using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Drawing;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using InABox.Clients;
using InABox.Configuration;
using InABox.Core;
using InABox.WPF;
using Expression = System.Linq.Expressions.Expression;

namespace InABox.DynamicGrid;

public interface IDynamicDataGrid : IDynamicGrid
{
    /// <summary>
    /// The tag the the DynamicGridColumns are stored against. If set to <see langword="null"/>,
    /// the name of <typeparamref name="TEntity"/> is used as a default.
    /// </summary>
    string? ColumnsTag { get; set; }

    IColumns LoadEditorColumns();
}

public class DynamicDataGrid<TEntity> : DynamicGrid<TEntity>, IDynamicDataGrid where TEntity : Entity, IRemotable, IPersistent, new()
{
    private Button MergeBtn = null!; //Late-initialised

    protected DynamicGridCustomColumnsComponent<TEntity> ColumnsComponent;
    public DynamicGridFilterButtonComponent<TEntity> FilterComponent;

    public DynamicDataGrid() : base()
    {
        var fields = DatabaseSchema.Properties(typeof(TEntity));

        foreach (var field in fields)
            if (!MasterColumns.Any(x => x.ColumnName == field.Name))
                MasterColumns.Add(new DynamicGridColumn { ColumnName = field.Name });

        var cols = LookupFactory.DefineColumns<TEntity>();

        // Minimum Columns for Lookup values
        foreach (var col in cols)
            HiddenColumns.Add(CoreUtils.CreateLambdaExpression<TEntity>(col.Property));

        // Minimum Columns for Successful Saving
        // This should be cross-checked with the relevant Store<>
        // so that clients will (usually) provide sufficient columns for saving
        foreach (var col in LookupFactory.RequiredColumns<TEntity>())
            HiddenColumns.Add(CoreUtils.CreateLambdaExpression<TEntity>(col.Property));

        //HiddenColumns.Add(x => x.ID);

        if (typeof(TEntity).GetInterfaces().Contains(typeof(IIssues)))
        {
            HiddenColumns.Add(x => (x as IIssues)!.Issues);
            var coltype = typeof(DynamicIssuesColumn<>).MakeGenericType(typeof(TEntity));
            ActionColumns.Add((Activator.CreateInstance(coltype, this) as DynamicActionColumn)!);
        }
    }

    protected override void Init()
    {
        FilterComponent = new(this,
            new GlobalConfiguration<CoreFilterDefinitions>(GetTag()),
            new UserConfiguration<CoreFilterDefinitions>(GetTag()));
        FilterComponent.OnFilterRefresh += () => Refresh(false, true);

        ColumnsComponent = new DynamicGridCustomColumnsComponent<TEntity>(this, GetTag());

        var dataComponent = new DynamicGridClientDataComponent<TEntity>(this);
        dataComponent.OnReload += DataComponent_OnReload;
        DataComponent = dataComponent;

        MergeBtn = AddButton("Merge", Wpf.Resources.merge.AsBitmapImage(Color.White), DoMerge);
    }

    protected override void SelectItems(CoreRow[]? rows)
    {
        base.SelectItems(rows);
        MergeBtn.Visibility = Options.MultiSelect && typeof(T).IsAssignableTo(typeof(IMergeable)) && Security.CanMerge<TEntity>()
            && rows != null && rows.Length > 1
            ? Visibility.Visible
            : Visibility.Collapsed;
    }

    private void DataComponent_OnReload(object sender, Filters<TEntity> criteria, Columns<TEntity> columns, ref SortOrder<TEntity>? sortby)
    {
        criteria.Add(FilterComponent.GetFilter());
    }

    protected override void OptionsChanged()
    {
        base.OptionsChanged();

