#!/usr/bin/ruby -w
#--
# apod - script to pull the astronomy picture of the day and generate an image
# suitable as a desktop wallpaper.
# See: http://antwrp.gsfc.nasa.gov/apod
#
# Copyright (c) 2006 Matthew Brandon Edens - brandon@cs.uri.edu
# 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 2 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.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#++

# This program requires both RMagick and wget to function.
require 'ftools'
require 'fileutils'
require 'date'
require 'tmpdir'
require 'RMagick'

# globals - tweak the program here
SCREEN_WIDTH=1280
SCREEN_HEIGHT=768

TMPDIR="/tmp/apod"

HOME="/home/brandon"
WALLPAPER="#{HOME}/wallpaper.jpg"
HIGHRES="#{HOME}/media/pictures/astronomy_picture_of_the_day/highres"
DESKTOP="#{HOME}/media/pictures/astronomy_picture_of_the_day/wallpaper"

def wrap(str, max_size)
    all = []
    line = ''
    for l in str.split
        if (line+l).length >= max_size
            all.push(line)
            line = ''
        end
        line += line == '' ? l : ' ' + l
    end
    all.push(line).join("\n")
end

def month_to_number(str)
  case str
  when "January"
    return 1
  when "February"
    return 2
  when "March"
    return 3
  when "April"
    return 4
  when "May"
    return 5
  when "June"
    return 6
  when "July"
    return 7
  when "August"
    return 8
  when "September"
    return 9
  when "October"
    return 10
  when "November"
    return 11
  when "December"
    return 12
  end
end


if $0 == __FILE__
  url = ARGV[0]

  # some initial directory creation
  FileUtils.mkdir(TMPDIR) unless File.directory?(TMPDIR)

  # pull down the needed astronomy picture of the day images and html
  wget = Kernel.system("wget -q -nd -nc -O#{TMPDIR}/index.html #{ARGV[0] ? ARGV[0] : 'http://antwrp.gsfc.nasa.gov/apod/index.html'}")
  wget = Kernel.system("wget -q -nd -nc -r -l1 -P#{TMPDIR} --accept jpg,png,gif,jpeg,index.html #{ARGV[0] ? ARGV[0] : 'http://antwrp.gsfc.nasa.gov/apod/index.html'}")
  # open the astronomy index.html to get names of images and explanation
  index = File.open("#{TMPDIR}/index.html")
  st = index.read =~ /<body.*?>/im
  index.rewind
  en = index.read =~ /<\/body>/im
  index.rewind
  text = index.read[st...en]

  # get the date from the index html page pulled down from the site
  re = /([0-9][0-9][0-9][0-9]) (January|February|March|April|May|June|July|August|September|October|November|December) ([0-9]+)/m
  md = re.match(text)
  year = md[1]
  month = month_to_number(md[2])
  day = md[3]
  date = "#{md[1]} #{md[2]} #{md[3]}"
  date_directory = "#{year}-#{month}-#{day}"

  # get the high resolution image filename
  re = /#{date}.*?<a href="(.*?)">/im
  md = re.match(text)
  tmp_str = md[1]
  re = /.*\/(.*?)$/m
  md = re.match(tmp_str)
  highres = md[1]

  # get the low resolution image filename
  re = /#{date}.*?<img src="(.*?)"/im
  md = re.match(text)
  tmp_str = md[1]
  re = /.*\/(.*?)$/m
  md = re.match(tmp_str)
  lowres = md[1]

  # get the explanation
  re = /(Explanation:.*?)Tomorrow's picture:/m
  md = re.match(text)
  explanation = md[1]
  explanation = wrap(explanation.gsub(/<.*?>/m, ""), 65)

  # generate the desktop wallpaper
  image = Magick::ImageList.new("#{TMPDIR}/#{lowres}")
  background = Magick::Image.new(SCREEN_WIDTH, SCREEN_HEIGHT) {
    self.background_color = 'black'
  }
  text = Magick::Draw.new
  wallpaper = background.composite(image,
                                   Magick::EastGravity,
                                   Magick::OverCompositeOp)
  text.annotate(wallpaper, (SCREEN_WIDTH - image.columns),
                SCREEN_HEIGHT, 10, 10, explanation) {
    self.gravity = Magick::WestGravity
    self.pointsize = 14
    self.stroke = 'transparent'
    self.fill = '#eeeeee'
    self.font_weight = Magick::BoldWeight
  }
  wallpaper.write("#{TMPDIR}/wallpaper.jpg")

  # make the directories for permanent storage
  FileUtils.mkdir("#{DESKTOP}/#{date_directory}") unless
    File.directory?("#{DESKTOP}/#{date_directory}")
  FileUtils.mkdir("#{HIGHRES}/#{date_directory}") unless
    File.directory?("#{HIGHRES}/#{date_directory}")

  # copy wallpaper to today's wallpaper location
  FileUtils.copy("#{TMPDIR}/wallpaper.jpg", "#{WALLPAPER}")

  # copy wallpaper to permanent location
  FileUtils.copy("#{TMPDIR}/wallpaper.jpg",
                 "#{DESKTOP}/#{date_directory}/wallpaper.jpg")

  # copy highres to its permanent location
  FileUtils.copy("#{TMPDIR}/#{highres}",
                 "#{HIGHRES}/#{date_directory}/#{highres}")

  # clean up afterwards
  #FileUtils.rm("#{TMPDIR}/index.html")
  #FileUtils.rm("#{TMPDIR}/#{highres}")
  #FileUtils.rm("#{TMPDIR}/#{lowres}")
  #FileUtils.rm("#{TMPDIR}/wallpaper.jpg")
  #FileUtils.rmdir("#{TMPDIR}")

  # set the X background
  Kernel.system("xsetbg -quiet -onroot -fullscreen #{WALLPAPER}")

end