import sys
import tempfile
import hotshot
import hotshot.stats
from cStringIO import StringIO

import cProfile
import pstats


def profile_this(fn):
    def profiled_fn(*args, **kwargs):
        filepath = "/tmp/%s.profile" % fn.__name__
        prof = cProfile.Profile()
        ret = prof.runcall(fn, *args, **kwargs)
        print "Writing to %s" % filepath
        prof.dump_stats(filepath)

        print "Printing stats"
        stats = pstats.Stats(filepath)
        stats.sort_stats('cumulative')
        stats.print_stats()

        return ret
    return profiled_fn


class BaseMiddleware(object):
    query_param = None

    def show_profile(self, request):
        return self.query_param in request.GET

    def process_request(self, request):
        if self.show_profile(request):
            if 'prof_file' in request.GET:
                # It's sometimes useful to generate a file of output that can
                # converted for use with kcachegrind.  To convert this file,
                # use:
                #
                #     pyprof2calltree -o /tmp/callgrind.stats -i /tmp/out.stats
                #
                # then open the file in kcachegrind.
                self.tmpfile = open('/tmp/out.stats', 'w')
            else:
                self.tmpfile = tempfile.NamedTemporaryFile()
            self.profile = self.profiler()

    def profiler(self):
        return None

    def process_view(self, request, callback, callback_args, callback_kwargs):
        # We profile the view call - note that this misses the rest of Django's
        # request processing (eg middleware etc)
        if self.show_profile(request):
            return self.profile.runcall(
                callback, request, *callback_args, **callback_kwargs)

    def process_response(self, request, response):
        if self.show_profile(request):
            stats = self.stats()

            if 'prof_strip' in request.GET:
                stats.strip_dirs()
            if 'prof_sort' in request.GET:
                # See # http://docs.python.org/2/library/profile.html#pstats.Stats.sort_stats
                # for the fields you can sort on.
                stats.sort_stats(*request.GET['prof_sort'].split(','))
            else:
                stats.sort_stats('time', 'calls')

            # Capture STDOUT temporarily
            old_stdout = sys.stdout
            out = StringIO()
            sys.stdout = out
            stats.print_stats()

            stats_str = out.getvalue()
            sys.stdout.close()
            sys.stdout = old_stdout

            # Print status within PRE block
            if response and response.content and stats_str:
                response.content = "<pre>" + stats_str + "</pre>"

        return response


class ProfileMiddleware(BaseMiddleware):
    query_param = 'cprofile'

    def profiler(self):
        return cProfile.Profile()

    def stats(self):
        self.profile.dump_stats(self.tmpfile.name)
        return pstats.Stats(self.tmpfile.name)


class HotshotMiddleware(BaseMiddleware):
    """
    Displays hotshot profiling for any view.
    http://yoursite.com/yourview/?prof

    Based on http://djangosnippets.org/snippets/186/
    """
    query_param = 'hotshot'

    def profiler(self):
        return hotshot.Profile(self.tmpfile.name)

    def stats(self):
        self.profile.close()
        return hotshot.stats.load(self.tmpfile.name)