# 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.

`recreate` <- function(x, snames = NULL) {
    if (is.null(x) | is.logical(x) | is.character(x)) return(x)
    withinobj <- function(x) {
        x <- gsub("\"|[[:space:]]", "", x)
        for (i in seq(length(x))) {
            if (!grepl("<=|<-|->|=>", x[i])) {
                x[i] <- gsub(">", "->", gsub("<", "<-", x[i]))
            }
            arrows <- c("<=", "<-", "=>", "->")
            for (j in seq(length(arrows))) {
                xs <- unlist(strsplit(x, split = arrows[j]))
                if (length(xs) == 2) {
                    if (all(grepl("\\*|\\+", xs))) {
                        stopError("The outcome should be a single condition.")
                    }
                    if (j < 3) { 
                        if (grepl("\\*|\\+", xs[2])) {
                            x[i] <- paste(xs[2], arrows[j + 2], xs[1], sep = "")
                            break
                        }
                    }
                    else { 
                        if (grepl("\\*|\\+", xs[1])) {
                            x[i] <- paste(xs[2], arrows[j - 2], xs[1], sep = "")
                            break
                        }
                    }
                }
            }
        }
        return(x)
    }
    typev <- typel <- FALSE
    callx <- identical(class(x), "call")
    dx <- deparse(x)
    if (callx) {
        typev <- is.name(x[[1]]) & identical(as.character(x[[1]]), "c")
        typel <- is.name(x[[1]]) & identical(as.character(x[[1]]), "list")
    }
    if (callx & (typev | typel)) {
        result <- dxlist <- vector(mode = "list", length = max(1, length(x) - 1))
        if (length(x) == 1) {
            if (typev) return(NULL)
            if (typel) return(list())
        }
        if (typev) {
            if (length(snames) > 0) { 
                dx <- as.character(x)[-1]
                if (all(is.element(dx, snames))) {
                    return(dx)
                }
            }
        }
        for (i in seq(length(result))) {
            dxlist[[i]] <- dx <- deparse(x[[i + 1]])
            result[[i]] <- tryCatch(eval(x[[i + 1]], envir = parent.frame(n = 2)), error = function(e) {
                withinobj(dx)
            })
            if (length(snames) > 0) {
                if (all(is.element(dx, snames))) {
                    result[[i]] <- dx
                }
            }
        }
        classes <- unlist(lapply(result, class))
        if (length(unique(classes)) > 1) {
            for (i in seq(length(result))) {
                if (identical(classes[i], "formula") | (identical(classes[i], "function") & typev)) {
                    result[[i]] <- withinobj(dxlist[[i]])
                }
                if (identical(classes[i], "logical") & typev & nchar(dxlist[[i]] == 1)) {
                    result[[i]] <- withinobj(dxlist[[i]])
                }
                if (identical(classes[i], "list")) {
                    if (is.element("function", unlist(lapply(result[[i]], class)))) {
                        result[[i]] <- dxlist[[i]]
                    } 
                }
            }
        }
        if (typev) {
            return(unlist(result))
        }
        else if (typel) {
            names(result) <- names(x[-1])
            return(result)
        }
    }
    if (length(snames) > 0 & all(!grepl("[[:punct:]]", notilde(dx)))) {
        if (all(is.element(notilde(dx), snames))) {
            return(dx)
        }
    }
    if (identical(class(x), "<-")) {
        return(withinobj(dx))
    }
    x <- tryCatch(eval(x, envir = parent.frame(n = 2)), error = function(e) withinobj(dx))
    if (identical(class(x), "formula")) {
        return(withinobj(dx))
    }
    return(x)
}
