// Copyright 2021 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include "Core/CheatGeneration.h"

#include <vector>

#include <fmt/format.h>

#include "Common/Align.h"
#include "Common/CommonTypes.h"
#include "Common/Result.h"
#include "Common/Swap.h"

#include "Core/ActionReplay.h"
#include "Core/CheatSearch.h"

constexpr int AR_SET_BYTE_CMD = 0x00;
constexpr int AR_SET_SHORT_CMD = 0x02;
constexpr int AR_SET_INT_CMD = 0x04;

static std::vector<ActionReplay::AREntry> ResultToAREntries(u32 addr, const Cheats::SearchValue& sv)
{
  std::vector<ActionReplay::AREntry> codes;
  std::vector<u8> data = Cheats::GetValueAsByteVector(sv);

  for (size_t i = 0; i < data.size(); ++i)
  {
    const u32 address = (addr + i) & 0x01ff'ffffu;
    if (Common::AlignUp(address, 4) == address && i + 3 < data.size())
    {
      const u8 cmd = AR_SET_INT_CMD;
      const u32 val = Common::swap32(&data[i]);
      codes.emplace_back((cmd << 24) | address, val);
      i += 3;
    }
    else if (Common::AlignUp(address, 2) == address && i + 1 < data.size())
    {
      const u8 cmd = AR_SET_SHORT_CMD;
      const u32 val = Common::swap16(&data[i]);
      codes.emplace_back((cmd << 24) | address, val);
      ++i;
    }
    else
    {
      const u8 cmd = AR_SET_BYTE_CMD;
      const u32 val = data[i];
      codes.emplace_back((cmd << 24) | address, val);
    }
  }

  return codes;
}

Common::Result<Cheats::GenerateActionReplayCodeErrorCode, ActionReplay::ARCode>
Cheats::GenerateActionReplayCode(const Cheats::CheatSearchSessionBase& session, size_t index)
{
  if (index >= session.GetResultCount())
    return Cheats::GenerateActionReplayCodeErrorCode::IndexOutOfRange;

  if (session.GetResultValueState(index) != Cheats::SearchResultValueState::ValueFromVirtualMemory)
    return Cheats::GenerateActionReplayCodeErrorCode::NotVirtualMemory;

  u32 address = session.GetResultAddress(index);

  // check if the address is actually addressable by the ActionReplay system
  if (((address & 0x01ff'ffffu) | 0x8000'0000u) != address)
    return Cheats::GenerateActionReplayCodeErrorCode::InvalidAddress;

  ActionReplay::ARCode ar_code;
  ar_code.enabled = true;
  ar_code.user_defined = true;
  ar_code.name = fmt::format("Generated by Cheat Search (Address 0x{:08x})", address);
  ar_code.ops = ResultToAREntries(address, session.GetResultValueAsSearchValue(index));

  return ar_code;
}