using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Routing;
using Microsoft.AspNetCore.Authorization;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json.Linq;

using AyaNova.Models;
using AyaNova.Api.ControllerHelpers;
using AyaNova.Biz;


namespace AyaNova.Api.Controllers
{

    /// <summary>
    /// Server metrics
    /// </summary>
    [ApiController]
    [ApiVersion("8.0")]
    [Route("api/v{version:apiVersion}/server-metric")]
    [Authorize]
    public class ServerMetricsController : ControllerBase
    {
        private readonly AyContext ct;
        private readonly ILogger<LogFilesController> log;
        private readonly ApiServerState serverState;


        /// <summary>
        /// ctor
        /// </summary>
        /// <param name="dbcontext"></param>
        /// <param name="logger"></param>
        /// <param name="apiServerState"></param>

        public ServerMetricsController(AyContext dbcontext, ILogger<LogFilesController> logger, ApiServerState apiServerState)
        {
            ct = dbcontext;
            log = logger;
            serverState = apiServerState;
        }



        /// <summary>
        /// Get all server metrics for time period specified
        /// </summary>  
        /// <param name="hours">Required value, timespan of hours worth of records to return from current moment backwards</param>
        /// <param name="maxRecords">Optional maximum records to return. If there are more records for the time period selected than this value the result will be downsampled using Largest-Triangle-Three-Buckets algorithm</param>
        /// <returns>Snapshot of metrics</returns>
        [HttpGet]
        public async Task<IActionResult> GetMetrics([FromQuery] int? hours, [FromQuery] int? maxRecords)
        {
            if (serverState.IsClosed)
                return StatusCode(503, new ApiErrorResponse(serverState.ApiErrorCode, null, serverState.Reason));

            if (!Authorized.HasReadFullRole(HttpContext.Items, AyaType.Metrics))
            {
                return StatusCode(403, new ApiNotAuthorizedResponse());
            }
            //use specified values or just return all           
            maxRecords ??= int.MaxValue;
            List<MetricMM> MinuteMetrics = new List<MetricMM>();
            //Query the data and downsample if required

            if (hours != null)
            {
                DateTime maxDate = DateTime.UtcNow.Subtract(new TimeSpan((int)hours, 0, 0, 0));
                MinuteMetrics = await ct.MetricMM.AsNoTracking().Where(z => z.t > maxDate).OrderBy(z => z.t).ToListAsync();
            }
            else
            {
                MinuteMetrics = await ct.MetricMM.AsNoTracking().OrderBy(z => z.t).ToListAsync();
            }


            //split out into seperate arrays
            //10 digits is epoch seconds
            //List<Tuple<double, double>> cpu=new List<Tuple<double, double>>();
            var cpu = MinuteMetrics.Select(z => new Tuple<double, double>(new DateTimeOffset(z.t).ToUnixTimeSeconds(), z.CPU)).ToList();


            if (maxRecords < MinuteMetrics.Count)
            {
                cpu = Util.DataUtil.LargestTriangleThreeBuckets(cpu, (int)maxRecords) as List<Tuple<double, double>>;
                //downsample it here
                ;//https://github.com/sveinn-steinarsson/flot-downsample/

            }

            //convert to efficient array of double pairs
            var v = cpu.Select(z => new double[] { z.Item1, z.Item2 }).ToArray();

            var ret = new
            {
                cpu = v
            };
            //Log
            await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserIdFromContext.Id(HttpContext.Items), 0, AyaType.Metrics, AyaEvent.Retrieved), ct);

            return Ok(ApiOkResponse.Response(ret));
        }




        //------------


    }
}