#pragma once
#include "common.h"
#include "llir.h"

using std::make_shared;

namespace codegen {

// a?, t?, ra are caller-saved
// s? are callee-saved
// x0,gp,tp are preserved in user-space
enum class RV64Reg {
  x0 = 0, // zero
  ra,     // ra, caller
  sp,     // sp, callee
  gp,     // gp
  tp,     // tp
  t0,     // t0, caller
  t1,
  t2, // t1-2, caller
  s0, // s0/fp, callee
  s1, // s1, callee
  a0,
  a1, // a0-1,caller
  a2,
  a3,
  a4,
  a5,
  a6,
  a7, // a2-7,caller
  s2,
  s3,
  s4,
  s5,
  s6,
  s7,
  s8,
  s9,
  s10,
  s11, // s2-11,callee
  t3,
  t4,
  t5,
  t6, // t3-6,caller
};

// riscv calling convention see: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc

const int XLEN = 8;

inline std::string RV64_RegName(RV64Reg reg) {
  std::string regname = "x" + std::to_string((int)reg);
  return regname;
}

inline RV64Reg RV64_RegOffset(RV64Reg reg, int offset) {
  auto xi = (int)reg + offset;
  return (RV64Reg)xi;
}

class MOperand;
class MInst;
class MBasicBlock;
class MFunction;

class MOperand {
public:
  enum class OpTag {
    Virt,
    Imm,
    Reg,
  } op_type = OpTag::Virt;
  int value = ~0;

private:
  MOperand(OpTag tag, int val) : op_type(tag), value(val) {}

public:
  static sptr(MOperand) NewVirtReg(int reg_no) {
    auto mop = std::make_shared<MOperand>(OpTag::Virt, reg_no);
    return mop;
  }

  static sptr(MOperand) NewImm(int imm_val) {
    auto mop = std::make_shared<MOperand>(OpTag::Imm, imm_val);
    return mop;
  }

  static sptr(MOperand) NewReg(RV64Reg phy_reg) {
    auto mop = std::make_shared<MOperand>(OpTag::Reg, (int)phy_reg);
    return mop;
  }
};

class MInst {
public:
  enum class MInstTag {
    Add,
    Sub,
    Rsb,
    Mul,
    Div,
    Mod,
    Lt,
    Le,
    Ge,
    Gt,
    Eq,
    Ne,
    And,
    Or,
    Move, // actually a pseudo, mv = addi rt, rs, 0
    Branch,
    Jump,
    Return,
    Load,
    Store,
    Compare,
    Call,
    Global,
  } tag;

  sptr(MBasicBlock) parent_bb;
  MInst(MInstTag tag, sptr(MBasicBlock) parent_bb) : tag(tag), parent_bb(parent_bb) {}
};

class MBasicBlock {
public:
  sptr(antlrSysY::BasicBlock) ir_bb;
  sptr(MFunction) parent_func;
  std::list<sptr(MInst)> inst_list;
  std::list<sptr(MBasicBlock)> pred_list;
  std::list<sptr(MBasicBlock)> succ_list;

  std::unordered_set<sptr(MOperand)> livein;
  std::unordered_set<sptr(MOperand)> liveout;
};

class MFunction {
public:
  std::list<sptr(MBasicBlock)> bb_list;
  sptr(antlrSysY::Function) ir_func;

  std::list<sptr(MInst)> stack_arg_reloc;

  unsigned virt_reg_cnt = 0;
};

class MGlobalVar {
public:
};

class MCModule {
public:
  std::list<sptr(MFunction)> function_list;
  std::list<sptr(MGlobalVar)> global_list;
  void IR2MC(const antlrSysY::Module &ir_module);
};

class MInstBinary : public MInst {
public:
};

class MInstJump : public MInst {
public:
  sptr(MBasicBlock) target;
  MInstJump(sptr(MBasicBlock) parent_bb) : MInst(MInstTag::Jump, parent_bb) {}

  static sptr(MInstJump) New(sptr(MBasicBlock) parent_bb) {
    auto inst = make_shared<MInstJump>(parent_bb);
    parent_bb->inst_list.push_back(inst);
    return inst;
  }
};

class MInstLoad : public MInst {
public:
  sptr(MOperand) dst;
  sptr(MOperand) addr;
  sptr(MOperand) offset;
  MInstLoad(sptr(MBasicBlock) parent_bb) : MInst(MInstTag::Load, parent_bb) {}

  static sptr(MInstLoad) New(sptr(MBasicBlock) parent_bb) {
    auto inst = make_shared<MInstLoad>(parent_bb);
    parent_bb->inst_list.push_back(inst);
    return inst;
  }
};

class MInstMove : public MInst {
public:
  sptr(MOperand) dst;
  sptr(MOperand) src;
  MInstMove(sptr(MBasicBlock) parent_bb) : MInst(MInstTag::Move, parent_bb) {}
  static sptr(MInstMove) New(sptr(MBasicBlock) parent_bb, bool insert_begin = false) {
    auto inst = make_shared<MInstMove>(parent_bb);
    if (insert_begin)
      parent_bb->inst_list.push_front(inst);
    else
      parent_bb->inst_list.push_back(inst);
    return inst;
  }
  static sptr(MInstMove) New(sptr(MInst) rel_inst, bool insert_after = false) {
    auto parent_bb = rel_inst->parent_bb;
    auto inst = make_shared<MInstMove>(parent_bb);
    auto rel_inst_itr = FIND(parent_bb->inst_list, rel_inst);
    assert(rel_inst_itr != parent_bb->inst_list.end());
    if (insert_after)
      std::advance(rel_inst_itr, 1);
    parent_bb->inst_list.insert(rel_inst_itr, inst);
    return inst;
  }
};

} // namespace codegen