// SPDX-License-Identifier: MIT
#include "Common/StringConv.h"
#include "Common/StringUtils.h"
#include "FEXCore/Utils/EnumUtils.h"

#include <FEXCore/Config/Config.h>
#include <FEXCore/Utils/Allocator.h>
#include <FEXCore/Utils/CPUInfo.h>
#include <FEXCore/Utils/FileLoading.h>
#include <FEXCore/Utils/LogManager.h>
#include <FEXCore/fextl/fmt.h>
#include <FEXCore/fextl/list.h>
#include <FEXCore/fextl/map.h>
#include <FEXCore/fextl/memory.h>
#include <FEXCore/fextl/string.h>
#include <FEXCore/fextl/unordered_map.h>
#include <FEXCore/fextl/vector.h>
#include <FEXHeaderUtils/Filesystem.h>

#include <array>
#include <cstdlib>
#include <functional>
#include <optional>
#include <stddef.h>
#include <stdint.h>
#include <string_view>
#include <system_error>
#include <type_traits>
#include <utility>

namespace FEXCore::Context {
  class Context;
}

namespace FEXCore::Config {
namespace DefaultValues {
#define P(x) x
#define OPT_BASE(type, group, enum, json, default) const P(type) P(enum) = P(default);
#define OPT_STR(group, enum, json, default) const std::string_view P(enum) = P(default);
#define OPT_STRARRAY(group, enum, json, default) OPT_STR(group, enum, json, default)
#define OPT_STRENUM(group, enum, json, default) const uint64_t P(enum) = FEXCore::ToUnderlying(P(default));
#include <FEXCore/Config/ConfigValues.inl>
}

  enum Paths {
    PATH_DATA_DIR = 0,
    PATH_CONFIG_DIR_LOCAL,
    PATH_CONFIG_DIR_GLOBAL,
    PATH_CONFIG_FILE_LOCAL,
    PATH_CONFIG_FILE_GLOBAL,
    PATH_LAST,
  };
  static std::array<fextl::string, Paths::PATH_LAST> Paths;

  void SetDataDirectory(const std::string_view Path) {
    Paths[PATH_DATA_DIR] = Path;
  }

  void SetConfigDirectory(const std::string_view Path, bool Global) {
    Paths[PATH_CONFIG_DIR_LOCAL + Global] = Path;
  }

  void SetConfigFileLocation(const std::string_view Path, bool Global) {
    Paths[PATH_CONFIG_FILE_LOCAL + Global] = Path;
  }

  fextl::string const& GetDataDirectory() {
    return Paths[PATH_DATA_DIR];
  }

  fextl::string const& GetConfigDirectory(bool Global) {
    return Paths[PATH_CONFIG_DIR_LOCAL + Global];
  }

  fextl::string const& GetConfigFileLocation(bool Global) {
    return Paths[PATH_CONFIG_FILE_LOCAL + Global];
  }

  fextl::string GetApplicationConfig(const std::string_view Program, bool Global) {
    fextl::string ConfigFile = GetConfigDirectory(Global);

    if (!Global &&
        !FHU::Filesystem::Exists(ConfigFile) &&
        !FHU::Filesystem::CreateDirectories(ConfigFile)) {
      LogMan::Msg::DFmt("Couldn't create config directory: '{}'", ConfigFile);
      // Let's go local in this case
      return fextl::fmt::format("./{}.json", Program);
    }

    ConfigFile += "AppConfig/";

    // Attempt to create the local folder if it doesn't exist
    if (!Global &&
        !FHU::Filesystem::Exists(ConfigFile) &&
        !FHU::Filesystem::CreateDirectories(ConfigFile)) {
      // Let's go local in this case
      return fextl::fmt::format("./{}.json", Program);
    }

    return fextl::fmt::format("{}{}.json", ConfigFile, Program);
  }

  void SetConfig(FEXCore::Context::Context *CTX, ConfigOption Option, uint64_t Config) {
  }

  void SetConfig(FEXCore::Context::Context *CTX, ConfigOption Option, fextl::string const &Config) {
  }

  uint64_t GetConfig(FEXCore::Context::Context *CTX, ConfigOption Option) {
    return 0;
  }

