# frozen_string_literal: true

require 'ffi'
require_relative 'time_spec'

module FFI
  class Stat
    # @!visibility private
    class Native < Struct
      case Platform::NAME

      when 'x86_64-linux'
        layout :st_dev,     :dev_t,
               :st_ino,     :ino_t,
               :st_nlink,   :nlink_t,
               :st_mode,    :mode_t,
               :st_uid,     :uid_t,
               :st_gid,     :gid_t,
               :__pad0,     :uint,
               :st_rdev,    :dev_t,
               :st_size,    :off_t,
               :st_blksize, :blksize_t,
               :st_blocks,  :blkcnt_t,
               :st_atimespec, TimeSpec,
               :st_mtimespec, TimeSpec,
               :st_ctimespec, TimeSpec,
               :unused, [:long, 3]

        [['', :string], ['l', :string], ['f', :int]].each do |(prefix, ftype)|
          native_func = :"native_#{prefix}stat"
          lib_func = :"#{prefix}stat"
          begin
            ::FFI::Stat.attach_function native_func, lib_func, [ftype, by_ref], :int
          rescue FFI::NotFoundError
            # gLibc 2.31 (Ubuntu focal) does not export these functions, it maps them to __xstat variants
            native_xfunc = :"native_#{prefix}xstat"
            lib_xfunc = :"__#{prefix}xstat"
            ::FFI::Stat.attach_function native_xfunc, lib_xfunc, [:int, ftype, by_ref], :int
            # 1 is 64 bit versions of struct stat,  3 is 32 bit
            ::FFI::Stat.define_singleton_method(native_func) { |file, buf| send(native_xfunc, 1, file, buf) }
          end
        end

      when 'x86_64-darwin', 'aarch64-darwin'
        #  man stat - this is stat with 64 bit inodes.
        layout :st_dev,       :dev_t,
               :st_mode,      :mode_t,
               :st_nlink,     :nlink_t,
               :st_ino,       :ino_t,
               :st_uid,       :uid_t,
               :st_gid,       :gid_t,
               :st_rdev,      :dev_t,
               :st_atimespec, TimeSpec,
               :st_mtimespec, TimeSpec,
               :st_ctimespec, TimeSpec,
               :st_birthtimespec, TimeSpec,
               :st_size,      :off_t,
               :st_blocks,    :blkcnt_t,
               :st_blksize,   :blksize_t,
               :st_flags,     :uint32,
               :st_gen,       :uint32,
               :st_lspare,     :int32,
               :st_gspare,     :int64

        begin
          # TODO: these functions are deprecated, but at least on Cataline -> Monterey the old stat functions
          #       use the stat struct *without* 64 bit inodes, but macfuse is compiled with 64 bit inodes
          ::FFI::Stat.attach_function :native_stat, :stat64, [:string, by_ref], :int
          ::FFI::Stat.attach_function :native_lstat, :lstat64, [:string, by_ref], :int
          ::FFI::Stat.attach_function :native_fstat, :fstat64, [:int, by_ref], :int
        rescue FFI::NotFoundError
          # these are only used in testing
        end

      else
        raise NotImplementedError, "FFI::Stat not implemented for FFI::Platform #{Platform::NAME}"
      end
    end
  end
end