#include "BasicBlock.h"
#include "Constant.h"
#include "Function.h"
#include "IRStmtBuilder.h"
#include "Module.h"
#include "Type.h"

#include <iostream>
#include <memory>

#ifdef DEBUG  // 用于调试信息,大家可以在编译过程中通过" -DDEBUG"来开启这一选项
#define DEBUG_OUTPUT std::cout << __LINE__ << std::endl;  // 输出行号的简单示例
#else
#define DEBUG_OUTPUT
#endif

#define CONST_INT(num) \
    ConstantInt::create(num, module)

#define CONST_FP(num) \
    ConstantFloat::create(num, module) // 得到常数值的表示,方便后面多次用到

using namespace SysYF::IR;

int main() {
  auto module = Module::create("if_test.sy");  // module name是if_test
  auto builder = IRStmtBuilder::create(nullptr, module);
  SysYF::Ptr<Type> Int32Type = Type::get_int32_type(module);

  // 生成全局变量a, b
  auto zero_initializer = ConstantZero::create(Int32Type, module);
  auto a = GlobalVariable::create("a", module, Int32Type, false, zero_initializer);
  auto b = GlobalVariable::create("b", module, Int32Type, false, zero_initializer);

  // 生成main函数
  auto mainFun = Function::create(FunctionType::create(Int32Type, {}),
                                  "main", module);
  // 生成一个基本块并进入
  auto entry = BasicBlock::create(module, "entry", mainFun);
  builder->set_insert_point(entry);

  // 给b,a赋值0,3
  builder->create_store(CONST_INT(0), b);
  builder->create_store(CONST_INT(3), a);
  
  // 设置三个BasicBlock
  auto while_cond = BasicBlock::create(module, "while_cond", mainFun);
  auto while_body = BasicBlock::create(module, "while_body", mainFun);
  auto while_end = BasicBlock::create(module, "while_end", mainFun);

  // 跳转while_cond
  builder->create_br(while_cond);

  // while_cond
  builder->set_insert_point(while_cond);
  // 把a加载到寄存器
  auto aReg = builder->create_load(a);
  // 创造一个比较语句，就是说a>0
  auto icmp = builder->create_icmp_gt(aReg, CONST_INT(0));  // n和4的比较  
  // 创建一个分支br
  builder->create_cond_br(icmp, while_body, while_end);
  
  // while_body
  builder->set_insert_point(while_body);
  // b = b + 1
  auto aReg2 = builder->create_load(a);
  auto bReg2 = builder->create_load(b);
  auto abReg = builder->create_iadd(aReg2, bReg2);
  builder->create_store(abReg, b);
  // a = a - 1，此时可以优化编译流程，不重新加载a
  auto aReg3 = builder->create_isub(aReg2, CONST_INT(1));
  builder->create_store(aReg3, a);
  // 跳转
  builder->create_br(while_cond);
  
  // while_body
  builder->set_insert_point(while_end);
  // 构建假的返回
  auto bReg3 = builder->create_load(b);
  builder->create_ret(bReg3);  
  
  std::cout << module->print();
  return 0;
}