# test_bisect.py -- Tests for bisect functionality
# Copyright (C) 2025 Jelmer Vernooij <jelmer@jelmer.uk>
#
# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
# General Public License as published by the Free Software Foundation; version 2.0
# or (at your option) any later version. You can redistribute it and/or
# modify it under the terms of either of these two licenses.
#
# 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.
#
# You should have received a copy of the licenses; if not, see
# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
# License, Version 2.0.
#

"""Tests for bisect functionality."""

import os
import shutil
import tempfile

from dulwich.bisect import BisectState
from dulwich.repo import Repo
from dulwich.tests.utils import make_commit

from . import TestCase


class BisectStateTests(TestCase):
    """Tests for BisectState class."""

    def setUp(self) -> None:
        self.test_dir = tempfile.mkdtemp()
        self.repo = Repo.init(self.test_dir)

    def tearDown(self) -> None:
        shutil.rmtree(self.test_dir)

    def test_is_active_false(self) -> None:
        """Test is_active when no bisect session is active."""
        state = BisectState(self.repo)
        self.assertFalse(state.is_active)

    def test_start_bisect(self) -> None:
        """Test starting a bisect session."""
        # Create at least one commit so HEAD exists
        c1 = make_commit(id=b"1" * 40, message=b"initial commit")
        self.repo.object_store.add_object(c1)
        self.repo.refs[b"HEAD"] = c1.id
        self.repo.refs[b"refs/heads/main"] = c1.id

        state = BisectState(self.repo)
        state.start()

        self.assertTrue(state.is_active)
        self.assertTrue(
            os.path.exists(os.path.join(self.repo.controldir(), "BISECT_START"))
        )
        self.assertTrue(
            os.path.exists(os.path.join(self.repo.controldir(), "BISECT_TERMS"))
        )
        self.assertTrue(
            os.path.exists(os.path.join(self.repo.controldir(), "BISECT_NAMES"))
        )
        self.assertTrue(
            os.path.exists(os.path.join(self.repo.controldir(), "BISECT_LOG"))
        )

    def test_start_bisect_no_head(self) -> None:
        """Test starting a bisect session when repository has no HEAD."""
        state = BisectState(self.repo)

        with self.assertRaises(ValueError) as cm:
            state.start()
        self.assertIn("Cannot start bisect: repository has no HEAD", str(cm.exception))

    def test_start_bisect_already_active(self) -> None:
        """Test starting a bisect session when one is already active."""
        # Create at least one commit so HEAD exists
        c1 = make_commit(id=b"1" * 40, message=b"initial commit")
        self.repo.object_store.add_object(c1)
        self.repo.refs[b"HEAD"] = c1.id

        state = BisectState(self.repo)
        state.start()

        with self.assertRaises(ValueError):
            state.start()

    def test_mark_bad_no_session(self) -> None:
        """Test marking bad commit when no session is active."""
        state = BisectState(self.repo)

        with self.assertRaises(ValueError):
            state.mark_bad()

    def test_mark_good_no_session(self) -> None:
        """Test marking good commit when no session is active."""
        state = BisectState(self.repo)

        with self.assertRaises(ValueError):
            state.mark_good()

    def test_reset_no_session(self) -> None:
        """Test resetting when no session is active."""
        state = BisectState(self.repo)

        with self.assertRaises(ValueError):
            state.reset()

    def test_bisect_workflow(self) -> None:
        """Test a complete bisect workflow."""
        # Create some commits
        c1 = make_commit(id=b"1" * 40, message=b"good commit 1")
        c2 = make_commit(id=b"2" * 40, message=b"good commit 2", parents=[b"1" * 40])
        c3 = make_commit(id=b"3" * 40, message=b"bad commit", parents=[b"2" * 40])
        c4 = make_commit(id=b"4" * 40, message=b"bad commit 2", parents=[b"3" * 40])

        # Add commits to object store
        for commit in [c1, c2, c3, c4]:
            self.repo.object_store.add_object(commit)

        # Set HEAD to latest commit
        self.repo.refs[b"HEAD"] = c4.id

        # Start bisect
        state = BisectState(self.repo)
        state.start()

        # Mark bad and good
        state.mark_bad(c4.id)
        state.mark_good(c1.id)

        # Check that refs were created
        self.assertTrue(
            os.path.exists(
                os.path.join(self.repo.controldir(), "refs", "bisect", "bad")
            )
        )
        self.assertTrue(
            os.path.exists(
                os.path.join(
                    self.repo.controldir(),
                    "refs",
                    "bisect",
                    f"good-{c1.id.decode('ascii')}",
                )
            )
        )

        # Reset
        state.reset()
        self.assertFalse(state.is_active)