  static fextl::map<FEXCore::Config::LayerType, fextl::unique_ptr<FEXCore::Config::Layer>> ConfigLayers;
  static FEXCore::Config::Layer *Meta{};

  constexpr std::array<FEXCore::Config::LayerType, 9> LoadOrder = {
    FEXCore::Config::LayerType::LAYER_GLOBAL_MAIN,
    FEXCore::Config::LayerType::LAYER_MAIN,
    FEXCore::Config::LayerType::LAYER_GLOBAL_STEAM_APP,
    FEXCore::Config::LayerType::LAYER_GLOBAL_APP,
    FEXCore::Config::LayerType::LAYER_LOCAL_STEAM_APP,
    FEXCore::Config::LayerType::LAYER_LOCAL_APP,
    FEXCore::Config::LayerType::LAYER_ARGUMENTS,
    FEXCore::Config::LayerType::LAYER_ENVIRONMENT,
    FEXCore::Config::LayerType::LAYER_TOP
  };

  Layer::Layer(const LayerType _Type)
    : Type {_Type} {
  }

  Layer::~Layer() {
  }

  class MetaLayer final : public FEXCore::Config::Layer {
  public:
    MetaLayer(const LayerType _Type)
      : FEXCore::Config::Layer (_Type) {
    }
    ~MetaLayer() {
    }
    void Load();

  private:
    void MergeConfigMap(const LayerOptions &Options);
    void MergeEnvironmentVariables(ConfigOption const &Option, LayerValue const &Value);
  };

  void MetaLayer::Load() {
    OptionMap.clear();

    for (auto CurrentLayer = LoadOrder.begin(); CurrentLayer != LoadOrder.end(); ++CurrentLayer) {
      auto it = ConfigLayers.find(*CurrentLayer);
      if (it != ConfigLayers.end() && *CurrentLayer != Type) {
        // Merge this layer's options to this layer
        MergeConfigMap(it->second->GetOptionMap());
      }
    }
  }


  void MetaLayer::MergeEnvironmentVariables(ConfigOption const &Option, LayerValue const &Value) {
    // Environment variables need a bit of additional work
    // We want to merge the arrays rather than overwrite entirely
    auto MetaEnvironment = OptionMap.find(Option);
    if (MetaEnvironment == OptionMap.end()) {
      // Doesn't exist, just insert
      OptionMap.insert_or_assign(Option, Value);
      return;
    }

    // If an environment variable exists in both current meta and in the incoming layer then the meta layer value is overwritten
    fextl::unordered_map<fextl::string, fextl::string> LookupMap;
    const auto AddToMap = [&LookupMap](FEXCore::Config::LayerValue const &Value) {
      for (const auto &EnvVar : Value) {
        const auto ItEq = EnvVar.find_first_of('=');
        if (ItEq == fextl::string::npos) {
          // Broken environment variable
          // Skip
          continue;
        }
        auto Key = fextl::string(EnvVar.begin(), EnvVar.begin() + ItEq);
        auto Value = fextl::string(EnvVar.begin() + ItEq + 1, EnvVar.end());

        // Add the key to the map, overwriting whatever previous value was there
        LookupMap.insert_or_assign(std::move(Key), std::move(Value));
      }
    };

    AddToMap(MetaEnvironment->second);
    AddToMap(Value);

    // Now with the two layers merged in the map
    // Add all the values to the option
    Erase(Option);
    for (auto &Val : LookupMap) {
      // Set will emplace multiple options in to its list
      Set(Option, Val.first + "=" + Val.second);
    }
  }

  void MetaLayer::MergeConfigMap(const LayerOptions &Options) {
    // Insert this layer's options, overlaying previous options that exist here
    for (auto &it : Options) {
      if (it.first == FEXCore::Config::ConfigOption::CONFIG_ENV ||
          it.first == FEXCore::Config::ConfigOption::CONFIG_HOSTENV) {
        MergeEnvironmentVariables(it.first, it.second);
      }
      else {
        OptionMap.insert_or_assign(it.first, it.second);
      }
    }
  }

  void Initialize() {
    AddLayer(fextl::make_unique<MetaLayer>(FEXCore::Config::LayerType::LAYER_TOP));
    Meta = ConfigLayers.begin()->second.get();
  }

  void Shutdown() {
    ConfigLayers.clear();
    Meta = nullptr;
  }

  void Load() {
    for (auto CurrentLayer = LoadOrder.begin(); CurrentLayer != LoadOrder.end(); ++CurrentLayer) {
      auto it = ConfigLayers.find(*CurrentLayer);
      if (it != ConfigLayers.end()) {
        it->second->Load();
      }
    }
  }

  fextl::string ExpandPath(fextl::string const &ContainerPrefix, fextl::string PathName) {
    if (PathName.empty()) {
      return {};
    }


