#include "ast_printer.hh"
#include "expr.hh"
#include <cassert>
#include <string>
#include <sstream>

std::string AstPrinter::print(const Expr &expr) {
  switch (expr.type) {
    case ExprType::BINARY: {
      std::shared_ptr<_Binary> ptr = std::get<std::shared_ptr<_Binary>>(expr.value);
      assert(ptr != nullptr);
      return parenthesize(ptr->op.lexeme, {&ptr->left, &ptr->right});
    }
    case ExprType::GROUPING: {
      std::shared_ptr<_Grouping> ptr = std::get<std::shared_ptr<_Grouping>>(expr.value);
      assert(ptr != nullptr);
      return parenthesize("group", {&ptr->expr});
    }
    case ExprType::LITERAL: {
      std::shared_ptr<_Literal> ptr = std::get<std::shared_ptr<_Literal>>(expr.value);
      assert(ptr != nullptr);
      return ptr->value.to_string();
    }
    case ExprType::UNARY: {
      std::shared_ptr<_Unary> ptr = std::get<std::shared_ptr<_Unary>>(expr.value);
      assert(ptr != nullptr);
      return parenthesize(ptr->op.lexeme, {&ptr->right});
    }
    case ExprType::VARIABLE: {
      std::shared_ptr<_Variable> ptr = std::get<std::shared_ptr<_Variable>>(expr.value);
      assert(ptr != nullptr);
      return ptr->name.lexeme;
    }
    case ExprType::ASSIGN: {
      std::shared_ptr<_Assign> ptr = std::get<std::shared_ptr<_Assign>>(expr.value);
      assert(ptr != nullptr);
      return ptr->name.lexeme;
    }
  }
}

std::string AstPrinter::parenthesize(const std::string &name, std::vector<const Expr *> exprs) {
  std::stringstream ss{};
  ss << '(' << name;
  for (const Expr *expr : exprs) {
    ss << ' ' << print(*expr);
  }
  ss << ')';

  return ss.str();
}