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;
using StackExchange.Profiling;

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;
        private const int DEFAULT_MAX_RECORDS = 400;
        private const long MB = (1024 * 1024);


        /// <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 Memory and CPU server metrics for time period specified
        /// </summary>  
        /// <param name="tsStart">Start timestamp UTC</param>
        /// <param name="tsEnd">End timestamp UTC</param>
        /// <param name="maxRecords">Optional maximum records to return (downsampled). There is a 400 record maximum fixed default</param>
        /// <returns>Snapshot of metrics</returns>
        [HttpGet("memcpu")]
        public async Task<IActionResult> GetMemCPUMetrics([FromQuery, Required] DateTime? tsStart, [FromQuery, Required] DateTime? tsEnd, [FromQuery] int? maxRecords)
        {
            //Note: the date and times are nullable and required so that the regular modelstate code kicks in to ensure they are present 
            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());
            if (!ModelState.IsValid)
                return BadRequest(new ApiErrorResponse(ModelState));

            maxRecords ??= DEFAULT_MAX_RECORDS;

            List<MetricMM> MinuteMetrics = new List<MetricMM>();
            //touniversal is because the parameters are converted to local time here
            //but then sent to the query as local time as well and not universal time which is what it should be
            MinuteMetrics = await ct.MetricMM.AsNoTracking().Where(z => z.t >= ((DateTime)tsStart).ToUniversalTime() && z.t <= ((DateTime)tsEnd).ToUniversalTime()).OrderBy(z => z.t).ToListAsync();


            var dsCPU = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.CPU)).ToList();
            dsCPU = Util.DataUtil.LargestTriangleThreeBuckets(dsCPU, (int)maxRecords) as List<Tuple<double, double>>;

            var dsAllocated = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.Allocated)).ToList();
            dsAllocated = Util.DataUtil.LargestTriangleThreeBuckets(dsAllocated, (int)maxRecords) as List<Tuple<double, double>>;

            var dsWorkingSet = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.WorkingSet)).ToList();
            dsWorkingSet = Util.DataUtil.LargestTriangleThreeBuckets(dsWorkingSet, (int)maxRecords) as List<Tuple<double, double>>;

            var dsPrivateBytes = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.PrivateBytes)).ToList();
            dsPrivateBytes = Util.DataUtil.LargestTriangleThreeBuckets(dsPrivateBytes, (int)maxRecords) as List<Tuple<double, double>>;

            var dsGen0 = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.Gen0)).ToList();
            dsGen0 = Util.DataUtil.LargestTriangleThreeBuckets(dsGen0, (int)maxRecords) as List<Tuple<double, double>>;

            var dsGen1 = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.Gen1)).ToList();
            dsGen1 = Util.DataUtil.LargestTriangleThreeBuckets(dsGen1, (int)maxRecords) as List<Tuple<double, double>>;

            var dsGen2 = MinuteMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.Gen2)).ToList();
            dsGen2 = Util.DataUtil.LargestTriangleThreeBuckets(dsGen2, (int)maxRecords) as List<Tuple<double, double>>;

            var ret = new
            {
                cpu = dsCPU.Select(z => new MetricDouble(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                gen0 = dsGen0.Select(z => new MetricInt(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                gen1 = dsGen1.Select(z => new MetricInt(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                gen2 = dsGen2.Select(z => new MetricInt(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                allocated = dsAllocated.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray(),
                workingSet = dsWorkingSet.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray(),
                privateBytes = dsPrivateBytes.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray()
            };

            await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserIdFromContext.Id(HttpContext.Items), 0, AyaType.Metrics, AyaEvent.Retrieved), ct);
            return Ok(ApiOkResponse.Response(ret));
        }


