#include "statement_nodes.hpp"

#include "error_handling.hpp"
#include "utils.hpp"
#include <algorithm>

namespace nodes {

// TODO: function overloading, etc. ??
bool FunctionDefinition::is_same_to(
    const FunctionDefinition &other_function_definition) const {
  if (*name_.get() != *other_function_definition.name_.get()) {
    return false;
  }
  return true;
}

// TODO: function overloading, etc. ??
CombineResult
FunctionDefinition::combine(FunctionDefinition &&other_function_definition) {
  // should be same in all definitions of one function
  if (*name_.get() != *other_function_definition.name_.get()) {
    return CombineResult::DIFFERENT_NAME_ERROR;
  }
  if (return_modifier_ != other_function_definition.return_modifier_) {
    return CombineResult::DIFFERNENT_MODIFIER_ERROR;
  }
  if (is_method_ != other_function_definition.is_method_) {
    return CombineResult::DIFFERNENT_MODIFIER_ERROR; // other error type ??
  }

  if (are_annotations_same_to_names_ !=
      other_function_definition.are_annotations_same_to_names_) {
    return CombineResult::ARGUMENTS_ERROR;
  }

  // only one definition should have constraints
  if (!constraints_.empty() &&
      !other_function_definition.constraints_.empty()) {
    return CombineResult::MORE_THEN_ONE_CONSTRAINTS_ERROR;
  }

  // only one definition should have expression
  if (expression_.has_value() &&
      other_function_definition.expression_.has_value()) {
    return CombineResult::MORE_THEN_ONE_DEFINITION_BODY_ERROR;
  }

  // only one definition should have documentation
  if (docs_.get_description().has_value() &&
      other_function_definition.docs_.get_description().has_value()) {
    return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
  }
  if (docs_.get_annotations_info_size() > 0 &&
      other_function_definition.docs_.get_annotations_info_size() > 0) {
    return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
  }

  // TODO: think about required checks
  // check, that function definitions have same named arguments count
  for (size_t i = 0; i < std::max(arguments_.size(),
                                  other_function_definition.arguments_.size());
       ++i) {
    if (i < arguments_.size() &&
        i < other_function_definition.arguments_.size()) {

      // check that all argument annotations are the same
      if ((!arguments_[i].get_annotation().has_value() &&
           !other_function_definition.arguments_[i]
                .get_annotation()
                .has_value()) ||
          (arguments_[i].get_annotation().has_value() &&
           other_function_definition.arguments_[i]
               .get_annotation()
               .has_value() &&
           *arguments_[i].get_annotation().value() !=
               *other_function_definition.arguments_[i]
                    .get_annotation()
                    .value())) {
        return CombineResult::ARGUMENTS_ERROR;
      }

      // check that all argument names are the same
      if ((!arguments_[i].get_name().has_value() &&
           !other_function_definition.arguments_[i].get_name().has_value()) ||
          (arguments_[i].get_name().has_value() &&
           other_function_definition.arguments_[i].get_name().has_value() &&
           *arguments_[i].get_name().value()->get() !=
               *other_function_definition.arguments_[i]
                    .get_name()
                    .value()
                    ->get())) {
        return CombineResult::ARGUMENTS_ERROR;
      }

      // check that types are are in zero or one set of arguments (TODO: can be
      // same and in two sets ??)
      if (arguments_[i].get_type().has_value() &&
          other_function_definition.arguments_[i].get_type().has_value()) {
        return CombineResult::ARGUMENTS_ERROR;
      }

      // argument modifiers should be same
      if (arguments_[i].get_before_modifier() !=
              other_function_definition.arguments_[i].get_before_modifier() ||
          arguments_[i].get_after_modifier() !=
              other_function_definition.arguments_[i].get_after_modifier()) {
        return CombineResult::ARGUMENTS_ERROR;
      }
    } else if (i < arguments_.size()) {
      // last arguments shouldn't be annotated (because they are not annotated
      // in other function definition statement)
      if (arguments_[i].get_annotation().has_value()) {
        return CombineResult::ARGUMENTS_ERROR;
      }

      // last arguments can only be unnamed arguments (returned values)
      if (arguments_[i].get_name().has_value()) {
        return CombineResult::ARGUMENTS_ERROR;
      }
    } else { // i < other_function_definition.size()
      // last arguments shouldn't be annotated (because they are not annotated
      // in other function definition statement)
      if (other_function_definition.arguments_[i]
              .get_annotation()
              .has_value()) {
        return CombineResult::ARGUMENTS_ERROR;
      }

      // last arguments can only be unnamed arguments (returned values)
      if (other_function_definition.arguments_[i].get_name().has_value()) {
        return CombineResult::ARGUMENTS_ERROR;
      }
    }
  }

