module JdbcSpec
  module MsSQL
    module Column
      def simplified_type(field_type)
        case field_type
          when /int|bigint|smallint|tinyint/i                        then :integer
          when /float|double|decimal|money|numeric|real|smallmoney/i then @scale == 0 ? :integer : :float
          when /datetime|smalldatetime/i                             then :datetime
          when /timestamp/i                                          then :timestamp
          when /time/i                                               then :time
          when /text|ntext/i                                         then :text
          when /binary|image|varbinary/i                             then :binary
          when /char|nchar|nvarchar|string|varchar/i                 then :string
          when /bit/i                                                then :boolean
          when /uniqueidentifier/i                                   then :string
        end
      end

      def type_cast(value)
        return nil if value.nil? || value =~ /^\s*null\s*$/i
        case type
        when :string    then value
        when :integer   then value == true || value == false ? value == true ? 1 : 0 : value.to_i
        when :primary_key then value == true || value == false ? value == true ? 1 : 0 : value.to_i 
        when :float     then value.to_f
        when :datetime  then cast_to_datetime(value)
        when :timestamp then cast_to_time(value)
        when :time      then cast_to_time(value)
        when :date      then cast_to_datetime(value)
        when :boolean   then value == true or (value =~ /^t(rue)?$/i) == 0 or value.to_s == '1'
        else value
        end
      end

      def cast_to_time(value)
        return value if value.is_a?(Time)
        time_array = ParseDate.parsedate(value)
        time_array[0] ||= 2000
        time_array[1] ||= 1
        time_array[2] ||= 1
        Time.send(ActiveRecord::Base.default_timezone, *time_array) rescue nil
      end

      def cast_to_datetime(value)
        if value.is_a?(Time)
          if value.year != 0 and value.month != 0 and value.day != 0
            return value
          else
            return Time.mktime(2000, 1, 1, value.hour, value.min, value.sec) rescue nil
          end
        end
        return cast_to_time(value) if value.is_a?(Date) or value.is_a?(String) rescue nil
        value
      end

      # These methods will only allow the adapter to insert binary data with a length of 7K or less
      # because of a SQL Server statement length policy.
      def self.string_to_binary(value)
        value.gsub(/(\r|\n|\0|\x1a)/) do
          case $1
            when "\r"   then  "%00"
            when "\n"   then  "%01"
            when "\0"   then  "%02"
            when "\x1a" then  "%03"
          end
        end
      end

      def self.binary_to_string(value)
        value.gsub(/(%00|%01|%02|%03)/) do
          case $1
            when "%00"    then  "\r"
            when "%01"    then  "\n"
            when "%02\0"  then  "\0"
            when "%03"    then  "\x1a"
          end
        end
      end
    end
    
    def modify_types(tp)
      tp[:primary_key] = "int NOT NULL IDENTITY(1, 1) PRIMARY KEY"
      tp[:integer][:limit] = nil
      tp[:boolean][:limit] = nil
      tp[:binary] = { :name => "image"}
      tp
    end

    def quote(value, column = nil)
      if column && column.type == :primary_key
        return value.to_s
      end
        case value
          when String                
            if column && column.type == :binary && column.class.respond_to?(:string_to_binary)
              val = quote_string(column.class.string_to_binary(value))
              "'#{val}'"
            else
              "'#{quote_string(value)}'"
            end
          when NilClass              then "NULL"
          when TrueClass             then '1'
          when FalseClass            then '0'
          when Float, Fixnum, Bignum then value.to_s
          when Date                  then "'#{value.to_s}'" 
          when Time, DateTime        then "'#{value.strftime("%Y-%m-%d %H:%M:%S")}'"
          else                            "'#{quote_string(value.to_yaml)}'"
        end
      end

      def quote_string(string)
        string.gsub(/\'/, "''")
      end

      def quoted_true
        "1"
      end
      
      def quoted_false
        "0"
      end

      def quote_column_name(name)
        "[#{name}]"
      end

    def add_limit_offset!(sql, options)
      if options[:limit] and options[:offset]
        total_rows = @connection.select_all("SELECT count(*) as TotalRows from (#{sql.gsub(/\bSELECT\b/i, "SELECT TOP 1000000000")}) tally")[0][:TotalRows].to_i
        if (options[:limit] + options[:offset]) >= total_rows
          options[:limit] = (total_rows - options[:offset] >= 0) ? (total_rows - options[:offset]) : 0
        end
        sql.sub!(/^\s*SELECT/i, "SELECT * FROM (SELECT TOP #{options[:limit]} * FROM (SELECT TOP #{options[:limit] + options[:offset]} ")
        sql << ") AS tmp1"
        if options[:order]
          options[:order] = options[:order].split(',').map do |field|
            parts = field.split(" ")
            tc = parts[0]
            if sql =~ /\.\[/ and tc =~ /\./ # if column quoting used in query
              tc.gsub!(/\./, '\\.\\[')
              tc << '\\]'
            end
            if sql =~ /#{tc} AS (t\d_r\d\d?)/
              parts[0] = $1
            end
            parts.join(' ')
          end.join(', ')
          sql << " ORDER BY #{change_order_direction(options[:order])}) AS tmp2 ORDER BY #{options[:order]}"
        else
          sql << " ) AS tmp2"
        end
      elsif sql !~ /^\s*SELECT (@@|COUNT\()/i
        sql.sub!(/^\s*SELECT([\s]*distinct)?/i) do
          "SELECT#{$1} TOP #{options[:limit]}"
        end unless options[:limit].nil?
      end
    end
    
    def recreate_database(name)
      drop_database(name)
      create_database(name)
    end
    
    def drop_database(name)
      execute "DROP DATABASE #{name}"
    end

    def create_database(name)
      execute "CREATE DATABASE #{name}"
    end

      def rename_table(name, new_name)
        execute "EXEC sp_rename '#{name}', '#{new_name}'"
      end
      
      def rename_column(table, column, new_column_name)
        execute "EXEC sp_rename '#{table}.#{column}', '#{new_column_name}'"
      end
      
      def change_column(table_name, column_name, type, options = {}) #:nodoc:
        sql_commands = ["ALTER TABLE #{table_name} ALTER COLUMN #{column_name} #{type_to_sql(type, options[:limit])}"]
        if options[:default]
          remove_default_constraint(table_name, column_name)
          sql_commands << "ALTER TABLE #{table_name} ADD CONSTRAINT DF_#{table_name}_#{column_name} DEFAULT #{options[:default]} FOR #{column_name}"
        end
        sql_commands.each {|c|
          execute(c)
        }
      end
      
      def remove_column(table_name, column_name)
        remove_default_constraint(table_name, column_name)
        execute "ALTER TABLE #{table_name} DROP COLUMN #{column_name}"
      end
      
      def remove_default_constraint(table_name, column_name)
        defaults = select "select def.name from sysobjects def, syscolumns col, sysobjects tab where col.cdefault = def.id and col.name = '#{column_name}' and tab.name = '#{table_name}' and col.id = tab.id"
        defaults.each {|constraint|
          execute "ALTER TABLE #{table_name} DROP CONSTRAINT #{constraint["name"]}"
        }
      end
      
      def remove_index(table_name, options = {})
        execute "DROP INDEX #{table_name}.#{index_name(table_name, options)}"
      end
  end
end