// for clangd
#include "../include/global_info.hpp"
#include "../include/error_handling.hpp"
#include <variant>

namespace info {

void GlobalInfo::NamespaceVisitor::AddImport(definition::Import&& import_info,
                                             const std::optional<std::string>& name) {
  if (name.has_value()) {
    global_info_.usages_[name.value()] = std::move(import_info);
  } else {
    global_info_.imports_.push_back(std::move(import_info));
  }
}

void GlobalInfo::NamespaceVisitor::AddEnterNamespace(const std::string& name,
                                                     const std::optional<definition::Namespace::Modifier>& modifier) {
  definition::Namespace* namespace_info = nullptr;
  if (modifier.has_value()) {
    namespace_info = &namespace_stack_.back()->variable_namespaces[name];
    namespace_stack_.push_back(namespace_info);

    namespace_info->modifier = modifier;
  } else {
    namespace_info = &namespace_stack_.back()->namespaces[name];
    namespace_stack_.push_back(namespace_info);
  }

  namespace_info->parent_namespace = namespace_stack_.back();

  namespace_info->type_name = name;
  current_path_.push_back(name);
}

void GlobalInfo::NamespaceVisitor::EnterNamespace(const std::string& name) {
  for (ssize_t i = (ssize_t)namespace_stack_.size() - 1; i >= 0; --i) {
    auto namespace_iter = namespace_stack_[i]->namespaces.find(name);
    if (namespace_iter != namespace_stack_[i]->namespaces.end()) {
      namespace_stack_.push_back(&namespace_iter->second);
      current_path_.push_back(name);
      return;
    }
  }

  error_handling::HandleInternalError("Can't find namespace", "GlobalInfo.NamespaceVisitor.EnterNamespace");
}

void GlobalInfo::NamespaceVisitor::ExitNamespace() {
  if (namespace_stack_.size() <= 1) {
    // error
    return;
  }

  namespace_stack_.pop_back();
  current_path_.pop_back();
}

void GlobalInfo::NamespaceVisitor::ToGlobalNamespace() {
  namespace_stack_.clear();
  current_path_.clear();

  namespace_stack_.push_back(&global_info_.global_namespace_);
}

utils::IdType GlobalInfo::NamespaceVisitor::AddFunctionDeclaration(const std::string& name,
    definition::FunctionDeclaration&& function_declaration_info) {
  size_t id = 0;

  auto function_id_iter = namespace_stack_.back()->functions.find(name);

  if (function_id_iter == namespace_stack_.back()->functions.end()) {
    id = global_info_.functions_.size();
    namespace_stack_.back()->functions[name] = id;
    global_info_.functions_.emplace_back();
    global_info_.functions_.back().argument_count = function_declaration_info.argument_types.size();
    global_info_.functions_.back().declaration = std::move(function_declaration_info);
  } else {
    id = function_id_iter->second;
    if (global_info_.functions_.back().argument_count != function_declaration_info.argument_types.size()) {
      error_handling::HandleInternalError("Not same argument count in function definition and declaration", "GlobalInfo");
    }
    global_info_.functions_[id].declaration = std::move(function_declaration_info);
  }

  return id;
}

utils::IdType GlobalInfo::NamespaceVisitor::AddFunctionDefinition(const std::string& name,
    definition::FunctionDefinition&& function_definition_info) {
  size_t id = 0;

  auto function_id_iter = namespace_stack_.back()->functions.find(name);

  if (function_id_iter == namespace_stack_.back()->functions.end()) {
    id = global_info_.functions_.size();
    namespace_stack_.back()->functions[name] = id;
    global_info_.functions_.emplace_back();
    global_info_.functions_.back().argument_count = function_definition_info.argument_names.size();
    global_info_.functions_.back().definition = std::move(function_definition_info);
  } else {
    id = function_id_iter->second;
    if (global_info_.functions_.back().argument_count != function_definition_info.argument_names.size()) {
      error_handling::HandleInternalError("Not same argument count in function definition and declaration", "GlobalInfo");
    }
    global_info_.functions_[id].definition = std::move(function_definition_info);
  }

  return id;
}

// TODO: internal types, etc.
// TODO: extended constructor names (point separated names)
utils::IdType GlobalInfo::NamespaceVisitor::AddType(const std::string& type,
                                                    definition::Type&& type_info) {
  size_t id = 0;

  auto type_id_iter = namespace_stack_.back()->types.find(type);

  if (type_id_iter == namespace_stack_.back()->types.end()) {
    id = global_info_.types_.size();
    namespace_stack_.back()->types[type] = id;
    global_info_.types_.push_back(std::move(type_info));
  } else {
    error_handling::HandleTypecheckError("More then one type with the same name in namespace");
  }

  definition::Type& moved_type_info = global_info_.types_.back();

