gistfile1.txt

require 'sequel'

# Database
#
# A helper class to wrap calls to Sequel Database, primarily for getting a database from a YAML config
# file and for migrating.
class Database
  
  @@configuration_file = File.join( File.dirname(__FILE__), "../config/database.yml" )
  raise Exception.new("No '#{@@configuration_file}' file was found. ") if @@configuration_file.nil?
  
  @@migration_path = File.join( File.dirname(__FILE__), "../db/migrations" )
  
  @@configuration     = YAML.load( File.open( @@configuration_file ) )
  
  @@current_database  = nil 
  
  def self.for_environment( environment, reload = false )
    @@current_database = nil if reload
    current_or_connect_to_database_for_environment( environment )
  end
  
  def self.migrate( environment, target = nil, current = nil )
    Sequel::Migrator.apply( for_environment( environment ), @@migration_path, target, current )
  end
  
  def self.reset( environment )
    db = current_or_connect_to_database_for_environment( environment )
    db.tables.each do |table|
      db.drop_table table
    end
    migrate( environment )
  end
  
  private
  
  def self.current_or_connect_to_database_for_environment( environment )
    @@current_database ||= connect_to_database_for_environment( environment )
  end
  
  def self.connect_to_database_for_environment( environment )
    Sequel.connect( connection_string_for( environment ) )
  end
  
  def self.connection_string_for( environment )
    config      = @@configuration[environment.to_s]
    unless config.nil?
      adapter     = config['adapter']
      database    = config['database'] 
      username    = config['username']
      password    = config['password']
      host        = config['host']
      port        = config['port']

      database_connection_string = "#{adapter}:"
      unless username.blank?
        database_connection_string << username 
        database_connection_string << ":#{password}" unless password.blank?
      end
      unless host.blank?
        database_connection_string << "@#{host}"
        database_connection_string << ":#{port}" unless port.blank?
      end
      database_connection_string << (database.blank? ? "/" : "//#{database}")    
    else
      raise Exception.new("No database found for '#{environment}' environment.  Please add to #{@@configuration_file}")
    end
  end
  
end