#include "pattern.hpp"
#include "error.hpp"
#include "type_checker.hpp"
#include "type_manager.hpp"

namespace lily {
    type* pattern_var::check_modifying(type_manager& mgr, std::shared_ptr<type_env> env) {
        type* parameter = mgr.create_type<type_parameter>();
        env->set_type(name, parameter);
        return parameter;
    }

    type* pattern_cons::check_modifying(type_manager& mgr, std::shared_ptr<type_env> env) {
        type* constructor_type = env->get_identifier_type(name);
        int arity = constructor_type->arity();
        if(arity != vnames.size())
            throw error("invalid number of arguments to constructor");

        if(arity == 0) {
            return constructor_type;
        } else {
            type_func* func_type;
            type* current = constructor_type;
            int index = 0;
            while((func_type = dynamic_cast<type_func*>(current))) {
                env->set_type(vnames[index++], func_type->left);
                current = func_type->right;
            }
            return current;
        }
    }
}