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

namespace IPClab3.Services;

public partial class ProcessHackerService
{
    private IntPtr _processHandle;

    const int PROCESS_VM_READ = 0x0010;
    const int PROCESS_VM_WRITE = 0x0020;
    const int PROCESS_VM_OPERATION = 0x0008;

    [LibraryImport("kernel32.dll", SetLastError = true)]
    public static partial IntPtr OpenProcess(int dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, int dwProcessId);

    [LibraryImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static partial bool ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [Out] byte[] lpBuffer, int dwSize, out IntPtr lpNumberOfBytesRead);

    [LibraryImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static partial bool WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer, int dwSize, out IntPtr lpNumberOfBytesWritten);

    [LibraryImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static partial bool CloseHandle(IntPtr hObject);

    public int StartProcess(string target)
    {
        var process = Process.Start(target);
        CloseHandle(_processHandle);
        _processHandle = OpenProcess(process.Id);
        return process.Id;
    }

    public int AttachProcess(int pid)
    {
        CloseHandle(_processHandle);
        _processHandle = OpenProcess(pid);
        return pid;
    }

    private IntPtr OpenProcess(int pid)
    {
        return OpenProcess(PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION, false, pid);
    }

    public bool ReadMemory(IntPtr address, int size, out byte[] bytes)
    {
        var buffer = new byte[size];
        var result = ReadProcessMemory(_processHandle, address, buffer, buffer.Length, out var bytesRead);
        bytes = buffer;
        return result;
    }

    public bool WriteMemory(IntPtr address, string newMemory)
    {
        var newBytes = Encoding.UTF8.GetBytes(newMemory + "\0");
        var result = WriteProcessMemory(_processHandle, address, newBytes, newBytes.Length, out var bytesWritten);
        return result;
    }
}