#include "StaticPass.hpp"
#include "lib/Node.hpp"
#include "TypeResolver.hpp"

namespace roza
{
  /*explicit*/ StaticPass::StaticPass(StatusLog& log)
    : StaticPass (log, SymTable {})
  {
  }

  /*explicit*/ StaticPass::StaticPass(StatusLog& log, SymTable const& sym_table)
    : m_log { log }
    , m_sym { SymTable(sym_table) }
  {
  }

  /*virtual*/ StaticPass::~StaticPass()
  {
  }

  void StaticPass::check(std::shared_ptr<Node> root)
  {
    TypeResolver resolver {m_log};
    assert(root);

    switch (root->type())
      {
      case NODE_CONSTDECL: {
        check(root->child(1));
        m_sym.declare(root->child(0)->repr(), root->child(1));
      } break;

      case NODE_VARDECL: {
        check(root->child(1));
        m_sym.declare_mut(root->child(0)->repr(), root->child(1));
      } break;

      case NODE_ASSIGN: {
        auto const& entry = m_sym.find(root->child(0)->repr());

        if (!entry.is_mut)
          {
            m_log.fatal(root->child(0)->loc(),
                        root->child(0)->repr() + " is not mutable");
          }

        auto lhs = resolver.find(entry.node, m_sym);
        auto rhs = resolver.find(root->child(1), m_sym);
        check_types(root, lhs, rhs);
      } break;

      case NODE_IDENT:
      case NODE_ASSERT_STATIC_FAIL:
      case NODE_INT:
      case NODE_BOOL:
        break;

      case NODE_EQ:
      case NODE_NE: {
        check_children(root);
        auto lhs = resolver.find(root->child(0), m_sym);
        auto rhs = resolver.find(root->child(1), m_sym);
        check_types(root, lhs, rhs);
      } break;

      case NODE_IMP:
      case NODE_OR:
      case NODE_AND: {
        check_children(root);
        auto lhs = resolver.find(root->child(0), m_sym);
        auto rhs = resolver.find(root->child(1), m_sym);
        check_types(root, lhs, std::make_shared<Type>(TY_BOOL));
        check_types(root, lhs, rhs);
      } break;

      case NODE_ASSERT:
      case NODE_NOT: {
        check_children(root);
        auto lhs = resolver.find(root->child(0), m_sym);
        check_types(root, lhs, std::make_shared<Type>(TY_BOOL));
      } break;

      case NODE_LT:
      case NODE_LE:
      case NODE_GT:
      case NODE_GE:
      case NODE_ADD:
      case NODE_SUB:
      case NODE_MUL:
      case NODE_DIV:
      case NODE_MOD:
      case NODE_POW: {
        check_children(root);
        auto lhs = resolver.find(root->child(0), m_sym);
        auto rhs = resolver.find(root->child(1), m_sym);

        check_types(root, lhs, std::make_shared<Type>(TY_INT));
        check_types(root, lhs, rhs);
      } break;

      case NODE_UADD:
      case NODE_USUB: {
        check_children(root);
        auto lhs = resolver.find(root->child(0), m_sym);
        check_types(root, lhs, std::make_shared<Type>(TY_INT));
      } break;

      case NODE_PROG: {
        check_children(root);
      } break;

      default:
        m_log.fatal(root->loc(), "cannot check node '" + root->string() + "'");
      }
  }

  void StaticPass::check_children(std::shared_ptr<Node> root)
  {
    for (size_t i=0; i<root->size(); i++)
      {
        check(root->child(i));
      }
  }

  void StaticPass::check_types(std::shared_ptr<Node> root,
                               std::shared_ptr<Type> lhs,
                               std::shared_ptr<Type> rhs)
  {
    assert(lhs);
    assert(rhs);

    if (!lhs->equals(*rhs))
      {
        m_log.fatal(root->loc(),
                    std::string()
                    + "type mismatch, expected '"
                    + lhs->string()
                    + "', got '"
                    + rhs->string()
                    + "'");
      }
  }

  void StaticPass::check_types(std::shared_ptr<Node> root,
                               std::shared_ptr<Type> lhs,
                               std::vector<std::shared_ptr<Type>> const& rhs)
  {
    for (auto const& ty: rhs)
      {
        if (lhs->equals(*ty))
          {
            return;
          }
      }

    std::stringstream ss;

    ss << "type mismatch, got '" << lhs->string() << "'";
    ss << "candidates are:" << std::endl;

    for (auto ty: rhs)
      {
        ss << "\t-> " << ty->string() << std::endl;
      }

    m_log.fatal(root->loc(), ss.str());
  }

}