        FilterComponent.ShowFilterList = Options.FilterRows && !Options.HideDatabaseFilters;

        if (MergeBtn != null)
            MergeBtn.Visibility = Visibility.Collapsed;
    }

    protected override void DoReconfigure(DynamicGridOptions options)
    {
        if (Security.CanEdit<TEntity>())
        {
            options.AddRows = true;
            options.EditRows = true;
        }
        if (Security.CanDelete<TEntity>())
            options.DeleteRows = true;
        if (Security.CanImport<TEntity>() && typeof(TEntity).HasInterface<IImportable>())
            options.ImportData = true;
        if (Security.CanExport<TEntity>() && typeof(TEntity).HasInterface<IExportable>())
            options.ExportData = true;
        if (Security.CanMerge<TEntity>())
            options.MultiSelect = true;
    }

    protected override void BeforeLoad(IDynamicEditorForm form, TEntity[] items)
    {
        form.ReadOnly = form.ReadOnly || !Security.CanEdit<TEntity>();
        base.BeforeLoad(form, items);
    }

    private string? _columnsTag;
    public string? ColumnsTag
    {
        get => _columnsTag;
        set
        {
            _columnsTag = value;
            ColumnsComponent.Tag = GetTag();
        }
    }

    public override void LoadEditorButtons(TEntity item, DynamicEditorButtons buttons)
    {
        base.LoadEditorButtons(item, buttons);
        if (ClientFactory.IsSupported<AuditTrail>())
            buttons.Add("Audit Trail", Wpf.Resources.view.AsBitmapImage(), item, AuditTrailClick);
    }

    private void AuditTrailClick(object sender, object? item)
    {
        var entity = (item as TEntity)!;
        var window = new AuditWindow(entity.ID);
        window.ShowDialog();
    }

    protected override DynamicGridColumns LoadColumns()
    {
        return ColumnsComponent.LoadColumns();
    }

    protected override void SaveColumns(DynamicGridColumns columns)
    {
        ColumnsComponent.SaveColumns(columns);
    }

    protected override void LoadColumnsMenu(ContextMenu menu)
    {
        base.LoadColumnsMenu(menu);
        ColumnsComponent.LoadColumnsMenu(menu);
    }

    private string GetTag()
    {
        var tag = typeof(TEntity).Name;
        if (!string.IsNullOrWhiteSpace(ColumnsTag))
            tag = string.Format("{0}.{1}", tag, ColumnsTag);
        return tag;
    }

    protected override DynamicGridSettings LoadSettings()
    {
        var tag = GetTag();

        var user = Task.Run(() => new UserConfiguration<DynamicGridSettings>(tag).Load());
        user.Wait();

        //var global = Task.Run(() => new GlobalConfiguration<DynamicGridSettings>(tag).Load());
        //global.Wait();
        //Task.WaitAll(user, global);
        //var columns = user.Result.Any() ? user.Result : global.Result;

        return user.Result;
    }
    protected override void SaveSettings(DynamicGridSettings settings)
    {
        var tag = GetTag();
        new UserConfiguration<DynamicGridSettings>(tag).Save(settings);
    }

    #region Duplicate

    protected bool Duplicate(
        CoreRow row,
        Expression<Func<TEntity, object?>> codefield,
        Type[] childtypes)
    {
        var id = row.Get<TEntity, Guid>(x => x.ID);

        var code = row.Get(codefield) as string;

        var tasks = new List<Task>();

        var itemtask = Task.Run(() =>
        {
            var filter = new Filter<TEntity>(x => x.ID).IsEqualTo(id);
            var result = new Client<TEntity>().Load(filter).FirstOrDefault()
                ?? throw new Exception("Entity does not exist!");
            return result;
        });
        tasks.Add(itemtask);
        //itemtask.Wait();

        Task<List<string?>>? codetask = null;
        if (!string.IsNullOrWhiteSpace(code))
        {
            codetask = Task.Run(() =>
            {
                var columns = Columns.None<TEntity>().Add(codefield);
                //columns.Add<String>(codefield);
                var filter = new Filter<TEntity>(codefield).BeginsWith(code);
                var table = new Client<TEntity>().Query(filter, columns);
                var result = table.Rows.Select(x => x.Get(codefield) as string).ToList();
                return result;
            });
            tasks.Add(codetask);
        }
        //codetask.Wait();

        var children = new Dictionary<Type, CoreTable>();
        foreach (var childtype in childtypes)
        {
            var childtask = Task.Run(() =>
            {
                var prop = childtype.GetProperties().FirstOrDefault(x =>
                    x.PropertyType.GetInterfaces().Contains(typeof(IEntityLink)) &&
                    x.PropertyType.GetInheritedGenericTypeArguments().FirstOrDefault() == typeof(TEntity));

