// SPDX-License-Identifier: MIT
/*
$info$
tags: LinuxSyscalls|common
$end_info$
*/

#pragma once
#include <FEXCore/Config/Config.h>
#include <FEXCore/fextl/map.h>
#include <FEXCore/fextl/string.h>
#include <FEXCore/fextl/unordered_set.h>

#include <cstdint>
#include <fcntl.h>
#include <functional>
#include <mutex>
#include <linux/limits.h>
#include <optional>
#include <stddef.h>
#include <sys/stat.h>
#include <unistd.h>

#include "LinuxSyscalls/EmulatedFiles/EmulatedFiles.h"

namespace FEXCore::Context {
class Context;
}

namespace FEX::HLE {
[[maybe_unused]]
static bool IsSymlink(int FD, const char *Filename) {
  // Checks to see if a filepath is a symlink.
  struct stat Buffer{};
  int Result = fstatat(FD, Filename, &Buffer, AT_SYMLINK_NOFOLLOW);
  return Result == 0 && S_ISLNK(Buffer.st_mode);
}

[[maybe_unused]]
static ssize_t GetSymlink(int FD, const char *Filename, char *ResultBuffer, size_t ResultBufferSize) {
  return readlinkat(FD, Filename, ResultBuffer, ResultBufferSize);
}

struct open_how;

class FileManager final {
public:
  FileManager() = delete;
  FileManager(FileManager &&) = delete;

  FileManager(FEXCore::Context::Context *ctx);
  ~FileManager();
  uint64_t Open(const char *pathname, int flags, uint32_t mode);
  uint64_t Close(int fd);
  uint64_t CloseRange(unsigned int first, unsigned int last, unsigned int flags);
  uint64_t Stat(const char *pathname, void *buf);
  uint64_t Lstat(const char *path, void *buf);
  uint64_t Access(const char *pathname, int mode);
  uint64_t FAccessat(int dirfd, const char *pathname, int mode);
  uint64_t FAccessat2(int dirfd, const char *pathname, int mode, int flags);
  uint64_t Readlink(const char *pathname, char *buf, size_t bufsiz);
  uint64_t Chmod(const char *pathname, mode_t mode);
  uint64_t Readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz);
  uint64_t Openat(int dirfs, const char *pathname, int flags, uint32_t mode);
  uint64_t Openat2(int dirfs, const char *pathname, FEX::HLE::open_how *how, size_t usize);
  uint64_t Statx(int dirfd, const char *pathname, int flags, uint32_t mask, struct statx *statxbuf);
  uint64_t Mknod(const char *pathname, mode_t mode, dev_t dev);
  uint64_t NewFSStatAt(int dirfd, const char *pathname, struct stat *buf, int flag);
  uint64_t NewFSStatAt64(int dirfd, const char *pathname, struct stat64 *buf, int flag);
  uint64_t Setxattr(const char *path, const char *name, const void *value, size_t size, int flags);
  uint64_t LSetxattr(const char *path, const char *name, const void *value, size_t size, int flags);
  uint64_t Getxattr(const char *path, const char *name, void *value, size_t size);
  uint64_t LGetxattr(const char *path, const char *name, void *value, size_t size);
  uint64_t Listxattr(const char *path, char *list, size_t size);
  uint64_t LListxattr(const char *path, char *list, size_t size);
  uint64_t Removexattr(const char *path, const char *name);
  uint64_t LRemovexattr(const char *path, const char *name);
  // vfs
  uint64_t Statfs(const char *path, void *buf);

  std::optional<std::string_view> GetSelf(const char *Pathname);

  void UpdatePID(uint32_t PID) { CurrentPID = PID; }

  fextl::string GetEmulatedPath(const char *pathname, bool FollowSymlink = false);
  using FDPathTmpData = std::array<char[PATH_MAX], 2>;
  std::pair<int, const char*> GetEmulatedFDPath(int dirfd, const char *pathname, bool FollowSymlink, FDPathTmpData &TmpFilename);

  bool SupportsProcFSInterpreterPath() const { return SupportsProcFSInterpreter; }

private:
  bool RootFSPathExists(const char* Filepath);

  struct ThunkDBObject {
    fextl::string LibraryName;
    fextl::unordered_set<fextl::string> Depends;
    fextl::vector<fextl::string> Overlays;
    bool Enabled{};
  };
  void LoadThunkDatabase(fextl::unordered_map<fextl::string, ThunkDBObject>& ThunkDB, bool Global);
  FEX::EmulatedFile::EmulatedFDManager EmuFD;

  fextl::map<fextl::string, fextl::string, std::less<>> ThunkOverlays;

  FEX_CONFIG_OPT(Filename, APP_FILENAME);
  FEX_CONFIG_OPT(LDPath, ROOTFS);
  FEX_CONFIG_OPT(ThunkGuestLibs, THUNKGUESTLIBS);
  FEX_CONFIG_OPT(ThunkGuestLibs32, THUNKGUESTLIBS32);
  FEX_CONFIG_OPT(ThunkConfig, THUNKCONFIG);
  FEX_CONFIG_OPT(AppConfigName, APP_CONFIG_NAME);
  FEX_CONFIG_OPT(Is64BitMode, IS64BIT_MODE);
  uint32_t CurrentPID{};
  int RootFSFD{AT_FDCWD};
  bool SupportsProcFSInterpreter{};
};
}