using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Runtime.InteropServices;



namespace ServerCore;

public static class MiniDump
{
    [Flags]
    public enum MiniDumpType : uint
    {
        // From dbghelp.h:
        Normal = 0x00000000,
        WithDataSegs = 0x00000001,
        WithFullMemory = 0x00000002,
        WithHandleData = 0x00000004,
        FilterMemory = 0x00000008,
        ScanMemory = 0x00000010,
        WithUnloadedModules = 0x00000020,
        WithIndirectlyReferencedMemory = 0x00000040,
        FilterModulePaths = 0x00000080,
        WithProcessThreadData = 0x00000100,
        WithPrivateReadWriteMemory = 0x00000200,
        WithoutOptionalData = 0x00000400,
        WithFullMemoryInfo = 0x00000800,
        WithThreadInfo = 0x00001000,
        WithCodeSegs = 0x00002000,
        WithoutAuxiliaryState = 0x00004000,
        WithFullAuxiliaryState = 0x00008000,
        WithPrivateWriteCopyMemory = 0x00010000,
        IgnoreInaccessibleMemory = 0x00020000,
        ValidTypeFlags = 0x0003ffff,
    };

    //typedef struct _MINIDUMP_EXCEPTION_INFORMATION {
    //    DWORD ThreadId;
    //    PEXCEPTION_POINTERS ExceptionPointers;
    //    BOOL ClientPointers;
    //} MINIDUMP_EXCEPTION_INFORMATION, *PMINIDUMP_EXCEPTION_INFORMATION;
    [StructLayout(LayoutKind.Sequential, Pack = 4)]  // Pack=4 is important! So it works also for x64!
    public struct MiniDumpExceptionInformation
    {
        public uint ThreadId;
        public IntPtr ExceptionPointers;
        [MarshalAs(UnmanagedType.Bool)]
        public bool ClientPointers;
    }

    //BOOL
    //WINAPI
    //MiniDumpWriteDump(
    //    __in HANDLE hProcess,
    //    __in DWORD ProcessId,
    //    __in HANDLE hFile,
    //    __in MINIDUMP_TYPE DumpType,
    //    __in_opt PMINIDUMP_EXCEPTION_INFORMATION ExceptionParam,
    //    __in_opt PMINIDUMP_USER_STREAM_INFORMATION UserStreamParam,
    //    __in_opt PMINIDUMP_CALLBACK_INFORMATION CallbackParam
    //    );

    // Overload requiring MiniDumpExceptionInformation
    [DllImport("dbghelp.dll", EntryPoint = "MiniDumpWriteDump", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
    static extern bool MiniDumpWriteDump(IntPtr hProcess, uint processId, SafeHandle hFile, uint dumpType, ref MiniDumpExceptionInformation expParam, IntPtr userStreamParam, IntPtr callbackParam);

    // Overload supporting MiniDumpExceptionInformation == NULL
    [DllImport("dbghelp.dll", EntryPoint = "MiniDumpWriteDump", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]

    static extern bool MiniDumpWriteDump(IntPtr hProcess, uint processId, SafeHandle hFile, uint dumpType, IntPtr expParam, IntPtr userStreamParam, IntPtr callbackParam);

    [DllImport("kernel32.dll", EntryPoint = "GetCurrentThreadId", ExactSpelling = true)]
    static extern uint GetCurrentThreadId();

    public static bool write(SafeHandle fileHandle, MiniDumpType dumpType)
    {
        Process currentProcess = Process.GetCurrentProcess();
        IntPtr currentProcessHandle = currentProcess.Handle;
        uint currentProcessId = (uint)currentProcess.Id;
        MiniDumpExceptionInformation exp;
        exp.ThreadId = GetCurrentThreadId();
        exp.ClientPointers = false;
        exp.ExceptionPointers = IntPtr.Zero;
        exp.ExceptionPointers = Marshal.GetExceptionPointers();

        bool bRet = false;
        if (exp.ExceptionPointers == IntPtr.Zero)
        {
            bRet = MiniDumpWriteDump(currentProcessHandle, currentProcessId, fileHandle, (uint)dumpType, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
        }
        else
        {
            bRet = MiniDumpWriteDump(currentProcessHandle, currentProcessId, fileHandle, (uint)dumpType, ref exp, IntPtr.Zero, IntPtr.Zero);
        }

        return bRet;
    }

    public static bool write(string fileName, MiniDumpType dumpType)
    {
        using (var fs = new FileStream(fileName, FileMode.Create, FileAccess.ReadWrite, FileShare.Write))
        {
            return write(fs.SafeFileHandle, dumpType);
        }
    }

    public static bool write(DumpConfig dumpCopnfig, Exception e)
    {
        using (var fs = new FileStream(dumpCopnfig.DumpFile, FileMode.Create, FileAccess.ReadWrite, FileShare.Write))
        {
            write(fs.SafeFileHandle, MiniDumpType.WithFullMemory);
        }

        DumpHandler.writeTxt(dumpCopnfig, e);

        return true;
    }
}