# Copyright (C) 2024 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import os
import unittest.mock as mock

import git.repo

from datetime import datetime, timedelta
from pathlib import Path
from git.gc import (
    MAX_AGE_EMPTY_REF_DIRS,
    MAX_AGE_INCOMING_PACKS,
    MAX_AGE_GC_LOCK,
    DeleteStaleIncomingPacksCleanupStep,
    DeleteEmptyRefDirsCleanupStep,
    GCLockHandlingInitStep,
    GitGarbageCollection,
    PackAllRefsAfterStep,
    PreservePacksInitStep,
)
from git.config import GitConfigWriter

DOUBLE_MAX_AGE_EMPTY_REF_DIRS = 2 * MAX_AGE_EMPTY_REF_DIRS
DOUBLE_MAX_AGE_INCOMING_PACKS = 2 * MAX_AGE_INCOMING_PACKS
DOUBLE_MAX_AGE_GC_LOCK = 2 * MAX_AGE_GC_LOCK


def test_GCLockHandlingInitStep(repo):
    lock_file = os.path.join(repo, "gc.pid")
    with open(lock_file, "w") as f:
        f.write("1234")

    task = GCLockHandlingInitStep()

    task.run(repo)
    assert os.path.exists(lock_file)

    _modify_last_modified(lock_file, DOUBLE_MAX_AGE_GC_LOCK)

    task.run(repo)
    assert not os.path.exists(lock_file)


def test_PreservePacksInitStep(repo):
    task = PreservePacksInitStep()

    pack_path = os.path.join(repo, "objects", "pack")
    preserved_pack_path = os.path.join(pack_path, "preserved")

    fake_pack = os.path.join(pack_path, "pack-fake.pack")
    fake_preserved_pack = os.path.join(preserved_pack_path, "pack-fake.old-pack")
    fake_idx = os.path.join(pack_path, "pack-fake.idx")
    fake_preserved_idx = os.path.join(preserved_pack_path, "pack-fake.old-idx")
    fake_rev = os.path.join(pack_path, "pack-fake.rev")
    fake_preserved_rev = os.path.join(preserved_pack_path, "pack-fake.old-rev")

    Path(fake_pack).touch()
    Path(fake_idx).touch()
    Path(fake_rev).touch()

    with GitConfigWriter(os.path.join(repo, "config")) as writer:
        writer.set("gc", None, "preserveoldpacks", False)
        writer.write()

    task.run(repo)

    assert not os.path.exists(fake_preserved_pack)
    assert not os.path.exists(fake_preserved_idx)
    assert not os.path.exists(fake_preserved_rev)

    with GitConfigWriter(os.path.join(repo, "config")) as writer:
        writer.set("gc", None, "preserveoldpacks", True)
        writer.write()

    task.run(repo)

    assert os.path.exists(fake_preserved_pack)
    assert os.path.exists(fake_preserved_idx)
    assert not os.path.exists(fake_preserved_rev)

    with GitConfigWriter(os.path.join(repo, "config")) as writer:
        writer.set("gc", None, "preserveoldpacks", False)
        writer.set("gc", None, "prunepreserved", True)
        writer.write()

    task.run(repo)

    assert not os.path.exists(fake_preserved_pack)
    assert not os.path.exists(fake_preserved_idx)


def test_DeleteEmptyRefDirsCleanupStep(repo):
    delete_path = os.path.join(repo, "refs", "heads", "delete")
    os.makedirs(delete_path)
    delete_change_path = os.path.join(repo, "refs", "changes", "01", "101", "meta")
    os.makedirs(delete_change_path)
    keep_path = os.path.join(repo, "refs", "heads", "keep")
    os.makedirs(keep_path)
    Path(os.path.join(keep_path, "abcd1234")).touch()

    task = DeleteEmptyRefDirsCleanupStep()

    task.run(repo)
    assert os.path.exists(delete_path)
    assert os.path.exists(keep_path)

