using dnlib.DotNet;
using dnlib.DotNet.Emit;
using System;
using System.Linq;

// Load the target assembly/module
ModuleDefMD module = ModuleDefMD.Load("target.dll");

// Define a global variable to store the opaque predicate result
FieldDef resultField = new FieldDefUser("result", new FieldSig(module.CorLibTypes.Boolean), FieldAttributes.Static | FieldAttributes.Private);

// Define a method to create an opaque predicate
private static void CreateOpaquePredicate(MethodDef method)
{
    // Create a new local variable to store the result of the comparison
    Local resultVar = new Local(method.Module.CorLibTypes.Boolean);
    method.Body.Variables.Add(resultVar);

    // Create a new label to jump to if the comparison fails
    Instruction target = Instruction.Create(OpCodes.Nop);

    // Create a new instruction to load a random value on the stack
    Instruction randomValue = Instruction.Create(OpCodes.Ldc_I4, new Random().Next());

    // Create a new instruction to load another random value on the stack
    Instruction anotherRandomValue = Instruction.Create(OpCodes.Ldc_I4, new Random().Next());

    // Create a new instruction to compare the two random values
    Instruction compare = Instruction.Create(OpCodes.Ceq);

    // Create a new instruction to store the result of the comparison in the local variable
    Instruction storeResult = Instruction.Create(OpCodes.Stloc, resultVar);

    // Create a new instruction to load the local variable on the stack
    Instruction loadResult = Instruction.Create(OpCodes.Ldloc, resultVar);

    // Create a new instruction to branch to the target label if the result of the comparison is false
    Instruction branchFalse = Instruction.Create(OpCodes.Brfalse, target);

    // Insert the new instructions in the method body
    method.Body.Instructions.Insert(0, randomValue);
    method.Body.Instructions.Insert(1, anotherRandomValue);
    method.Body.Instructions.Insert(2, compare);
    method.Body.Instructions.Insert(3, storeResult);
    method.Body.Instructions.Insert(4, loadResult);
    method.Body.Instructions.Insert(5, branchFalse);

    // Insert the target label at the end of the method body
    method.Body.Instructions.Add(target);

    // Update the global variable with the result of the opaque predicate
    method.Body.Instructions.Add(Instruction.Create(OpCodes.Ldloc, resultVar));
    method.Body.Instructions.Add(Instruction.Create(OpCodes.Stsfld, resultField));
}

// Iterate through all the types in the module
foreach (TypeDef type in module.Types)
{
    // Iterate through all the methods in the type
    foreach (MethodDef method in type.Methods)
    {
        // Create an opaque predicate in the method
        CreateOpaquePredicate(method);
    }
}

// Iterate through all the methods in the module again
foreach (TypeDef type in module.Types)
{
    foreach (MethodDef method in type.Methods)
    {
        // Create a new label to jump to if the global variable is true
        Instruction target = Instruction.Create(OpCodes.Nop);

        // Create a new instruction to load the global variable on the stack
        Instruction loadResult = Instruction.Create(OpCodes.Ldsfld, resultField);

        // Create a new instruction to branch to the target label if the global variable is true
        Instruction branchTrue = Instruction.Create(OpCodes.Brtrue, target);

        // Insert the new instructions at the beginning of the method body
        method.Body.Instructions.Insert(0, loadResult);
        method.Body.Instructions.Insert(1, branchTrue);

        // Insert the target label
        method.Body.Instructions.Insert(2, target);
        method.Body.Instructions.Add(Instruction.Create(OpCodes.Ret));
    }
}

// Save the obfuscated module to disk
module.Write("obfuscated.dll");