require 'active_record'
require 'logger'


module DbInstall
  def self.migrate migrations_path, db_config_path
    @CFG_D = db_config_path

    self.connection_data

    begin
      self.drop_database @connection_data['test_db']
    rescue
      puts "DB drop: Could not find database #{@connection_data['database']}"
    end

    self.create_database @connection_data['test_db']

    self.with_db do
      ActiveRecord::Migrator.migrate(migrations_path, ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
    end
  end

  def connection_data
    @connection_data ||= YAML.load_file("#{@CFG_D}/database.yml")
  end

  def with_db &block
    begin
      ActiveRecord::Base.establish_connection(connection_data['test_db'])
      ActiveRecord::Base.logger = Logger.new(STDOUT)
      ActiveRecord::Base.logger.level = Logger::WARN
      yield connection_data
    rescue
      raise
    ensure
      ActiveRecord::Base.connection.disconnect!
    end
  end

  # copied and modified activerecord-3.0.4/lib/active_record/railties/database.rake
  def drop_database(config)
    case config['adapter']
    when /sqlite/
      FileUtils.rm (config['database'])
    when /mysql/
      ActiveRecord::Base.establish_connection(config)
      ActiveRecord::Base.connection.drop_database config['database']
    when 'postgresql'
      ActiveRecord::Base.establish_connection(config.merge('database' => 'postgres', 'schema_search_path' => 'public'))
      ActiveRecord::Base.connection.drop_database config['database']
    end
  end

  # dito
  def create_database(config)
    case config['adapter']

    when /mysql/
      require 'mysql'
      @charset   = ENV['CHARSET']   || 'utf8'
      @collation = ENV['COLLATION'] || 'utf8_unicode_ci'
      creation_options = {:charset => (config['charset'] || @charset), :collation => (config['collation'] || @collation)}
      error_class = config['adapter'] =~ /mysql2/ ? Mysql2::Error : Mysql::Error
      access_denied_error = 1045
      begin
        ActiveRecord::Base.establish_connection(config.merge('database' => nil))
        ActiveRecord::Base.connection.create_database(config['database'], creation_options)
        ActiveRecord::Base.establish_connection(config)
      rescue error_class => sqlerr
        if sqlerr.errno == access_denied_error
          print "#{sqlerr.error}. \nPlease provide the root password for your mysql installation\n>"
          root_password = $stdin.gets.strip
          grant_statement = "GRANT ALL PRIVILEGES ON #{config['database']}.* " \
          "TO '#{config['username']}'@'localhost' " \
          "IDENTIFIED BY '#{config['password']}' WITH GRANT OPTION;"
          ActiveRecord::Base.establish_connection(config.merge('database' => nil, 'username' => 'root', 'password' => root_password))
          ActiveRecord::Base.connection.create_database(config['database'], creation_options)
          ActiveRecord::Base.connection.execute grant_statement
          ActiveRecord::Base.establish_connection(config)
        else
          $stderr.puts sqlerr.error
          $stderr.puts "Couldn't create database for #{config.inspect}, charset: #{config['charset'] || @charset}, collation: #{config['collation'] || @collation}"
          $stderr.puts "(if you set the charset manually, make sure you have a matching collation)" if config['charset']
        end
      end
    when 'postgresql'
      @encoding = config['encoding'] || ENV['CHARSET'] || 'utf8'
      begin
        ActiveRecord::Base.establish_connection(config.merge('database' => 'postgres', 'schema_search_path' => 'public'))
        ActiveRecord::Base.connection.create_database(config['database'], config.merge('encoding' => @encoding))
        ActiveRecord::Base.establish_connection(config)
      rescue Exception => e
        $stderr.puts e, *(e.backtrace)
        $stderr.puts "Couldn't create database for #{config.inspect}"
      end
    end

  end

end