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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.


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

arrange.arrow_dplyr_query <- function(.data, ..., .by_group = FALSE) {
  try_arrow_dplyr({
    .data <- as_adq(.data)
    exprs <- expand_across(.data, quos(...))

    if (.by_group) {
      # when the data is grouped and .by_group is TRUE, order the result by
      # the grouping columns first
      exprs <- c(quos(!!!dplyr::groups(.data)), exprs)
    }
    if (length(exprs) == 0) {
      # Nothing to do
      return(.data)
    }
    .data <- as_adq(.data)
    # find and remove any dplyr::desc() and tidy-eval
    # the arrange expressions inside an Arrow data_mask
    sorts <- vector("list", length(exprs))
    descs <- logical(0)
    mask <- arrow_mask(.data)
    for (i in seq_along(exprs)) {
      x <- find_and_remove_desc(exprs[[i]])
      exprs[[i]] <- x[["quos"]]
      sorts[[i]] <- arrow_eval(exprs[[i]], mask)
      names(sorts)[i] <- format_expr(exprs[[i]])
      if (length(mask$.aggregations)) {
        # dplyr lets you arrange on e.g. x < mean(x), but we haven't implemented it.
        # But we could, the same way it works in mutate() via join, if someone asks.
        # Until then, just error.
        # TODO: add a test for this
        arrow_not_supported(
          .actual_msg = "Expression not supported in arrange() in Arrow",
          call = expr
        )
      }
      descs[i] <- x[["desc"]]
    }
    .data$arrange_vars <- c(sorts, .data$arrange_vars)
    .data$arrange_desc <- c(descs, .data$arrange_desc)
    .data
  })
}
arrange.Dataset <- arrange.ArrowTabular <- arrange.RecordBatchReader <- arrange.arrow_dplyr_query

# Helper to handle desc() in arrange()
# * Takes a quosure as input
# * Returns a list with two elements:
#   1. The quosure with any wrapping parentheses and desc() removed
#   2. A logical value indicating whether desc() was found
# * Performs some other validation
find_and_remove_desc <- function(quosure) {
  expr <- quo_get_expr(quosure)
  descending <- FALSE
  if (length(all.vars(expr)) < 1L) {
    validation_error(
      "Expression in arrange() does not contain any field names",
      call = quosure
    )
  }
  # Use a while loop to remove any number of nested pairs of enclosing
  # parentheses and any number of nested desc() calls. In the case of multiple
  # nested desc() calls, each one toggles the sort order.
  while (identical(typeof(expr), "language") && is.call(expr)) {
    if (identical(expr[[1]], quote(`(`))) {
      # remove enclosing parentheses
      expr <- expr[[2]]
    } else if (identical(expr[[1]], quote(desc)) || identical(expr[[1]], quote(dplyr::desc))) {
      # ensure desc() has only one argument (when an R expression is a function
      # call, length == 2 means it has exactly one argument)
      if (length(expr) > 2) {
        validation_error(
          "desc() expects only one argument",
          call = expr
        )
      }
      # remove desc() and toggle descending
      expr <- expr[[2]]
      descending <- !descending
    } else {
      break
    }
  }
  return(
    list(
      quos = quo_set_expr(quosure, expr),
      desc = descending
    )
  )
}
