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

namespace Common
{
    public static class MiniDump
    {
        [Flags]
        public enum Option : uint
        {
            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,
        }

        enum ExceptionInfo
        {
            None,
            Present
        }

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

        // MiniDumpWriteDump function declarations
        [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);

        [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();

        static bool Write(SafeHandle fileHandle, Option options, ExceptionInfo exceptionInfo, Exception exception = null)
        {
            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;

            if (exceptionInfo == ExceptionInfo.Present && exception != null)
            {
                // Get exception pointers
                exp.ExceptionPointers = Marshal.GetExceptionPointers();
            }

            // Write dump
            bool result = exp.ExceptionPointers == IntPtr.Zero
                          ? MiniDumpWriteDump(currentProcessHandle, currentProcessId, fileHandle, (uint)options, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero)
                          : MiniDumpWriteDump(currentProcessHandle, currentProcessId, fileHandle, (uint)options, ref exp, IntPtr.Zero, IntPtr.Zero);

            if (exception != null)
            {
               
            }

            return result;
        }

     

        public static Boolean TryDump(String dmpPath, Option dmpType = Option.Normal, Exception exception = null)
        {
            var path = Path.Combine(Environment.CurrentDirectory, dmpPath);
            var dir = Path.GetDirectoryName(path);
            if (dir != null && !Directory.Exists(dir))
            {
                Directory.CreateDirectory(dir);
            }

            using (var fs = new FileStream(path, FileMode.Create))
            {
                return Write(fs.SafeFileHandle, dmpType, exception == null ? ExceptionInfo.None : ExceptionInfo.Present, exception);
            }
        }
    }

}