require 'active_record'

module Apartment
  
  module Adapters
  
    class AbstractAdapter
      
      #   @constructor
      #   @param {Hash} config Database config
      #   @param {Hash} defaults Some default options
      # 
      def initialize(config, defaults)
        @config = config
        @defaults = defaults
      end
      
      #   Connect to db or schema, do stuff, reset (equivalent to a switch... do stuff... reset)
      # 
      #   @param {String} database Database or schema to connect to
      def process(database)
		    connect_to_new(database)
		    yield if block_given?
		  ensure
  		  reset
	    end
      
      #   Create new postgres schema
      # 
      #   @param {String} database Database name
  		def create(database)
        # TODO create_database unless using_schemas?

  			process(database) do
    			import_database_schema

    			# Manually init schema migrations table (apparently there were issues with Postgres when this isn't done)
    			ActiveRecord::Base.connection.initialize_schema_migrations_table
    			
          # Seed data if appropriate
          seed_data if Apartment.seed_after_create
  			end
  		end
    
      #   Reset the base connection
      def reset
        ActiveRecord::Base.establish_connection @config
      end
      
      # Switch to new connection (or schema if appopriate)
      def switch(database = nil)
        # Just connect to default db and return
  			return reset if database.nil?

        connect_to_new(database)
  		end
  		
  		def seed_data
	      load_or_abort("#{Rails.root}/db/seeds.rb")
      end
	    alias_method :seed, :seed_data
      
      # Return the current database name
      def current_database
        ActiveRecord::Base.connection.current_database
      end
      
      protected
      
        def create_schema
          # noop
        end
      
        def connect_to_new(database)
          ActiveRecord::Base.establish_connection multi_tenantify(database)
			  end
        
  	    def import_database_schema
  	      load_or_abort("#{Rails.root}/db/schema.rb")
  	    end
  	    
  	    # Return a new config that is multi-tenanted
        def multi_tenantify(database)
    			@config.clone.tap do |config|
    			  config['database'].gsub!(Rails.env.to_s, "#{database}_#{Rails.env}")
  			  end
    		end
        
        # Remove all non-alphanumeric characters
  	    def sanitize(database)
  	      database.gsub(/[\W]/,'')
        end
        
        # Whether or not to use postgresql schemas
        def using_schemas?
          false
        end
        
        def load_or_abort(file)
          if File.exists?(file)
            load(file)
          else
            abort %{#{file} doesn't exist yet}
          end
        end
      
    end
      
      
  
  end
end