#!/usr/bin/env python3
import bz2
import sys
import math
import numbers
import dictdiffer
from collections import Counter

from tools.lib.logreader import LogReader

EPSILON = sys.float_info.epsilon


def save_log(dest, log_msgs, compress=True):
  dat = b"".join(msg.as_builder().to_bytes() for msg in log_msgs)

  if compress:
    dat = bz2.compress(dat)

  with open(dest, "wb") as f:
    f.write(dat)


def remove_ignored_fields(msg, ignore):
  msg = msg.as_builder()
  for key in ignore:
    attr = msg
    keys = key.split(".")
    if msg.which() != keys[0] and len(keys) > 1:
      continue

    for k in keys[:-1]:
      try:
        attr = getattr(msg, k)
      except AttributeError:
        break
    else:
      v = getattr(attr, keys[-1])
      if isinstance(v, bool):
        val = False
      elif isinstance(v, numbers.Number):
        val = 0
      else:
        raise NotImplementedError
      setattr(attr, keys[-1], val)
  return msg.as_reader()


def get_field_tolerance(diff_field, field_tolerances):
  diff_field_str = diff_field[0]
  for s in diff_field[1:]:
    # loop until number in field
    if not isinstance(s, str):
      break
    diff_field_str += '.'+s
  if diff_field_str in field_tolerances:
    return field_tolerances[diff_field_str]


def compare_logs(log1, log2, ignore_fields=None, ignore_msgs=None, tolerance=None, field_tolerances=None):
  if ignore_fields is None:
    ignore_fields = []
  if ignore_msgs is None:
    ignore_msgs = []
  if field_tolerances is None:
    field_tolerances = {}
  default_tolerance = EPSILON if tolerance is None else tolerance

  log1, log2 = (list(filter(lambda m: m.which() not in ignore_msgs, log)) for log in (log1, log2))

  if len(log1) != len(log2):
    cnt1 = Counter(m.which() for m in log1)
    cnt2 = Counter(m.which() for m in log2)
    raise Exception(f"logs are not same length: {len(log1)} VS {len(log2)}\n\t\t{cnt1}\n\t\t{cnt2}")

  diff = []
  for msg1, msg2 in zip(log1, log2):
    if msg1.which() != msg2.which():
      print(msg1, msg2)
      raise Exception("msgs not aligned between logs")

    msg1_bytes = remove_ignored_fields(msg1, ignore_fields).as_builder().to_bytes()
    msg2_bytes = remove_ignored_fields(msg2, ignore_fields).as_builder().to_bytes()

    if msg1_bytes != msg2_bytes:
      msg1_dict = msg1.to_dict(verbose=True)
      msg2_dict = msg2.to_dict(verbose=True)

      dd = dictdiffer.diff(msg1_dict, msg2_dict, ignore=ignore_fields)

      # Dictdiffer only supports relative tolerance, we also want to check for absolute
      # TODO: add this to dictdiffer
      def outside_tolerance(diff):
        try:
          if diff[0] == "change":
            field_tolerance = default_tolerance
            if (tol := get_field_tolerance(diff[1], field_tolerances)) is not None:
              field_tolerance = tol
            a, b = diff[2]
            finite = math.isfinite(a) and math.isfinite(b)
            if finite and isinstance(a, numbers.Number) and isinstance(b, numbers.Number):
              return abs(a - b) > max(field_tolerance, field_tolerance * max(abs(a), abs(b)))
        except TypeError:
          pass
        return True

      dd = list(filter(outside_tolerance, dd))

      diff.extend(dd)
  return diff


if __name__ == "__main__":
  log1 = list(LogReader(sys.argv[1]))
  log2 = list(LogReader(sys.argv[2]))
  print(compare_logs(log1, log2, sys.argv[3:]))
