# Support for enum. (Currently Mysql adapter only)
# 
# add_column :animals, :name, :enum, :enum_values => %w(bunnitard wolphin orca), :default => 'wolphin', :null => false
#
unless defined?(MigrationEnumSupport)
module MigrationEnumSupport
  
  module AbstractEnumSchema
    def self.included(base)
      base.class_eval do
        alias_method_chain :native_database_types, :enum unless method_defined?(:native_database_types_without_enum)
        alias_method_chain :add_column_options!, :enum unless method_defined?(:add_column_options_without_enum!)
      end
    end
  
    def native_database_types_with_enum
      types = native_database_types_without_enum
      types[:enum] = native_database_type_enum if respond_to?(:native_database_type_enum)
      types
    end
      
    def add_column_options_with_enum!(sql, options)
      add_enum_options!(sql, options) if options[:enum_values]
      add_column_options_without_enum!(sql, options)
    end
    
    def add_enum_options!(sql, options)
      enum_coulumn_sql options[:enum_values] if options[:enum_values]
      super
    end
  end
  
  #name other adapters the same as 
  module MysqlAdapter
    
    def self.included(base)
      base.send :include, AbstractEnumSchema
    end
    
    #override for specific adapter if necessary
    def native_database_type_enum
      { :name => "enum" }
    end
    
    def enum_coulumn_sql(sql, options)
       enum_values = Array(options[:enum_values]).collect{|val| quote(val.to_s)}.join(', ')
       sql << "(#{enum_values})"
    end
    
    #parse the sql column definition to get the enumerated vals
    # ex. enum('a','b','c')
    def enum_sql_to_enum_vals(column)
      match = column.sql_type.match(/enum\s?\((.*)\)/)
      (match ? match[1].split(/,\s*/) : [])
    end
  end
end


#dirty filthy hack to fix the dumper
#this is in place of replacing the really table method to account for enum
module SchemaDumperReplace
   def self.included(base)
    base.class_eval do
      private 
      alias_method_chain :table, :enum unless method_defined?(:table_without_enum)
    end
  end
  
  def table_with_enum(table_name, stream)
    table_stream = StringIO.new
    table_without_enum table_name, table_stream
    table_stream.rewind
    if (table_schema_txt = table_stream.read).include?(":string, :limit => 0")
      columns = @connection.columns(table_name)
      columns.each {|column|  
        enum_vals = @connection.enum_sql_to_enum_vals column
        next if enum_vals.blank?
        table_schema_txt.gsub!("t.column \"#{column.name}\", :string, :limit => 0", 
                               "t.column \"#{column.name}\", :enum, :enum_values => #{enum_vals.inspect}" )                 
      }
    end
    stream.print table_schema_txt
  end
end

#ActiveRecord::SchemaDumper.send(:include, SchemaDumperReplace)
ActiveRecord::ConnectionAdapters::MysqlAdapter.send :include, MigrationEnumSupport::MysqlAdapter 
end