  // TODO: constructors for tuple types, function types (??), array types (??), ...

  if (std::holds_alternative<definition::AnyType>(moved_type_info.type)) {
    definition::AnyType& any_type_info = std::get<definition::AnyType>(moved_type_info.type);
    if (std::holds_alternative<std::unique_ptr<interpreter::tokens::VariantType>>(*any_type_info.value)) {
      interpreter::tokens::VariantType& variant_type_info = *std::get<std::unique_ptr<interpreter::tokens::VariantType>>(*any_type_info.value);
      for (size_t i = 0; i < variant_type_info.constructors.size(); ++i) {
        std::string constructor_name;
        definition::Constructor constructor_info;

        constructor_info.type_id = id;
        constructor_info.order = i;

        if (std::holds_alternative<interpreter::tokens::Constructor>(variant_type_info.constructors[i])) {
          constructor_name = std::get<interpreter::tokens::Constructor>(variant_type_info.constructors[i]);
        } else if (std::holds_alternative<
            std::unique_ptr<interpreter::tokens::TupleType>>(variant_type_info.constructors[i])) {
          constructor_info.constructor_tuple_node =
            std::get<std::unique_ptr<interpreter::tokens::TupleType>>(variant_type_info.constructors[i]).get();

          auto maybe_constructor_name = constructor_info.constructor_tuple_node.value()->type;

          if (maybe_constructor_name.has_value()) {
            constructor_name = maybe_constructor_name.value();
          } else {
            constructor_name = type;
          }
        } else {
          // error
        }

        constructor_info.name = constructor_name;

        AddConstructor(constructor_name, std::move(constructor_info));
      }
    }
  }

  return id;
}

// TODO: link abstract type with let definitions
utils::IdType GlobalInfo::NamespaceVisitor::AddAbstractType(const std::string& abstract_type,
                                                            definition::AbstractType&& abstract_type_info) {
  if (!FindAbstractType(abstract_type).has_value()) {
    size_t id = global_info_.abstract_types_.size();
    global_info_.name_to_abstract_type_[abstract_type] = id;
    global_info_.abstract_types_.push_back(std::move(abstract_type_info));
  }

  error_handling::HandleTypecheckError("More then one abstract type with the same name in namespace");
  return 0;
}

utils::IdType GlobalInfo::NamespaceVisitor::AddTypeclass(const std::string& typeclass,
                                                         definition::Typeclass&& typeclass_info) {
  if (!FindTypeclass(typeclass).has_value()) {
    size_t id = global_info_.typeclasses_.size();
    global_info_.name_to_typeclass_[typeclass] = id;
    global_info_.typeclasses_.push_back(std::move(typeclass_info));
  }


  error_handling::HandleTypecheckError("More then one typeclass with the same name in namespace");
  return 0;
}

utils::IdType GlobalInfo::NamespaceVisitor::AddConstructor(const std::string& constructor,
                                                           definition::Constructor&& constructor_info) {
  auto constructor_id_iter = namespace_stack_.back()->constructors.find(constructor);

  if (constructor_id_iter == namespace_stack_.back()->constructors.end()) {
    size_t id = global_info_.constructors_.size();
    namespace_stack_.back()->constructors[constructor] = id;
    global_info_.constructors_.push_back(std::move(constructor_info));
  }

  error_handling::HandleTypecheckError("More then one constructor with the same name in namespace");
  return 0;
}

std::optional<definition::Namespace*> GlobalInfo::NamespaceVisitor::FindNamespace(const std::optional<std::vector<std::string>>& path) {
  return FindSomething<definition::Namespace*>(path,
      [] (definition::Namespace* current_namespace) -> std::optional<definition::Namespace*> {
    return current_namespace;
  });
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindFunction(
    const std::optional<std::vector<std::string>>& path,
    const std::string& name) {
  return FindSomething<utils::IdType>(path,
      [name] (definition::Namespace* current_namespace) -> std::optional<utils::IdType> {