    // Expand home if it exists
    if (FHU::Filesystem::IsRelative(PathName)) {
      fextl::string Home = getenv("HOME") ?: "";
      // Home expansion only works if it is the first character
      // This matches bash behaviour
      if (PathName.at(0) == '~') {
        PathName.replace(0, 1, Home);
        return PathName;
      }

      // Expand relative path to absolute
      char ExistsTempPath[PATH_MAX];
      char *RealPath = FHU::Filesystem::Absolute(PathName.c_str(), ExistsTempPath);
      if (RealPath) {
        PathName = RealPath;
      }

      // Only return if it exists
      if (FHU::Filesystem::Exists(PathName)) {
        return PathName;
      }
    }
    else {
      // If the containerprefix and pathname isn't empty
      // Then we check if the pathname exists in our current namespace
      // If the path DOESN'T exist but DOES exist with the prefix applied
      // then redirect to the prefix
      //
      // This might not be expected behaviour for some edge cases but since
      // all paths aren't mounted inside the container, then it'll be fine
      //
      // Main catch case for this is the default thunk install folders
      // HostThunks: $CMAKE_INSTALL_PREFIX/lib/fex-emu/HostThunks/
      // GuestThunks: $CMAKE_INSTALL_PREFIX/share/fex-emu/GuestThunks/
      if (!ContainerPrefix.empty() && !PathName.empty()) {
        if (!FHU::Filesystem::Exists(PathName)) {
          auto ContainerPath = ContainerPrefix + PathName;
          if (FHU::Filesystem::Exists(ContainerPath)) {
            return ContainerPath;
          }
        }
      }
    }
    return {};
  }

  constexpr char ContainerManager[] = "/run/host/container-manager";

  fextl::string FindContainer() {
    // We only support pressure-vessel at the moment
    if (FHU::Filesystem::Exists(ContainerManager)) {
      fextl::vector<char> Manager{};
      if (FEXCore::FileLoading::LoadFile(Manager, ContainerManager)) {
        // Trim the whitespace, may contain a newline
        fextl::string ManagerStr = Manager.data();
        ManagerStr = FEXCore::StringUtils::Trim(ManagerStr);
        return ManagerStr;
      }
    }
    return {};
  }

  fextl::string FindContainerPrefix() {
    // We only support pressure-vessel at the moment
    if (FHU::Filesystem::Exists(ContainerManager)) {
      fextl::vector<char> Manager{};
      if (FEXCore::FileLoading::LoadFile(Manager, ContainerManager)) {
        // Trim the whitespace, may contain a newline
        fextl::string ManagerStr = Manager.data();
        ManagerStr = FEXCore::StringUtils::Trim(ManagerStr);
        if (strncmp(ManagerStr.data(), "pressure-vessel", Manager.size()) == 0) {
          // We are running inside of pressure vessel
          // Our $CMAKE_INSTALL_PREFIX paths are now inside of /run/host/$CMAKE_INSTALL_PREFIX
          return "/run/host/";
        }
      }
    }
    return {};
  }

  void ReloadMetaLayer() {
    Meta->Load();

    // Do configuration option fix ups after everything is reloaded
    {
      // Always fix up the number of threads and create the configuration
      // Otherwise the application could receive zero as the number of threads
      FEX_CONFIG_OPT(Cores, THREADS);
      if (Cores == 0) {
        // When the number of emulated CPU cores is zero then auto detect
        FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_THREADS, fextl::fmt::format("{}", FEXCore::CPUInfo::CalculateNumberOfCPUs()));
      }
    }