  // combine docs
  // all docs should be in one definition
  if (other_function_definition.docs_.get_description().has_value() ||
      other_function_definition.docs_.get_annotations_info_size() > 0) {
    if (docs_.get_annotations_info_size() > 0 ||
        docs_.get_description().has_value()) {
      return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
    }

    docs_ = std::move(other_function_definition.docs_);
  }

  if (!other_function_definition.constraints_.empty()) {
    constraints_ = std::move(other_function_definition.constraints_);
  }

  if (other_function_definition.expression_.has_value()) {
    expression_ = other_function_definition.expression_;
  }

  for (size_t i = 0; i < other_function_definition.arguments_.size(); ++i) {
    if (i < arguments_.size()) {
      if (other_function_definition.arguments_[i].get_type().has_value()) {
        if (arguments_[i].update_type_from(
                other_function_definition.arguments_[i])) {
          error_handling::handle_internal_error(
              "Function arguments are not properly checked before merging "
              "during combination",
              *this);
        }
      }
    } else {
      arguments_.push_back(std::move(other_function_definition.arguments_[i]));
    }
  }

  return CombineResult::OK;
}

bool TypeDefinition::is_same_to(
    const TypeDefinition &other_type_definition) const {
  if (*name_.get() != *other_type_definition.name_.get()) {
    return false;
  }
  return true;
}

CombineResult TypeDefinition::combine(TypeDefinition &&other_type_definition) {
  // should be same in all definitions of one type
  if (*name_.get() != *other_type_definition.name_.get()) {
    return CombineResult::DIFFERENT_NAME_ERROR;
  }
  if (is_on_heap_ != other_type_definition.is_on_heap_) {
    return CombineResult::DIFFERNENT_MODIFIER_ERROR;
  }

  // only one definition should have documentation
  if (docs_.get_description().has_value() &&
      other_type_definition.docs_.get_description().has_value()) {
    return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
  }
  if (docs_.get_annotations_info_size() > 0 &&
      other_type_definition.docs_.get_annotations_info_size() > 0) {
    return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
  }

  // only one definition should define type and arguments (they should be
  // defined in one place)
  if ((other_type_definition.type_.has_value() ||
       !other_type_definition.arguments_.empty()) &&
      (type_.has_value() || !arguments_.empty())) {
    return CombineResult::ARGUMENTS_ERROR;
  }

  // combine docs
  // all docs should be in one definition
  if (other_type_definition.docs_.get_description().has_value() ||
      other_type_definition.docs_.get_annotations_info_size() > 0) {
    if (docs_.get_annotations_info_size() > 0 ||
        docs_.get_description().has_value()) {
      return CombineResult::MORE_THEN_ONE_DOCS_ERROR;
    }

    docs_ = std::move(other_type_definition.docs_);
  }

  if (!other_type_definition.arguments_.empty()) {
    arguments_ = std::move(other_type_definition.arguments_);
  }

  if (other_type_definition.type_.has_value()) {
    type_ = std::move(other_type_definition.type_);
  }

  return CombineResult::OK;
}

bool Statement::is_same_to(const Statement &other_statement) const {
  if (expression_.index() != other_statement.expression_.index()) {
    return false;
  }

  switch (expression_.index()) {
  case 0: // Import
    return false;
  case 1: // TypeDefinition
    return std::get<TypeDefinition>(expression_)
        .is_same_to(
            std::move(std::get<TypeDefinition>(other_statement.expression_)));
  case 2: // FunctionDefinition
    return std::get<FunctionDefinition>(expression_)
        .is_same_to(std::move(
            std::get<FunctionDefinition>(other_statement.expression_)));
  case 3: // EmptyLines
    return false;
  default:
    break;
  }

  error_handling::handle_general_error("Unreachable");
  exit(1);
}

CombineResult Statement::combine(Statement &&other_statement) {
  if (expression_.index() != other_statement.expression_.index()) {
    return CombineResult::DIFFERENT_STATEMENT_TYPES;
  }

  switch (expression_.index()) {
  case 0: // Import
    return CombineResult::STATEMENTS_CANT_BE_COMBINED_ERROR;
  case 1: // TypeDefinition
    return std::get<TypeDefinition>(expression_)
        .combine(
            std::move(std::get<TypeDefinition>(other_statement.expression_)));
  case 2: // FunctionDefinition
    return std::get<FunctionDefinition>(expression_)
        .combine(std::move(
            std::get<FunctionDefinition>(other_statement.expression_)));
  case 3: // EmptyLines
    return CombineResult::STATEMENTS_CANT_BE_COMBINED_ERROR;
  default:
    break;
  }

  error_handling::handle_general_error("Unreachable");
  exit(1);
}

} // namespace nodes