#include "irgen/IRGen.h"

#include <stdexcept>

#include "SysYParser.h"
#include "ir/IR.h"
#include "utils/Log.h"

ir::Value* IRGenImpl::GenExpr(SysYParser::ExpContext& expr) {
  if (auto* paren = dynamic_cast<SysYParser::ParenExpContext*>(&expr)) {
    return GenExpr(*paren->exp());
  }
  if (auto* number = dynamic_cast<SysYParser::NumberExpContext*>(&expr)) {
    if (!number->number() || !number->number()->ILITERAL()) {
      throw std::runtime_error(FormatError("irgen", "当前仅支持整数字面量"));
    }
    return builder_.CreateConstInt(std::stoi(number->number()->getText()));
  }
  if (auto* var = dynamic_cast<SysYParser::VarExpContext*>(&expr)) {
    if (!var->var() || !var->var()->ID()) {
      throw std::runtime_error(FormatError("irgen", "当前仅支持普通整型变量"));
    }
    auto* decl = sema_.ResolveVarUse(var->var());
    if (!decl) {
      throw std::runtime_error(
          FormatError("irgen",
                      "变量使用缺少语义绑定: " + var->var()->ID()->getText()));
    }
    auto it = storage_map_.find(decl);
    if (it == storage_map_.end()) {
      throw std::runtime_error(
          FormatError("irgen",
                      "变量声明缺少存储槽位: " + var->var()->ID()->getText()));
    }
    return builder_.CreateLoad(it->second, module_.GetContext().NextTemp());
  }
  if (auto* binary = dynamic_cast<SysYParser::AdditiveExpContext*>(&expr)) {
    ir::Value* lhs = GenExpr(*binary->exp(0));
    ir::Value* rhs = GenExpr(*binary->exp(1));
    return builder_.CreateBinary(ir::Opcode::Add, lhs, rhs,
                                 module_.GetContext().NextTemp());
  }
  throw std::runtime_error(FormatError("irgen", "暂不支持的表达式形式"));
}