using System.Collections.Generic;
using System.Linq;
using Comal.Classes;
using InABox.Core;
using System;
using ExCSS;
using InABox.Database.Stores;
using InABox.Database;
using InABox.Configuration;
using Comal.Stores;
using PRSStores.AssignmentCosting;

namespace PRSStores
{
    internal class AssignmentStore : BaseStore<Assignment>
    {
        public override void Init()
        {
            base.Init();

            GlobalSettingsStore.RegisterSubStore<AssignmentCostSettings, AssignmentCosting.AssignmentCostingUtils>();
        }

        private void CheckActivityForms(Assignment assignment)
        {
            if (!assignment.ActivityLink.HasOriginalValue(x => x.ID))
            {
                return;
            }

            List<AssignmentForm> assignmentForms;
            if(assignment.ID != Guid.Empty)
            {
                assignmentForms = Provider.Query(
                    Filter<AssignmentForm>.Where(x => x.Parent.ID).IsEqualTo(assignment.ID),
                    Columns.None<AssignmentForm>().Add(x => x.ID, x => x.FormData)
                ).Rows.Select(x => x.ToObject<AssignmentForm>()).ToList();
            }
            else
            {
                assignmentForms = new();
            }

            var toDelete = assignmentForms.Where(x => string.IsNullOrWhiteSpace(x.FormData));
            Provider.Delete(toDelete, UserID);

            var activityForms = Provider.Query(
                Filter<ActivityForm>.Where(x => x.Activity.ID).IsEqualTo(assignment.ActivityLink.ID)
                    .And(x => x.Form.AppliesTo).IsEqualTo(nameof(Assignment)));

            var newForms = new List<AssignmentForm>();
            foreach (var row in activityForms.Rows)
            {
                var formID = row.Get<ActivityForm, Guid>(x => x.Form.ID);
                if (!(assignmentForms.Any(x => x.Form.ID == formID) && !toDelete.Any(x => x.Form.ID == formID)))
                {
                    var assignmentForm = new AssignmentForm();
                    assignmentForm.Form.ID = formID;
                    assignmentForm.Parent.ID = assignment.ID;
                    newForms.Add(assignmentForm);
                }
            }
            Provider.Save(newForms);
        }

        protected override void AfterSave(Assignment entity)
        {
            base.AfterSave(entity);

            CheckActivityForms(entity);

            CheckAssignmentCosts(entity);
        }

        private void CheckAssignmentCosts(Assignment entity)
        {
            if(!entity.Actual.IsChanged()
                && !entity.Booked.IsChanged()
                && !entity.HasOriginalValue(x => x.EmployeeLink.ID)
                && !entity.HasOriginalValue(x => x.Date))
            {
                // No change we care about.
                return;
            }

            var changedEmployee = entity.TryGetOriginalValue(x => x.EmployeeLink.ID, out var employeeID);
            if (!changedEmployee)
            {
                employeeID = entity.EmployeeLink.ID;
            }

            var changedDate = entity.TryGetOriginalValue(x => x.Date, out var date);
            if (!changedDate)
            {
                date = entity.Date;
            }
            if(changedEmployee || changedDate)
            {
                AssignmentCostingUtils.CheckAssignmentCosts(this, date, employeeID);
            }

            AssignmentCostingUtils.CheckAssignmentCosts(this, entity.Date, entity.EmployeeLink.ID);
        }
    }
}