    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_CORE)) {
      // Sanitize Core option
      FEX_CONFIG_OPT(Core, CORE);
#if (_M_X86_64)
      constexpr uint32_t MaxCoreNumber = 2;
#else
      constexpr uint32_t MaxCoreNumber = 1;
#endif
      constexpr uint32_t MinCoreNumber = 1;
      if (Core > MaxCoreNumber || Core < MinCoreNumber) {
        // Sanitize the core option by setting the core to the JIT if invalid
        FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_CORE, fextl::fmt::format("{}", static_cast<uint32_t>(FEXCore::Config::CONFIG_IRJIT)));
      }
    }

    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_CACHEOBJECTCODECOMPILATION)) {
      FEX_CONFIG_OPT(CacheObjectCodeCompilation, CACHEOBJECTCODECOMPILATION);
      FEX_CONFIG_OPT(Core, CORE);
    }

    fextl::string ContainerPrefix { FindContainerPrefix() };
    auto ExpandPathIfExists = [&ContainerPrefix](FEXCore::Config::ConfigOption Config, fextl::string PathName) {
      auto NewPath = ExpandPath(ContainerPrefix, PathName);
      if (!NewPath.empty()) {
        FEXCore::Config::EraseSet(Config, NewPath);
      }
    };

    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_ROOTFS)) {
      FEX_CONFIG_OPT(PathName, ROOTFS);
      auto ExpandedString = ExpandPath(ContainerPrefix,PathName());
      if (!ExpandedString.empty()) {
        // Adjust the path if it ended up being relative
        FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_ROOTFS, ExpandedString);
      }
      else if (!PathName().empty()) {
        // If the filesystem doesn't exist then let's see if it exists in the fex-emu folder
        fextl::string NamedRootFS = GetDataDirectory() + "RootFS/" + PathName();
        if (FHU::Filesystem::Exists(NamedRootFS)) {
          FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_ROOTFS, NamedRootFS);
        }
      }
    }
    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_THUNKHOSTLIBS)) {
      FEX_CONFIG_OPT(PathName, THUNKHOSTLIBS);
      ExpandPathIfExists(FEXCore::Config::CONFIG_THUNKHOSTLIBS, PathName());
    }
    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_THUNKGUESTLIBS)) {
      FEX_CONFIG_OPT(PathName, THUNKGUESTLIBS);
      ExpandPathIfExists(FEXCore::Config::CONFIG_THUNKGUESTLIBS, PathName());
    }
    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_THUNKCONFIG)) {
      FEX_CONFIG_OPT(PathName, THUNKCONFIG);
      auto ExpandedString = ExpandPath(ContainerPrefix, PathName());
      if (!ExpandedString.empty()) {
        // Adjust the path if it ended up being relative
        FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_THUNKCONFIG, ExpandedString);
      }
      else if (!PathName().empty()) {
        // If the filesystem doesn't exist then let's see if it exists in the fex-emu folder
        fextl::string NamedConfig = GetDataDirectory() + "ThunkConfigs/" + PathName();
        if (FHU::Filesystem::Exists(NamedConfig)) {
          FEXCore::Config::EraseSet(FEXCore::Config::CONFIG_THUNKCONFIG, NamedConfig);
        }
      }
    }
    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_OUTPUTLOG)) {
      FEX_CONFIG_OPT(PathName, OUTPUTLOG);
      if (PathName() != "stdout" && PathName() != "stderr" && PathName() != "server") {
        ExpandPathIfExists(FEXCore::Config::CONFIG_OUTPUTLOG, PathName());
      }
    }

    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_DUMPIR) &&
        !FEXCore::Config::Exists(FEXCore::Config::CONFIG_PASSMANAGERDUMPIR)) {
      // If DumpIR is set but no PassManagerDumpIR configuration is set, then default to `afteropt`
      FEX_CONFIG_OPT(PathName, DUMPIR);
      if (PathName() != "no") {
        EraseSet(FEXCore::Config::ConfigOption::CONFIG_PASSMANAGERDUMPIR, fextl::fmt::format("{}", static_cast<uint64_t>(FEXCore::Config::PassManagerDumpIR::AFTEROPT)));
      }
    }

