namespace :db do
  desc "Migrate all the databases found in sitesdb through scripts in db/migrate. Target specific version with VERSION=x"
  task :migrate_all => :environment do

    adapter  = "mysql"
    host     = "mysql_host"
    username = "mysql_user"
    password = "mysql_pass"
    sitesdb  = "projects"
    prefix   = "project_"

    # there is a #{sitesdb}.sites table with string column database
    class Site < ActiveRecord::Base
    end

    ActiveRecord::Base.establish_connection :adapter  => adapter,
                                            :host     => host,
                                            :username => username,
                                            :password => password,
                                            :database => sitesdb

    sites = Site.find(:all)
    sites.each do |site|
      ActiveRecord::Base.establish_connection :adapter  => adapter,
                                              :host     => host,
                                              :username => username,
                                              :password => password,
                                              :database => "#{prefix}#{site.database}"
      ActiveRecord::Migrator.migrate("db/migrate/", ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
      Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
    end
  end
end