require "socket"
require "csv"
require "yaml"
require "optparse"
require "fileutils"

@include_env = false
@result_file = nil
@iterations = 500
@best_of = 1
@mem_stats = false
@unicorn = false
@dump_heap = false

opts = OptionParser.new do |o|
  o.banner = "Usage: ruby bench.rb [options]"

  o.on("-n", "--with_default_env", "Include recommended Discourse env") do
    @include_env = true
  end
  o.on("-o", "--output [FILE]", "Output results to this file") do |f|
    @result_file = f
  end
  o.on("-i", "--iterations [ITERATIONS]", "Number of iterations to run the bench for") do |i|
    @iterations = i.to_i
  end
  o.on("-b", "--best_of [NUM]", "Number of times to run the bench taking best as result") do |i|
    @best_of = i.to_i
  end
  o.on("-d", "--heap_dump") do
    @dump_heap = true
    # We need an env var for config/boot.rb to enable allocation tracing prior to framework init
    ENV['DISCOURSE_DUMP_HEAP'] = "1"
  end
  o.on("-m", "--memory_stats") do
    @mem_stats = true
  end
  o.on("-u", "--unicorn", "Use unicorn to serve pages as opposed to thin") do
    @unicorn = true
  end
end
opts.parse!

def run(command, opt = nil)
  exit_status =
    if opt == :quiet
      system(command, out: "/dev/null", err: :out)
    else
      system(command, out: $stdout, err: :out)
    end

  abort("Command '#{command}' failed with exit status #{$?}") unless exit_status
end

begin
  require 'facter'
rescue LoadError
  run "gem install facter"
  # Facter requires CFPropertyList, but doesn't install it.
  run "gem install CFPropertyList"
  puts "please rerun script"
  exit
end

@timings = {}

def measure(name)
  start = Time.now
  yield
  @timings[name] = ((Time.now - start) * 1000).to_i
end

def prereqs
  puts "Be sure to following packages are installed:

sudo apt-get -y install build-essential libssl-dev libyaml-dev git libtool libxslt-dev libxml2-dev libpq-dev gawk curl pngcrush python-software-properties software-properties-common tasksel

sudo tasksel install postgresql-server
OR
apt-get install postgresql-server^

sudo apt-add-repository -y ppa:rwky/redis
sudo apt-get update
sudo apt-get install redis-server
  "
end

puts "Running bundle"
if run("bundle", :quiet)
  puts "Quitting, some of the gems did not install"
  prereqs
  exit
end

puts "Ensuring config is setup"

%x{which ab > /dev/null 2>&1}
unless $? == 0
  abort "Apache Bench is not installed. Try: apt-get install apache2-utils or brew install ab"
end

unless File.exists?("config/database.yml")
  puts "Copying database.yml.development.sample to database.yml"
  `cp config/database.yml.development-sample config/database.yml`
end

ENV["RAILS_ENV"] = "profile"

discourse_env_vars = %w(DISCOURSE_DUMP_HEAP RUBY_GC_HEAP_INIT_SLOTS RUBY_GC_HEAP_FREE_SLOTS RUBY_GC_HEAP_GROWTH_FACTOR RUBY_GC_HEAP_GROWTH_MAX_SLOTS RUBY_GC_MALLOC_LIMIT RUBY_GC_OLDMALLOC_LIMIT RUBY_GC_MALLOC_LIMIT_MAX RUBY_GC_OLDMALLOC_LIMIT_MAX RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR)

if @include_env
  puts "Running with tuned environment"
  discourse_env_vars - %w(RUBY_GC_MALLOC_LIMIT).each do |v|
    ENV.delete v
  end
else
  # clean env
  puts "Running with the following custom environment"
  discourse_env_vars.each do |w|
    puts "#{w}: #{ENV[w]}"
  end
end

def port_available?(port)
  server = TCPServer.open("0.0.0.0", port)
  server.close
  true
rescue Errno::EADDRINUSE
  false
end