                if (prop is not null)
                {
                    var filter = Core.Filter.Create(childtype);
                    filter.Expression = CoreUtils.GetMemberExpression(childtype, prop.Name + ".ID");
                    filter.Operator = Operator.IsEqualTo;
                    filter.Value = id;
                    var sort = LookupFactory.DefineSort(childtype);
                    var client = ClientFactory.CreateClient(childtype);
                    var table = client.Query(filter, null, sort);
                    foreach (var r in table.Rows)
                    {
                        r["ID"] = Guid.Empty;
                        r[prop.Name + ".ID"] = Guid.Empty;
                    }

                    children[childtype] = table;
                }
                else
                {
                    Logger.Send(LogType.Error, "", $"DynamicDataGrid<{typeof(TEntity)}>.Duplicate(): No parent property found for child type {childtype}");
                }
            });
            tasks.Add(childtask);
            //childtask.Wait();
        }

        //var manytomanys = CoreUtils.TypeList(
        //    AppDomain.CurrentDomain.GetAssemblies(),
        //    x => x.GetInterfaces().Any(intf => intf.IsGenericType && intf.GetGenericTypeDefinition() == typeof(IManyToMany<,>) && intf.GenericTypeArguments.Contains(typeof(T)))
        //);

        //Task<CoreTable> childtask = Task.Run(() =>
        //{
        //    var result = new CoreTable();
        //    result.LoadColumns(typeof(TChild));
        //    var children = new Client<TChild>().Load(new Filter<TChild>(x => linkfield).IsEqualTo(id));
        //    foreach (var child in children)
        //    {
        //        child.ID = Guid.Empty;
        //        String linkprop = CoreUtils.GetFullPropertyName<TChild, Guid>(linkfield, ".");
        //        CoreUtils.SetPropertyValue(child, linkprop, Guid.Empty);
        //        var newrow = result.NewRow();
        //        result.LoadRow(newrow, child);
        //        result.Rows.Add(newrow);
        //    }
        //    return result;
        //});
        //tasks.Add(childtask);

        Task.WaitAll(tasks.ToArray());

        var item = itemtask.Result;
        item.ID = Guid.Empty;

        if (codetask != null)
        {
            var codes = codetask.Result;
            var i = 1;

            while (codes.Contains(string.Format("{0} ({1})", code, i)))
                i++;
            var codeprop = CoreUtils.GetFullPropertyName(codefield, ".");
            CoreUtils.SetPropertyValue(item, codeprop, string.Format("{0} ({1})", code, i));
        }

        var grid = new DynamicDataGrid<TEntity>();
        return grid.EditItems(new[] { item }, t => children.ContainsKey(t) ? children[t] : null, true);
    }

    protected override IEnumerable<TEntity> LoadDuplicatorItems(CoreRow[] rows)
    {
        return rows.Select(x => x.ToObject<TEntity>());
    }

    #endregion

    protected override bool BeforePaste(IEnumerable<TEntity> items, ClipAction action)
    {
        if (action == ClipAction.Copy)
        {
            foreach (var item in items)
                item.ID = Guid.Empty;
            return true;
        }

        return base.BeforePaste(items, action);
    }

    protected override IEnumerable<Tuple<Type?, CoreTable>> LoadExportTables(Filters<TEntity> filter, IEnumerable<Tuple<Type, IColumns>> tableColumns)
    {
        var queries = new Dictionary<string, IQueryDef>();
        var columns = tableColumns.ToList();
        foreach (var table in columns)
        {
            var tableType = table.Item1;

            PropertyInfo? property = null;

            var m2m = CoreUtils.GetManyToMany(tableType, typeof(TEntity));

            IFilter? queryFilter = null;
            if (m2m != null)
            {
                property = CoreUtils.GetManyToManyThisProperty(tableType, typeof(TEntity));
            }
            else
            {
                var o2m = CoreUtils.GetOneToMany(tableType, typeof(TEntity));
                if (o2m != null)
                {
                    property = CoreUtils.GetOneToManyProperty(tableType, typeof(TEntity));
                }
            }

            if (property != null)
            {
                var subQuery = new SubQuery<TEntity>();
                subQuery.Filter = filter.Combine();
                subQuery.Column = new Column<TEntity>(x => x.ID);

