egit

#pragma once

#include <tuple>
#include <string>
#include <memory>
#include <type_traits>
#include <erl_nif.h>
#include "egit_atoms.hpp"

/*
#define SMART_PTR(var, deleter) \
  std::unique_ptr<std::remove_pointer<decltype(var)>::type, void(*)(decltype(var))> p ## var(var, deleter)
*/

template <typename T>
struct SmartPtr {
  using type = T;
  typedef void(*Deleter)(T*);

  explicit SmartPtr(Deleter del, T* p = nullptr) : m_ptr(p), m_del(del) {
    assert(m_del);
  }

  ~SmartPtr() {
    if (m_ptr) { m_del(m_ptr); m_ptr = nullptr; }
  }

  T**      operator&()        { return &m_ptr; }
  T const* operator->() const { return m_ptr;  }
  //T*       operator->()       { return m_ptr; }

  bool     operator!()  const { return m_ptr == nullptr; }

  // Cast operator
  operator const T*()   const { return (const T*)m_ptr;  }
  operator T*()         const { return m_ptr;            }
  operator bool()       const { return m_ptr != nullptr; }

  T const* get()        const { return m_ptr; }
  T*       get()              { return m_ptr; }

  template <typename U>
  U cast() { return reinterpret_cast<U>(m_ptr); }
private:
  T*      m_ptr;
  Deleter m_del;
};

template <typename T>
struct ScopeCleanup {
  ScopeCleanup(T fun) : m_fun(fun) {}
  ~ScopeCleanup() { m_fun(); }
private:
  T m_fun;
};

inline std::string oid_to_str(git_oid const& oid)
{
  auto out = std::string(GIT_OID_SHA1_HEXSIZE, '\0');
  git_oid_tostr(out.data(), out.size()+1, &oid);
  return out;
}

inline std::string oid_to_str(git_oid const* oid) { return oid_to_str(*oid); }

inline std::tuple<ERL_NIF_TERM, unsigned char*>
make_binary(ErlNifEnv* env, size_t size)
{
  ERL_NIF_TERM term;
  auto   p = enif_make_new_binary(env, size, &term);
  return std::make_tuple(term, p);
}

inline ERL_NIF_TERM make_binary(ErlNifEnv* env, std::string_view const& str)
{
  auto [term, p] = make_binary(env, str.length());
  memcpy(p, str.data(), str.length());
  return term;
}

inline ERL_NIF_TERM fmt_git_error(ErlNifEnv* env, std::string const& pfx)
{
  char        buf[256];
  const char* delim = "";
  const char* err   = "";

  if (git_error_last())
    err = git_error_last()->message;

  if (git_error_last() && !pfx.empty())
    delim = ": ";

  snprintf(buf, sizeof(buf), "%s%s%s", pfx.c_str(), delim, err);
  return make_binary(env, buf);
}

inline ERL_NIF_TERM raise_git_error(ErlNifEnv* env, std::string const& pfx)
{
  return enif_raise_exception(env, fmt_git_error(env, pfx));
}

inline ERL_NIF_TERM make_git_error(ErlNifEnv* env, std::string const& pfx)
{
  return enif_make_tuple2(env, ATOM_ERROR, fmt_git_error(env, pfx));
}

inline ERL_NIF_TERM make_error(ErlNifEnv* env, std::string_view const& err)
{
  return enif_make_tuple2(env, ATOM_ERROR, make_binary(env, err));
}

inline ERL_NIF_TERM make_error(ErlNifEnv* env, ERL_NIF_TERM err)
{
  return enif_make_tuple2(env, ATOM_ERROR, err);
}