using Unity.Properties;
using UnityEngine;
using UnityEngine.UIElements;

namespace KitsuneCafe.UI
{
    [UxmlElement]
    public partial class MenuView : VisualElement
    {
        public const string BaseClass = "kitsunecafe__menu-view";
        public const string HeaderClass = "kitsunecafe__menu-view_header";
        public const string TitleClass = "kitsunecafe__menu-view_title";
        public const string OptionClass = "kitsunecafe__menu-view_option";

        private VisualElement headerElement;
        private Label titleLabel;

        private string title;

        [UxmlAttribute, CreateProperty, Delayed]
        public string Title
        {
            get => title;
            set
            {
                if (title == value)
                {
                    title = value;
                    UpdateTitle();
                }
            }
        }

        private string[] options = new string[0];

        [UxmlAttribute, CreateProperty, Delayed]
        public string[] Options
        {
            get => options;
            set
            {
                if (options != value)
                {
                    options = value;
                    UpdateOptions();
                }
            }
        }

        public MenuView()
        {
            AddToClassList(BaseClass);
            CreateTitle();
            UpdateTitle();
            UpdateOptions();
        }

        private void CreateTitle()
        {
            titleLabel = new Label();
            titleLabel.AddToClassList(TitleClass);

            headerElement = new VisualElement();
            headerElement.AddToClassList(HeaderClass);

            headerElement.Add(titleLabel);
            hierarchy.Add(headerElement);
        }

        private void UpdateTitle()
        {
            if (title == null)
            {
                headerElement.visible = false;
            }
            else
            {
                headerElement.visible = false;
                titleLabel.text = title;
            }
        }

        private VisualElement CreateOption(string option)
        {
            var label = new Label();
            label.AddToClassList(OptionClass);
            label.text = option;
            return label;
        }

        private void UpdateOptions()
        {
            var count = options.Length - childCount;

            if (count == 0)
            {
                return;
            }
            else if (count > 0)
            {
                CreateOptions(count);
            }
            else if (count < 0)
            {
                RemoveOptions(-count);
            }

            Rebind();
        }

        private void CreateOptions(int count)
        {
            for (int i = 0; i < count; i++)
            {
                var option = CreateOption(options[i]);
                Add(option);
            }
        }

        private void RemoveOptions(int count)
        {
            for (int i = 0; i < count; i++)
            {
                RemoveAt(i);
            }
        }

        private void Rebind()
        {
            for (int i = 0; i < childCount; i++)
            {
                Label child = this[i] as Label;
                child.text = options[i];
            }
        }
    }
}