#!/usr/bin/python

import argparse
import math
import os
import re
import subprocess
import sys

BENCHMARKS = []

def BENCHMARK(name, pattern):
  regex = re.compile(pattern + "\n" + r"elapsed: (\d+\.\d+)", re.MULTILINE)
  BENCHMARKS.append([name, regex, None])

BENCHMARK("binary_trees", """stretch tree of depth 15\t check: -1
32768\t trees of depth 4\t check: -32768
8192\t trees of depth 6\t check: -8192
2048\t trees of depth 8\t check: -2048
512\t trees of depth 10\t check: -512
128\t trees of depth 12\t check: -128
32\t trees of depth 14\t check: -32
long lived tree of depth 14\t check: -1""")

BENCHMARK("fib", r"""832040
832040
832040
832040
832040""")

BENCHMARK("method_call", r"""true
false""")

LANGUAGES = [
  ("wren",   "../build/Release/wren", ".wren"),
  ("js",     "node",                  ".js"),
  ("lua",    "lua",                   ".lua"),
  ("python", "python",                ".py"),
  ("ruby",   "ruby",                  ".rb")
]

# How many times to run a given benchmark. Should be an odd number to get the
# right median.
NUM_TRIALS = 7

results = []

def green(text):
  if sys.platform == 'win32':
    return text
  return '\033[32m' + text + '\033[0m'

def red(text):
  if sys.platform == 'win32':
    return text
  return '\033[31m' + text + '\033[0m'

def yellow(text):
  if sys.platform == 'win32':
    return text
  return '\033[33m' + text + '\033[0m'


def calc_stats(nums):
  """Calculates the mean, median, and std deviation of a list of numbers."""
  mean = sum(nums) / len(nums)
  nums.sort()
  median = nums[(len(nums) - 1) / 2]
  diffs = ((n - mean) * (n - mean) for n in nums)
  std_dev = math.sqrt(sum(diffs) / len(nums))
  return [mean, median, std_dev]


def run_benchmark_once(benchmark, language):
  args = [language[1], benchmark[0] + language[2]]
  out = subprocess.check_output(args, universal_newlines=True)
  match = benchmark[1].match(out)
  if match:
    return float(match.group(1))
  else:
    print "Incorrect output:"
    print out
    return None


def run_benchmark_language(benchmark, language):
  name = "{0} - {1}".format(benchmark[0], language[0])
  print "{0:22s}".format(name),

  if not os.path.exists(benchmark[0] + language[2]):
    print "No implementation for this language"
    return

  times = []
  for i in range(0, NUM_TRIALS):
    time = run_benchmark_once(benchmark, language)
    if not time:
      return
    times.append(time)
    sys.stdout.write(".")

  times.sort()
  stats = calc_stats(times)

  comparison = ""
  if language[0] == "wren":
    if benchmark[2] != None:
      ratio = 100 * stats[1] / benchmark[2]
      comparison =  "{0:.2f}% of baseline".format(ratio)
      if ratio > 105:
        comparison = red(comparison)
      if ratio < 95:
        comparison = green(comparison)
    else:
      comparison = "no baseline"
  else:
    # Hack: assumes wren is first language.
    wren_time = results[0][2]
    ratio = stats[1] / wren_time
    comparison =  "{0:.2f}x wren".format(ratio)
    if ratio < 1:
      comparison = red(comparison)
    if ratio > 1:
      comparison = green(comparison)

  print " mean: {0:.2f} median: {1:.2f} std_dev: {2:.2f} {3:s}".format(
      stats[0], stats[1], stats[2], comparison)

  results.append([name, times, stats[1]])
  return stats


def run_benchmark(benchmark, languages):
  for language in LANGUAGES:
    if not languages or language[0] in languages:
      run_benchmark_language(benchmark, language)
  graph_results()
  del results[0:len(results)]


def graph_results():
  print

  INCREMENT = {
    '-': 'o',
    'o': 'O',
    'O': '0',
    '0': '0'
  }

  # Scale everything by the highest time.
  highest = 0
  for result in results:
    time = max(result[1])
    if time > highest: highest = time

  print "{0:22s}0.0 {1:64.4f}".format("", highest)
  for result in results:
    line = ["-"] * 68
    for time in result[1]:
      index = int(time / highest * 67)
      line[index] = INCREMENT[line[index]]
    print "{0:22s}{1}".format(result[0], "".join(line))
  print


def read_baseline():
  if os.path.exists("baseline.txt"):
    with open("baseline.txt") as f:
      for line in f.readlines():
        name, mean, median = line.split(",")
        for benchmark in BENCHMARKS:
          if benchmark[0] == name:
            benchmark[2] = float(median)


def generate_baseline():
  print "generating baseline"
  baseline_text = ""
  for benchmark in BENCHMARKS:
    stats = run_benchmark_language(benchmark, LANGUAGES[0])
    baseline_text += ("{},{},{}\n".format(
          benchmark[0], stats[0], stats[1]))

  # Write them to a file.
  with open("baseline.txt", 'w') as out:
    out.write(baseline_text)


def main():
  parser = argparse.ArgumentParser(description="Run the benchmarks")
  parser.add_argument("benchmark", nargs='?',
      default="all",
      help="The benchmark to run")
  parser.add_argument("--generate-baseline",
      action="store_true",
      help="Generate a baseline file")
  parser.add_argument("-l", "--language",
      action="append",
      help="Which language(s) to run benchmarks for")

  args = parser.parse_args()

  if args.generate_baseline:
    generate_baseline()
    return

  read_baseline()

  if args.benchmark == "all":
    for benchmark in BENCHMARKS:
      run_benchmark(benchmark, args.language)
    return

  # Run the given benchmark.
  for benchmark in BENCHMARKS:
    if benchmark[0] == args.benchmark:
      run_benchmark(benchmark, args.language)

main()