import unittest
import hashlib
import os
import base64
import sys
from pathlib import Path
from unittest.mock import patch, AsyncMock
from unittest.mock import MagicMock

EMMA_DIR = Path(__file__).resolve().parents[1] / "emma"
if str(EMMA_DIR) not in sys.path:
    sys.path.insert(0, str(EMMA_DIR))

import server  # Følger eksisterende mønster

KMS_KEY_NAME = "projects/p/locations/l/keyRings/k/cryptoKeys/k"


class TestProposeGiteaChange(unittest.IsolatedAsyncioTestCase):

    @patch('server.handle_get_file_content', new_callable=AsyncMock)
    async def test_get_file_wrapper_enforces_server_repo(self, mock_handler):
        sentinel_response = {
            "requested_ref": "main",
            "resolved_commit_sha": "a" * 40,
            "content": "file content"
        }
        mock_handler.return_value = sentinel_response

        params = {
            "path": "README.md",
            "ref": "main",
            "repo": "untrusted/repo",
        }
        result = await server.get_file(params)

        mock_handler.assert_awaited_once_with(params, server.GITEA_REPO)
        self.assertIs(result, sentinel_response)


    def setUp(self):
        """Set up valid parameters for tests."""
        self.valid_params = {
            "repo": server.GITEA_REPO,
            "branch": "feature/new-idea",
            "path": "docs/new-file.md",
            "new_content": "This is new content.",
            "base_sha": "a" * 40,
            "commit_message": "A valid commit message.",
        }

    def tearDown(self):
        patch.stopall()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_rejects_main_branch_before_io(self, mock_resolve_sha, mock_get_details, mock_create_plan):
        params = self.valid_params | {"branch": "main"}
        with self.assertRaisesRegex(ValueError, "Direct writes to protected branch 'main' are not allowed."):
            await server.propose_gitea_change(params)

        mock_resolve_sha.assert_not_awaited()
        mock_get_details.assert_not_awaited()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_rejects_master_branch_before_io(self, mock_resolve_sha, mock_get_details, mock_create_plan):
        params = self.valid_params | {"branch": "master"}
        with self.assertRaisesRegex(ValueError, "Direct writes to protected branch 'master' are not allowed."):
            await server.propose_gitea_change(params)

        mock_resolve_sha.assert_not_awaited()
        mock_get_details.assert_not_awaited()
        mock_create_plan.assert_not_awaited()

    @patch("server.create_gitea_change_plan", new_callable=AsyncMock)
    @patch("server._get_gitea_file_details", new_callable=AsyncMock)
    @patch("server.resolve_branch_to_commit_sha", new_callable=AsyncMock)
    @patch("server._validate_admin_gitea_path")
    async def test_rejects_dot_git_path_via_new_write_policy(
        self,
        mock_admin_path_validator,
        mock_resolve_sha,
        mock_get_details,
        mock_create_plan,
    ):
        params = self.valid_params | {"path": "some/dir/.git/config"}

        with self.assertRaisesRegex(
            ValueError,
            r"Changes within a '.git' directory are not allowed.",
        ):
            await server.propose_gitea_change(params)

        mock_admin_path_validator.assert_called_once_with(params["path"])
        mock_resolve_sha.assert_not_awaited()
        mock_get_details.assert_not_awaited()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_rejects_base_sha_mismatch(self, mock_resolve_sha, mock_get_details, mock_create_plan):
        mock_resolve_sha.return_value = "c" * 40  # Mismatched SHA

        with self.assertRaisesRegex(ValueError, "Branch head does not match the supplied base_sha"):
            await server.propose_gitea_change(self.valid_params)

        mock_resolve_sha.assert_awaited_once()
        mock_get_details.assert_not_awaited()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_rejects_no_op_diff(self, mock_resolve_sha, mock_get_details, mock_create_plan):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_get_details.return_value = (self.valid_params["new_content"], "b" * 40)

        with self.assertRaisesRegex(ValueError, "Proposed content produces no file change."):
            await server.propose_gitea_change(self.valid_params)

        mock_resolve_sha.assert_awaited_once()
        mock_get_details.assert_awaited_once()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock, return_value=("old content", "b" * 40))
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_happy_path_creates_pending_plan(self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan):
        mock_kms_client = AsyncMock()
        mock_kms_client.encrypt.return_value = MagicMock(ciphertext=b"encrypted-data")
        mock_kms_constructor.return_value.__aenter__ = AsyncMock(return_value=mock_kms_client)
        mock_kms_constructor.return_value.__aexit__ = AsyncMock(return_value=False)

        mock_resolve_sha.return_value = self.valid_params["base_sha"]

