#!/usr/bin/env python2
# -*- coding: utf-8 -*-
#
# Copyright 2008-2009 Zuza Software Foundation
#
# This file is part of Virtaal.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.

def label(code):
    if isinstance(code, str):
        return ('~', 0, code)    # built-in functions ('~' sorts at the end)
    else:
        return '%s %s:%d' % (code.co_name, code.co_filename, code.co_firstlineno)


class KCacheGrind(object):
    def __init__(self, profiler):
        self.data = profiler.getstats()
        self.out_file = None

    def output(self, out_file):
        self.out_file = out_file
        print >> out_file, 'events: Ticks'
        self._print_summary()
        for entry in self.data:
            self._entry(entry)

    def _print_summary(self):
        max_cost = 0
        for entry in self.data:
            totaltime = int(entry.totaltime * 1000)
            max_cost = max(max_cost, totaltime)
        print >> self.out_file, 'summary: %d' % (max_cost,)

    def _entry(self, entry):
        out_file = self.out_file
        code = entry.code
        inlinetime = int(entry.inlinetime * 1000)
        #print >> out_file, 'ob=%s' % (code.co_filename,)
        if isinstance(code, str):
            print >> out_file, 'fi=~'
        else:
            print >> out_file, 'fi=%s' % (code.co_filename,)
        print >> out_file, 'fn=%s' % (label(code),)
        if isinstance(code, str):
            print >> out_file, '0 ', inlinetime
        else:
            print >> out_file, '%d %d' % (code.co_firstlineno, inlinetime)
        # recursive calls are counted in entry.calls
        if entry.calls:
            calls = entry.calls
        else:
            calls = []
        if isinstance(code, str):
            lineno = 0
        else:
            lineno = code.co_firstlineno
        for subentry in calls:
            self._subentry(lineno, subentry)
        print >> out_file

    def _subentry(self, lineno, subentry):
        out_file = self.out_file
        code = subentry.code
        totaltime = int(subentry.totaltime * 1000)
        #print >> out_file, 'cob=%s' % (code.co_filename,)
        print >> out_file, 'cfn=%s' % (label(code),)
        if isinstance(code, str):
            print >> out_file, 'cfi=~'
            print >> out_file, 'calls=%d 0' % (subentry.callcount,)
        else:
            print >> out_file, 'cfi=%s' % (code.co_filename,)
            print >> out_file, 'calls=%d %d' % (
                subentry.callcount, code.co_firstlineno)
        print >> out_file, '%d %d' % (lineno, totaltime)


def profile_func(filename=None, mode='w+'):
    """Function/method decorator that will cause only the decorated callable to
    be profiled (with a :class:`KCacheGrind` profiler) and saved to the
    specified file.

    :type filename: str
    :param filename: The filename to write the profile to. If not specified the
                     decorated function's name is used, followed by
                     ``_func.profile``.
    :type mode: str
    :param mode: The mode in which to open ``filename``. Default is ``w+``.
    """
    def proffunc(f):
        def profiled_func(*args, **kwargs):
            import cProfile
            import logging

            logging.info('Profiling function %s' % (f.__name__))

            try:
                profile_file = open(filename or '%s_func.profile' % (f.__name__), mode)
                profiler = cProfile.Profile()
                retval = profiler.runcall(f, *args, **kwargs)
                k_cache_grind = KCacheGrind(profiler)
                k_cache_grind.output(profile_file)
                profile_file.close()
            except IOError:
                logging.exception(_("Could not open profile file '%(filename)s'") % {"filename": filename})

            return retval

        return profiled_func
    return proffunc
