require File.dirname(__FILE__) + '/../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

end