require "benchmark/ips"
require "securerandom"

require "ob64"
require "base64"

$run_encode_benchmark = false
$run_decode_benchmark = false
$run_urlsafe_encode_benchmark = false
$run_urlsafe_decode_benchmark = true

def to_size(bytes)
  bytes >= 2**20 ? "#{bytes / 2**20} MB" : "#{bytes / 2**10} kB"
end

def each_block
  [
    [1, :kb],
    [4, :kb],
    [64, :kb],
    [1, :mb],
    [10, :mb],
    [64, :mb]
  ].each do |(n, unit)|
    yield(n * 2**({kb: 10, mb: 20}.fetch(unit)))
  end
end

def benchmark(setup_block)
  each_block do |size|
    setup_block.call(size)
    GC.start
    puts "\n\n#{"=" * 60}\nbenchmark with block size #{to_size(size)}"
    yield
  end
end

def encode_benchmark(&block)
  benchmark(
    lambda { |size| $unencoded = File.open("/dev/urandom") { |f| f.read(size) } },
    &block
  )
end

def decode_benchmark(&block)
  benchmark(
    lambda { |size| $encoded = SecureRandom.base64(size) },
    &block
  )
end

encode_benchmark do
  Benchmark.ips do |x|
    x.time = 5
    x.warmup = 2

    x.report("base64 .strict_encode64") do
      Base64.strict_encode64($unencoded)
    end

    x.report("ob64 .encode") do
      Ob64.encode($unencoded)
    end

    x.compare!
  end
end if $run_encode_benchmark

decode_benchmark do
  Benchmark.ips do |x|
    x.time = 5
    x.warmup = 2

    x.report("base64 .strict_decode64") do
      Base64.strict_decode64($encoded)
    end

    x.report("ob64 .decode") do
      Ob64.decode($encoded)
    end

    x.compare!
  end
end if $run_decode_benchmark

encode_benchmark do
  Benchmark.ips do |x|
    x.time = 5
    x.warmup = 2

    x.report("base64 .urlsafe_encode64") do
      Base64.urlsafe_encode64($unencoded)
    end

    x.report("ob64 .urlsafe_encode") do
      Ob64.urlsafe_encode($unencoded)
    end

    x.compare!
  end
end if $run_urlsafe_encode_benchmark

decode_benchmark do
  Benchmark.ips do |x|
    x.time = 5
    x.warmup = 2

    x.report("base64 .urlsafe_decode64") do
      Base64.urlsafe_decode64($encoded)
    end

    x.report("ob64 .urlsafe_decode") do
      Ob64.urlsafe_decode($encoded)
    end

    x.compare!
  end
end if $run_urlsafe_decode_benchmark