using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using HybridCLR;
using UnityEngine;

namespace TH1_Logic.Hotfix
{
    public static class HotfixBootstrap
    {
        private static bool _initialized;
        private static bool _aotMetadataLoaded;
        private static readonly HashSet<string> InvokedEntryAssemblies = new HashSet<string>();

        public static bool IsLoaded { get; private set; }
        public static Assembly LoadedAssembly { get; private set; }
        public static string LoadedAssemblyFullName { get; private set; }

        public static bool InitializeFromStreamingAssets(bool requireHotfix, bool invokeEntry = true)
        {
            try
            {
                var root = Path.Combine(Application.streamingAssetsPath, HotfixManifest.RootFolderName);
                LoadAotMetadata(root);

                if (_initialized) return IsLoaded;

                var hotfixPath = Path.Combine(root, HotfixManifest.HotfixDllFolderName, HotfixManifest.HotfixAssemblyFileName);
                if (!File.Exists(hotfixPath))
                {
                    if (requireHotfix)
                    {
                        Debug.LogWarning($"[TH1.Hotfix] Hotfix dll missing: {hotfixPath}");
                    }

                    return false;
                }

                var assembly = Assembly.Load(File.ReadAllBytes(hotfixPath));
                LoadedAssembly = assembly;
                LoadedAssemblyFullName = assembly.FullName;
                RefreshRuntimeTypeCaches();
                if (invokeEntry)
                {
                    InvokeHotfixEntry(assembly);
                }

                _initialized = true;
                IsLoaded = true;
                Debug.Log($"[TH1.Hotfix] Loaded {LoadedAssemblyFullName}");
                return true;
            }
            catch (Exception e)
            {
                Debug.LogError($"[TH1.Hotfix] Initialize failed: {e}");
                return false;
            }
        }

        public static void EnsureAotMetadataLoaded()
        {
            try
            {
                var root = Path.Combine(Application.streamingAssetsPath, HotfixManifest.RootFolderName);
                LoadAotMetadata(root);
            }
            catch (Exception e)
            {
                Debug.LogWarning($"[TH1.Hotfix] Ensure AOT metadata failed: {e.Message}");
            }
        }

        public static void InvokeHotfixEntry(Assembly assembly)
        {
            if (assembly == null) return;

            var assemblyKey = assembly.FullName ?? assembly.GetName().Name;
            if (!InvokedEntryAssemblies.Add(assemblyKey)) return;

            InvokeHotfixEntryInternal(assembly);
        }

        private static void LoadAotMetadata(string root)
        {
            if (_aotMetadataLoaded) return;

            var aotDir = Path.Combine(root, HotfixManifest.AotMetadataFolderName);
            var allLoaded = true;

            foreach (var fileName in HotfixManifest.AotMetadataAssemblyFileNames)
            {
                var path = Path.Combine(aotDir, fileName);
                if (!File.Exists(path))
                {
                    allLoaded = false;
                    Debug.LogWarning($"[TH1.Hotfix] AOT metadata missing: {path}");
                    continue;
                }

                var result = RuntimeApi.LoadMetadataForAOTAssembly(File.ReadAllBytes(path), HomologousImageMode.SuperSet);
                Debug.Log($"[TH1.Hotfix] Load AOT metadata {fileName}: {result}");
            }

            _aotMetadataLoaded = allLoaded;
        }

        private static void InvokeHotfixEntryInternal(Assembly assembly)
        {
            var entryType = assembly.GetType(HotfixManifest.EntryTypeName);
            if (entryType == null)
            {
                Debug.LogWarning($"[TH1.Hotfix] Entry type not found: {HotfixManifest.EntryTypeName}");
                return;
            }

            var method = entryType.GetMethod(HotfixManifest.EntryMethodName, BindingFlags.Public | BindingFlags.Static);
            if (method == null)
            {
                Debug.LogWarning($"[TH1.Hotfix] Entry method not found: {HotfixManifest.EntryMethodName}");
                return;
            }

            method.Invoke(null, null);
        }

        private static Type FindType(string fullName)
        {
            return AppDomain.CurrentDomain.GetAssemblies()
                .Select(assembly => assembly.GetType(fullName, false))
                .FirstOrDefault(type => type != null);
        }

        public static void RefreshRuntimeTypeCaches()
        {
            InvokeStaticNoArg("ParadoxNotion.ReflectionTools", "FlushMem");
            InvokeStaticNoArg("ParadoxNotion.Serialization.JSONSerializer", "FlushMem");
        }

        private static void InvokeStaticNoArg(string typeName, string methodName)
        {
            var type = FindType(typeName);
            var method = type?.GetMethod(methodName, BindingFlags.Public | BindingFlags.Static);
            method?.Invoke(null, null);
        }
    }
}