ioquatix/utopia-gallery

# Copyright, 2012, by Samuel G. D. Williams. <http://www.codeotaku.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.

require 'trenni/reference'

module Utopia
    module Gallery
        class Cache
            # @param root [String] The root path for media files.
            def initialize(media_root, cache_root, cache_path, media, processes)
                # TODO: It's a lot of things to keep track of... perhaps a configuration class?
                @media_root = media_root
                @cache_root = cache_root
                @cache_path = cache_path
                @media = media
                
                @processes = processes
            end
            
            attr :media_root
            attr :cache_root
            attr :processes
            attr :media
            
            def input_path
                File.join(@media_root, @media.path)
            end
            
            def output_paths
                @processes.values.collect{|process| output_path_for(process)}
            end
            
            def outputs
                return to_enum(:outputs) unless block_given?
                
                @processes.values do |process|
                    yield process, output_path_for(process)
                end
            end
            
            def output_path_for(process)
                File.join(@cache_root, process.relative_path(@media))
            end
            
            def source_path_for(process)
                File.join(@cache_path, process.relative_path(@media))
            end
            
            # Process the media, update files in the cache.
            def update
                @processes.values.each do |process|
                    process.call(self)
                end
                
                return self
            end
            
            # Original path.
            def to_s
                original.to_s
            end
            
            def original
                Trenni::Reference.new(@media.path)
            end
            
            # This allows dynamic path lookup based on process name, e.g. `cache.small`.
            def method_missing(name, *args)
                if process = @processes[name]
                    return Trenni::Reference.new(source_path_for(process))
                else
                    super
                end
            end
            
            def respond_to?(name)
                @processes.include?(name) || super
            end
        end
    end
end