using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using PARR.BLL.Services.Interfaces;
using PARR.Constants;
using PARR.DAL.Models;
using PARR.DAL.Services.Interfaces;
using PARR.DAL.TransformServices;

namespace PARR.TemplateDistributor
{
    internal class TemplateDistributor : ITemplateDistributor
    {
        private readonly ILogger<TemplateDistributor> logger;
        private readonly ITemplateService templateService;
        private readonly IApplicationsInWorkService applicationsInWorkService;
        private readonly IEsppSchTypeScheduleService esppSchTypeScheduleService;
        private readonly ICalendarService calendarService;
        private readonly IEsppScheduleTransformService esppScheduleTransformService;
        private readonly IWeekendDayService weekendDayService;

        public TemplateDistributor(
            ILogger<TemplateDistributor> logger,
            ITemplateService templateService,
            IApplicationsInWorkService applicationsInWorkService,
            IEsppSchTypeScheduleService esppSchTypeScheduleService,
            ICalendarService calendarService,
            IEsppScheduleTransformService esppScheduleTransformService,
            IWeekendDayService weekendDayService
            )
        {
            this.logger = logger;
            this.templateService = templateService;
            this.applicationsInWorkService = applicationsInWorkService;
            this.esppSchTypeScheduleService = esppSchTypeScheduleService;
            this.calendarService = calendarService;
            this.esppScheduleTransformService = esppScheduleTransformService;
            this.weekendDayService = weekendDayService;
        }


        public async Task UpdateScheduleAsync(Guid applicationInWorkId)
        {
            // все шаблоны по applicationInWorkId
            // группирует по РР
            // -> DistributeTemplateForPeriodAsync
            // сохранить в БД
            //applicationInWorkId = Guid.Parse("bdfefd77-bce3-4f62-a484-5042c06f4467");

            //var appInWork = await applicationsInWorkService.Get()
            //                                                .Include(aiw => aiw.EsppSchValues)
            //                                                    .ThenInclude(esv => esv.EsppSchTypeValue)
            //                                                    .ThenInclude(etv => etv!.DistributionPeriod)
            //                                                .FirstOrDefaultAsync(t => t.Id == applicationInWorkId);

            var templates = await templateService.Get()
                                                    .Include(t => t.Host)
                                                        .ThenInclude(h => h.WorkGroup)
                                                    .Where(t => t.ApplicationInWorkId == applicationInWorkId)
                                                    .ToListAsync();


            var workGroupsWithTemplates = templates.GroupBy(t => t.Host!.WorkGroupId);

            foreach (var workGroupWithTemplates in workGroupsWithTemplates)
            {
                var wgId = workGroupWithTemplates.Key ?? Guid.NewGuid();//TODO сделать правильно
                var values = workGroupWithTemplates.ToList();

                if (!values.Any())
                    continue;

                var distrTemplates = await DistributeTemplateAsync(values, applicationInWorkId, wgId);
            }

            // saveChanges
            if (!await applicationsInWorkService.CommitAsync())
                logger.LogError($"Ошибка записи изменений в БД при перераспределении NextRun шаблонов");
        }


        public async Task<List<Template>> DistributeTemplateAsync(List<Template> templates, Guid applicationInWorkId, Guid workGroupId)
        {
            var appInWork = await applicationsInWorkService.Get()
                                                            .Include(aiw => aiw.EsppSchValues)
                                                                .ThenInclude(esv => esv.EsppSchTypeValue)
                                                                .ThenInclude(etv => etv!.DistributionPeriod)
                                                            .FirstOrDefaultAsync(t => t.Id == applicationInWorkId);
            var refDate = appInWork!.ReferenceDate;

            //Проверяем наличие распределения РР на период
            if (appInWork!.IsAutoDistributionEnabled)
            {
                var existingTemplates = await templateService.Get()
                                                    .Include(t => t.Host)
                                                    .Where(t => t.ApplicationInWorkId == applicationInWorkId && t.Host!.WorkGroupId == workGroupId)
                                                    .ToListAsync();
                //Если распределенная РР получаем начало
                var period = appInWork.EsppSchValues.FirstOrDefault()?.EsppSchTypeValue?.DistributionPeriod;
                var periodType = ParseDistributionPeriodType(period!.Type);

                var workDays = await GetWorkDaysAsync(appInWork);