@port = 60079

while !port_available? @port
  @port += 1
end

puts "Ensuring profiling DB exists and is migrated"
puts `bundle exec rake db:create`
`bundle exec rake db:migrate`

puts "Timing loading Rails"
measure("load_rails") do
  `bundle exec rake middleware`
end

puts "Populating Profile DB"
run("bundle exec ruby script/profile_db_generator.rb")

puts "Getting api key"
api_key = `bundle exec rake api_key:get`.split("\n")[-1]

def bench(path, name)
  puts "Running apache bench warmup"
  add = ""
  add = "-c 3 " if @unicorn
  `ab #{add} -n 20 -l "http://127.0.0.1:#{@port}#{path}"`
  puts "Benchmarking #{name} @ #{path}"
  `ab #{add} -n #{@iterations} -l -e tmp/ab.csv "http://127.0.0.1:#{@port}#{path}"`

  percentiles = Hash[*[50, 75, 90, 99].zip([]).flatten]
  CSV.foreach("tmp/ab.csv") do |percent, time|
    percentiles[percent.to_i] = time.to_i if percentiles.key? percent.to_i
  end

  percentiles
end

begin
  # critical cause cache may be incompatible
  puts "precompiling assets"
  run("bundle exec rake assets:precompile")

  pid =
    if @unicorn
      ENV['UNICORN_PORT'] = @port.to_s
      FileUtils.mkdir_p(File.join('tmp', 'pids'))
      spawn("bundle exec unicorn -c config/unicorn.conf.rb")
    else
      spawn("bundle exec thin start -p #{@port}")
    end

  while port_available? @port
    sleep 1
  end

  puts "Starting benchmark..."
  append = "?api_key=#{api_key}&api_username=admin1"

  # asset precompilation is a dog, wget to force it
  run "wget http://127.0.0.1:#{@port}/ -o /dev/null -O /dev/null"

  tests = [
    ["categories", "/categories"],
    ["home", "/"],
    ["topic", "/t/oh-how-i-wish-i-could-shut-up-like-a-tunnel-for-so/179"]
    # ["user", "/u/admin1/activity"],
  ]

  tests.concat(tests.map { |k, url| ["#{k}_admin", "#{url}#{append}"] })

  tests.each do |_, path|
    if `curl -s -I "http://127.0.0.1:#{@port}#{path}"` !~ /200 OK/
      raise "#{path} returned non 200 response code"
    end
  end

  # NOTE: we run the most expensive page first in the bench

  def best_of(a, b)
    return a unless b
    return b unless a

    a[50] < b[50] ? a : b
  end

  results = {}
  @best_of.times do
    tests.each do |name, url|
      results[name] = best_of(bench(url, name), results[name])
    end
  end

  puts "Your Results: (note for timings- percentile is first, duration is second in millisecs)"

  # Prevent using external facts because it breaks when running in the
  # discourse/discourse_bench docker container.
  Facter::Util::Config.external_facts_dirs = []
  facts = Facter.to_hash

  facts.delete_if { |k, v|
    !["operatingsystem", "architecture", "kernelversion",
    "memorysize", "physicalprocessorcount", "processor0",
    "virtual"].include?(k)
  }

  run("RAILS_ENV=profile bundle exec rake assets:clean")

  def get_mem(pid)
    YAML.load `ruby script/memstats.rb #{pid} --yaml`
  end

  mem = get_mem(pid)

  results = results.merge("timings" => @timings,
                          "ruby-version" => "#{RUBY_VERSION}-p#{RUBY_PATCHLEVEL}",
                          "rss_kb" => mem["rss_kb"],
                          "pss_kb" => mem["pss_kb"]).merge(facts)

  if @unicorn
    child_pids = `ps --ppid #{pid} | awk '{ print $1; }' | grep -v PID`.split("\n")
    child_pids.each do |child|
      mem = get_mem(child)
      results["rss_kb_#{child}"] = mem["rss_kb"]
      results["pss_kb_#{child}"] = mem["pss_kb"]
    end
  end

  puts results.to_yaml

  if @mem_stats
    puts
    puts open("http://127.0.0.1:#{@port}/admin/memory_stats#{append}").read
  end

  if @dump_heap
    puts
    puts open("http://127.0.0.1:#{@port}/admin/dump_heap#{append}").read
  end

  if @result_file
    File.open(@result_file, "wb") do |f|
      f.write(results)
    end
  end

ensure
  Process.kill "KILL", pid
end