using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using Comal.Classes;
using InABox.Core;

namespace Comal.Stores
{
    internal class KanbanStore : ScheduleActionStore<Kanban>
    {
        private void CheckNotifications(Kanban entity)
        {
            if (entity.HasOriginalValue(x => x.Completed) && !entity.Completed.IsEmpty())
            {
                // Find all notifications linked to this task
                var notifications = Provider.Query(
                    new Filter<Notification>(x => x.EntityType).IsEqualTo(typeof(Kanban).EntityName()).And(x => x.EntityID).IsEqualTo(entity.ID)
                        .And(x => x.Closed).IsEqualTo(DateTime.MinValue),
                    new Columns<Notification>(x => x.ID)
                ).Rows.Select(x => x.ToObject<Notification>());
                foreach (var notification in notifications)
                    notification.Closed = entity.Completed;
                if (notifications.Any())
                    FindSubStore<Notification>().Save(notifications, "");
            }
        }

        private void NotifyUsers(Kanban entity)
        {
            var Subject = string.Format("Updated Task: {0} (Due: {1:dd MMM yy})", entity.Title, entity.DueDate);        
            var emps = Provider.Query(
                new Filter<KanbanSubscriber>(x => x.Kanban.ID).IsEqualTo(entity.ID),
                new Columns<KanbanSubscriber>(x => x.Employee.ID, x => x.Employee.UserLink.ID));          
            var senderrow = emps.Rows.FirstOrDefault(r => r.Get<KanbanSubscriber, Guid>(c => c.Employee.UserLink.ID).Equals(UserGuid));
            var senderid = senderrow != null ? senderrow.Get<KanbanSubscriber, Guid>(c => c.Employee.ID) : Guid.Empty;
            var notifications = new List<Notification>();
            foreach (var row in emps.Rows)
            {
                var userid = row.Get<KanbanSubscriber, Guid>(c => c.Employee.UserLink.ID);
                if (userid != UserGuid)
                {
                    var notification = new Notification();
                    notification.Employee.ID = row.Get<KanbanSubscriber, Guid>(c => c.Employee.ID);
                    notification.Sender.ID = senderid;
                    notification.Title = Subject;
                    notification.EntityType = typeof(Kanban).EntityName();
                    notification.EntityID = entity.ID;
                    notification.Description = BuildDescription(entity);
                    notifications.Add(notification);
                }
            }
            if (emps.Rows.Count == 0)
            {
                var userID = Provider.Query(
                    new Filter<Employee>(x => x.ID).IsEqualTo(entity.EmployeeLink.ID),
                    new Columns<Employee>(x => x.UserLink.ID)
                    ).Rows.FirstOrDefault()?.Get<Employee, Guid>(x => x.UserLink.ID);
                if(userID != UserGuid)
                {
                    Notification notification = new Notification();
                    notification.Employee.ID = entity.EmployeeLink.ID;
                    notification.Sender.ID = entity.ManagerLink.ID;
                    notification.Title = Subject;
                    notification.EntityType = typeof(Kanban).EntityName();
                    notification.EntityID = entity.ID;
                    notification.Description = BuildDescription(entity);
                    notifications.Add(notification);
                }
            }
            if (notifications.Any())
                FindSubStore<Notification>().Save(notifications, "");
        }

        private string BuildDescription(Kanban entity)
        {
            var notes = entity.Notes != null
                ? string.Join("\r\n", entity.Notes)
                    .Split(new[] { "===================================\r\n" }, StringSplitOptions.RemoveEmptyEntries)
                : new string[] { };
            var summary = notes.LastOrDefault();
            if (string.IsNullOrEmpty(summary))
                summary = entity.Summary;
            if (string.IsNullOrEmpty(summary))
                summary = "";
            summary = Regex.Replace(summary.Replace("\r", "\n"), @"( |\r?\n|\r|\n)\1+", "$1");

            var sb = new StringBuilder();
            if (entity.EmployeeLink.HasOriginalValue(x => x.ID))
                sb.AppendLine("The above task has been assigned to you. Please check the relevant details, and action as required.");
            else
                sb.AppendLine("The above task has been changed.  Please check the relevant details, and action as required.");

            if (entity.HasOriginalValue(x => x.Category) && !string.IsNullOrEmpty(entity.GetOriginalValue(x => x.Category)))
            {
                sb.AppendLine();
                sb.AppendLine(string.Format("- The task has progressed from {0} to {1}.", entity.GetOriginalValue(x => x.Category),
                    entity.Category));
            }
            if (entity.HasOriginalValue(x => x.DueDate) && entity.GetOriginalValue(x => x.DueDate) != DateTime.MinValue)
            {
                sb.AppendLine();
                sb.AppendLine(string.Format("- The due date for the task has been changed from {0} to {1}.",
                    entity.OriginalValues["DueDate"],
                    entity.DueDate));
            }
            if (entity.HasOriginalValue(x => x.Notes) && entity.Notes.Count() > 1)
            {
                sb.AppendLine("- The notes for the task have been updated as follows:");
                foreach (var line in summary.Split('\n'))
                    sb.AppendLine("    " + line);
            }
            return sb.ToString();
        }

        private void CheckNotificationRequired(Kanban entity)
        {
            if (entity.EmployeeLink.HasOriginalValue(x => x.ID) || entity.HasOriginalValue(x => x.Notes) ||
                    entity.HasOriginalValue(x => x.Category) ||
                    entity.HasOriginalValue(x => x.Summary) || entity.HasOriginalValue(x => x.DueDate))
            {
                NotifyUsers(entity);
            }
            else if (entity.ID != Guid.Empty && entity.HasOriginalValue(x => x.ID))
            {
                if (entity.GetOriginalValue<Kanban, Guid>("ID") == Guid.Empty)
                {
                    NotifyUsers(entity);
                }
            }
        }

        protected override void BeforeSave(Kanban entity)
        {
            base.BeforeSave(entity);
            if (entity.Completed.IsEmpty())
                entity.Closed = DateTime.MinValue;
        }

        private void CheckKanbanTypeForms(Kanban kanban)
        {
            if(!kanban.Type.HasOriginalValue(x => x.ID))
            {
                return;
            }
            var kanbanForms = Provider.Query(
                new Filter<KanbanForm>(x => x.Parent.ID).IsEqualTo(kanban.ID)).Rows.Select(x => x.ToObject<KanbanForm>());
            var toDelete = kanbanForms.Where(x => string.IsNullOrWhiteSpace(x.FormData));
            Provider.Delete(toDelete, UserID);

            var kanbanTypeForms = Provider.Query(
                new Filter<KanbanTypeForm>(x => x.Type.ID).IsEqualTo(kanban.Type.ID)
                    .And(x => x.Form.AppliesTo).IsEqualTo(nameof(Kanban)));

            var newForms = new List<KanbanForm>();
            foreach(var row in kanbanTypeForms.Rows)
            {
                var formID = row.Get<KanbanTypeForm, Guid>(x => x.Form.ID);
                if (!(kanbanForms.Any(x => x.Form.ID == formID) && !toDelete.Any(x => x.Form.ID == formID)))
                {
                    var kanbanForm = new KanbanForm();
                    kanbanForm.Form.ID = formID;
                    kanbanForm.Parent.ID = kanban.ID;
                    newForms.Add(kanbanForm);
                }
            }
            Provider.Save(newForms);
        }

        protected override void AfterSave(Kanban entity)
        {
            base.AfterSave(entity);
            CheckNotifications(entity);
            CheckNotificationRequired(entity);
            CheckKanbanTypeForms(entity);
        }
    }
}