#!/usr/bin/env python3
# Copyright 2014 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Scans the Chromium source of UseCounter, formats the Feature enum for
histograms.xml and merges it. This script can also generate a python code
snippet to put in uma.py of Chromium Dashboard. Make sure that you review the
output for correctness.
"""

import os
import re

import setup_modules  # pylint: disable=unused-import

import chromium_src.tools.metrics.common.path_util as path_util
import chromium_src.tools.metrics.histograms.update_histogram_enum as update_histogram_enum


USE_COUNTER_MOJOM_PATH = (
  'third_party/blink/public/mojom/use_counter/metrics/css_property_id.mojom'
)


def EnumToCssProperty(enum_name):
  """Converts a camel cased enum name to the lower case CSS property."""
  # The first group also searches for uppercase letters to account for single
  # uppercase letters, such as in "ZIndex" that need to convert to "z-index".

  # Special case total page measured for backward compat.
  if enum_name == 'TotalPagesMeasured':
    return 'Total Pages Measured'

  return re.sub(r'([a-zA-Z])([A-Z])', r'\1-\2', enum_name).lower()


def ReadCssProperties(filename):
  # Read the file as a list of lines
  with open(path_util.GetInputFile(filename)) as f:
    content = f.readlines()

  # Looking for a single line like "kFontWeight = 10,"
  ENUM_REGEX = re.compile(
    r"""k(\w+)\s*=       # capture the enum name
                              \s*(\d+),?       # capture the id
                              """,
    re.VERBOSE,
  )

  properties = {}
  for line in content:
    enum_match = ENUM_REGEX.search(line)
    if enum_match:
      enum_name = enum_match.group(1)
      property_id = int(enum_match.group(2))
      # Properties with id = 0 are invalid. Skip them.
      if property_id == 0:
        continue
      label = EnumToCssProperty(enum_name)
      if line.strip().startswith('//'):
        label += ' (obsolete)'
      properties[property_id] = label

  return properties


if __name__ == '__main__':
  update_histogram_enum.UpdateHistogramFromDict(
    'tools/metrics/histograms/metadata/blink/enums.xml',
    'MappedCSSProperties',
    ReadCssProperties(USE_COUNTER_MOJOM_PATH),
    USE_COUNTER_MOJOM_PATH,
    os.path.basename(__file__),
  )