#include <fuzzer/FuzzedDataProvider.h>

#include "behaviortree_cpp/bt_factory.h"

#include "behaviortree_cpp/xml_parsing.h"

#include <string>

// List of valid node types we can use to construct valid-ish XML

constexpr const char* NODE_TYPES[] = {

  "Sequence",         "Fallback",         "ParallelAll",

  "ReactiveSequence", "ReactiveFallback", "IfThenElse",

  "WhileDoElse",      "Inverter",         "RetryUntilSuccessful",

  "Repeat",           "Timeout",          "Delay",

  "ForceSuccess",     "ForceFailure",     "AlwaysSuccess",

  "AlwaysFailure",    "SetBlackboard",    "SubTree"

};

// Attributes that can be added to nodes

constexpr const char* NODE_ATTRIBUTES[] = { "name",      "ID",         "port_1",

                                            "port_2",    "timeout_ms", "delay_ms",

                                            "threshold", "max_repeats" };

std::string generateFuzzedNodeXML(FuzzedDataProvider& fdp, int depth = 0)

{

  // Prevent stack overflow with max depth

  if(depth > 6)

  {  // Reasonable limit for XML tree depth

    return "<AlwaysSuccess/>";

  }

  std::string xml;

  const std::string node_type = fdp.PickValueInArray(NODE_TYPES);

  xml += "<" + node_type;

  size_t num_attributes = fdp.ConsumeIntegralInRange<size_t>(0, 3);

  for(size_t i = 0; i < num_attributes; i++)

  {

    const std::string attr = fdp.PickValueInArray(NODE_ATTRIBUTES);

    std::string value = fdp.ConsumeRandomLengthString(10);

    xml += " " + attr + "=\"" + value + "\"";

  }

  if(depth > 3 || fdp.ConsumeBool())

  {

    xml += "/>";

  }

  else

  {

    xml += ">";

    // Add some child nodes recursively with depth limit

    size_t num_children = fdp.ConsumeIntegralInRange<size_t>(0, 2);

    for(size_t i = 0; i < num_children; i++)

    {

      xml += generateFuzzedNodeXML(fdp, depth + 1);

    }

    xml += "</" + node_type + ">";

  }

  return xml;

}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)

{

  if(size < 4)

  {

    return 0;

  }

  FuzzedDataProvider fdp(data, size);

  BT::BehaviorTreeFactory factory;

  try

  {

    // Strategy 1: Test with completely random data

    if(fdp.ConsumeBool())

    {

      std::string random_xml = fdp.ConsumeRandomLengthString(size - 1);

      try

      {

        factory.createTreeFromText(random_xml);

      }

      catch(const std::exception&)

      {}

    }

    // Strategy 2: Generate semi-valid XML

    else

    {

      std::string xml = R"(

                <root BTCPP_format="4">

                    <BehaviorTree ID="MainTree">)";

      size_t num_nodes = fdp.ConsumeIntegralInRange<size_t>(1, 5);

      for(size_t i = 0; i < num_nodes; i++)

      {

        xml += generateFuzzedNodeXML(fdp);

      }

      xml += R"(

                    </BehaviorTree>

                </root>)";

      auto blackboard = BT::Blackboard::create();

      switch(fdp.ConsumeIntegralInRange<int>(0, 2))

      {

        case 0:

          factory.createTreeFromText(xml, blackboard);

          break;

        case 1:

          BT::VerifyXML(xml, {});

          break;

        case 2:

          factory.registerBehaviorTreeFromText(xml);

          if(!factory.registeredBehaviorTrees().empty())

          {

            factory.createTree(factory.registeredBehaviorTrees().front(), blackboard);

          }

          break;

      }

    }

  }

  catch(const std::exception&)

  {}

  return 0;

}