                //Готовим план распределения
                var distrPlan = GetDistributionPlan(workDays, templates.Count + existingTemplates.Count);

                var templateToDistrib = new List<Template>();

                if (existingTemplates.Count > 0)
                    templateToDistrib = GetTemplatesToDistribute(ref distrPlan, existingTemplates);

                templateToDistrib.AddRange(templates);

                var distributedTemplates = 0;

                foreach (var workDay in distrPlan)
                {
                    var templatesCountForCurDay = workDay.Value;

                    templateToDistrib.Skip(distributedTemplates).Take(templatesCountForCurDay).ToList().ForEach(t =>
                    {
                        var nextRun = new DateTimeOffset(
                                workDay.Key.Year, workDay.Key.Month, workDay.Key.Day,
                                refDate.Hour, refDate.Minute, refDate.Second,
                                new TimeSpan(0, 0, 0));
                        if (nextRun < DateTimeOffset.UtcNow)
                            nextRun = esppScheduleTransformService.GetNextDateForDistributionRun(nextRun, periodType, period.Duration);

                        t.NextRun = nextRun;
                    });

                    distributedTemplates += templatesCountForCurDay;
                }

                return templateToDistrib;



                //var d = new Dictionary<DateOnly, List<Template>>();
                //foreach (var wd in workDays)
                //{
                //    var wrokDateTimeOffset = new DateTimeOffset(
                //            wd.Year, wd.Month, wd.Day,
                //            refDate.Hour, refDate.Minute, refDate.Second,
                //            new TimeSpan(0, 0, 0));
                //    if (wrokDateTimeOffset < DateTimeOffset.UtcNow)
                //        wrokDateTimeOffset = esppScheduleTransformService.GetNextDateForDistributionRun(wrokDateTimeOffset, periodType, period.Duration);

                //    var assignedTemplates = existingTemplates.Where(t => t.NextRun == wrokDateTimeOffset).ToList();
                //    d.Add(wd, assignedTemplates);
                //}

                //var templatesPerStep = (double)templates.Count() / workDays.Count();//
                //var currentTemplateStep = (int)Math.Ceiling(templatesPerStep);
                //var delta = templatesPerStep - currentTemplateStep;
                ////templates.First().NextRun = currentDay;
                //var templateDistributed = 0;

                ////Отталкиваясь от количества 
                //while (templateDistributed < templates.Count())
                //{
                //    var wdCounts = d.Select(wd => wd.Value).OrderBy(count => count).ToArray();
                //    var templateCountDelta = d.Max(t => t.Value.Count()) - d.Min(t => t.Value.Count());
                //    var addingTemplatesCount = wdCounts.Length > 1 ?
                //       (templateCountDelta == 0) ? (int)Math.Ceiling(templatesPerStep) : templateCountDelta :
                //        (int)Math.Ceiling(templatesPerStep);
                //    var workDaysWithMinTemplates = d.Where(wd => wd.Value == wdCounts[0]).ToArray();

                //    if (workDaysWithMinTemplates.Length * addingTemplatesCount < templates.Count())
                //    {
                //        foreach (var wd in workDaysWithMinTemplates)
                //        {
                //            //Считаем DateTimeOffset, потому что у нас только дата пока 
                //            var currentDay = new DateTimeOffset(
                //            wd.Key.Year, wd.Key.Month, wd.Key.Day,
                //            refDate.Hour, refDate.Minute, refDate.Second,
                //            new TimeSpan(0, 0, 0));

                //            templates.Skip(templateDistributed).Take(addingTemplatesCount).ToList().ForEach(t =>
                //            {
                //                t.NextRun = currentDay;
                //                d[wd.Key].Add(t);
                //            });
                //            templateDistributed += addingTemplatesCount;

                //        }
                //    }
                //    else
                //    {
                //        while (templateDistributed < templates.Count())
                //        {
                //            var wd = d.Where(wd => wd.Value == d.Min(t => t.Value)).First();
                //            //Считаем DateTimeOffset, потому что у нас только дата пока 
                //            var currentDay = new DateTimeOffset(
                //            wd.Key.Year, wd.Key.Month, wd.Key.Day,
                //            refDate.Hour, refDate.Minute, refDate.Second,
                //            new TimeSpan(0, 0, 0));

