using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using AyaNova.Models;

namespace AyaNova.Biz
{


    /// <summary>
    /// Clean up notification system, keep items down to 90 days
    /// 
    /// </summary>
    internal static class CoreNotificationSweeper
    {
        private static ILogger log = AyaNova.Util.ApplicationLogging.CreateLogger("CoreNotificationSweeper");
        private static DateTime lastSweep = DateTime.MinValue;
        private static TimeSpan DELETE_AFTER_AGE = new TimeSpan(90, 0, 0, 0);
        private static TimeSpan SWEEP_EVERY_INTERVAL = new TimeSpan(8, 0, 0);//once every 8 hours, three times a day

        ////////////////////////////////////////////////////////////////////////////////////////////////
        // DoSweep
        //
        public static async Task DoWorkAsync()
        {
            //This will get triggered roughly every minute, but we don't want to sweep that frequently
            if (DateTime.UtcNow - lastSweep < SWEEP_EVERY_INTERVAL)
                return;
            DateTime dtDeleteCutoff = DateTime.UtcNow - DELETE_AFTER_AGE;
            DateTime dtPastEventCutoff = DateTime.UtcNow - SWEEP_EVERY_INTERVAL;

            log.LogTrace("Sweep starting");
            using (AyContext ct = AyaNova.Util.ServiceProviderProvider.DBContext)
            {
                //Notification (App notifications table) - deletes all APP notifications older than 90 days (if they want to keep it then can turn it into a reminder or SAVE it somehow)
                await ct.Database.ExecuteSqlInterpolatedAsync($"delete from anotification where created < {dtDeleteCutoff}");

                //NotifyEvent - deletes any notifyevent with no event date created more than 90 days ago
                await ct.Database.ExecuteSqlInterpolatedAsync($"delete from anotifyevent where eventdate is null and created < {dtDeleteCutoff}");

                //NotifyEvent - If has event date and it's in the past by more than an 8 hours (or whatever sweep interval is, to allow for items about to be delivered momentarily as delivery is on briefer cycle than sweep) 
                //then deletes it if created more than 90 days ago (pretty sure there are no back dated events, once it's passed it's past)
                await ct.Database.ExecuteSqlInterpolatedAsync($"delete from anotifyevent where eventdate < {dtPastEventCutoff} and created < {dtDeleteCutoff}");

                //NotifyDeliveryLog - deletes all log items older than 90 days
                await ct.Database.ExecuteSqlInterpolatedAsync($"delete from anotifydeliverylog where processed < {dtDeleteCutoff}");

            }
            lastSweep = DateTime.UtcNow;
        }


        private static async Task sweepAsync(AyContext ct, DateTime dtDeleteCutoff, JobStatus jobStatus)
        {
            //Get the deleteable succeeded jobs list
            var jobs = await ct.OpsJob
                   .AsNoTracking()
                   .Where(z => z.Created < dtDeleteCutoff && z.JobStatus == jobStatus)
                   .OrderBy(z => z.Created)
                   .ToListAsync();

            log.LogTrace($"SweepAsync processing: cutoff={dtDeleteCutoff.ToString()}, for {jobs.Count.ToString()} jobs of status {jobStatus.ToString()}");

            foreach (OpsJob j in jobs)
            {
                try
                {

                    await JobsBiz.RemoveJobAndLogsAsync(j.GId);
                }
                catch (Exception ex)
                {
                    log.LogError(ex, "sweepAsync exception calling JobsBiz.RemoveJobAndLogsAsync");
                    //for now just throw it but this needs to be removed when logging added and better handling 
                    throw (ex);
                }
            }
        }


        /// <summary>
        /// Kill jobs that have been stuck in "running" state for too long
        /// </summary>        
        private static async Task killStuckJobsAsync(AyContext ct, DateTime dtRunningDeadline)
        {
            //Get the deleteable succeeded jobs list
            var jobs = await ct.OpsJob
                   .AsNoTracking()
                   .Where(z => z.Created < dtRunningDeadline && z.JobStatus == JobStatus.Running)
                   .OrderBy(z => z.Created)
                   .ToListAsync();

            log.LogTrace($"killStuckJobsAsync processing: cutoff={dtRunningDeadline.ToString()}, for {jobs.Count.ToString()} jobs of status {JobStatus.Running.ToString()}");

            foreach (OpsJob j in jobs)
            {
                //OPSMETRIC
                await JobsBiz.LogJobAsync(j.GId, "Job took too long to run - setting to failed");
                log.LogError($"Job found job stuck in running status and set to failed: deadline={dtRunningDeadline.ToString()}, jobId={j.GId.ToString()}, jobname={j.Name}, jobtype={j.JobType.ToString()}, jobObjectType={j.ObjectType.ToString()}, jobObjectId={j.ObjectId.ToString()}");
                await JobsBiz.UpdateJobStatusAsync(j.GId, JobStatus.Failed);
            }
        }


        private static async Task SweepInternalJobsLogsAsync(AyContext ct, DateTime dtDeleteCutoff)
        {
            //Get the deleteable list (this is for reporting, could easily just do it in one go)
            var logs = await ct.OpsJobLog
                   .AsNoTracking()
                   .Where(z => z.Created < dtDeleteCutoff)
                   .OrderBy(z => z.Created)
                   .ToListAsync();

            log.LogTrace($"SweepInternalJobsLogsAsync processing: cutoff={dtDeleteCutoff.ToString()}, for {logs.Count.ToString()} log entries");

            foreach (OpsJobLog l in logs)
            {
                try
                {
                    await ct.Database.ExecuteSqlInterpolatedAsync($"delete from aopsjoblog where gid = {l.GId}");
                }
                catch (Exception ex)
                {
                    log.LogError(ex, "SweepInternalJobsLogsAsync exception removed old log entries");
                    throw (ex);
                }
            }
        }

        /////////////////////////////////////////////////////////////////////

    }//eoc


}//eons