        /// <summary>
        /// Get storage server metrics for time period specified
        /// </summary>  
        /// <param name="tsStart">Start timestamp UTC</param>
        /// <param name="tsEnd">End timestamp UTC</param>
        /// <param name="maxRecords">Optional maximum records to return (downsampled). There is a 400 record maximum fixed default</param>
        /// <returns>Snapshot of metrics</returns>
        [HttpGet("storage")]
        public async Task<IActionResult> GetStorageMetrics([FromQuery, Required] DateTime? tsStart, [FromQuery, Required] DateTime? tsEnd, [FromQuery] int? maxRecords)
        {
            //Note: the date and times are nullable and required so that the regular modelstate code kicks in to ensure they are present 
            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());
            if (!ModelState.IsValid)
                return BadRequest(new ApiErrorResponse(ModelState));

            maxRecords ??= DEFAULT_MAX_RECORDS;

            List<MetricDD> DailyMetrics = new List<MetricDD>();
            //touniversal is because the parameters are converted to local time here
            //but then sent to the query as local time as well and not universal time which is what it should be
            DailyMetrics = await ct.MetricDD.AsNoTracking().Where(z => z.t >= ((DateTime)tsStart).ToUniversalTime() && z.t <= ((DateTime)tsEnd).ToUniversalTime()).OrderBy(z => z.t).ToListAsync();


            var dsAttachmentFileCount = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.AttachmentFileCount)).ToList();
            dsAttachmentFileCount = Util.DataUtil.LargestTriangleThreeBuckets(dsAttachmentFileCount, (int)maxRecords) as List<Tuple<double, double>>;

            var dsAttachmentFileSize = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.AttachmentFileSize)).ToList();
            dsAttachmentFileSize = Util.DataUtil.LargestTriangleThreeBuckets(dsAttachmentFileSize, (int)maxRecords) as List<Tuple<double, double>>;

            var dsAttachmentFilesAvailableSpace = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.AttachmentFilesAvailableSpace)).ToList();
            dsAttachmentFilesAvailableSpace = Util.DataUtil.LargestTriangleThreeBuckets(dsAttachmentFilesAvailableSpace, (int)maxRecords) as List<Tuple<double, double>>;

            var dsUtilityFileCount = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.UtilityFileCount)).ToList();
            dsUtilityFileCount = Util.DataUtil.LargestTriangleThreeBuckets(dsUtilityFileCount, (int)maxRecords) as List<Tuple<double, double>>;

            var dsUtilityFileSize = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.UtilityFileSize)).ToList();
            dsUtilityFileSize = Util.DataUtil.LargestTriangleThreeBuckets(dsUtilityFileSize, (int)maxRecords) as List<Tuple<double, double>>;

            var dsUtilityFilesAvailableSpace = DailyMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.UtilityFilesAvailableSpace)).ToList();
            dsUtilityFilesAvailableSpace = Util.DataUtil.LargestTriangleThreeBuckets(dsUtilityFilesAvailableSpace, (int)maxRecords) as List<Tuple<double, double>>;

            var ret = new
            {
                attachmentFileCount = dsAttachmentFileCount.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                attachmentFileSize = dsAttachmentFileSize.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray(),
                attachmentFilesAvailableSpace = dsAttachmentFilesAvailableSpace.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray(),
                utilityFileCount = dsUtilityFileCount.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2)).ToArray(),
                utilityFileSize = dsUtilityFileSize.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray(),
                utilityFilesAvailableSpace = dsUtilityFilesAvailableSpace.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray()

            };



            await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserIdFromContext.Id(HttpContext.Items), 0, AyaType.Metrics, AyaEvent.Retrieved), ct);
            return Ok(ApiOkResponse.Response(ret));
        }



        /// <summary>
        /// Get database related metrics for time period specified
        /// </summary>  
        /// <param name="tsStart">Start timestamp UTC</param>
        /// <param name="tsEnd">End timestamp UTC</param>
        /// <param name="maxRecords">Optional maximum records to return (downsampled). There is a 400 record maximum fixed default</param>
        /// <returns>Snapshot of metrics</returns>
        [HttpGet("db")]
        public async Task<IActionResult> GetDBMetrics([FromQuery, Required] DateTime? tsStart, [FromQuery, Required] DateTime? tsEnd, [FromQuery] int? maxRecords)
        {
            //Note: the date and times are nullable and required so that the regular modelstate code kicks in to ensure they are present 
            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());
            if (!ModelState.IsValid)
                return BadRequest(new ApiErrorResponse(ModelState));

            maxRecords ??= DEFAULT_MAX_RECORDS;