                //            templates.Skip(templateDistributed).Take(addingTemplatesCount).ToList().ForEach(t =>
                //            {
                //                t.NextRun = currentDay;
                //                d[wd.Key].Add(t);
                //            });
                //            templateDistributed += addingTemplatesCount;
                //        }
                //    }
                //}
            }
            else
                templates.ForEach(t => t.NextRun = appInWork!.ReferenceDate);

            return templates;
        }

        private async Task<List<DateOnly>> GetWorkDaysAsync(ApplicationsInWork appInWork)
        {

            var period = appInWork.EsppSchValues.FirstOrDefault()?.EsppSchTypeValue?.DistributionPeriod;
            var periodType = ParseDistributionPeriodType(period!.Type);
            var startPeriod = await esppScheduleTransformService.GetStartPeriodForDateAsync(appInWork.Id, appInWork.ReferenceDate, appInWork.ReferenceDate, periodType, period.Duration);

            var result = calendarService.GetWorkDatesForPeriod(startPeriod, periodType, period.Duration, weekendDayService.GetWeekends);

            result.ForEach(wd =>
            {
                var wrokDateTimeOffset = new DateTimeOffset(
                                            wd.Year, wd.Month, wd.Day,
                                            0, 0, 0,
                                            new TimeSpan(0, 0, 0));
                if (wrokDateTimeOffset < DateTimeOffset.UtcNow)
                {
                    wrokDateTimeOffset = esppScheduleTransformService.GetNextDateForDistributionRun(wrokDateTimeOffset, periodType, period.Duration);
                    wd = DateOnly.FromDateTime(wrokDateTimeOffset.DateTime);
                }
            });

            return result;
        }


        private List<Template> GetTemplatesToDistribute(ref Dictionary<DateOnly, int> distributionPlan, List<Template> templates)
        {
            var result = new List<Template>();

            foreach (var wd in distributionPlan)
            {
                var templatesInWd = templates.Where(t => DateOnly.FromDateTime(t.NextRun.DateTime) == wd.Key).ToList();

                var templatesToDistribute = templatesInWd.Skip(wd.Value).Take(templatesInWd.Count - wd.Value).ToList();

                distributionPlan[wd.Key] -= templatesInWd.Count;

                result.AddRange(templatesToDistribute);
            }



            return result;
        }


        private DistributionPeriodTypeEnum ParseDistributionPeriodType(string value)
        {
            var result = (DistributionPeriodTypeEnum)Enum.Parse(typeof(DistributionPeriodTypeEnum), value);

            return result;
        }


        private Dictionary<DateOnly, int> GetDistributionPlan(List<DateOnly> workDays, int templateCount)
        {
            var d = new Dictionary<DateOnly, int>();
            foreach (var wd in workDays)
            {
                var workDateTimeOffset = new DateOnly(wd.Year, wd.Month, wd.Day);
                d.Add(workDateTimeOffset, 0);
            }

            var templateDistributed = 0;

            if (templateCount > workDays.Count)
            {
                var mainPartTemplateCountToDistribute = templateCount / workDays.Count;
                foreach (var item in d)
                {
                    d[item.Key] = mainPartTemplateCountToDistribute;

                    templateDistributed += mainPartTemplateCountToDistribute;
                }
            }

            var templatesPerWorkDay = (double)workDays.Count / (templateCount % workDays.Count);
            var currentStep = (double)Math.Floor(templatesPerWorkDay);//??????? точно double?
            var balance = (double)templatesPerWorkDay - Math.Floor(currentStep);
            var currentIndex = 0;

            while (templateDistributed < templateCount)
            {
                if (currentStep > 0)
                {
                    d[d.ElementAt(currentIndex).Key] += 1;
                    templateDistributed++;
                    currentIndex += (int)Math.Floor(currentStep);

                    currentStep = templatesPerWorkDay + balance;
                    balance = currentStep - templatesPerWorkDay;
                }

            }

            return d;
        }
    }

}