using System;
using System.Collections.Generic;
using System.Globalization;
using Sensors;
using Sensors.Polar;
using UniRx;
using UnityEngine;

namespace Logging
{
    public readonly struct PolarSensorEcgLog : ISerializable
    {
        private readonly long timestamp;
        private readonly float ecg;

        public PolarSensorEcgLog(int timestamp, float ecg)
        {
            this.timestamp = timestamp;
            this.ecg = ecg;
        }

        public KeyValuePair<long, string[]> Serialize() =>
            new KeyValuePair<long, string[]>(timestamp, new[]
            {
                ecg.ToString("F4", CultureInfo.InvariantCulture)
            });
    }

    public class PolarEcgDataLogger : SensorDataLogger<PolarSensorEcgLog>
    {
        public override string Key => "polar_ecg_data";

        private long startTime = -1;
        private TimeSync timeSync;
        private const int ECG_SAMPLE_RATE = 130;

        private IDisposable sub;

        public override async void Start()
        {
            base.Start();
            timeSync = new TimeSync
            {
                StartTime = DateTime.Now,
                DifDataStreamStart = -1
            };
            var bikeSensorData = BikeSensorData.Instance;
            await bikeSensorData.PolarReceiverAvailable;
            sub = bikeSensorData.RawEcgData?.Subscribe(data => OnData(data));
        }

        private void OnData(in EcgData data)
        {
            if (timeSync.DifDataStreamStart < 0)
            {
                timeSync.DifDataStreamStart = (long) (DateTime.Now - timeSync.StartTime).TotalMilliseconds;
            }

            if (startTime < 0)
            {
                startTime = data.Timestamp;
            }

            var internalTimestamp =
                (data.Timestamp - startTime) / 1000000;
            var timestamp = Mathf.RoundToInt(internalTimestamp + timeSync.DifDataStreamStart);
            foreach (var item in data.Values)
            {
                Log(new PolarSensorEcgLog(timestamp, item));
                timestamp += 1000 / ECG_SAMPLE_RATE;
            }
        }

        public override IEnumerable<PolarSensorEcgLog> ReadLog(IEnumerable<IEnumerable<string>> lines)
        {
            throw new System.NotImplementedException(); //TODO
        }

        private void OnDestroy()
        {
            sub?.Dispose();
        }
    }
}