    _modify_last_modified(keep_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    _modify_last_modified(delete_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    _modify_last_modified(delete_change_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    delete_change_path_parent = Path(delete_change_path).parent
    _modify_last_modified(delete_change_path_parent, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    task.run(repo)
    assert not os.path.exists(delete_path)
    assert not os.path.exists(delete_change_path)
    assert not os.path.exists(delete_change_path_parent)


def test_DeleteEmptyRefDirsCleanupStep_keeps_ref_dir(repo):
    refs_path = os.path.join(repo, "refs")
    heads_path = os.path.join(refs_path, "heads")
    tags_path = os.path.join(refs_path, "tags")
    delete_change_path = os.path.join(refs_path, "changes", "01", "101", "meta")
    os.makedirs(delete_change_path)
    _modify_last_modified(refs_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    _modify_last_modified(heads_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    _modify_last_modified(tags_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)
    _modify_last_modified(delete_change_path, DOUBLE_MAX_AGE_EMPTY_REF_DIRS)

    task = DeleteEmptyRefDirsCleanupStep()
    task.run(repo)

    assert not os.path.exists(delete_change_path)
    assert os.path.exists(refs_path)
    assert os.path.exists(heads_path)
    assert os.path.exists(tags_path)


def test_DeleteStaleIncomingPacksCleanupStep(repo):
    task = DeleteStaleIncomingPacksCleanupStep()

    objects_path = os.path.join(repo, "objects")
    pack_path = os.path.join(objects_path, "pack")
    pack_file = os.path.join(pack_path, "pack-1234.pack")
    Path(pack_file).touch()
    object_shard = os.path.join(objects_path, "f8")
    os.makedirs(object_shard)
    object_file = os.path.join(objects_path, "f8", "abcd")
    Path(object_file).touch()
    incoming_pack_file = os.path.join(objects_path, "incoming_1234.pack")
    Path(incoming_pack_file).touch()

    task.run(repo)

    assert os.path.exists(pack_file)
    assert os.path.exists(object_file)
    assert os.path.exists(incoming_pack_file)

    _modify_last_modified(pack_file, DOUBLE_MAX_AGE_INCOMING_PACKS)
    _modify_last_modified(object_file, DOUBLE_MAX_AGE_INCOMING_PACKS)
    _modify_last_modified(incoming_pack_file, DOUBLE_MAX_AGE_INCOMING_PACKS)

    task.run(repo)

    assert os.path.exists(pack_file)
    assert os.path.exists(object_file)
    assert not os.path.exists(incoming_pack_file)


def test_PackAllRefsAfterStep(repo, local_repo):
    test_file = Path(os.path.join(local_repo, "test.txt"))
    test_file.touch()
    git.repo.add(local_repo, [test_file])
    git.repo.commit(local_repo, "test commit")

    target_loose_ref_count = 15
    loose_ref_count = 0
    while loose_ref_count < target_loose_ref_count:
        loose_ref_count += 1
        git.repo.push(local_repo, "origin", f"HEAD:refs/heads/test{loose_ref_count}")

    task = PackAllRefsAfterStep()
    task.run(repo)

    assert len(os.listdir(os.path.join(repo, "refs", "heads"))) == 0
    packed_refs_file = os.path.join(repo, "packed-refs")
    assert os.path.exists(packed_refs_file)
    with open(packed_refs_file, "r") as f:
        assert (
            len(f.readlines()) == target_loose_ref_count + 1
        )  # First line is a comment

    git.repo.push(
        local_repo, "origin", f"HEAD:refs/heads/test{target_loose_ref_count + 1}"
    )
    task.run(repo)
    assert len(os.listdir(os.path.join(repo, "refs", "heads"))) == 1
    with open(packed_refs_file, "r") as f:
        assert (
            len(f.readlines()) == target_loose_ref_count + 1
        )  # First line is a comment


@mock.patch("subprocess.run")
def test_gc_executed(mock_subproc_run, repo):
    gc = GitGarbageCollection([], [])
    gc.run(repo)
    mock_subproc_run.assert_called()
    assert mock_subproc_run.call_count == 1


def _modify_last_modified(file, time_delta):
    file_stat = os.stat(file)
    new_mod_timestamp = datetime.timestamp(
        datetime.fromtimestamp(file_stat.st_mtime) - time_delta
    )
    os.utime(file, (file_stat.st_atime, new_mod_timestamp))