using System;
using System.Linq;
using Streamingle.Utils.LerpConstraints;
using UnityEditor;
using UnityEngine;

namespace Streamingle.Utils.LerpConstraintsEditor
{
    [InitializeOnLoad]
    internal static class LerpConstraintIconInstaller
    {
        private const string IconDirectory = "Packages/com.streamingle.utilities/Editor/Constraints/Icons";

        private static readonly IconDefinition[] IconDefinitions =
        {
            new IconDefinition(typeof(LerpAimConstraint), "LerpAimConstraintIcon"),
            new IconDefinition(typeof(LerpLookAtConstraint), "LerpLookAtConstraintIcon"),
            new IconDefinition(typeof(LerpParentConstraint), "LerpParentConstraintIcon"),
            new IconDefinition(typeof(LerpPositionConstraint), "LerpPositionConstraintIcon"),
            new IconDefinition(typeof(LerpRotationConstraint), "LerpRotationConstraintIcon"),
            new IconDefinition(typeof(LerpScaleConstraint), "LerpScaleConstraintIcon")
        };

        static LerpConstraintIconInstaller()
        {
            EditorApplication.delayCall += ApplyIcons;
        }

        private static void ApplyIcons()
        {
            string[] scriptGuids = AssetDatabase.FindAssets(
                "t:MonoScript",
                new[] { "Packages/com.streamingle.utilities/Runtime/Constraints" });

            foreach (IconDefinition definition in IconDefinitions)
            {
                Texture2D icon = AssetDatabase.LoadAssetAtPath<Texture2D>(
                    $"{IconDirectory}/{definition.IconName}.png");
                if (icon == null)
                {
                    continue;
                }

                MonoScript script = scriptGuids
                    .Select(AssetDatabase.GUIDToAssetPath)
                    .Select(AssetDatabase.LoadAssetAtPath<MonoScript>)
                    .FirstOrDefault(candidate => candidate != null && candidate.GetClass() == definition.ConstraintType);

                if (script != null)
                {
                    EditorGUIUtility.SetIconForObject(script, icon);
                }
            }
        }

        private readonly struct IconDefinition
        {
            public IconDefinition(Type constraintType, string iconName)
            {
                ConstraintType = constraintType;
                IconName = iconName;
            }

            public Type ConstraintType { get; }

            public string IconName { get; }
        }
    }
}