using UdonSharp;
using UnityEditor;
using UnityEngine;

namespace AUMSS.EditorTools
{
    /// <summary>
    /// Makes sure AUMSS's U# programs are compiled. The package ships them uncompiled, and U# only compiles when a
    /// script's source differs from what it last compiled: after an update that changes no script, the programs
    /// would stay uncompiled, and editor code (U#'s own, or a world's tools) couldn't write to AUMSS components.
    /// So they're checked whenever the editor loads, and whenever the package's program assets are reimported (an
    /// update while the editor is open, which reloads nothing if no script changed).
    /// </summary>
    [InitializeOnLoad]
    public static class AUMSSProgramCheck
    {
        const string PackagePath = "Packages/dev.av2x.aumss/";

        static AUMSSProgramCheck()
        {
            EditorApplication.delayCall += CheckOnLoad;
        }

        class ImportCheck : AssetPostprocessor
        {
            static void OnPostprocessAllAssets(string[] imported, string[] deleted, string[] moved, string[] movedFrom)
            {
                foreach (string path in imported)
                {
                    if (!path.StartsWith(PackagePath) || !path.EndsWith(".asset")) continue;
                    // U#'s own compile saves these too; by then they're compiled, so the check does nothing
                    EditorApplication.delayCall -= CheckOnLoad;
                    EditorApplication.delayCall += CheckOnLoad;
                    return;
                }
            }
        }

        static void CheckOnLoad()
        {
            if (EditorApplication.isPlayingOrWillChangePlaymode) return;
            if (EditorApplication.isCompiling || EditorApplication.isUpdating)
            {
                EditorApplication.delayCall += CheckOnLoad;
                return;
            }
            // U# can't compile while C# has errors; it gets compiled once they're fixed (a script change, so U# does)
            if (EditorUtility.scriptCompilationFailed || !NeedsCompile()) return;
            Debug.Log("[AUMSS] Compiling UdonSharp programs: the package's arrived uncompiled.");
            UdonSharpProgramAsset.CompileAllCsPrograms(forceCompile: true);
        }

        /// <summary>True if any of the package's U# programs hasn't been compiled yet.</summary>
        public static bool NeedsCompile()
        {
            foreach (UdonSharpProgramAsset program in UdonSharpProgramAsset.GetAllUdonSharpPrograms())
            {
                if (program == null || program.sourceCsScript == null) continue;
                if (!AssetDatabase.GetAssetPath(program).StartsWith(PackagePath)) continue;
                if (!IsCompiled(program)) return true;
            }
            return false;
        }

        static bool IsCompiled(UdonSharpProgramAsset program)
        {
            // The field definitions alone aren't enough: reimporting an uncompiled program (an update while the editor is
            // open) clears its compiled program but leaves the field definitions from before in memory
            if (program.fieldDefinitions == null) return false;
            using (var serialized = new SerializedObject(program))
                return serialized.FindProperty("serializedUdonProgramAsset")?.objectReferenceValue != null;
        }
    }
}