`%$%` <- function(f, x) f(x)
`%.%` <- function(f, g) function(...) f(g(...))
flip <- function(f) function(x, y) f(y, x)

clear_na <- function(xs) xs[!is.na(xs)]

check_directory <- function(path, create=F) {
    # check if download_dir exists
    if(file.access(path, mode=0) == -1) {
        if (create) {
            tryCatch(dir.create(path),
                     error = stop_dir_not_creatable,
                     warning = stop_dir_not_creatable)
        } else {
            stop("Directory does not exist. Use create = TRUE if you wish to create the directory.")
        }
    } else if (file.access(path, mode=2) == -1) {
        stop("Directory exists, but is not writeable.")
    }
}

stop_dir_not_creatable <- function(cond) {
    # currently this has call: dir.create(download_dir)
    # do we want to change this to fetch_all(...) ?
    cond$message <- "Directory does not exist and can't be created. Probably because the path is not writeable."
    stop(cond)
}

# appends a file seperator at end of path if needed
make_directory_path <- function(path) {
    if (!str_ends(path, .Platform$file.sep)) str_c(path, .Platform$file.sep)
    else path
}

# check if res is of expected format
is_valid_res <- function(res) {
    stopifnot("Data is missing relevant tables. Is this a return value of read_all or repair?"
              = all(c("speaker", "speeches", "talks", "comments", "applause") %in% names(res)))
    stopifnot("Some entries of res are no tibbles."
              = all(sapply(res, typeof) == "list" & "tbl" %in% sapply(res, class)))
    stopifnot("Speaker table is of wrong format."
              = all(c("id", "prename", "lastname", "fraction", "title", "role_short", "role_long")
                    %in% names(res$speaker)) &&
                all(sapply(res$speaker, is.character)))
    stopifnot("Speeches table is of wrong format."
              = all(c("id", "speaker", "date") %in% names(res$speeches)) &&
                is.character(res$speeches$id) &&
                is.character(res$speeches$speaker) &&
                lubridate::is.Date(res$speeches$date))
    stopifnot("Talks table is of wrong format."
              = all(c("speech_id", "speaker", "content") %in% names(res$talks)) &&
                all(sapply(res$talks, is.character)))
    stopifnot("Comments table is of wrong format."
              = all(c("speech_id", "on_speaker", "fraction", "commenter", "content")
                    %in% names(res$comments)) &&
                all(sapply(res$comments, is.character)))
    stopifnot("Applause table is of wrong format."
              = all(c("speech_id", "on_speaker", "CDU_CSU", "SPD", "FDP", "DIE_LINKE", "BUENDNIS_90_DIE_GRUENEN", "AfD")
                    %in% names(res$applause)) &&
                is.character(res$applause$speech_id) &&
                is.character(res$applause$on_speaker) &&
                is.logical(res$applause$`CDU_CSU`) &&
                is.logical(res$applause$`SPD`) &&
                is.logical(res$applause$`FDP`) &&
                is.logical(res$applause$`DIE_LINKE`) &&
                is.logical(res$applause$`AfD`) &&
                is.logical(res$applause$`BUENDNIS_90_DIE_GRUENEN`))
}