#encoding: UTF-8
=begin
/***************************************************************************
 *   2023-2024, Michael Uplawski <michael.uplawski@uplawski.eu>            *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the WTFPL 2.0 or later, see                     * 
 *   http://www.wtfpl.net/about/                                           *
 *                                                                         *
 *   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.                  *
 *                                                                         *
 ***************************************************************************/
=end

# This class manages a dialog to alter the behavior of the
# post-processor on a “per article” basis. It can be displayed
# before posting, to do some “last minute” changes,
# notably to deactivate them.
#
# Post-processing CANNOT be deactivated completely in this dialog.
# I do not remember, why a previous comment stated the contrary.

require_relative 'basic_logging'

class OverrideDlg

  include BasicLogging

  XTERM    = 'xterm'
  # TERMINAL = 'x-terminal-emulator'
  WHIPTAIL = 'whiptail'
  YAD      = 'yad'
  ZENITY   = 'zenity'
  # The external programs which are supported for the time. They will be run in
  # a new process (IO.popen() ).  The first program from this array, which is
  # found in the Path, will be used. Whiptail and a pure ruby dialog
  # necessitate that xterm be found, too.
  @@Executables = [YAD, ZENITY, WHIPTAIL, XTERM]
  @@LIBDIR = File::dirname(__FILE__)
  # The configuration variables that can be unset.
  # This class instance variable is exposed via a getter.
  @cvars = [:GROUP_SIGS, :CUSTOM_HEADERS, :NO_ARCHIVE_GROUPS, :VFY_URLS, :DEBUG_LOG]

  # ... here
  # For the record: this is rather cool.
  #      ... believe me! It is!
  class << self
    attr_reader :cvars
  end
  # Love it.

  # Create the object
  def initialize
    @config = Configuration::instance
    # find the supported programs 
    @executables = @@Executables.select do |ex_name|
      program?(ex_name) 
    end
    # As we are calling external programs anyway, 
    # why not continue with that ...
    @xmsg = ENV['PATH'].split(':').any? {|d| Dir.children(d).include?('xmessage')}
    # bof.
  end

  # display a dialog and return the new options.
  def show
    if(@executables && !@executables.empty?)
      debug('found executables ' << @executables.join(', '))
      opts = nil
      begin
        if has?(YAD)
          return yad_dlg.split.collect {|o| o.to_s}.join(' ')
        elsif has?(ZENITY)
          return zenity_dlg.split.collect {|o| o.to_s}.join(' ')
        elsif has? XTERM
          if has?(WHIPTAIL)
            return whiptail_dlg.split.collect {|o| o.to_s}.join(' ')
          else
            debug 'using naked xterm'
            return ruby_dlg.split.collect {|o| o.to_s}.join(' ')
          end
        end
      rescue SystemExit
        msg = 'Process is cancelled (SystemExit)'
        info msg
        exit true
      rescue Exception => ex
        msg = 'Error upon showing dialog ' << ex.message
        error(msg)
      end
    # no program to show the dialog 
    else 
      msg = "#{File.basename($0)}: No suitable executable found to display the dialog"
      warn msg
      # if xmessage is available, give the user a last chance.
      if @xmsg
        io = IO.popen('xmessage -buttons continue:0,abort:1 -default abort -print ' << msg) 
        Process.wait(io.pid)
        # ATTN! read io only once!
        exit if ('continue' != io.read.to_s.strip )
        # ... but then again, we still have a log.
        debug('continue with configured settings')
      end
    end
  end

  private
  # I know what it does and that there is some
  # redundancy with the following method, but I
  # do not feel like sorting it out, now.
  def program?(ex_name)
    ENV['PATH'].split(':').each do |dir_name| 
      return true if Dir.entries(dir_name).include?(ex_name) 
    end
    return false
  end

  # returns true if the executable ex_name is to be 
  # called for the dialog
  def has?(ex_name)
    @executables.include? ex_name 
  end

  ###### The following methods call a script, each, in an external process.
  # There appears to be some Exception handling missing, but it does not
  # hurt for the time being. Anyway, I do not care.

  # creates a whiptail dialog in xterm.
  def whiptail_dlg
    debug('whiptail dialog')
    tf = Tempfile.new
    # dlg = @config.BINDIR << File::Separator << 'whiptail_dlg'
    dlg = @@LIBDIR << File::Separator << 'whiptail_dlg'
    dialog = XTERM.dup << ' -e ' << dlg << ' ' << tf.path
    io = IO::popen(dialog)
    Process.wait(io.pid )
    nopts = tf.read
    exit true if('exit' == nopts.strip)
    tf.unlink
    return nopts 
  end

  # creates a textual dialog in xterm.
  def ruby_dlg
    debug('xterm dialog')
    tf = Tempfile.new
    # dlg = @config.BINDIR << File::Separator << 'ruby_dlg'
    dlg = @@LIBDIR << File::Separator << 'ruby_dlg'
    begin
      dialog = XTERM.dup  << ' -e ' << dlg << ' ' << tf.path
      debug('dialog will be ' << dialog)
    rescue Exception => ex
      error ex.message
      wait_for_user
      exit false
    end
    io = IO::popen(dialog)
    debug('wait for ' << io.pid.to_s)
    Process.wait(io.pid )
    nopts = tf.read
    exit true if('exit' == nopts.strip)
    tf.unlink
    return nopts 
  end

  # creates a Zenity dialog.
  def zenity_dlg
    debug('Zenity dialog')
    # dialog = @config.BINDIR << File::Separator << 'zenity_dlg'
    dialog = @@LIBDIR << File::Separator << 'zenity_dlg'
    io = IO.popen(dialog)
    Process::wait(io.pid)
    rc = $?.exitstatus 

    exit true if rc != 0

    nopts = io.read
    return nopts
  end

  # creates a YAD dialog.
  def yad_dlg
    debug('yad dialog')
    # dialog = @config.BINDIR << File::Separator << 'yad_dlg'
    dialog = @@LIBDIR << File::Separator << 'yad_dlg'
    debug('dialog will be ' << dialog)
    io = IO::popen(dialog)
    Process::wait(io.pid)
    exit true if $?.exitstatus != 0

    nopts = io.read
    return nopts
  end

end 

# EOF