require 'activefacts/metamodel'
require 'activefacts/rmap'
require 'active_support'
require 'digest/sha1'

module ActiveFacts
  module RMap
    def self.rails_name_trunc name
      if name.length > 63
        hash = Digest::SHA1.hexdigest name
        name = name[0, 53] + '__' + hash[0, 8]
      end
      name
    end

    def self.rails_plural_name name
      # Crunch spaces and pluralise the first part, all in snake_case
      name.pop if name.is_a?(Array) and name.last == []
      name = name[0]*'_' if name.is_a?(Array) and name.size == 1
      if name.is_a?(Array)
        name = ActiveSupport::Inflector.tableize((name[0]*'_').gsub(/\s+/, '_')) +
          '_' +
          ActiveSupport::Inflector.underscore((name[1..-1].flatten*'_').gsub(/\s+/, '_'))
      else
        ActiveSupport::Inflector.tableize(name.gsub(/\s+/, '_'))
      end
    end

    def self.rails_singular_name name
      # Crunch spaces and convert to snake_case
      name = name.flatten*'_' if name.is_a?(Array)
      ActiveSupport::Inflector.underscore(name.gsub(/\s+/, '_'))
    end

    class Column
      def rails_name
        RMap::rails_singular_name(name('_'))
      end

      def rails_type
        type_name, params, constraints = *type()
        rails_type = case type_name
          when /^Auto ?Counter$/i
            'serial'        # REVISIT: Need to detect surrogate ID fields and handle them correctly

          when /^[Ug]uid$/i
            'uuid'

          when /^Unsigned ?Integer$/i,
            /^Integer$/i,
            /^Signed ?Integer$/i,
            /^Unsigned ?Small ?Integer$/i,
            /^Signed ?Small ?Integer$/i,
            /^Unsigned ?Tiny ?Integer$/i
            length = nil
            'integer'

          when /^Decimal$/i
            'decimal'

          when /^Float$/i, /^Double$/i, /^Real$/i
            'float'

          when /^Fixed ?Length ?Text$/i, /^Char$/i
            'string'
          when /^Variable ?Length ?Text$/i, /^String$/i
            'string'
          when /^Large ?Length ?Text$/i, /^Text$/i
            'text'

          when /^Date ?And ?Time$/i, /^Date ?Time$/i
            'datetime'
          when /^Date$/i
            'datetime'
          when /^Time$/i
            'time'
          when /^Auto ?Time ?Stamp$/i
            'timestamp'

          when /^Money$/i
            'decimal'
          when /^Picture ?Raw ?Data$/i, /^Image$/i, /^Variable ?Length ?Raw ?Data$/i, /^Blob$/i
            'binary'
          when /^BIT$/i, /^Boolean$/i
            'boolean'
          else
            type_name # raise "ActiveRecord type unknown for standard type #{type}"
          end
        [rails_type, params[:length]]
      end
    end

    class Index
      def rails_name
        column_names = columns.map{|c| c.rails_name }
        index_name = "index_#{on.rails_name+'_on_'+column_names*'_'}"
        RMap.rails_name_trunc index_name
      end
    end

    class ForeignKey
      def rails_from_association_name
        RMap::rails_singular_name(to_name.join('_'))
      end

      def rails_to_association
        jump = jump_reference
        if jump.is_one_to_one
          [ "has_one", RMap::rails_singular_name(from_name)]
        else
          [ "has_many", RMap::rails_plural_name(from_name)]
        end
      end
    end
  end

  module Metamodel
    class ObjectType
      def rails_name
        RMap::rails_plural_name(name)
      end

      def rails_singular_name
        RMap::rails_singular_name(name)
      end

      def rails_class_name
        ActiveSupport::Inflector.camelize(name.gsub(/\s+/, '_'))
      end
    end
  end
end