R/HelpFunctions.R

In Boodogs/zoon-clone: Reproducible, Accessible & Shareable Species Distribution Modelling

#'ModuleHelp
#'
#'Returns the help file for a zoon module.
#'
#'@param module The name of a zoon module
#'
#'@return Prints the help page to screen.
#'@seealso \code{\link{GetModuleList}}
#'@name ModuleHelp
#'@export

ModuleHelp <- function(module){

  module <- as.character(substitute(module))
  if(!is.character(module) | !length(module) == 1) stop('module must be a character of length 1')

  helpURL <- paste0('https://raw.githubusercontent.com/zoonproject/modules/master/man/', module, '.Rd')

  if(url.exists(helpURL)){
    
#     txt <- getURL(helpURL, ssl.verifypeer=FALSE)
#     helpFile <- paste0(tempdir(), '/',  module, '.Rd')
#     writeLines(txt, helpFile)
#     tools::Rd2txt(tools::parse_Rd(helpFile))
    DisplayModuleHelp(helpURL)
    
  } else {
    modList <- GetModuleList()
    closeMatches <- unlist(modList)[agrep(module, unlist(modList), max.distance = 0.3)]
    if(length(closeMatches) == 0){
      stop("Can't find '", module, "' or any modules with closely matching names.") 
    } else if (length(closeMatches) == 1){
      stop("Can't find '", module, "'. Did you mean '", closeMatches, "'?")
    } else {
      stop("Can't find '", module, "'. Did you mean one of '", paste(closeMatches, collapse="', "), "'?")
    }
  }
}


# Download a file with libcurl and no messages to the console
#'@importFrom utils download.file

DownloadQuietly <- function(url, file) {
  download.file(url,
                file,
                method = 'libcurl',
                quiet = TRUE)
}



# Display a module helpfile in accordance with the 'help_type' option
# help is either displayed as an HTML or text, pdf is not supported and 
# an error is returned
#'@importFrom utils browseURL

DisplayModuleHelp <- function (url) {
  
  # get Rd file
  f_raw <- tempfile()
  DownloadQuietly(url, f_raw)
  
  # get the help type
  types <- c("text", "html", "pdf")
  type <- getOption('help_type')
  if (is.null(type)) {
    type <- 'text'
  }
  
  match.arg(tolower(type), types)
  
  # html case (opens in default viewer)
  if (type == "html") {
    
    # create a temporary help file and stick the html version in it
    tempDir <- tempfile()
    dir.create(tempDir)
    htmlFile <- file.path(tempDir, "index.html")
    htmlFile <- tools::Rd2HTML(f_raw,
                               out = htmlFile)
    
    browser <- getOption('viewer')
    
    if (is.null(browser)) {
      
      # Produce a warning and continue using text
      warning (paste('To display html help files (your default option) you',
                     'need to specify a default viewer. Try changing your',
                     'viewer via options. Printing to console instead', sep = '\n'))
      
      temp <- tools::Rd2txt(f_raw)  
      
    } else {
    
      # view the help file
      browseURL(url = htmlFile,
                browser = browser)
      
    }
    
  } 
  
  if (type == "text") {
    
    # otherwise just dump to the console
    temp <- tools::Rd2txt(f_raw)
    
  }
  
  if (type == "pdf") {
  
    warning (paste('pdf help files (your default option) cannot currently be displayed',
                   'for zoon modules. Try changing your help viewing settings with:',
                   'options(help_type = "html") or options(help_type = "text"). Printing',
                   'to console instead', sep = '\n'))
    temp <- tools::Rd2txt(f_raw)  
    
  }
  
  invisible(NULL)
  
}