# 
# Copyright (C) 2007 Mobio Networks, Inc.
# 
# 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.
# 
# You should have received a copy of the GNU General Public License along with
# this program.  If not, see <http://www.gnu.org/licenses/>.
# 
# 
# This module manages yaml-based configuration sets. Uses some logic from the
# rfacebook gem.
# 
# The config_manager is a yaml-based property management system which follows
# the same methodology for managing property sets as database.yml. To use the
# config_manager, perform the following steps:
# 
# 1. In environment.rb, add the following two lines to the bottom of the file
#   (we want to load the configuration statically):
# 
# <pre>require 'rmobio/config_manager'</pre>
# 
# 2. Run the following rake task to generate the boilerplate configs:
# 
# <pre>rake rmobio:setup</pre>
# 
# 3. Edit config/rmobio.yml and add your properties (here we set a property
#   called "ad_network" with a value of "ad_sense")
# 
# <pre>
#    development:
#       ad_network: ad_sense
# </pre>
# 
# 4. To use a property, reference the hash accordingly.  e.g. @adnetwork =
#   MOBIO_CONFIG['ad_network']
# 
module Rmobio
  module ConfigManager
    
    EXTERNAL_CONTEXT_PROP = '_external_context' unless defined? EXTERNAL_CONTEXT_PROP
    
    if defined? RAILS_DEFAULT_LOGGER
      logger = RAILS_DEFAULT_LOGGER
    else
      logger = nil
    end
    begin
      app_yaml_file = YAML.load_file("#{RAILS_ROOT}/config/rmobio.yml")
    rescue Exception => e
      raise StandardError, "config/rmobio.yml could not be loaded."
    end

    if app_yaml_file
      if app_yaml_file[RAILS_ENV]
        
        remove_const :MOBIO_CONFIG if defined? MOBIO_CONFIG
        MOBIO_CONFIG = app_yaml_file[RAILS_ENV]
        
        # Replace all properties containing @somekey@ with the value of
        # "somekey"
        MOBIO_CONFIG.each do |key, value|
          
          # Run the value filter process
          filter_value = value.to_s.strip
          filter_key = /@(.*)@/.match(filter_value).to_s.strip
          if filter_key and filter_key != ''
            filter_key = filter_key.gsub(/@/,'')
            if filter_key and filter_value and filter_key != ''
              filter_value = filter_value.gsub(/@.*@/, MOBIO_CONFIG[filter_key.strip])
              logger.debug('ConfigManager: filtered key: ' + key + ' filtered value: ' + 
                  filter_value) unless logger.nil?
              MOBIO_CONFIG[key] = filter_value
            end     
          end
        end
      else
        raise StandardError, "config/rmobio.yml exists, but doesn't" +
          "have a configuration for RAILS_ENV=#{RAILS_ENV}."
      end
    else
      raise StandardError, "config/rmobio.yml does not exist."
    end
    
    # get_request_context This method checks for the existence of a
    # "mobio-context" header. If the header exists, then the method returns the
    # filtered value for the MOBIO_CONFIG array with the key "url."
    # 
    # Below is the flow:
    # 
    # A request is made to the server which contains a mobio-context header with
    # a value of "mycustomcontext" to "/news"
    # 
    # Calling get_request_context(some_url_property) would return
    # 
    # "/mycustomcontext/news"
    # 
    # If no header exists, the method returns the value of the property,
    # unfiltered
    # 
    def get_external_context(url=nil)
      
      context = request.env['HTTP_MOBIO_CONTEXT']
      
      if url
        if context and context != ''
          external_context = MOBIO_CONFIG[url].gsub(EXTERNAL_CONTEXT_PROP, context)
          RAILS_DEFAULT_LOGGER.debug 'ConfigManager: Setting the uri to: "' + 
            external_context + '" for the current request.' unless not defined? RAILS_DEFAULT_LOGGER
          return external_context
        else
          return MOBIO_CONFIG[url].gsub('/' + EXTERNAL_CONTEXT_PROP, '')
        end 
      end
    end
  end
end
# Now we want to initialize the MOBIO_CONFIG constant
include Rmobio::ConfigManager