# Copyright (c) 2011, Google Inc. All rights reserved.
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import re


class CrashLogs(object):

    def __init__(self, host):
        self._host = host

    def find_newest_log(self, process_name, pid=None, include_errors=False, newer_than=None):
        if self._host.platform.is_mac():
            return self._find_newest_log_darwin(process_name, pid, include_errors, newer_than)
        return None

    def _log_directory_darwin(self):
        log_directory = self._host.filesystem.expanduser('~')
        log_directory = self._host.filesystem.join(log_directory, 'Library', 'Logs')
        if self._host.filesystem.exists(self._host.filesystem.join(log_directory, 'DiagnosticReports')):
            log_directory = self._host.filesystem.join(log_directory, 'DiagnosticReports')
        else:
            log_directory = self._host.filesystem.join(log_directory, 'CrashReporter')
        return log_directory

    def _find_newest_log_darwin(self, process_name, pid, include_errors, newer_than):
        def is_crash_log(basename):
            return basename.startswith(process_name + '_') and basename.endswith('.crash')

        log_directory = self._log_directory_darwin()
        logs = self._host.filesystem.files_under(
            log_directory,
            file_filter=lambda fs, dirname, basename: is_crash_log(basename))
        first_line_regex = re.compile(r'^Process:\s+(?P<process_name>.*) \[(?P<pid>\d+)\]$')
        errors = ''
        for path in reversed(sorted(logs)):
            try:
                if not newer_than or self._host.filesystem.mtime(path) > newer_than:
                    contents = self._host.filesystem.read_text_file(path)
                    match = first_line_regex.match(contents[0:contents.find('\n')])
                    if match and match.group('process_name') == process_name and (pid is None or int(match.group('pid')) == pid):
                        return errors + contents
            except IOError as error:
                if include_errors:
                    errors += "ERROR: Failed to read '%s': %s\n" % (path, error)
            except OSError as error:
                if include_errors:
                    errors += "ERROR: Failed to read '%s': %s\n" % (path, error)

        if include_errors and errors:
            return errors
        return None