$:.unshift(File.dirname(__FILE__)) unless
	$:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))
require 'open-uri'
require 'digest/md5'
require 'RipXploreLog'
require 'RipXplore'

class FileCacheItem < File
  def set_path(path)
    @path=path
  end
  def path
    @path
  end
end

#creates and manages a local cache of files,  so an URL can be requested, if it is in the cache, the local copy is used, otherwise the file is downloaded to the local cache
class FileCache
  attr_accessor :url_cache_dir,:url_cache_list,:native_file_cache_dir
  
  
  def cache_name_for_url(url)
    "#{url_cache_dir}/#{Digest::MD5.hexdigest(url)}.cached"
  end
  
  def cache_name_for_native_file(native_file,extension)
    image=native_file.file_system_image
    index=image.files.index(native_file)
    "#{native_file_cache_dir}/#{Digest::MD5.hexdigest(image.filename)}-#{index}.#{extension}"
  end
  
  def initialize(url_cache_dir,native_file_cache_dir)
    @url_cache_dir=url_cache_dir
    @native_file_cache_dir=native_file_cache_dir
    @url_cache_list="#{url_cache_dir}/cache.urls"
    Dir.mkdir(url_cache_dir) unless File.exists?(url_cache_dir)
    raise "cache directory #{url_cache_dir} invalid" unless File.directory?(url_cache_dir)
    Dir.mkdir(native_file_cache_dir) unless File.exists?(native_file_cache_dir)
    raise "cache directory #{native_file_cache_dir} invalid" unless File.directory?(native_file_cache_dir)
  end
  
  def purge_url(url)
    local_file_name=cache_name_for_url(url)
    if File.exists?(local_file_name) then
      RipXploreLog.log "purging local copy of #{url}"
      File.delete(local_file_name)
    end
  end
  
  def get_url(url)
    local_file_name=cache_name_for_url(url)
    if !File.exists?(local_file_name) then
      RipXploreLog.log "downloading #{url}"
      remote_file=open(url,"rb")
      local_file=File.open(local_file_name,"wb")      
      local_file<<remote_file.read
      local_file.close
      local_file_info_filename="#{local_file_name}.info"
      local_file_info_file=File.open(local_file_info_filename,"w")
      local_file_info_file<<url
      local_file_info_file.close
    end
    file=FileCacheItem.open(local_file_name,"rb")
    file.set_path(url)
    file
  end
  
  def get_file_system_image(url)
    file=get_url(url)    
    image=RipXplore.best_fit_from_file(file)
    @@file_system_image_urls<<url if (!@@file_system_image_urls.nil? && !@@file_system_image_urls.include?(url))    
    return image
  end
  
  @@file_system_image_urls=nil
  def file_system_image_urls_in_cache
    if @@file_system_image_urls.nil? then
      make_file_system_image_list unless File.exists?(@url_cache_list)
      @@file_system_image_urls=File.open(@url_cache_list,"r").readlines.collect{|url| url.chomp}
    end
    @@file_system_image_urls
  end
  
  def make_file_system_image_list
    urls=[]
    Dir.glob("#{url_cache_dir}/*.cached.info").each do |info_file|
      url=File.open(info_file,"r").read.chomp
      urls<<url if (FileSystemImage.is_file_system_image_filename?(url))
    end
    File.open(@url_cache_list,"w") {|f| f<< urls.join("\n")}
  end
  
  
  def random_file_system_image(collection_type=nil)
    all_image_urls=file_system_image_urls_in_cache    
    all_image_urls.length.times do
      begin
        index=rand(all_image_urls.length)
        image=get_file_system_image(all_image_urls[index%all_image_urls.length])
        return image if ((collection_type==nil) || (image.send(collection_type).length>0))
      rescue #silently swallow any exception
      end    
    end
    raise 'no suitable image found in cache'
  end

def force_native_file_to_cache(native_file,method_to_cache_on_native_file,extension)
  cache_filename=cache_name_for_native_file(native_file,extension)
  if ! File.exists?(cache_filename) then    
      local_file=File.open(cache_filename,"wb")      
      local_file<<native_file.send(method_to_cache_on_native_file)
      local_file.close        
    end
    return cache_filename
end

def purge_native_file_from_cache(native_file)
  Dir.glob(cache_name_for_native_file(native_file,'*')).each do |filename|
    RipXploreLog.log "purging local #{filename}"
    File.delete(filename)  
  end
end

end



# == Author
# Jonno Downes (jonno@jamtronix.com)
#
# == Copyright
# Copyright (c) 2008 Jonno Downes (jonno@jamtronix.com)
#
#Permission is hereby granted, free of charge, to any person obtaining
#a copy of this software and associated documentation files (the
#"Software"), to deal in the Software without restriction, including
#without limitation the rights to use, copy, modify, merge, publish,
#distribute, sublicense, and/or sell copies of the Software, and to
#permit persons to whom the Software is furnished to do so, subject to
#the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.