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": KMS_KEY_NAME}):
            result = await server.propose_gitea_change(self.valid_params)

        self.assertEqual(result["status"], "PENDING")
        self.assertEqual(result["repo"], self.valid_params["repo"])
        self.assertEqual(result["branch"], self.valid_params["branch"])
        self.assertEqual(result["path"], self.valid_params["path"])
        self.assertIn("approval_subject_hash", result)

        expected_hash = hashlib.sha256(self.valid_params["new_content"].encode("utf-8")).hexdigest()
        self.assertEqual(result["content_hash"], expected_hash)

        mock_kms_client.encrypt.assert_awaited_once()
        mock_create_plan.assert_awaited_once()

        # Verify the object passed to create_gitea_change_plan is the real Pydantic model
        call_args = mock_create_plan.call_args[0][0]
        self.assertIsInstance(call_args, server.GiteaChangePlan)
        self.assertEqual(call_args.repo, self.valid_params["repo"])
        self.assertEqual(call_args.branch, self.valid_params["branch"])
        self.assertEqual(call_args.path, self.valid_params["path"])
        self.assertEqual(call_args.base_sha, self.valid_params["base_sha"])
        self.assertEqual(call_args.existing_file_sha, "b" * 40)

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_patch2a_missing_kms_key_fails_after_gitea_reads(
        self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan
    ):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_get_details.return_value = ("old content", "b" * 40)

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": ""}):
            with self.assertRaisesRegex(RuntimeError, "KMS key is not configured"):
                await server.propose_gitea_change(self.valid_params)

        mock_resolve_sha.assert_awaited_once()
        mock_get_details.assert_awaited_once()
        mock_kms_constructor.assert_not_called()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock)
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_patch2a_invalid_kms_key_fails_before_kms_construction(
        self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan
    ):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_get_details.return_value = ("old content", "b" * 40)

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": "invalid-key-format"}):
            with self.assertRaisesRegex(RuntimeError, "invalid format"):
                await server.propose_gitea_change(self.valid_params)

        mock_resolve_sha.assert_awaited_once()
        mock_get_details.assert_awaited_once()
        mock_kms_constructor.assert_not_called()
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock, return_value=("old content", "b" * 40))
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_patch2a_empty_kms_ciphertext_is_rejected(
        self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan
    ):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_kms_client = AsyncMock()
        mock_kms_client.encrypt.return_value = MagicMock(ciphertext=b"")
        mock_kms_constructor.return_value.__aenter__ = AsyncMock(return_value=mock_kms_client)
        mock_kms_constructor.return_value.__aexit__ = AsyncMock(return_value=False)

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": KMS_KEY_NAME}):
            with self.assertRaisesRegex(RuntimeError, "invalid empty ciphertext"):
                await server.propose_gitea_change(self.valid_params)

        mock_kms_client.encrypt.assert_awaited_once_with(
            request={
                "name": KMS_KEY_NAME,
                "plaintext": self.valid_params["new_content"].encode("utf-8"),
            }
        )
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock, return_value=("old content", "b" * 40))
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_patch2a_non_bytes_kms_ciphertext_is_rejected(
        self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan
    ):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_kms_client = AsyncMock()
        mock_kms_client.encrypt.return_value = MagicMock(ciphertext=None)
        mock_kms_constructor.return_value.__aenter__ = AsyncMock(return_value=mock_kms_client)
        mock_kms_constructor.return_value.__aexit__ = AsyncMock(return_value=False)

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": KMS_KEY_NAME}):
            with self.assertRaisesRegex(RuntimeError, "invalid empty ciphertext"):
                await server.propose_gitea_change(self.valid_params)

        mock_kms_client.encrypt.assert_awaited_once_with(
            request={
                "name": KMS_KEY_NAME,
                "plaintext": self.valid_params["new_content"].encode("utf-8"),
            }
        )
        mock_create_plan.assert_not_awaited()