            List<MetricDD> DBMetrics = new List<MetricDD>();
            //touniversal is because the parameters are converted to local time here
            //but then sent to the query as local time as well and not universal time which is what it should be
            DBMetrics = await ct.MetricDD.AsNoTracking().Where(z => z.t >= ((DateTime)tsStart).ToUniversalTime() && z.t <= ((DateTime)tsEnd).ToUniversalTime()).OrderBy(z => z.t).ToListAsync();
            var dsDBTotalSize = DBMetrics.Select(z => new Tuple<double, double>(z.t.ToOADate(), z.DBTotalSize)).ToList();
            dsDBTotalSize = Util.DataUtil.LargestTriangleThreeBuckets(dsDBTotalSize, (int)maxRecords) as List<Tuple<double, double>>;

            //table distribution, top 10
            List<MetricNameLongValue> TopTables = new List<MetricNameLongValue>();
            using (var command = ct.Database.GetDbConnection().CreateCommand())
            {
                //top 10 tables by size
                command.CommandText = @"SELECT relname AS ""table_name"", pg_table_size(C.oid) AS ""table_size"" FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) WHERE nspname NOT IN ('pg_catalog', 'information_schema') AND nspname !~ '^pg_toast' AND relkind IN ('r') ORDER BY pg_table_size(C.oid) DESC;";
                ct.Database.OpenConnection();
                using (var dr = command.ExecuteReader())
                {
                    if (dr.HasRows)
                    {
                        while (dr.Read())
                        {
                            long tableSize = dr.GetInt64(1);
                            string tableName = dr.GetString(0);
                            if (tableSize > 0)
                            {
                                tableSize = tableSize / MB;
                            }
                            TopTables.Add(new MetricNameLongValue() { name = tableName, value = tableSize });
                        }
                    }
                    ct.Database.CloseConnection();
                }
            }

            //trim out tables we don't want here
            TopTables = TopTables.Where(z => z.value > 0).OrderByDescending(z => z.value).ToList();

            long DBTotalSize = 0;
            using (var command = ct.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = "select pg_database_size(current_database());";
                ct.Database.OpenConnection();
                using (var dr = command.ExecuteReader())
                {
                    if (dr.HasRows)
                    {
                        DBTotalSize = dr.Read() ? (dr.GetInt64(0) / MB) : 0;
                    }
                    ct.Database.CloseConnection();
                }
            }

            long ttSize = 0;
            foreach (MetricNameLongValue tt in TopTables)
            {
                ttSize += tt.value;
            }
            TopTables.Add(new MetricNameLongValue() { name = "other", value = DBTotalSize - ttSize });

            var ret = new
            {
                TopTables = TopTables,
                totalSize = dsDBTotalSize.Select(z => new MetricLong(DateTime.FromOADate(z.Item1), z.Item2 / MB)).ToArray()
            };



            await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserIdFromContext.Id(HttpContext.Items), 0, AyaType.Metrics, AyaEvent.Retrieved), ct);
            return Ok(ApiOkResponse.Response(ret));
        }



        //------------
        public class MetricLong
        {
            public DateTime x { get; set; }
            public long y { get; set; }
            public MetricLong(DateTime px, double py)
            {
                x = px;
                y = (long)py;

            }
        }

        public class MetricInt
        {
            public DateTime x { get; set; }
            public int y { get; set; }
            public MetricInt(DateTime px, double py)
            {
                x = px;
                y = (int)py;

            }
        }

        public class MetricDouble
        {
            public DateTime x { get; set; }
            public double y { get; set; }
            public MetricDouble(DateTime px, double py)
            {
                x = px;
                y = py;

            }
        }

        public class MetricNameLongValue
        {
            public string name { get; set; }
            public long value { get; set; }
        }
        //----------

    }
}