using System;
using System.Collections;
using System.Linq;
using System.Reflection;
using AOT.Boot;
using UnityEngine;
using YooAsset;
#if !UNITY_EDITOR
using HybridCLR;
#endif

namespace AOT.HotUpdate
{
    /// <summary>
    /// 加载热更程序集并调用稳定入口 HotUpdate.Entry.Start(BootContext)。
    /// </summary>
    public static class HotUpdateLoader
    {
        const string EntryTypeName = "HotUpdate.Entry";
        const string EntryMethodName = "Start";

        public static IEnumerator LoadAndStart(BootContext ctx, BootSettings settings, Action<string> onError)
        {
#if UNITY_EDITOR
            if (settings.EditorDirectHotUpdate || ctx.Package == null)
            {
                var err = InvokeEntry(FindLoadedAssembly("HotUpdate.Runtime"), ctx);
                if (err != null) onError?.Invoke(err);
                yield break;
            }
#endif

            if (ctx.Package == null)
            {
                onError?.Invoke("ResourcePackage 为空，无法加载热更 DLL");
                yield break;
            }

            var handle = ctx.Package.LoadAssetAsync<RawFileObject>(settings.HotUpdateDllLocation);
            yield return handle;
            if (handle.Status != EOperationStatus.Succeeded)
            {
                onError?.Invoke($"加载热更 DLL 失败: {handle.Error}");
                yield break;
            }

            var raw = handle.GetAssetObject<RawFileObject>();
            if (raw == null)
            {
                onError?.Invoke("热更 DLL RawFileObject 为空");
                yield break;
            }

            byte[] dllBytes = raw.GetBytes();
            handle.Release();

            if (dllBytes == null || dllBytes.Length < 64)
            {
                onError?.Invoke($"热更 DLL 字节异常 length={dllBytes?.Length ?? 0}");
                yield break;
            }

            Debug.Log($"[HotUpdateLoader] RawFile loaded location={settings.HotUpdateDllLocation} bytes={dllBytes.Length}");

#if UNITY_EDITOR
            // 编辑器域内已加载同名程序集，不能重复 Assembly.Load；验证 RawFile 后走反射入口。
            {
                var err = InvokeEntry(FindLoadedAssembly("HotUpdate.Runtime"), ctx);
                if (err != null) onError?.Invoke(err);
                yield break;
            }
#else
            // AOT 补充元数据：后续由 HybridCLR Generate 产物批量加载。
            // HybridCLR.RuntimeApi.LoadMetadataForAOTAssembly(metaBytes, HomologousImageMode.SuperSet);

            Assembly asm;
            try
            {
                asm = Assembly.Load(dllBytes);
            }
            catch (Exception e)
            {
                onError?.Invoke($"Assembly.Load 失败: {e.Message}");
                yield break;
            }

            var invokeErr = InvokeEntry(asm, ctx);
            if (invokeErr != null)
                onError?.Invoke(invokeErr);
#endif
        }

        static Assembly FindLoadedAssembly(string name)
        {
            return AppDomain.CurrentDomain.GetAssemblies()
                .FirstOrDefault(a => string.Equals(a.GetName().Name, name, StringComparison.Ordinal));
        }

        static string InvokeEntry(Assembly asm, BootContext ctx)
        {
            if (asm == null)
                return "未找到热更程序集 HotUpdate.Runtime";

            var type = asm.GetType(EntryTypeName, throwOnError: false);
            if (type == null)
                return $"未找到类型 {EntryTypeName}";

            var method = type.GetMethod(EntryMethodName, BindingFlags.Public | BindingFlags.Static);
            if (method == null)
                return $"未找到方法 {EntryTypeName}.{EntryMethodName}";

            try
            {
                method.Invoke(null, new object[] { ctx });
                return null;
            }
            catch (Exception e)
            {
                var inner = e is TargetInvocationException tie && tie.InnerException != null
                    ? tie.InnerException
                    : e;
                return $"调用热更入口失败: {inner.Message}";
            }
        }
    }
}