require 'spec_helper'

describe Performant::Array do

  describe "memory_efficient_intersect" do
    it "should intersect empty arrays correctly" do
      arys = [[3,4], [1,2,3], []]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should handle intermediate empty results correctly" do
      arys = [[5,4], [1,2,3], [3,4,5,8,9]]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should intersect correctly" do
      arys = [[3,4], [1,2,3], [3,4,5,8,9]]

      Performant::Array.memory_efficient_intersect(arys).should == [3]
    end
    it "should intersect correctly again" do
      arys = [[1,2,3,5,6,7], [3,4,5,6,7,8,9], [3,4,5,6,7]]
      Performant::Array.memory_efficient_intersect(arys).should == [3,5,6,7]
    end
    it "should intersect many arrays" do
      arys = [[3,4,5,6,7], [1,2,3,5,6,7], [3,4,5,6,7,8,9], [1,2,3,4,5,6,7,8,9,10], [2,3,5,6,7,19], [1,2,3,4,5,6,7,8,9,10], [2,3,5,6,7,19]]

      Performant::Array.memory_efficient_intersect(arys).should == [3,5,6,7]
    end
    it "should handle random arrays" do
      proto = Array.new(100, 3_500_000)
      arys = [proto.map { |e| rand e }, proto.map { |e| rand e }, proto.map { |e| rand e }]

      Performant::Array.memory_efficient_intersect(arys).should == arys.inject(arys.shift.dup) { |total, ary| total & arys }
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [(1..50).to_a, (10_000..20_000).to_a << 7]

      # Brute force.
      #
      performance_of { Performant::Array.memory_efficient_intersect(arys) }.should < 0.001
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [(1..50).to_a, (10_000..20_000).to_a << 7]

      # &
      #
      performance_of do
        arys.inject(arys.shift.dup) do |total, ary|
          total & arys
        end
      end.should < 0.0015
    end
  end

  describe "memory_efficient_intersect with symbols" do
    it "should intersect empty arrays correctly" do
      arys = [[:c,:d], [:a,:b,:c], []]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should handle intermediate empty results correctly" do
      arys = [[:e,:d], [:a,:b,:c], [:c,:d,:e,:h,:i]]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should intersect correctly" do
      arys = [[:c,:d], [:a,:b,:c], [:c,:d,:e,:h,:i]]

      Performant::Array.memory_efficient_intersect(arys).should == [:c]
    end
    it "should intersect many arrays" do
      arys = [[:c,:d,:e,:f,:g], [:a,:b,:c,:e,:f,:g], [:c,:d,:e,:f,:g,:h,:i], [:a,:b,:c,:d,:e,:f,:g,:h,:i,:j], [:b,:c,:e,:f,:g,:s], [:a,:b,:c,:d,:e,:f,:g,:h,:i,:j], [:b,:c,:e,:f,:g,:s]]

      Performant::Array.memory_efficient_intersect(arys).should == [:c,:e,:f,:g]
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [(:'1'..:'50').to_a, (:'10_000'..:'20_000').to_a]

      # Brute force.
      #
      performance_of { Performant::Array.memory_efficient_intersect(arys) }.should < 0.001
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [(:'1'..:'50').to_a, (:'10_000'..:'20_000').to_a << 7]

      # &
      #
      performance_of do
        arys.inject(arys.shift.dup) do |total, ary|
          total & arys
        end
      end.should < 0.0015
    end
  end
  
  describe "memory_efficient_intersect with strings" do
    it "should intersect empty arrays correctly" do
      arys = [['c','d'], ['a','b','c'], []]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should handle intermediate empty results correctly" do
      arys = [['e','d'], ['a','b','c'], ['c','d','e','h','i']]

      Performant::Array.memory_efficient_intersect(arys).should == []
    end
    it "should intersect correctly" do
      arys = [['c','d'], ['a','b','c'], ['c','d','e','h','i']]

      Performant::Array.memory_efficient_intersect(arys).should == ['c']
    end
    it "should intersect many arrays" do
      arys = [['c','d','e','f','g'], ['a','b','c','e','f','g'], ['c','d','e','f','g','h','i'], ['a','b','c','d','e','f','g','h','i','j'], ['b','c','e','f','g','s'], ['a','b','c','d','e','f','g','h','i','j'], ['b','c','e','f','g','s']]

      Performant::Array.memory_efficient_intersect(arys).should == ['c','e','f','g']
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [('1'..'50').to_a, ('10000'..'20000').to_a]

      # Brute force - note that it is slower than the Symbols/Integers version.
      #
      performance_of { Performant::Array.memory_efficient_intersect(arys) }.should < 0.0015
    end
    it "should be optimal for many small arrays of length == 10" do
      arys = [('1'..'10').to_a, ('10'..'20').to_a, ['10'] + ('10000'..'20000').to_a]

      # Brute force - note that it is slower than the Symbols/Integers version.
      #
      performance_of { Performant::Array.memory_efficient_intersect(arys) }.should < 0.0015
    end
    it "should be optimal for 2 small arrays of 50/10_000" do
      arys = [('1'..'50').to_a, ('10000'..'20000').to_a << 7]

      # &
      #
      performance_of do
        arys.inject(arys.shift.dup) do |total, ary|
          total & arys
        end
      end.should < 0.0015
    end
  end

end