                queryFilter = (Activator.CreateInstance(typeof(Filter<>).MakeGenericType(tableType)) as IFilter)!;
                queryFilter.Expression = CoreUtils.GetMemberExpression(tableType, property.Name + ".ID");
                queryFilter.InQuery(subQuery);

                queries[tableType.Name] = new QueryDef(tableType)
                {
                    Filter = queryFilter,
                    Columns = table.Item2
                };
            }
        }

        var results = Client.QueryMultiple(queries);

        return columns.Select(x => new Tuple<Type?, CoreTable>(x.Item1, results[x.Item1.Name]));
    }

    protected override CoreTable LoadImportKeys(String[] fields)
    {
        return Client.Query(null, Columns.None<TEntity>().Add(fields));
    }
    

    #region Merge

    private bool DoMerge(Button arg1, CoreRow[] arg2)
    {
        if (arg2 == null || arg2.Length <= 1)
            return false;
        var targetid = arg2.Last().Get<T, Guid>(x => x.ID);
        var target = arg2.Last().ToObject<T>().ToString();
        var otherids = arg2.Select(r => r.Get<T, Guid>(x => x.ID)).Where(x => x != targetid).ToArray();
        string[] others = arg2.Where(r => otherids.Contains(r.Get<Guid>("ID"))).Select(x => x.ToObject<T>().ToString()!).ToArray();
        var rows = arg2.Length;
        if (MessageBox.Show(
                string.Format(
                    "This will merge the following items:\n\n- {0}\n\n into:\n\n- {1}\n\nAfter this, the items will be permanently removed.\nAre you sure you wish to do this?",
                    string.Join("\n- ", others),
                    target
                ),
                "Merge Items Warning",
                MessageBoxButton.YesNo,
                MessageBoxImage.Stop) != MessageBoxResult.Yes
           )
            return false;

        using (new WaitCursor())
        {
            var types = CoreUtils.Entities.Where(
                x =>
                    x.IsClass
                    && !x.IsGenericType
                    && x.IsSubclassOf(typeof(Entity))
                    && !x.Equals(typeof(AuditTrail))
                    && !x.Equals(typeof(T))
                    && x.GetCustomAttribute<AutoEntity>() == null
                    && x.HasInterface<IRemotable>()
                    && x.HasInterface<IPersistent>()
            ).ToArray();

            foreach (var type in types)
            {
                var props = CoreUtils.PropertyList(
                    type,
                    x =>
                        x.PropertyType.GetInterfaces().Contains(typeof(IEntityLink))
                        && x.PropertyType.GetInheritedGenericTypeArguments().Contains(typeof(T))
                );
                foreach (var prop in props)
                {
                    var propname = string.Format(prop.Name + ".ID");
                    var filter = Core.Filter.Create(type);
                    filter.Expression = CoreUtils.CreateMemberExpression(type, propname);
                    filter.Operator = Operator.InList;
                    filter.Value = otherids;
                    var columns = Columns.None(type)
                        .Add("ID")
                        .Add(propname);
                    var updates = ClientFactory.CreateClient(type).Query(filter, columns).Rows.Select(r => r.ToObject(type)).ToArray();
                    if (updates.Any())
                    {
                        foreach (var update in updates)
                            CoreUtils.SetPropertyValue(update, propname, targetid);
                        ClientFactory.CreateClient(type).Save(updates,
                            string.Format("Merged {0} Records", typeof(T).EntityName().Split('.').Last()));
                    }
                }
            }

            var histories = new Client<AuditTrail>()
                .Query(
                    new Filter<AuditTrail>(x => x.EntityID).InList(otherids),
                    Columns.None<AuditTrail>()
                        .Add(x => x.ID).Add(x => x.EntityID))
                .ToArray<AuditTrail>();
            foreach (var history in histories)
                history.EntityID = targetid;
            if (histories.Length != 0)
                new Client<AuditTrail>().Save(histories, "");

            var deletes = new List<object>();
            foreach (var otherid in otherids)
            {
                var delete = new T();
                CoreUtils.SetPropertyValue(delete, "ID", otherid);
                deletes.Add(delete);
            }

            ClientFactory.CreateClient(typeof(T))
                .Delete(deletes, string.Format("Merged {0} Records", typeof(T).EntityName().Split('.').Last()));
            return true;
        }
    }

    #endregion
}