require 'foreigner/connection_adapters/sql_2003'

module Foreigner
  module ConnectionAdapters
    module OracleEnhancedAdapter
      include Foreigner::ConnectionAdapters::Sql2003

      def foreign_keys(table_name)
        (owner, table_name) = @connection.describe(table_name)

        # RSI: changed select from all_constraints to user_constraints - much faster in large data dictionaries
        fks = select_rows(<<-SQL, 'Foreign Keys')
          select parent_c.table_name to_table, cc.column_name column_name, c.r_constraint_name name, c.delete_rule 
            from user_constraints c, user_constraints parent_c, user_cons_columns cc
          where c.owner = '#{owner}'
            and c.table_name = '#{table_name}'
            and c.r_constraint_name = parent_c.constraint_name
            and c.constraint_type = 'R'
            and cc.owner = c.owner
            and cc.constraint_name = c.constraint_name
        SQL

        fks.map do |row|
          options = {:column => row[1], :name => row[2]}
          if row[3] == 'CASCADE'
            options[:dependent] = :delete
          elsif $1 == 'SET NULL'
            options[:dependent] = :nullify
          end
          ForeignKeyDefinition.new(table_name, row[0], options)
        end
      end

      def foreign_keys_of(table_name)
        (owner, table_name) = @connection.describe(table_name)

        # RSI: changed select from all_constraints to user_constraints - much faster in large data dictionaries
        fks = select_rows(<<-SQL, 'Remote Foriegn Keys')
          select c.table_name, cc.column_name, c.delete_rule 
            from user_constraints c, user_constraints parent_c, user_cons_columns cc
          where c.owner = '#{owner}'
            and parent_c.table_name = '#{table_name}'
            and c.r_constraint_name = parent_c.constraint_name
            and c.constraint_type = 'R'
            and cc.owner = c.owner
            and cc.constraint_name = c.constraint_name
        SQL
        fks.map do |row| 
          dependent = case row[2] 
            when 'CASCADE'
              :destroy
            when 'SET NULL'
              :nullify
            end
          options = {:to_table => row[0].downcase, :foreign_key =>row[1].downcase.to_sym }
          options[:dependent] = dependent unless dependent.nil?
          options
        end
      end

      def constraints(table_name)
        (owner, table_name) = @connection.describe(table_name)

        # RSI: changed select from all_constraints to user_constraints - much faster in large data dictionaries
        fks = select_rows(<<-SQL, 'User Contraints')
          select c.constraint_name, c.search_condition
            from user_constraints c
          where c.owner = '#{owner}'
            and c.table_name = '#{table_name}'
            and c.constraint_type = 'C'
            and c.generated = 'USER NAME'
            and c.status = 'ENABLED'
        SQL
      end
    end
  end
end

module ActiveRecord
  module ConnectionAdapters
    OracleEnhancedAdapter.class_eval do
      include Foreigner::ConnectionAdapters::OracleEnhancedAdapter
    end
  end
end