# Copyright (c) 2013-2016 SUSE LLC
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of version 3 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.   See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, contact SUSE LLC.
#
# To contact SUSE about this file by physical or electronic mail,
# you may find current contact information at www.suse.com

#  Inspect name, version, and other attributes of the operating system
class OsInspector < Inspector
  has_priority 10

  def strip_arch_from_name(name)
    # architecture information in the name might be misleading
    # information with regards to the real architecture name.
    # in addition the architecture information is not consistently
    # added for all distributions. Thus we strip this part
    name.gsub(/\((i.86|x86_64|s390|ia64|ppc|arm).*\)/, "").strip
  end

  # checks for additional version information like Beta or RC
  def get_additional_version
    issue = @system.read_file("/etc/issue")
    special_version = issue.scan(/Beta\d+|RC\d|GMC\d*/).first if issue

    special_version ? " #{special_version.gsub(/[0-9]{1,2}/," \\0")}" : ""
  end

  def initialize(system, description)
    @system = system
    @description = description
  end

  def inspect(_filter, _options = {})
    @system.check_requirement("cat", "--version") if @system.is_a?(RemoteSystem)

    os = get_os
    if os
      os.architecture = @system.arch
      os.version += get_additional_version if os.version
    else
      raise Machinery::Errors::UnknownOs
    end

    @description.os = os
  end

  def summary
    "Found operating system '#{@description.os.name}' version '#{@description.os.version}'."
  end

  private

  def get_os
    # Use os-release file by default
    os = get_os_from_os_release

    # Fall back to SuSE-release file
    unless os
      os = get_os_from_suse_release
    end

    # Fall back to redhat-release file
    unless os
      os = get_os_from_redhat_release
    end

    os
  end

  # check for freedesktop standard: /etc/os-release
  def get_os_from_os_release
    os_release = @system.read_file("/etc/os-release")
    return unless os_release

    result = Hash.new
    key_value_pairs = Hash[os_release.split("\n").reject(&:empty?).map { |l| l.split("=") }]
    key_value_pairs.each_pair do |k,v|
      result[k.downcase] = v.strip.gsub(/^"|"$/,"")
    end
    if result["pretty_name"]
      result["pretty_name"] = strip_arch_from_name(result["pretty_name"])

      # remove always changing Tumbleweed version from pretty name
      if result["pretty_name"] =~ /^openSUSE.*Tumbleweed/
        result["pretty_name"] = "openSUSE Tumbleweed"
      end

      # remove Leap version from pretty name
      if result["pretty_name"] =~ /^openSUSE.*Leap/
        result["pretty_name"] = "openSUSE Leap"
      end

      # converts SLES11 SP4 result to SP3 style
      # the results are different because SP4 has an os-release
      if result["pretty_name"] =~ /^SUSE Linux Enterprise Server 11 (SP\d)$/
        result["pretty_name"] = "SUSE Linux Enterprise Server 11"
        result["version"] = "11 #{$1}"
      end
    end
    # return pretty_name as name as it contains the actual full length
    # name instead of an abbreviation
    os = Os.for(result["pretty_name"] || result["name"])
    os.version = result["version"]

    # since Tumbleweed does no longer store the version number in the
    # "version" property, we've to read from the "version_id" property
    if os.version == "Tumbleweed" || os.name == "openSUSE Tumbleweed"
      os.version = result["version_id"]
    end

    os
  end

  # checks for old suse standard: /etc/SuSE-release
  def get_os_from_suse_release
    suse_release = @system.read_file("/etc/SuSE-release")
    return unless suse_release

    result = Hash.new
    # name is always the first line in /etc/SuSE-release
    result["name"] = strip_arch_from_name(suse_release.split("\n").first)

    result["patchlevel"] = nil
    suse_release.split("\n").slice(1, suse_release.length).each do |line|
      unless line.start_with?("#")
        key, value = line.split("=")
        result[key.strip.downcase] = value.strip
      end
    end

    if result["version"] && !result["patchlevel"].nil?
      result["version"] = "#{result["version"]} SP#{result["patchlevel"]}"
    end

    if result["codename"] == "Tumbleweed"
      os = Os.for ("openSUSE Tumbleweed")
    else
      os = Os.for(result["name"])
    end

    os.version = result["version"]
    os
  end

  # checks for redhat standard: /etc/redhat-release
  def get_os_from_redhat_release
    redhat_release = @system.read_file("/etc/redhat-release")
    return unless redhat_release

    result = Hash.new
    result["name"], result["version"] = redhat_release.split("\n").first.split(" release ")

    os = Os.for(result["name"])
    os.version = result["version"]
    os
  end
end