using System.Globalization;
using Unity.Properties;
using UnityEngine;
using UnityEngine.UIElements;

namespace Uigenx.Binding
{
    /// <summary>
    /// Converter groups the compiler can name from UXML (`source-to-ui-converters="ugx.percent"`)
    /// or the connector can apply in code. Registered once per domain load.
    /// </summary>
    public static class UgxConverters
    {
        public const string IntToString = "ugx.int-to-string";
        public const string PercentWidth = "ugx.percent-width";
        public const string BoolToDisplay = "ugx.bool-to-display";

        static bool _registered;

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
        public static void Register()
        {
            if (_registered) return;
            _registered = true;

            var intToString = new ConverterGroup(IntToString, "Integer to text");
            intToString.AddConverter((ref int v) => v.ToString(CultureInfo.InvariantCulture));
            intToString.AddConverter((ref long v) => v.ToString(CultureInfo.InvariantCulture));
            ConverterGroups.RegisterConverterGroup(intToString);

            // 0..1 becomes a percentage Length, which is what a bar's width binding wants.
            var percent = new ConverterGroup(PercentWidth, "Normalised value to percent width");
            percent.AddConverter((ref float v) => new StyleLength(Length.Percent(Mathf.Clamp01(v) * 100f)));
            percent.AddConverter((ref float v) => Length.Percent(Mathf.Clamp01(v) * 100f));
            ConverterGroups.RegisterConverterGroup(percent);

            var display = new ConverterGroup(BoolToDisplay, "Boolean to display style");
            display.AddConverter((ref bool v) => v ? DisplayStyle.Flex : DisplayStyle.None);
            display.AddConverter((ref bool v) => new StyleEnum<DisplayStyle>(v ? DisplayStyle.Flex : DisplayStyle.None));
            ConverterGroups.RegisterConverterGroup(display);
        }

        public static bool TryGet(string id, out ConverterGroup group)
        {
            Register();
            return ConverterGroups.TryGetConverterGroup(id, out group);
        }

#if UNITY_EDITOR
        [UnityEditor.InitializeOnLoadMethod]
        static void RegisterInEditor() => Register();
#endif
    }
}