using System;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using System.Linq;
using AyaNova.Util;
using AyaNova.Api.ControllerHelpers;
using Microsoft.Extensions.Logging;
using AyaNova.Models;
using Newtonsoft.Json.Linq;

namespace AyaNova.Biz
{
    internal class UnitMeterReadingBiz : BizObject, ISearchAbleObject, IReportAbleObject, IExportAbleObject
    {
        internal UnitMeterReadingBiz(AyContext dbcontext, long currentUserId, long userTranslationId, AuthorizationRoles UserRoles)
        {
            ct = dbcontext;
            UserId = currentUserId;
            UserTranslationId = userTranslationId;
            CurrentUserRoles = UserRoles;
            BizType = AyaType.UnitMeterReading;
        }

        internal static UnitMeterReadingBiz GetBiz(AyContext ct, Microsoft.AspNetCore.Http.HttpContext httpContext = null)
        {
            if (httpContext != null)
                return new UnitMeterReadingBiz(ct, UserIdFromContext.Id(httpContext.Items), UserTranslationIdFromContext.Id(httpContext.Items), UserRolesFromContext.Roles(httpContext.Items));
            else
                return new UnitMeterReadingBiz(ct, 1, ServerBootConfig.AYANOVA_DEFAULT_TRANSLATION_ID, AuthorizationRoles.BizAdmin);
        }

        ////////////////////////////////////////////////////////////////////////////////////////////////
        //EXISTS 
        internal async Task<bool> ExistsAsync(long id)
        {
            return await ct.UnitMeterReading.AnyAsync(z => z.Id == id);
        }

        ////////////////////////////////////////////////////////////////////////////////////////////////
        //CREATE   
        //
        internal async Task<UnitMeterReading> CreateAsync(UnitMeterReading newObject)
        {
            await ValidateAsync(newObject);
            if (HasErrors)
                return null;
            else
            {

                await ct.UnitMeterReading.AddAsync(newObject);
                await ct.SaveChangesAsync();
                await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserId, newObject.Id, BizType, AyaEvent.Created), ct);
                await SearchIndexAsync(newObject, true);
                await HandlePotentialNotificationEvent(AyaEvent.Created, newObject);
                return newObject;
            }
        }


        ////////////////////////////////////////////////////////////////////////////////////////////////
        //GET 
        //      
        internal async Task<UnitMeterReading> GetAsync(long id, bool logTheGetEvent = true)
        {
            var ret = await ct.UnitMeterReading.AsNoTracking().SingleOrDefaultAsync(m => m.Id == id);
            if (logTheGetEvent && ret != null)
                await EventLogProcessor.LogEventToDatabaseAsync(new Event(UserId, id, BizType, AyaEvent.Retrieved), ct);
            return ret;
        }

        ////////////////////////////////////////////////////////////////////////////////////////////////
        //SEARCH
        //
        private async Task SearchIndexAsync(UnitMeterReading obj, bool isNew)
        {
            var SearchParams = new Search.SearchIndexProcessObjectParameters(UserTranslationId, obj.Id, BizType);
            DigestSearchText(obj, SearchParams);
            if (isNew)
                await Search.ProcessNewObjectKeywordsAsync(SearchParams);
            else
                await Search.ProcessUpdatedObjectKeywordsAsync(SearchParams);
        }

        public async Task<Search.SearchIndexProcessObjectParameters> GetSearchResultSummary(long id, AyaType specificType)
        {
            var obj = await GetAsync(id, false);
            var SearchParams = new Search.SearchIndexProcessObjectParameters();
            DigestSearchText(obj, SearchParams);
            return SearchParams;
        }

        public void DigestSearchText(UnitMeterReading obj, Search.SearchIndexProcessObjectParameters searchParams)
        {
            if (obj != null)
                searchParams.AddText(obj.Notes)
                            .AddText(obj.Meter);
        }



        ////////////////////////////////////////////////////////////////////////////////////////////////
        //VALIDATION
        //

        private async Task ValidateAsync(UnitMeterReading proposedObj)
        {
            //Unit required
            var unit = await ct.Unit.AsNoTracking().FirstOrDefaultAsync(z => z.Id == proposedObj.UnitId);
            if (unit == null)
            {
                AddError(ApiErrorCode.VALIDATION_INVALID_VALUE, "UnitId", "Unit not found with that id");//api issue not user issue so no need to translate
                return;
            }

            if (!unit.Metered)
            {
                AddError(ApiErrorCode.VALIDATION_INVALID_VALUE, "UnitId", "This is not a metered unit, reading cannot be saved");//api issue not user issue so no need to translate
                return;
            }

            if (proposedObj.WorkOrderItemUnitId != null)
            {
                if (!await ct.WorkOrderItemUnit.AnyAsync(z => z.Id == proposedObj.WorkOrderItemUnitId))
                {
                    AddError(ApiErrorCode.VALIDATION_INVALID_VALUE, "WorkOrderItemUnitId", "work order item unit record was not found");//api issue not user issue so no need to translate
                    return;
                }
            }

            //No negative amounts allowed, a meter can count down to zero or up to whatever but it can't go negative or the math breaks down
            if (proposedObj.Meter < 0)
            {
                AddError(ApiErrorCode.VALIDATION_INVALID_VALUE, "Meter", "Negative meter readings not supported");
            }


