using System;
using System.IO;
using System.Runtime.InteropServices;

internal static class CrashAddressMap
{
    private const long DefaultTarget = 0x29a79ec;

    internal static bool Enabled => !_disabled;

    internal static long TargetRva => _target;

    private static readonly bool _disabled = IsDisabled();

    private static readonly long _target = ReadTarget();

    private static bool IsDisabled()
    {
        try
        {
            var raw = Environment.GetEnvironmentVariable("RADICADE_ADDR_MAP");
            if (string.IsNullOrWhiteSpace(raw)) return false;
            return raw.Trim().ToLowerInvariant() is "0" or "off" or "false" or "no";
        }
        catch { return false; }
    }

    private static long ReadTarget()
    {
        try
        {
            var raw = Environment.GetEnvironmentVariable("RADICADE_ADDR_TARGET");
            if (string.IsNullOrWhiteSpace(raw)) return DefaultTarget;
            raw = raw.Trim();
            if (raw.StartsWith("0x", StringComparison.OrdinalIgnoreCase)) raw = raw.Substring(2);
            return long.TryParse(raw, System.Globalization.NumberStyles.HexNumber,
                System.Globalization.CultureInfo.InvariantCulture, out var value) ? value : DefaultTarget;
        }
        catch { return DefaultTarget; }
    }

    internal static void Start()
    {
        if (!Enabled) return;
        var thread = new System.Threading.Thread(Run) { IsBackground = true, Name = "RadicadeAddrMap" };
        thread.Start();
    }

    private static void Run()
    {
        try { System.Threading.Thread.Sleep(5000); } catch { }

        var log = RadicadeEacBypassPlugin.LogSource;

        IntPtr baseAddress = IntPtr.Zero;
        var moduleSize = 0L;
        try
        {
            using (var self = System.Diagnostics.Process.GetCurrentProcess())
            {
                foreach (System.Diagnostics.ProcessModule module in self.Modules)
                {
                    if (!string.Equals(module.ModuleName, "GameAssembly.dll", StringComparison.OrdinalIgnoreCase)) continue;
                    baseAddress = module.BaseAddress;
                    moduleSize = module.ModuleMemorySize;
                    break;
                }
            }
        }
        catch (Exception ex)
        {
            log.LogError("[AddrMap] could not locate GameAssembly.dll: " + ex.Message);
            return;
        }

        if (baseAddress == IntPtr.Zero || moduleSize <= 0)
        {
            log.LogError("[AddrMap] GameAssembly.dll is not loaded - nothing to map");
            return;
        }

        var gameRoot = Path.GetDirectoryName(UnityEngine.Application.dataPath) ?? ".";
        var path = Path.Combine(gameRoot, "BepInEx", "radicade-addr-map.txt");

        var baseValue = baseAddress.ToInt64();
        var mapped = 0;
        var images = 0;
        var unmappable = 0;
        var bestBelow = -1L;
        string bestBelowName = null;
        long bestAbove = -1;
        string bestAboveName = null;
        var failures = 0;

        try
        {
            using (var writer = new StreamWriter(path, false))
            {
                writer.WriteLine("# il2cpp RVA -> method map, written by RadicadeAugustClient (run 24)");
                writer.WriteLine("# GameAssembly.dll base 0x" + baseValue.ToString("x") + ", mapped size 0x" + moduleSize.ToString("x"));
                writer.WriteLine("# rva<TAB>image<TAB>Namespace.Class::Method - rva is relative to the base above");

                unsafe
                {
                    var domain = Il2CppInterop.Runtime.IL2CPP.il2cpp_domain_get();
                    if (domain == IntPtr.Zero)
                    {
                        log.LogError("[AddrMap] no il2cpp domain; nothing to map");
                        return;
                    }

                    uint assemblyCount = 0;
                    var assemblies = Il2CppInterop.Runtime.IL2CPP.il2cpp_domain_get_assemblies(domain, ref assemblyCount);
                    for (uint a = 0; a < assemblyCount; a++)
                    {
                        var image = Il2CppInterop.Runtime.IL2CPP.il2cpp_assembly_get_image(assemblies[a]);
                        if (image == IntPtr.Zero) continue;
                        images++;

                        string imageName;
                        try { imageName = Marshal.PtrToStringAnsi(Il2CppInterop.Runtime.IL2CPP.il2cpp_image_get_name(image)) ?? "?"; }
                        catch { imageName = "?"; }

                        var classCount = Il2CppInterop.Runtime.IL2CPP.il2cpp_image_get_class_count(image);
                        for (uint c = 0; c < classCount; c++)
                        {
                            var klass = Il2CppInterop.Runtime.IL2CPP.il2cpp_image_get_class(image, c);
                            if (klass == IntPtr.Zero) continue;

                            string className;
                            try
                            {
                                var namespaze = Marshal.PtrToStringAnsi(Il2CppInterop.Runtime.IL2CPP.il2cpp_class_get_namespace(klass));
                                var name = Marshal.PtrToStringAnsi(Il2CppInterop.Runtime.IL2CPP.il2cpp_class_get_name(klass));
                                className = string.IsNullOrEmpty(namespaze) ? name : namespaze + "." + name;
                            }
                            catch { className = "?"; failures++; }

                            var iterator = IntPtr.Zero;
                            IntPtr methodInfo;
                            while ((methodInfo = Il2CppInterop.Runtime.IL2CPP.il2cpp_class_get_methods(klass, ref iterator)) != IntPtr.Zero)
                            {
                                long entry;
                                try { entry = Marshal.ReadIntPtr(methodInfo).ToInt64(); }
                                catch { entry = 0; }

                                if (entry <= baseValue || entry >= baseValue + moduleSize)
                                {
                                    unmappable++;
                                    continue;
                                }

                                var rva = entry - baseValue;
                                string methodName;
                                try { methodName = Marshal.PtrToStringAnsi(Il2CppInterop.Runtime.IL2CPP.il2cpp_method_get_name(methodInfo)) ?? "?"; }
                                catch { methodName = "?"; failures++; }

                                writer.WriteLine("0x" + rva.ToString("x") + "\t" + imageName + "\t" + className + "::" + methodName);
                                mapped++;

                                var full = className + "::" + methodName;
                                if (rva <= _target && rva > bestBelow) { bestBelow = rva; bestBelowName = full; }
                                if (rva > _target && (bestAbove < 0 || rva < bestAbove)) { bestAbove = rva; bestAboveName = full; }
                            }
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            log.LogError("[AddrMap] pass failed after " + mapped + " methods: " + ex);
            return;
        }


        if (bestBelow < 0)
        {
            log.LogWarning("[AddrMap] no method starts below the target 0x" + _target.ToString("x")
                + " - the crash is in code no managed method owns (il2cpp runtime or native plugin)."
                + (bestAboveName != null ? " Nearest above: 0x" + bestAbove.ToString("x") + " " + bestAboveName : string.Empty));
            return;
        }

        var span = bestAbove > bestBelow ? bestAbove - bestBelow : -1;
        log.LogWarning("[AddrMap] crash target 0x" + _target.ToString("x") + " -> containing method 0x" + bestBelow.ToString("x")
            + " " + bestBelowName + " (+0x" + (_target - bestBelow).ToString("x") + " into it)"
            + (span > 0 ? "; next method 0x" + bestAbove.ToString("x") + " " + bestAboveName + " (span 0x" + span.ToString("x") + ")" : string.Empty)
            + (failures > 0 ? "; " + failures + " name reads failed" : string.Empty));
    }
}