#!/usr/bin/env ruby

require File.expand_path(File.dirname(__FILE__)) + '/../test/test_helper.rb'
require 'benchmark'

RUNS = 20

def measure(instance, &block)
  samples = []
  $errors = 0
  RUNS.times do
    if block
      samples << Benchmark.measure(&block).real * 1000
    else
      samples << Benchmark.measure do
        DATA.each do |i|
          instance[i] = i
        end
        DATA.each do |i|
          $errors += 1 unless instance[i] == i
        end
      end.real * 1000
    end
  end
  puts "#{$errors} ERRORS" if $errors > 0
  instance.clear
  samples
end

DICT = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890'.freeze
def uniform
  min, max = 3, 1024
  1000.times.map do
    n = rand(max - min) + max
    (1..n).map { DICT[rand(DICT.length)] }.join
  end
end
DATA = uniform

def run(instance, message = '', &blk)
  puts "Running benchmarks for #{instance.class.name} #{message}"
  measure instance, &blk
  report measure(instance, &blk)
  puts '=' * 64
ensure
  instance.clear if instance.respond_to? :clear
  instance.close if instance.respond_to? :close
end

def report(samples)
  samples.sort!
  total  = samples.inject(:+)
  mean   = total / samples.length
  stddev = Math.sqrt(samples.inject(0) {|m, s| m += (s - mean) ** 2 } / samples.length)
  puts '%d samples, average time: %.4f ms, std. dev: %.4f ms' % [samples.length, mean, stddev]
  puts '95%% < %.4f ms' % samples.slice((samples.length * 0.95).to_i)
end

begin
  require 'dbm'
  run DBM.new(DB_PATH + '.dbm')
rescue Exception => ex
  puts "DBM not benchmarked: #{ex.message}"
end

begin
  require 'gdbm'
  run GDBM.new(DB_PATH + '.gdbm')
rescue Exception => ex
  puts "GDBM not benchmarked: #{ex.message}"
end

run Hash.new
db = Daybreak::DB.new DB_PATH
run db

db = Daybreak::DB.new DB_PATH
run db, 'with lock' do
  DATA.each do |i|
    db.lock { db[i] = i }
  end
  DATA.each do |i|
    db.lock { $errors += 1 unless db[i] == i }
  end
end

db = Daybreak::DB.new DB_PATH
run db, 'with load' do
  DATA.each do |i|
    db[i] = i
    db.sunrise
  end
  DATA.each do |i|
    $errors += 1 unless db[i] == i
    db.sunrise
  end
end

hash = DATA.reduce({}) {|m, v| m.merge! v => v }
db = Daybreak::DB.new DB_PATH
run db, 'bulk updates' do
  db.update hash
end

db = Daybreak::DB.new DB_PATH
run db, 'bulk updates, synced' do
  db.update! hash
end