require_relative '../rcm_utils'

module RCM
  class Apt
    APT_GET = '/usr/bin/apt-get'.freeze
    DPKG_QUERY = '/usr/bin/dpkg-query'.freeze
    APT_CACHE = '/usr/bin/apt-cache'.freeze

    def update()
      status = ::RCM.cmd("#{APT_GET} update")
      raise "Updating apt cache failed. \n\n#{status[:error]}\n\nstdout:\n#{status[:output]}"
    end

    def status(pkg_name)
      ::RCM.cmd("#{DPKG_QUERY} --status #{pkg_name}")
    end

    def install(pkg_name, version = '')
      name = ''
      version_string = "=#{version}" unless version.empty?
      if pkg_name.is_a?(String)
        name = pkg_name
        version_string = "=#{version}" unless version.empty?
      elsif pkg_name.is_a?(::RCM::Package)
        name = pkg_name.name
        v = pkg_name.version
        version_string = "=#{v}" unless v.empty?
      end

      ::RCM.cmd("#{APT_GET} install --yes #{name}#{version_string}")
    end

    def multi_install(pkgs)
      raise 'multi_install expects array of ::RCM.Package' unless pkgs.is_a?(Array)

      # Construct string of packages to install in one go.
      pkgs_string = ''
      pkgs.each do |pkg|
        version_string = "=#{pkg.version}" unless pkg.version.empty?
        pkgs_string += "#{pkg.name}#{version_string} "
      end

      ::RCM.cmd("#{APT_GET} install --yes #{pkgs_string}")
    end

    def get_versions(pkg_name)
      name = ''
      if pkg_name.is_a?(String)
        name = pkg_name
      elsif pkg_name.is_a?(::RCM::Package)
        name = pkg_name.name
      end
      status = ::RCM.cmd("#{APT_CACHE} madison #{name}")
      return [] if !status[:output] || status[:output] =~ /Unable to locate package/

      # Collect all versions by splitting on new line, and then collecting second
      # field from every line with delimiter ' | '
      available_versions = status[:output].split("\n").collect { |l| l.split(' | ')[1] }
      available_versions.uniq
    end

    def remove(pkg_name)
      # Remove is idempotent and returns with success even if package is not installed.
      status = ::RCM.cmd("#{APT_GET} remove --yes #{pkg_name}")
      error_message = "Removing #{pkg_name} failed!\n\nstderr:\n#{status[:error]}\n\nstdout:\n#{status[:output]}"
      raise error_message unless status[:exit_code] == 0
    end
  end
end