    if (FEXCore::Config::Exists(FEXCore::Config::CONFIG_SINGLESTEP)) {
      // Single stepping also enforces single instruction size blocks
      Set(FEXCore::Config::ConfigOption::CONFIG_MAXINST, "1");
    }
  }

  void AddLayer(fextl::unique_ptr<FEXCore::Config::Layer> _Layer) {
    ConfigLayers.emplace(_Layer->GetLayerType(), std::move(_Layer));
  }

  bool Exists(ConfigOption Option) {
    return Meta->OptionExists(Option);
  }

  std::optional<LayerValue*> All(ConfigOption Option) {
    return Meta->All(Option);
  }

  std::optional<fextl::string*> Get(ConfigOption Option) {
    return Meta->Get(Option);
  }

  void Set(ConfigOption Option, std::string_view Data) {
    Meta->Set(Option, Data);
  }

  void Erase(ConfigOption Option) {
    Meta->Erase(Option);
  }

  void EraseSet(ConfigOption Option, std::string_view Data) {
    Meta->EraseSet(Option, Data);
  }

  template<typename T>
  T Value<T>::Get(FEXCore::Config::ConfigOption Option) {
    T Result;
    auto Value = FEXCore::Config::Get(Option);

    if (!FEXCore::StrConv::Conv(**Value, &Result)) {
      LOGMAN_MSG_A_FMT("Attempted to convert invalid value");
    }
    return Result;
  }

  template<typename T>
  T Value<T>::GetIfExists(FEXCore::Config::ConfigOption Option, T Default) {
    T Result;
    auto Value = FEXCore::Config::Get(Option);

    if (Value && FEXCore::StrConv::Conv(**Value, &Result)) {
      return Result;
    }
    else {
      return Default;
    }
  }

  template<>
  fextl::string Value<fextl::string>::GetIfExists(FEXCore::Config::ConfigOption Option, fextl::string Default) {
    auto Value = FEXCore::Config::Get(Option);
    if (Value) {
      return **Value;
    }
    else {
      return Default;
    }
  }

  template<>
  fextl::string Value<fextl::string>::GetIfExists(FEXCore::Config::ConfigOption Option, std::string_view Default) {
    auto Value = FEXCore::Config::Get(Option);
    if (Value) {
      return **Value;
    }
    else {
      return fextl::string(Default);
    }
  }

  template bool     Value<bool>::GetIfExists(FEXCore::Config::ConfigOption Option, bool Default);
  template int8_t   Value<int8_t>::GetIfExists(FEXCore::Config::ConfigOption Option, int8_t Default);
  template uint8_t  Value<uint8_t>::GetIfExists(FEXCore::Config::ConfigOption Option, uint8_t Default);
  template int16_t   Value<int16_t>::GetIfExists(FEXCore::Config::ConfigOption Option, int16_t Default);
  template uint16_t  Value<uint16_t>::GetIfExists(FEXCore::Config::ConfigOption Option, uint16_t Default);
  template int32_t  Value<int32_t>::GetIfExists(FEXCore::Config::ConfigOption Option, int32_t Default);
  template uint32_t Value<uint32_t>::GetIfExists(FEXCore::Config::ConfigOption Option, uint32_t Default);
  template int64_t  Value<int64_t>::GetIfExists(FEXCore::Config::ConfigOption Option, int64_t Default);
  template uint64_t Value<uint64_t>::GetIfExists(FEXCore::Config::ConfigOption Option, uint64_t Default);

  // Constructor
  template Value<fextl::string>::Value(FEXCore::Config::ConfigOption _Option, fextl::string Default);
  template Value<bool>::Value(FEXCore::Config::ConfigOption _Option, bool Default);
  template Value<uint8_t>::Value(FEXCore::Config::ConfigOption _Option, uint8_t Default);
  template Value<uint64_t>::Value(FEXCore::Config::ConfigOption _Option, uint64_t Default);

  template<typename T>
  void Value<T>::GetListIfExists(FEXCore::Config::ConfigOption Option, fextl::list<fextl::string> *List) {
    auto Value = FEXCore::Config::All(Option);
    List->clear();
    if (Value) {
      *List = **Value;
    }
  }
  template void Value<fextl::string>::GetListIfExists(FEXCore::Config::ConfigOption Option, fextl::list<fextl::string> *List);
}