# Copyright (c) 2019 - 2022, Adrian Dusa
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, in whole or in part, are permitted provided that the
# following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * The names of its contributors may NOT be used to endorse or promote products
#       derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL ADRIAN DUSA BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

`possibleNumeric` <- function(x, each = FALSE) {
    result <- rep(NA, length(x))
    isna <- is.na(x)
    if (all(isna)) {
        if (each) {
            return(result)
        }
        return(FALSE)
    }
    if (is.logical(x)) {
        if (each) {
            result <- logical(length(x))
            result[isna] <- NA
            return(result)
        }
        return(FALSE)
    }
    if (inherits(x, "haven_labelled") || inherits(x, "declared")) {
        num <- Recall(unclass(x), each = each)
        labels <- attr(x, "labels", exact = TRUE)
        if (!is.null(labels) && !each && num) {
            return(Recall(labels))
        }
        return(num)
    }
    if (is.numeric(x)) {
        if (each) {
            result[!isna] <- TRUE
            return(result)
        }
        return(TRUE)
    }
    if (is.factor(x)) {
        x <- as.character(x)
    }
    irv <- c(194, 160)
    multibyte_space <- rawToChar(as.raw(irv))
    x <- gsub(multibyte_space, " ", x)
    multibyte <- grepl("[^!-~ ]", x)
    if (any(multibyte)) {
        isna[multibyte] <- TRUE
        result[multibyte] <- FALSE
        x[multibyte] <- NA
    }
    if (each) {
        x <- suppressWarnings(as.numeric(na.omit(x)))
        result[!isna] <- !is.na(x)
        return(result)
    }
    return(!any(is.na(suppressWarnings(as.numeric(na.omit(x))))))
}
