cran.rb

# frozen_string_literal: true

module Ecosystem
  class Cran < Base
    def registry_url(package, _version = nil)
      "https://cran.r-project.org/package=#{package.name}"
    end

    def download_url(package, version)
      return nil unless version.present?
      "https://cran.r-project.org/src/contrib/#{package.name}_#{version}.tar.gz"
    end

    def documentation_url(package, _version = nil)
      "http://cran.r-project.org/web/packages/#{package.name}/#{package.name}.pdf"
    end

    def check_status(package)
      url = "https://cran.r-project.org/web/packages/#{package.name}/index.html"
      html = get_html(url)
      return 'removed' if html.css('.container').text.match?("Package ‘#{package.name}’ was removed from the CRAN repository.")
    end

    def all_package_names
      html = get_html("https://cran.r-project.org/web/packages/available_packages_by_date.html")
      html.css("tr")[1..-1].map { |tr| tr.css("td")[1].text.strip }
    rescue
      []
    end

    def recently_updated_package_names
      all_package_names.uniq.first(100)
    end

    def fetch_package_metadata(name)
      html = get_html("https://cran.r-project.org/web/packages/#{name}/index.html")
      properties = {}
      table = html.css("table")[0]
      return nil if table.nil?

      table.css("tr").each do |tr|
        tds = tr.css("td").map(&:text)
        properties[tds[0]] = tds[1]
      end

      { name: name, html: html, properties: properties }
    rescue
      nil
    end

    def map_package_metadata(package)
      return false unless package
      {
        name: package[:name],
        homepage: package[:properties].fetch("URL:", "").split(",").first,
        description: package[:html].css("h2").text.split(":")[1..-1].join(":").strip,
        licenses: package[:properties]["License:"],
        repository_url: repo_fallback(package[:properties].fetch("URL:", "").split(",").first.presence, (package[:properties].fetch("URL:", "").split(",").last.presence || package[:properties]["BugReports:"])).to_s[0, 255],
        properties: package[:properties],
        downloads: downloads(package),
        downloads_period: "last-month",
      }
    end

    def downloads(package)
      get_json("https://cranlogs.r-pkg.org/downloads/total/last-month/#{package[:name]}")[0]['downloads']
    rescue
      nil
    end

    def versions_metadata(pkg_metadata, existing_version_numbers = [])
      [{
        number: pkg_metadata[:properties]["Version:"],
        published_at: pkg_metadata[:properties]["Published:"],
      }] + find_old_versions(pkg_metadata)
    end

    def find_old_versions(pkg_metadata)
      archive_page = get_html("https://cran.r-project.org/src/contrib/Archive/#{pkg_metadata[:name]}/")
      return [] if archive_page.nil?
      trs = archive_page.css("table").css("tr").select do |tr|
        tds = tr.css("td")
        tds[1]&.text&.match(/tar\.gz$/)
      end
      trs.map do |tr|
        tds = tr.css("td")
        {
          number: tds[1].text.strip.split("_").last.gsub(".tar.gz", ""),
          published_at: tds[2].text.strip,
        }
      end
    end

    def dependencies_metadata(name, version, mapped_package)
      find_and_map_dependencies(name, version, mapped_package)
    end

    def find_dependencies(name, version)
      begin
        url = "https://cran.rstudio.com/src/contrib/#{name}_#{version}.tar.gz"
        connection = Faraday.new do |builder|
          builder.use Faraday::FollowRedirects::Middleware
          builder.adapter Faraday.default_adapter
        end

        head_response = connection.head(url)
        raise if head_response.status != 200
      rescue StandardError
        url = "https://cran.rstudio.com/src/contrib/Archive/#{name}/#{name}_#{version}.tar.gz"
      end

      folder_name = "#{name}_#{version}"
      tarball_name = "#{folder_name}.tar.gz"
      downloaded_file = File.open "/tmp/#{tarball_name}", "wb"

      connection = Faraday.new
      response = connection.get(url)

      File.open(downloaded_file, 'wb') do |file|
        file.write(response.body)
      end

      return [] if response.status != 200

      cmd = `mkdir /tmp/#{folder_name} && tar xzf /tmp/#{tarball_name} -C /tmp/#{folder_name}  --strip-components 1`

      contents = `cat /tmp/#{folder_name}/DESCRIPTION`

      `rm -rf /tmp/#{folder_name}` if folder_name.present?
      `rm -rf /tmp/#{tarball_name}` if tarball_name.present?

      Bibliothecary.analyse_file("DESCRIPTION", contents).first.fetch(:dependencies)
    ensure
      `rm -rf /tmp/#{folder_name}` if folder_name.present?
      `rm -rf /tmp/#{tarball_name}` if tarball_name.present?
      []
    end

    def maintainers_metadata(name)
      pkg = fetch_package_metadata(name)
      return [] unless pkg
      maintainers = pkg[:properties].fetch("Maintainer:", "").split(",")
      maintainers.map do |string|
        name, email = string.split(' <')
        next if email.nil?
        email = email.gsub('>','').gsub(' at ', '@')
        {
          uuid: email,
          name: name.strip,
          email: email
        }
      end.compact
    end
  end
end