"""Compilation of utility functions for working with Android.mk and make."""

from __future__ import absolute_import
import collections
import os
import re

# Example: path/to/file.c:123:4: error: this is an error
_MAKE_ERROR_PATTERN = (r'^(?P<filename>[^:]+):(?P<linenum>\d+):(?P<column>\d+):'
                       r' error: (?P<err_msg>.*)$')
_MAKE_TOO_MANY_ERRORS_MSG = 'Too many errors! See the logs for the rest.'


def make_error_to_comments(make_output, directory):
  """Convert a make failure message to comments for a gerrit review.

  In general, a when make has an error it prints to stderr and it looks like:

  [...snip...]
  external/iw/wowlan.c:27:3: error: expected ')' before 'return'
    return 1;
    ^
  external/iw/wowlan.c:182:1: error: expected expression before '}' token
   }
   ^
  cc1.elf: some warnings being treated as errors
  make: *** [out/obj/EXECUTABLES/iw_intermediates/wowlan.o] Error 1
  [...snip...]

  And this extracts out the 'error' lines from the rest of the log.

  Args:
    make_output: stderr output from a make build command. (Note: it's possible
        this may contain output from other commands. In general though, make
        errors occur early in the build process and stop the build.)
    directory: The path to strip off of the beginning of filenames in the
        make output. Example:
          make errors are for "path/to/your/files.cc"
          directory == "path/to" => comments are for "your/files.cc"

  Returns:
    A dictionary of file comments to be added to a review.
    Keys are filenames and values are lists of dictionaries with 'line' and
    'message' entries.
    { 'path/to/file.cc': [{'line': 5, 'message': 'error!'}, ...]}
    An empty dict is returned if no comments are found.
  """
  comments = collections.defaultdict(list)

  for line in make_output.splitlines():
    match = re.match(_MAKE_ERROR_PATTERN, line)
    if match:
      filename = match.group('filename')
      # Strip off directory name and slash
      if directory and filename.startswith(directory):
        filename = filename[len(directory) + len(os.path.sep):]
      linenum = int(match.group('linenum'))
      comments[filename].append({'line': linenum, 'message': line})

  return comments