using System.Collections.ObjectModel;

namespace Terminal.Gui;

/// <summary>
///     Abstract implementation of <see cref="IAutocomplete"/> allows for tailoring how autocomplete is
///     rendered/interacted with.
/// </summary>
public abstract class AutocompleteBase : IAutocomplete
{
    /// <inheritdoc/>
    public abstract View HostControl { get; set; }

    /// <inheritdoc/>
    public bool PopupInsideContainer { get; set; }

    /// <inheritdoc/>
    public ISuggestionGenerator SuggestionGenerator { get; set; } = new SingleWordSuggestionGenerator ();

    /// <inheritdoc/>
    public virtual int MaxWidth { get; set; } = 10;

    /// <inheritdoc/>
    public virtual int MaxHeight { get; set; } = 6;

    /// <inheritdoc/>
    /// <inheritdoc/>
    public virtual bool Visible { get; set; }

    /// <inheritdoc/>
    public virtual ReadOnlyCollection<Suggestion> Suggestions { get; set; } = new (new Suggestion [0]);

    /// <inheritdoc/>
    public virtual int SelectedIdx { get; set; }

    /// <inheritdoc/>
    public abstract ColorScheme ColorScheme { get; set; }

    /// <inheritdoc/>
    public virtual Key SelectionKey { get; set; } = Key.Enter;

    /// <inheritdoc/>
    public virtual Key CloseKey { get; set; } = Key.Esc;

    /// <inheritdoc/>
    public virtual Key Reopen { get; set; } = Key.Space.WithCtrl.WithAlt;

    /// <inheritdoc/>
    public virtual AutocompleteContext Context { get; set; }

    /// <inheritdoc/>
    public abstract bool OnMouseEvent (MouseEventArgs me, bool fromHost = false);

    /// <inheritdoc/>
    public abstract bool ProcessKey (Key a);

    /// <inheritdoc/>
    public abstract void RenderOverlay (Point renderAt);

    /// <inheritdoc/>
    /// >
    public virtual void ClearSuggestions () { Suggestions = Enumerable.Empty<Suggestion> ().ToList ().AsReadOnly (); }

    /// <inheritdoc/>
    public virtual void GenerateSuggestions (AutocompleteContext context)
    {
        Suggestions = SuggestionGenerator.GenerateSuggestions (context).ToList ().AsReadOnly ();

        EnsureSelectedIdxIsValid ();
    }

    /// <summary>Updates <see cref="SelectedIdx"/> to be a valid index within <see cref="Suggestions"/></summary>
    public virtual void EnsureSelectedIdxIsValid () { SelectedIdx = Math.Max (0, Math.Min (Suggestions.Count - 1, SelectedIdx)); }
}