#!/usr/bin/ruby

require 'test/unit'
require 'flexnbd'
require 'test_file_writer'

class NBDScenarios < Test::Unit::TestCase
  def setup
    @blocksize = 1024
    @filename1 = ".flexnbd.test.#{$$}.#{Time.now.to_i}.1"
    @filename2 = ".flexnbd.test.#{$$}.#{Time.now.to_i}.2"
    @ip = "127.0.0.1"
    @available_ports = [*40000..41000] - listening_ports
    @port1 = @available_ports.shift
    @port2 = @available_ports.shift
    @nbd1 = FlexNBD.new("../flexnbd", @ip, @port1)
  end 
  
  def teardown
    @nbd1.kill rescue nil
    [@filename1, @filename2].each do |f|
      File.unlink(f) if File.exists?(f)
    end
  end
  
  def test_read1
    writefile1("f"*64)
    serve1
    
    [0, 12, 63].each do |num|
    
      assert_equal(
        @nbd1.read(num*@blocksize, @blocksize), 
        @file1.read(num*@blocksize, @blocksize)
      )
    end
    
    [124, 1200, 10028, 25488].each do |num|
      assert_equal(@nbd1.read(num, 4), @file1.read(num, 4))
    end
  end
  
  # Check that we're not 
  #
  def test_writeread1
    writefile1("0"*64)
    serve1
    
    [0, 12, 63].each do |num|
      data = "X"*@blocksize
      @nbd1.write(num*@blocksize, data)
      assert_equal(data, @file1.read(num*@blocksize, data.size))
      assert_equal(data, @nbd1.read(num*@blocksize, data.size))
    end
  end
  
  # Check that we're not overstepping or understepping where our writes end
  # up.
  #
  def test_writeread2
    writefile1("0"*1024)
    serve1
    
    d0 = "\0"*@blocksize
    d1 = "X"*@blocksize
    (0..63).each do |num|
      @nbd1.write(num*@blocksize*2, d1)
    end
    (0..63).each do |num|
      assert_equal(d0, @nbd1.read(((2*num)+1)*@blocksize, d0.size))
    end
  end
  
  protected
  def serve1(*acl)
    @nbd1.serve(@ip, @port1, @filename1, *acl)
  end
  
  def writefile1(data)
    @file1 = TestFileWriter.new(@filename1, @blocksize).write(data)
  end
  
  def listening_ports
    `netstat -ltn`.
      split("\n").
      map { |x| x.split(/\s+/) }[2..-1].
      map { |l| l[3].split(":")[-1].to_i }
  end
end