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#
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# The following S3 methods are registered on load if dplyr is present

distinct.arrow_dplyr_query <- function(.data, ..., .keep_all = FALSE) {
  if (.keep_all == TRUE) {
    # TODO(ARROW-14045): the function is called "hash_one" (from ARROW-13993)
    # May need to call it: `summarize(x = one(x), ...)` for x in non-group cols
    arrow_not_supported("`distinct()` with `.keep_all = TRUE`")
  }

  original_gv <- dplyr::group_vars(.data)
  if (length(quos(...))) {
    # group_by() calls mutate() if there are any expressions in ...
    .data <- dplyr::group_by(.data, ..., .add = TRUE)
    # `data %>% group_by() %>% summarise()` returns cols in order supplied
    # but distinct() returns cols in dataset order, so sort group vars
    .data$group_by_vars <- names(.data)[names(.data) %in% .data$group_by_vars]
  } else {
    # distinct() with no vars specified means distinct across all cols
    .data <- dplyr::group_by(.data, !!!syms(names(.data)))
  }

  out <- dplyr::summarize(.data, .groups = "drop")
  # distinct() doesn't modify group by vars, so restore the original ones
  if (length(original_gv)) {
    out$group_by_vars <- original_gv
  }
  out
}

distinct.Dataset <- distinct.ArrowTabular <- distinct.RecordBatchReader <- distinct.arrow_dplyr_query
