#!/usr/bin/ruby -wKU
#
# whatever-dl, a script to download online (web-based) videos.
#
# Copyright Michael Orlitzky
#
# http://michael.orlitzky.com/
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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.
#
# http://www.fsf.org/licensing/licenses/gpl.html
#

# We need Pathname to get the real filesystem path
# of this script (and not, for example, the path of
# a symlink which points to it.
require 'pathname'

# And getoptlong to check for our one option, --continue.
require 'getoptlong'

# This bit of magic adds the parent directory (the
# project root) to the list of ruby load paths.
# Thus, our require statements will work regardless of
# how or from where the script was run.
executable = Pathname.new(__FILE__).realpath.to_s
$: << File.dirname(executable) + '/../'

# Load our config file.
require 'bin/configuration'

# And the downloaders...
require 'src/downloader'

# The Dir.glob that's coming up doesn't use the
# Ruby library path so we need to tell it where to
# look explicitly.
websites_pattern = File.dirname(executable) + '/../src/websites/*.rb'

# All of the website classes are located in one
# directory, so we can 'require' them automatically.
Dir.glob(websites_pattern).each do |r|
  require r
end


EXIT_SUCCESS = 0
EXIT_NO_URL = 1
EXIT_INVALID_URL = 2
EXIT_COULDNT_GET_VIDEO_URL = 3
EXIT_IO_ERROR = 4
EXIT_ERROR_READING_FROM_VIDEO_URL = 5
EXIT_CONNECTION_REFUSED = 6
EXIT_HTTP_ERROR = 7
EXIT_ACCESS_DENIED = 8

def usage()
  puts <<EOF

Usage: whatever-dl [options] <url>

Options:
  -c, --continue        Continue downloading a previously-attempted file.

EOF

end

# Only actually do something if this script was called
# directly (i.e. not from the tests).
if (__FILE__ == $0) then
  # Default options.
  options = { :continue => false }

  # Parse the command-line options into the options hash.
  opts = GetoptLong.new(["--continue", "-c", GetoptLong::NO_ARGUMENT],
                        ["--help", "-h", GetoptLong::NO_ARGUMENT])

  opts.each do |opt, arg|
    case opt
    when '--help'
      usage()
      Kernel.exit(EXIT_SUCCESS)
    when '--continue'
      options[:continue] = true
    end
  end

  # Warn about nonsensical options.
  if options[:continue] and not (Configuration::DOWNLOAD_METHOD == :wget)
    puts 'WARNING: The --continue flag does nothing unless DOWNLOAD_METHOD is :wget.'
  end

  # Note that GetoptLong steals its arguments from ARGV, so we don't need
  # to take optional arguments into account when figuring out whether or not
  # we were passed a URL.
  if (ARGV.length < 1) then
    # If the user didn't give us a URL, yell
    # at him or her.
    usage()
    Kernel.exit(EXIT_NO_URL)
  end

  # Factory method.
  site = Website.create(ARGV[0])

  if site.nil?
    puts 'Invalid URL.'
    exit(EXIT_INVALID_URL)
  end
  
  video_url = site.get_video_url()

  if video_url.nil?
    puts 'Error retrieving video URL.'
    exit(EXIT_COULDNT_GET_VIDEO_URL)
  end

  # The Downloader class is a factory; it should decide
  # which subclass we get.
  downloader = Downloader.create(Configuration::DOWNLOAD_METHOD)
  
  # Attempt to download the file, and rescue and report
  # any (predictable) exceptions. The wget downloader will
  # naturally not report any of these, since it will die in
  # its own process.
  begin
    downloader.download(video_url,
                        site.get_video_filename(),
                        site.headers(),
                        continue=options[:continue])
  rescue Errno::ECONNREFUSED => e
    puts 'The connection to the server (to download the video file) was refused. Check your connection, and try again later.'
    Kernel.exit(EXIT_CONNECTION_REFUSED)
  rescue Errno::EACCES => e
    puts "Access denied. Check that you have write permission to the output file/directory. Details: #{e.message}."
  rescue OpenURI::HTTPError => e
    puts "An HTTP error occurred while downloading the video file: #{e.message}."
    Kernel.exit(EXIT_HTTP_ERROR)
  rescue IOError => e
    puts "Input/Output Error: #{e.message}"
    Kernel.exit(EXIT_IO_ERROR)
  end

  # Write an empty line at the end for aesthetic reasons.
  puts ''
  
  Kernel.exit(EXIT_SUCCESS)
end