# Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors
#
# This module is part of GitPython and is released under the
# 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/

"""Performance tests for commits (iteration, traversal, and serialization)."""

import gc
from io import BytesIO
from time import time
import sys

from .lib import TestBigRepoRW
from git import Commit
from gitdb import IStream
from test.test_commit import TestCommitSerialization


class TestPerformance(TestBigRepoRW, TestCommitSerialization):
    def tearDown(self):
        gc.collect()

    # ref with about 100 commits in its history.
    ref_100 = "0.1.6"

    def _query_commit_info(self, c):
        c.author
        c.authored_date
        c.author_tz_offset
        c.committer
        c.committed_date
        c.committer_tz_offset
        c.message
        c.parents

    def test_iteration(self):
        no = 0
        nc = 0

        # Find the first commit containing the given path. Always do a full iteration
        # (restricted to the path in question). This should return quite a lot of
        # commits. We just take one and hence abort the operation.

        st = time()
        for c in self.rorepo.iter_commits(self.ref_100):
            nc += 1
            self._query_commit_info(c)
            for obj in c.tree.traverse():
                obj.size
                no += 1
            # END for each object
        # END for each commit
        elapsed_time = time() - st
        print(
            "Traversed %i Trees and a total of %i uncached objects in %s [s] ( %f objs/s )"
            % (nc, no, elapsed_time, no / elapsed_time),
            file=sys.stderr,
        )

    def test_commit_traversal(self):
        # Bound to cat-file parsing performance.
        nc = 0
        st = time()
        for c in self.gitrorepo.commit().traverse(branch_first=False):
            nc += 1
            self._query_commit_info(c)
        # END for each traversed commit
        elapsed_time = time() - st
        print(
            "Traversed %i Commits in %s [s] ( %f commits/s )" % (nc, elapsed_time, nc / elapsed_time),
            file=sys.stderr,
        )

    def test_commit_iteration(self):
        # Bound to stream parsing performance.
        nc = 0
        st = time()
        for c in Commit.iter_items(self.gitrorepo, self.gitrorepo.head):
            nc += 1
            self._query_commit_info(c)
        # END for each traversed commit
        elapsed_time = time() - st
        print(
            "Iterated %i Commits in %s [s] ( %f commits/s )" % (nc, elapsed_time, nc / elapsed_time),
            file=sys.stderr,
        )

    def test_commit_serialization(self):
        self.assert_commit_serialization(self.gitrwrepo, "58c78e6", True)

        rwrepo = self.gitrwrepo
        make_object = rwrepo.odb.store
        # Direct serialization - deserialization can be tested afterwards.
        # Serialization is probably limited on IO.
        hc = rwrepo.commit(rwrepo.head)

        nc = 5000
        st = time()
        for i in range(nc):
            cm = Commit(
                rwrepo,
                Commit.NULL_BIN_SHA,
                hc.tree,
                hc.author,
                hc.authored_date,
                hc.author_tz_offset,
                hc.committer,
                hc.committed_date,
                hc.committer_tz_offset,
                str(i),
                parents=hc.parents,
                encoding=hc.encoding,
            )

            stream = BytesIO()
            cm._serialize(stream)
            slen = stream.tell()
            stream.seek(0)

            cm.binsha = make_object(IStream(Commit.type, slen, stream)).binsha
        # END commit creation
        elapsed = time() - st

        print(
            "Serialized %i commits to loose objects in %f s ( %f commits / s )" % (nc, elapsed, nc / elapsed),
            file=sys.stderr,
        )