    auto function_info_iter = current_namespace->functions.find(name);
    if (function_info_iter == current_namespace->functions.end()) {
      return std::nullopt;
    }

    return function_info_iter->second;
  });
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindMethod(
    const std::optional<std::vector<std::string>>& path,
    const std::string& type,
    const std::string& name) {
  // TODO: remove overhead

  return GlobalInfo::NamespaceVisitor::FindSomething<utils::IdType>(path,
      [type, name] (definition::Namespace* current_namespace) -> std::optional<utils::IdType> {

    auto variable_namespace_iter = current_namespace->variable_namespaces.find(type);
    if (variable_namespace_iter == current_namespace->variable_namespaces.end()) {
      return std::nullopt;
    }

    auto method_iter = variable_namespace_iter->second.functions.find(name);
    if (method_iter == variable_namespace_iter->second.functions.end()) {
        return std::nullopt;
    }

    return method_iter->second;
  });
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindType(
    const std::optional<std::vector<std::string>>& path,
    const std::string& type) {
  return FindSomething<utils::IdType>(path,
      [type] (definition::Namespace* current_namespace) -> std::optional<utils::IdType> {

    auto type_info_iter = current_namespace->types.find(type);
    if (type_info_iter == current_namespace->types.end()) {
      return std::nullopt;
    }

    return type_info_iter->second;
  });
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindLocalType(const std::string& type) {
  auto type_id_iter = namespace_stack_.back()->types.find(type);

  if (type_id_iter != namespace_stack_.back()->types.end()) {
    return type_id_iter->second;
  }

  return std::nullopt;
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindAbstractType(const std::string& abstract_type) {
  auto abstract_type_id_iter = global_info_.name_to_abstract_type_.find(abstract_type);

  if (abstract_type_id_iter != global_info_.name_to_abstract_type_.end()) {
    return abstract_type_id_iter->second;
  }

  return std::nullopt;
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindTypeclass(const std::string& typeclass) {
  auto typeclass_id_iter = global_info_.name_to_typeclass_.find(typeclass);

  if (typeclass_id_iter != global_info_.name_to_typeclass_.end()) {
    return typeclass_id_iter->second;
  }

  return std::nullopt;
}

std::optional<utils::IdType> GlobalInfo::NamespaceVisitor::FindConstructor(
    const std::optional<std::vector<std::string>>& path,
    const std::string& constructor) {
  return FindSomething<utils::IdType>(path,
      [constructor] (definition::Namespace* current_namespace) -> std::optional<utils::IdType> {

    auto constructor_info_iter = current_namespace->constructors.find(constructor);
    if (constructor_info_iter == current_namespace->constructors.end()) {
      return std::nullopt;
    }

    return constructor_info_iter->second;
  });
}

template<typename T>
std::optional<T> GlobalInfo::NamespaceVisitor::FindSomething(
    const std::optional<std::vector<std::string>>& path,
    std::function<std::optional<T>(definition::Namespace*)> search_func) {
  for (ssize_t i = namespace_stack_.size() - 1; i >= 0; --i) {
    definition::Namespace* current_namespace = nullptr;
    if (path.has_value()) {
      auto maybe_namespace = FindNamespaceIn(namespace_stack_[i], path.value());

      if (!maybe_namespace.has_value()) {
        continue;
      }
    } else {
      current_namespace = namespace_stack_[i];
    }

    std::optional<T> result = search_func(current_namespace);

    if (result.has_value()) {
      return result.value();
    }
  }

  return std::nullopt;
}

std::optional<definition::Namespace*> GlobalInfo::NamespaceVisitor::FindNamespaceIn(
    definition::Namespace* current_namespace,
    const std::vector<std::string>& path) {
  definition::Namespace* next_namespace = current_namespace;
  for (auto& name : path) {
    auto next_namespace_iter = next_namespace->namespaces.find(name);
    if (next_namespace_iter == next_namespace->namespaces.end()) {
      return std::nullopt;
    }
    next_namespace = &next_namespace_iter->second;
  }

  return next_namespace;
}

} // namespace info