        }


        ////////////////////////////////////////////////////////////////////////////////////////////////
        //REPORTING
        //
        public async Task<JArray> GetReportData(DataListSelectedRequest dataListSelectedRequest, Guid jobId)
        {
            var idList = dataListSelectedRequest.SelectedRowIds;
            JArray ReportData = new JArray();
            while (idList.Any())
            {
                var batch = idList.Take(IReportAbleObject.REPORT_DATA_BATCH_SIZE);
                idList = idList.Skip(IReportAbleObject.REPORT_DATA_BATCH_SIZE).ToArray();
                //query for this batch, comes back in db natural order unfortunately
                var batchResults = await ct.UnitMeterReading.AsNoTracking().Where(z => batch.Contains(z.Id)).ToArrayAsync();
                //order the results back into original
                var orderedList = from id in batch join z in batchResults on id equals z.Id select z;
                batchResults = null;
                foreach (UnitMeterReading w in orderedList)
                {
                    if (!ReportRenderManager.KeepGoing(jobId)) return null;
                    await PopulateVizFields(w);
                    var jo = JObject.FromObject(w);
                    ReportData.Add(jo);
                }
                orderedList = null;
            }
            vc.Clear();
            return ReportData;
        }
        private VizCache vc = new VizCache();


        //populate viz fields from provided object
        private async Task PopulateVizFields(UnitMeterReading o)
        {
            if (!vc.Has("unitserial", o.UnitId))
                vc.Add(await ct.Unit.AsNoTracking().Where(x => x.Id == o.UnitId).Select(x => x.Serial).FirstOrDefaultAsync(), "unitserial", o.UnitId);
            o.UnitViz = vc.Get("unitserial", o.UnitId);

            if (o.WorkOrderItemUnitId != null)
            {
                if (!vc.Has("woserial", o.WorkOrderItemUnitId))
                    vc.Add((await WorkOrderBiz.GetWorkOrderSerialFromRelativeAsync(AyaType.WorkOrderItemUnit, (long)o.WorkOrderItemUnitId, ct)).ToString(), "woserial", o.WorkOrderItemUnitId);
                o.WorkOrderViz = vc.Get("woserial", o.WorkOrderItemUnitId);
            }
        }


        ////////////////////////////////////////////////////////////////////////////////////////////////       
        // IMPORT EXPORT
        //

        public async Task<JArray> GetExportData(DataListSelectedRequest dataListSelectedRequest, Guid jobId)
        {
            //for now just re-use the report data code
            //this may turn out to be the pattern for most biz object types but keeping it seperate allows for custom usage from time to time
            return await GetReportData(dataListSelectedRequest, jobId);
        }






        ////////////////////////////////////////////////////////////////////////////////////////////////
        // NOTIFICATION PROCESSING
        //
        public async Task HandlePotentialNotificationEvent(AyaEvent ayaEvent, UnitMeterReading proposedObj)
        {
            ILogger log = AyaNova.Util.ApplicationLogging.CreateLogger<UnitMeterReadingBiz>();
            if (ServerBootConfig.SEEDING || ServerBootConfig.MIGRATING) return;
            log.LogDebug($"HandlePotentialNotificationEvent processing:  [AyaType:{this.BizType}, AyaEvent:{ayaEvent}]");

            //SPECIFIC EVENTS FOR THIS OBJECT

            //UnitMeterReadingMultipleExceeded event         
            {
                //see if any subscribers
                var subs = await ct.NotifySubscription.AsNoTracking().Where(z => z.EventType == NotifyEventType.UnitMeterReadingMultipleExceeded).ToListAsync();
                if (subs.Count == 0) return;
                var unitInfo = await ct.Unit.AsNoTracking().Where(x => x.Id == proposedObj.UnitId).Select(x => new { x.Name, x.Serial, x.Tags }).FirstOrDefaultAsync();
                foreach (var sub in subs)
                {
                    //not for inactive users
                    if (!await UserBiz.UserIsActive(sub.UserId)) continue;

                    if (!NotifyEventHelper.ObjectHasAllSubscriptionTags(unitInfo.Tags, sub.Tags)) continue;

                    //is multiple exceeded??
                    //Formula is to retrieve last highest reading, if it's not found then it's zero
                    //subtract last meter reading from current meter reading and if it's equal or more than threshold trigger notification

                    var lastMeterReading = await ct.UnitMeterReading.AsNoTracking()
                                                                    .Where(x => x.UnitId == proposedObj.UnitId)
                                                                    .OrderByDescending(z => z.MeterDate)//note: if in future there is an issue with not being most recent this sb id instead of date but if date is manually updatable then no
                                                                    .Skip(1)//because it's already saved this current reading by the time it gets here
                                                                    .Take(1)
                                                                    .FirstOrDefaultAsync();
                    long lastReading = 0;
                    if (lastMeterReading != null)
                        lastReading = lastMeterReading.Meter;
                    //NOTE: this will cover scenarios where the meter wraps back to zero or is reset to zero or a meter counts **down** instead of up
                    //meter readings are always positive due to biz rule, dec value is always within long range and greater than 4 (arbitrarily)
                    long diff = Math.Abs(proposedObj.Meter - lastReading);

                    if (diff >= sub.DecValue)
                    {
                        //notification is a go
                        NotifyEvent n = new NotifyEvent()
                        {
                            EventType = NotifyEventType.UnitMeterReadingMultipleExceeded,
                            UserId = sub.UserId,
                            AyaType = AyaType.UnitMeterReading,
                            ObjectId = proposedObj.Id,
                            NotifySubscriptionId = sub.Id,
                            Name = $"{unitInfo.Serial}, {unitInfo.Name}",
                            DecValue = diff
                        };
                        await ct.NotifyEvent.AddAsync(n);
                        log.LogDebug($"Adding NotifyEvent:  [{n.ToString()}]");
                        await ct.SaveChangesAsync();
                    }
                }

            }

        }//end of process notifications




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

    }//eoc


}//eons