    @patch('server.create_gitea_change_plan', new_callable=AsyncMock)
    @patch("server.kms_v1.KeyManagementServiceAsyncClient")
    @patch('server._get_gitea_file_details', new_callable=AsyncMock, return_value=("old content", "b" * 40))
    @patch('server.resolve_branch_to_commit_sha', new_callable=AsyncMock)
    async def test_patch2a_successful_encrypted_proposal(
        self, mock_resolve_sha, mock_get_details, mock_kms_constructor, mock_create_plan
    ):
        mock_resolve_sha.return_value = self.valid_params["base_sha"]
        mock_kms_client = AsyncMock()
        mock_kms_client.encrypt.return_value = MagicMock(ciphertext=b"encrypted-data")
        mock_kms_constructor.return_value.__aenter__ = AsyncMock(return_value=mock_kms_client)
        mock_kms_constructor.return_value.__aexit__ = AsyncMock(return_value=False)

        with patch.dict(os.environ, {"GITEA_PLAN_KMS_KEY_NAME": KMS_KEY_NAME}):
            result = await server.propose_gitea_change(self.valid_params)

        mock_resolve_sha.assert_awaited_once()
        mock_get_details.assert_awaited_once()
        mock_kms_client.encrypt.assert_awaited_once_with(
            request={
                "name": KMS_KEY_NAME,
                "plaintext": self.valid_params["new_content"].encode("utf-8"),
            }
        )

        mock_create_plan.assert_awaited_once()
        persisted_plan = mock_create_plan.call_args.args[0]

        self.assertIsInstance(persisted_plan, server.GiteaChangePlan)
        self.assertIsInstance(
            persisted_plan.encrypted_payload,
            server.EncryptedPayloadV1,
        )
        self.assertEqual(persisted_plan.encrypted_payload.payload_version, "1")
        self.assertEqual(persisted_plan.encrypted_payload.kms_key_name, KMS_KEY_NAME)
        self.assertEqual(
            persisted_plan.encrypted_payload.ciphertext,
            base64.b64encode(b"encrypted-data").decode("ascii"),
        )
        self.assertNotIn("new_content", persisted_plan.model_dump(mode="json"))

        expected_content_hash = hashlib.sha256(self.valid_params["new_content"].encode("utf-8")).hexdigest()
        self.assertEqual(persisted_plan.content_hash, expected_content_hash)
        self.assertEqual(result["content_hash"], expected_content_hash)

        self.assertEqual(
            persisted_plan.approval_subject_hash,
            server._calculate_approval_subject_hash(persisted_plan),
        )
        self.assertEqual(result["approval_subject_hash"], persisted_plan.approval_subject_hash)

        for field in ("new_content", "encrypted_payload", "ciphertext", "kms_key_name"):
            self.assertNotIn(field, result)

    def test_legacy_plan_parses_without_patch2a_fields(self):
        current_plan = server.GiteaChangePlan(
            repo="o/r", branch="b", path="p", base_sha="a" * 40,
            content_hash="c" * 64, commit_message="m", unified_diff="d"
        )
        legacy_dict = current_plan.model_dump(mode="json")
        legacy_dict.pop("encrypted_payload", None)
        legacy_dict.pop("approval_subject_hash", None)

        legacy_plan = server.GiteaChangePlan(**legacy_dict)
        self.assertIsNone(legacy_plan.encrypted_payload)
        self.assertIsNone(legacy_plan.approval_subject_hash)

    def test_malformed_base64_in_hash_raises_error(self):
        plan_with_bad_payload = server.GiteaChangePlan(
            plan_id="plan-123", repo="o/r", branch="b", path="p", base_sha="a"*40, content_hash="c"*64,
            commit_message="m", unified_diff="d",
            encrypted_payload=server.EncryptedPayloadV1(
                kms_key_name=KMS_KEY_NAME, ciphertext="not-valid-base64!"
            )
        )
        with self.assertRaisesRegex(ValueError, "Encrypted payload ciphertext is invalid"):
            server._calculate_approval_subject_hash(plan_with_bad_payload)

    def test_approval_subject_hash_sensitivity(self):
        base_plan = server.GiteaChangePlan(
            plan_id="plan-123", repo="o/r", branch="b", path="p",
            base_sha="a" * 40, existing_file_sha="b" * 40, content_hash="c" * 64,
            commit_message="m", unified_diff="d",
            encrypted_payload=server.EncryptedPayloadV1(
                kms_key_name=KMS_KEY_NAME,
                ciphertext=base64.b64encode(b"secret").decode("ascii"),
            ),
        )
        base_hash = server._calculate_approval_subject_hash(base_plan)

        fields_to_test = {
            "plan_id": "plan-456", "repo": "o/r2", "branch": "b2", "path": "p2",
            "base_sha": "A" * 40, "existing_file_sha": "B" * 40, "content_hash": "C" * 64,
            "commit_message": "m2", "unified_diff": "d2",
        }

