super.rb

# * - Eqauls to
# / - Not equals to
# >, >=, <, <= works as expected
#
# Examples :
#
# Item.where(:colour * 'Red', :quanity > 10, :price <= 200)
# Post.where(:comments_count >= 1, :taggings_count < 5)
# User.where(:country / 'US') # Non american users

require "cases/helper"
require 'models/tag'
require 'models/tagging'
require 'models/post'
require 'models/topic'
require 'models/comment'
require 'models/reply'
require 'models/author'
require 'models/comment'
require 'models/entrant'
require 'models/developer'
require 'models/company'

class SuperCondition
  attr_reader :operation, :value

  def self.[](column, value, operation)
    SuperCondition.new(column, value, operation)
  end

  def initialize(column, value, operation)
    @column = column
    @value = value
    @operation = operation
  end

  def column
    @column.to_s
  end
end

class Symbol
  def *(value)
    SuperCondition[self, value, :eq]
  end

  def /(value)
    SuperCondition[self, value, :neq]
  end

  def >(value)
    SuperCondition[self, value, :gt]
  end

  def >=(value)
    SuperCondition[self, value, :gte]
  end

  def <(value)
    SuperCondition[self, value, :lt]
  end

  def <=(value)
    SuperCondition[self, value, :lte]
  end
end

module SuperWhere
  extend ActiveSupport::Concern

  included do
    alias_method_chain :where, :power
  end

  def where_with_power(*args)
    if Array.wrap(args).all? {|x| x.kind_of?(SuperCondition) }
      conditions = []

      args.each do |super_condition|
        if super_condition.column.include?('.')
          table, column = attr.split('.', 2)
          table = @klass.connection.quote_table_name(table)
        else
          table, column = @klass.table_name, super_condition.column
        end

        quoted_column_name = "#{table}.#{@klass.connection.quote_column_name(column)}"
        value = super_condition.value

        conditions << case super_condition.operation
        when :eq
          where_clause = @klass.send(:attribute_condition, quoted_column_name, value)
          replace_bind_variable(where_clause, value)
        when :neq
          replace_bind_variable("#{quoted_column_name} <> ?", value)
        when :gt
          replace_bind_variable("#{quoted_column_name} > ?", value)
        when :gte
          replace_bind_variable("#{quoted_column_name} >= ?", value)
        when :lt
          replace_bind_variable("#{quoted_column_name} < ?", value)
        when :lte
          replace_bind_variable("#{quoted_column_name} <= ?", value)
        end
      end

      relation = spawn
      conditions.each {|c| relation = relation.where(c) }
      relation
    else
      where_without_power(*args)
    end
  end

  private

  def replace_bind_variable(clause, value)
    @klass.send(:replace_bind_variables, clause, [value])
  end
end

class ActiveRecord::Relation
  include SuperWhere
end

class SuperRelationsTest < ActiveRecord::TestCase
  fixtures :authors, :topics, :entrants, :developers, :companies, :developers_projects, :accounts, :categories, :categorizations, :posts, :comments,
    :taggings

  def test_sanity
    assert_equal ["David"], Author.where(:name => 'David').map(&:name)
    assert_equal ['Mary'],  Author.where(["name = ?", 'Mary']).map(&:name)
    assert_equal ['Mary'],  Author.where("name = ?", 'Mary').map(&:name)
  end

  def test_super
    puts Author.where(:name * 'David', :author_address_id > 2).to_sql
    puts Post.where(:comments_count >= 1, :taggings_count < 5).to_sql
  end
end