageEntity.Outgoing;

namespace GasConcentrations_Yt95h
{
    public class SensorHandler
    {
        public byte DeviceAddress { get; set; }
        public EventHandler<string> OnJsonDataRecieved;

        private IContext<byte[], MessageBase> context;
        private readonly Queue<MessageBase> presetRequestQueue = new Queue<MessageBase>();
        private ILogger logger = null;
        private DeviceState deviceState = DeviceState.Disconnected;

        public SensorHandler(byte deviceAddress, ILogger logger)
        {
            DeviceAddress = deviceAddress;
            this.logger = logger;

            logger.LogInformation($"Create sensor handler with deviceAddress: {deviceAddress}");
        }

        public void Init(IContext<byte[], MessageBase> context)
        {
            this.context = context;
            this.context.Incoming.OnLongTimeNoSeeMessage += (_, __) =>
            {
                this.deviceState = DeviceState.Disconnected;
                FireStateChange(this.deviceState);
            };
            this.context.Incoming.LongTimeNoSeeMessageTimeout = 6000;
        }

        public void PresetRegister(short lowAlarm, short highAlarm)
        {
            if (presetRequestQueue.Count < 8)
            {
                presetRequestQueue.Enqueue(new PresetSingleRegister_Request(this.DeviceAddress, 8, lowAlarm));
                presetRequestQueue.Enqueue(new PresetSingleRegister_Request(this.DeviceAddress, 10, highAlarm));
            }
        }

        public MessageBase GetRequestMessage()
        {
            switch (this.deviceState)
            {
                case DeviceState.Connected:
                    {
                        if (presetRequestQueue.Count > 0)
                        {
                            return presetRequestQueue.Dequeue();
                        }
                        else
                            return new ReadConcentration_Request(this.DeviceAddress);
                    }
                case DeviceState.Disconnected:
                    {
                        return new ReadConcentration_Request(this.DeviceAddress);
                    }
                default: { return null; }
            };
        }

        public Task Process(IContext<byte[], MessageBase> context)
        {
            if (this.deviceState != DeviceState.Connected)
            {
                this.deviceState = DeviceState.Connected;
                FireStateChange(this.deviceState);
            }

            FireDataRecieved(context.Incoming.Message);
            return Task.CompletedTask;
        }

        private void FireDataRecieved(MessageBase message)
        {
            dynamic response = null;
            switch (message.FunctionCode)
            {
                case FunctionCode.READ_HOLDING_REGISTERS:
                    response = message as ReadRegisters_Response;
                    logger.LogInformation($"Device: {DeviceAddress}, received response message with" +
                        $" Concentration {response.Concentration.ToString("f2")}, GasType {response.GasType}, Unit {response.Unit}, AlarmType {response.AlarmType}");
                    OnJsonDataRecieved?.Invoke(this, JsonSerializer.Serialize(new { DeviceAddress = this.DeviceAddress, Concentration = response.Concentration }));
                    break;
                default:
                    logger.LogError($"Unexpected respone msg type: {message.GetType().FullName}");
                    break;
            }
        }

        private void FireStateChange(DeviceState deviceState)
        {
            logger.LogInformation($"Device: {this.DeviceAddress}, DeviceState is {deviceState}");
            OnJsonDataRecieved?.Invoke(this, JsonSerializer.Serialize(new { DeviceAddress = this.DeviceAddress, DeviceState = deviceState.ToString() }));
        }
    }
}