require 'active_support/core_ext'
require 'active_record'
require 'cohort_scope'
require 'earth/conversions_ext'
require 'earth/inflectors'
require 'data_miner'
require 'falls_back_on'
require 'weighted_average'
require 'fixed_width'
require 'errata'
require 'mini_record'
require 'table_warnings'
require 'loose_tight_dictionary'
require 'loose_tight_dictionary/cached_result'

# The earth module is an interface for loading data models from various domains.
module Earth
  autoload :Utils, 'earth/utils'
  
  extend self

  # Takes argument like Earth.search(['air'])
  # Default is search all domains
  # For example, <tt>[ 'Aircraft', 'Airline' ]</tt>
  def search(*search_domains)
    search_domains = search_domains.empty? ? [:all] : search_domains.flatten.map(&:to_sym)
    if search_domains.include? :all
      resources
    else
      resource_map.select do |resource, domain|
        search_domains.include? domain.to_sym
      end.map do |resource, domain|
        resource
      end
    end
  end

  def gem_root 
    File.expand_path File.join(File.dirname(__FILE__), '..')
  end

  def domains
    resource_map.values.uniq.sort
  end
  
  def resources
    resource_map.keys.sort
  end

  def resource_map
    @resource_map ||= Dir[File.join(gem_root, 'lib', 'earth', '*')].select do |path|
      File.directory? path
    end.inject({}) do |memo, domain_path|
      Dir[File.join(domain_path, '*.rb')].each do |resource_path|
        resource = File.basename(resource_path, '.rb').camelcase
        unless resource == 'DataMiner'
          memo[resource] = File.basename domain_path
        end
      end
      memo
    end
  end

  # Earth.init will load any specified domains, any needed ActiveRecord plugins, 
  # and will apply each domain model's schema to the database if the 
  # :apply_schemas option is given. See Earth.domains for the list of allowable 
  # domains.
  #
  # Earth.init should be performed after a connection is made to the database and 
  # before any domain models are referenced.
  def init(*args)
    options = args.last.is_a?(Hash) ? args.pop.symbolize_keys : {}
    domains = args.empty? ? [ :all ] : args.map(&:to_sym)

    _warn_unless_mysql_ansi_mode
    _load_plugins
    _load_domains domains, options
    _decorate_resources options
    _load_schemas search(domains), options
  end

  private
  
  def _warn_unless_mysql_ansi_mode
    if ActiveRecord::Base.connection.adapter_name =~ /mysql/i
      sql_mode = ActiveRecord::Base.connection.select_value("SELECT @@GLOBAL.sql_mode") + ActiveRecord::Base.connection.select_value("SELECT @@SESSION.sql_mode")
      $stderr.puts "[earth gem] Warning: MySQL detected, but PIPES_AS_CONCAT not set. Importing from scratch will fail. Consider setting sql-mode=ANSI in my.cnf." unless sql_mode =~ /pipes_as_concat/i
    end
  end
  
  # TODO sabshere don't use directories to specify domains
  # * you have 20 million data_miner.rb files which are easy to confuse
  # * you have to go all over the filesystem to figure things out
  def _load_domains(domains, options)
    return if domains.include? :none
    if domains.empty? or domains.include?(:all)
      # sabshere 9/16/10 why maintain this separately?
      require 'earth/all'
      require 'earth/data_miner' if options[:apply_schemas] or options[:load_data_miner]
    else
      domains.each do |domain| 
        require "earth/#{domain}"
        require "earth/#{domain}/data_miner" if options[:apply_schemas] or options[:load_data_miner]
      end
    end
  end

  def _load_plugins
    Dir[File.join(Earth.gem_root, 'vendor', '**', 'init.rb')].each do |pluginit|
      $:.unshift File.join(File.dirname(pluginit), 'lib')
      load pluginit
    end
  end
  
  def _append_pull_dependencies_step_to_data_miner(resource)
    resource_model = resource.constantize
    return if resource_model.data_miner_config.steps.any? { |step| step.description == :run_data_miner_on_parent_associations! }

    pull_dependencies_step = DataMiner::Process.new resource_model.data_miner_config, :run_data_miner_on_parent_associations!

    resource_model.data_miner_config.steps.push pull_dependencies_step
  end
  
  def _prepend_auto_upgrade_step_to_data_miner(resource)
    resource_model = resource.constantize
    return if resource_model.data_miner_config.steps.any? { |step| step.description == :auto_upgrade! }

    auto_upgrade_step = DataMiner::Process.new resource_model.data_miner_config, :auto_upgrade!

    resource_model.data_miner_config.steps.unshift auto_upgrade_step
  end
  
  TAPS_STEP = 'Tap the Brighter Planet data server'
  TAPS_SOURCE = 'http://carbon:neutral@data.brighterplanet.com:5000'
  def _prepend_taps_step_to_data_miner(resource)
    resource_model = resource.constantize
    return if resource_model.data_miner_config.steps.any? { |step| step.description == TAPS_STEP }
    
    taps_step = DataMiner::Tap.new resource_model.data_miner_config, TAPS_STEP, TAPS_SOURCE
    
    resource_model.data_miner_config.steps.unshift taps_step
  end
  
  def _decorate_resources(options)
    resources.each do |resource|
      next unless ::Object.const_defined?(resource)
      _append_pull_dependencies_step_to_data_miner resource
      if options[:apply_schemas] or options[:load_data_miner]
        _prepend_auto_upgrade_step_to_data_miner resource
      else
        _prepend_taps_step_to_data_miner resource
      end
    end
  end

  def _load_schemas(selected_resources, options)
    return unless options[:apply_schemas]
    selected_resources.each do |resource|
      resource.constantize.auto_upgrade!
    end
  end
end