using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using Pf2eModel;
using Pf2eModel.Model.Base;
using Pf2eModel.Model.Common.I18n;
using Pf2eModel.Model.Enum;
using Timer = System.Windows.Forms.Timer;

namespace Pf2eViewer.DatabaseViewer;

public partial class DatabaseViewerControl : UserControl
{
    public readonly Pf2eDbContext Context = new();

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public int PerPage
    {
        get => _perPage;
        set
        {
            _perPage = value;
            UpdateView();
        }
    }
    private int _perPage = 30;

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public int Page
    {
        get => _page;
        set
        {
            _page = value;
            UpdateView();
        }
    }
    private int _page = 1;

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public EntityType Type
    {
        get => _type;
        set
        {
            _page = 1;
            _type = value;
            UpdateView();
        }
    }
    private EntityType _type;

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public int Count { get; private set; }

    public int MaxPage => Convert.ToInt32(Math.Ceiling(1.0 * Count / PerPage));

    [AllowNull]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public EntityView CurrentEntity { get; private set; }

    private bool _isBusy = true;

    private DatabaseQueryPerformer? _performer;

    private Timer? _typingTimer;

    private string _lastSearch = "";

    public DatabaseViewerControl()
    {
        InitializeComponent();

        BindingNavigator.BindingSource = DbBindingSource;
        //DataGridView.AutoGenerateColumns = true;
        DataGridView.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

        _isBusy = false;
    }

    // Control events

    private void BindingNavigator_RefreshItems(object sender, EventArgs e)
    {
        if (_isBusy)
        {
            return;
        }

        Page = (int)(BindingNavigator?.BindingSource?.Current ?? 1);
        UpdateView();
    }

    private void DataGridView_RowStateChanged(object sender, DataGridViewRowStateChangedEventArgs e)
    {
        if (_isBusy)
        {
            return;
        }

        UpdateEntity();
    }

    private void SearchTextBox_Leave(object sender, EventArgs e)
    {
        if (_isBusy || SearchTextBox.Text == _lastSearch)
        {
            return;
        }

        UpdateView();
    }

    private void SearchTextBox_TextChanged(object sender, EventArgs e)
    {
        if (_isBusy)
        {
            return;
        }

        if (_typingTimer == null)
        {
            _typingTimer = new();
            _typingTimer.Interval = 3000;
            _typingTimer.Tick += HandleTypingTimerTimeout;
        }
        _typingTimer.Stop(); // Resets the timer
        _typingTimer.Tag = (sender as TextBox)!.Text; // This should be done with EventArgs
        _typingTimer.Start();
    }

    private void HandleTypingTimerTimeout(object? sender, EventArgs e)
    {
        if (_isBusy || sender is not Timer timer)
        {
            return;
        }

        UpdateView();
        timer.Stop();
    }

    // Updater

    private void SetBusyStatus(bool busy)
    {
        if (InvokeRequired)
        {
            Invoke(SetBusyStatus, busy);
            return;
        }

        _isBusy = busy;

        BindingNavigator.Enabled = !busy;
        DataGridView.Enabled = !busy;
        SearchTextBox.Enabled = !busy;

        DataGridView.ColumnHeadersHeightSizeMode = !busy
            ? DataGridViewColumnHeadersHeightSizeMode.AutoSize
            : DataGridViewColumnHeadersHeightSizeMode.DisableResizing;
    }

    public void UpdateView(bool force = false)
    {
        if (_isBusy && !force)
        {
            return;
        }

        SetBusyStatus(true);

        _performer?.Abort();

        _performer = new()
        {
            Type = Type,
            Page = Page,
            PerPage = PerPage,
            Search = SearchTextBox.Text,
        };

        _performer.OnQueryCompleted += HandleQueryCompleted;

        _performer.Query();
    }

    private void HandleQueryCompleted(DatabaseQueryPerformer sender, DatabaseQueryResult result)
    {
        if (sender != _performer)
        {
            return;
        }

        Count = result.Count;
        _lastSearch = SearchTextBox.Text;

        InvokeControl(
            BindingNavigator,
            b =>
            {
                PagesBindingSource.DataSource = Enumerable.Range(1, MaxPage).ToList();
                b.BindingSource = PagesBindingSource;
            }
        );

        InvokeControl(
            DataGridView,
            view =>
            {
                view.DataSource = result
                    .Entities.Select(e => new EntityGridRow(e))
                    .OrderBy(r => r.Id)
                    .ToList();

                SetBusyStatus(false);

                if (view.Rows.Count > 0)
                {
                    view.Rows[0].Selected = true;
                    UpdateEntity();
                }
            }
        );
    }

    private void InvokeControl<T>(T control, Action<T> action)
        where T : Control
    {
        if (control.InvokeRequired)
        {
            control.Invoke(action, control);
        }
        else
        {
            action(control);
        }
    }

    private void UpdateEntity()
    {
        if (DataGridView.SelectedRows.Count == 0)
        {
            return;
        }

        EntityGridRow? data = (EntityGridRow?)DataGridView.SelectedRows[0].DataBoundItem;

        try
        {
            CurrentEntity = data is not null ? new(Context, Type, data.Id) : null;
        }
        catch (Exception)
        {
            // ignored
        }

        EntityChange?.Invoke(CurrentEntity);
    }

    // Output events

    public delegate void EntityChangeHandler(EntityView newEntity);

    public event EntityChangeHandler? EntityChange;

    internal class EntityGridRow(Entity e)
    {
        public int Id { get; set; } = e.Id;

        public string Name { get; set; } = e.Name[LocaleType.English];

        public EntityRarity Rarity { get; set; } = e.Rarity;
    }
}