R/import_theia_download.R

In pobsteta/theia2r: An R toolbox to find, download and preprocess Sentinel-2 data

#' @title Import theia_download python module
#' @description [theia_download](https://github.com/olivierhagolle/theia_download) is
#'  a collection of python scripts used to download
#'  and correct Sentinel-2 images, and it is required by this package.
#'  This internal function check if their dependences (python, wget and aria2) 
#'  are installed, and imports the module.
#' @param with_aria2 (optional) Logical: if TRUE (default), the presence of 
#'  aria2 is checked; if FALSE, only Wget and python are checked.
#' @param ... Optional parameters of \code{\link[reticulate]{import}}
#' @return `theia_download` python module
#'
#' @author Pascal Obstetar (20178 \email{pascal.obstetar@@gmail.com}
#' @note License: GPL 3.0
#' @importFrom reticulate import_from_path import_builtins py_to_r use_python

import_theia_download <- function(with_aria2 = TRUE, ...) {
    
    # define the required binary dependencies
    mandeps <- c("python", "wget")
    optdeps <- if (with_aria2 == TRUE) {
        c("aria2c")
    } else {
        character()
    }
    dependencies <- c(mandeps, optdeps)
    
    # define theia_download path
    theia_download_path <- system.file("theia_download", package = "theia2r")
    
    # check that git, python2 and wget are installed
    binpaths <- load_binpaths(dependencies)
    
    missing_dep <- dependencies[binpaths[dependencies] == ""]
    if (length(missing_dep) > 0) 
        {
            if (Sys.info()["sysname"] != "Windows") {
                # On Linux, send an error / a warning if something is missing
                print_message(type = if (length(mandeps[binpaths[mandeps] == ""]) > 0) {
                  "error"
                } else {
                  "warning"
                }, "Some dependencies (", paste(missing_dep, collapse = ", "), ") were not found in your system; ", "please install them or update your system PATH. ")
            } else {
                # On Windows, download and install (them) or inform how to install them) Download wget and aria2
                suppressMessages(install_wget())
                if (with_aria2 == TRUE) {
                  suppressMessages(install_aria2())
                }
                # If other ones are missing:
                if (length(missing_dep[!missing_dep %in% c("wget", "aria2c")]) > 0) {
                  print_message(type = if (length(mandeps[binpaths[mandeps] == ""]) > 0) {
                    "error"
                  } else {
                    "warning"
                  }, "Some dependencies (", paste(missing_dep, collapse = ", "), ") were not found in your system; ", "please install them or update your system PATH.", 
                    if ("python" %in% missing_dep) {
                      paste0("\nTo install python, we suggest to use the OSGeo4W installer ", "(http://download.osgeo.org/osgeo4w/osgeo4w-setup-x86", if (Sys.info()["machine"] == 
                        "x86-64") {
                        "_64"
                      }, ".exe), ", "to choose the \"Advanced install\" and to check ", "the package \"gdal-python\".")
                    })
                }
            }
        }  #TODO pip2 not working to install gitPython
    
    # checks the python version and import modules
    py <- init_python()
    # load theia_download
    theia_download <- tryCatch(reticulate::import_from_path("theia_download", theia_download_path, ...), error = print)
    theia_download$inst_path <- theia_download_path
    return(theia_download)
    
}