        for field, new_value in fields_to_test.items():
            with self.subTest(field=field):
                modified_plan = base_plan.model_copy(update={field: new_value})
                new_hash = server._calculate_approval_subject_hash(modified_plan)
                self.assertNotEqual(base_hash, new_hash)

        with self.subTest(field="kms_key_name"):
            modified_plan_kms = base_plan.model_copy(deep=True)
            modified_plan_kms.encrypted_payload.kms_key_name = "projects/p/locations/l/keyRings/k/cryptoKeys/k2"
            self.assertNotEqual(base_hash, server._calculate_approval_subject_hash(modified_plan_kms))

        with self.subTest(field="ciphertext"):
            modified_plan_cipher = base_plan.model_copy(deep=True)
            modified_plan_cipher.encrypted_payload.ciphertext = base64.b64encode(b"secret2").decode("ascii")
            self.assertNotEqual(base_hash, server._calculate_approval_subject_hash(modified_plan_cipher))


class TestIsGiteaChangePlanExpired(unittest.TestCase):
    def _create_test_plan(self, expires_at):
        return server.GiteaChangePlan(
            repo="o/r",
            branch="b",
            path="p",
            base_sha="a" * 40,
            content_hash="c" * 64,
            commit_message="m",
            unified_diff="d",
            expires_at=expires_at,
        )

    def test_future_aware_is_not_expired(self):
        from datetime import datetime, timedelta, timezone
        future_time = datetime.now(timezone.utc) + timedelta(days=1)
        plan = self._create_test_plan(future_time)
        self.assertFalse(server.is_gitea_change_plan_expired(plan))

    def test_past_aware_is_expired(self):
        from datetime import datetime, timedelta, timezone
        past_time = datetime.now(timezone.utc) - timedelta(days=1)
        plan = self._create_test_plan(past_time)
        self.assertTrue(server.is_gitea_change_plan_expired(plan))

    def test_past_naive_is_expired(self):
        from datetime import datetime, timedelta
        past_time_naive = datetime.utcnow() - timedelta(days=1)
        plan = self._create_test_plan(past_time_naive)
        self.assertTrue(server.is_gitea_change_plan_expired(plan))

    def test_default_status_is_pending_constant(self):
        from datetime import datetime, timedelta, timezone
        future_time = datetime.now(timezone.utc) + timedelta(days=1)
        plan = self._create_test_plan(future_time)
        self.assertEqual(
            plan.status,
            server.GITEA_CHANGE_PLAN_STATUS_PENDING,
        )
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_PENDING, "PENDING")
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_APPROVED, "APPROVED")
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_APPLYING, "APPLYING")
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_APPLIED, "APPLIED")
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_REJECTED, "REJECTED")
        self.assertEqual(server.GITEA_CHANGE_PLAN_STATUS_EXPIRED, "EXPIRED")


class TestGiteaChangePlanStatusTransitions(unittest.TestCase):
    def test_allowed_transitions(self):
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            )
        )
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                server.GITEA_CHANGE_PLAN_STATUS_REJECTED,
            )
        )
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                server.GITEA_CHANGE_PLAN_STATUS_EXPIRED,
            )
        )
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
                server.GITEA_CHANGE_PLAN_STATUS_APPLYING,
            )
        )
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
                server.GITEA_CHANGE_PLAN_STATUS_EXPIRED,
            )
        )
        self.assertTrue(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPLYING,
                server.GITEA_CHANGE_PLAN_STATUS_APPLIED,
            )
        )

    def test_disallowed_transitions(self):
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                server.GITEA_CHANGE_PLAN_STATUS_PENDING,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
                server.GITEA_CHANGE_PLAN_STATUS_APPLIED,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPLYING,
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_APPLIED,
                server.GITEA_CHANGE_PLAN_STATUS_APPLYING,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_REJECTED,
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_EXPIRED,
                server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                "UNKNOWN", server.GITEA_CHANGE_PLAN_STATUS_PENDING
            )
        )
        self.assertFalse(
            server.is_valid_gitea_change_plan_status_transition(
                server.GITEA_CHANGE_PLAN_STATUS_PENDING, "UNKNOWN"
            )
        )


class TestTransitionGiteaChangePlanStatus(unittest.IsolatedAsyncioTestCase):
    @patch("google.cloud.firestore.AsyncClient")
    async def test_rejects_invalid_transition_before_firestore(self, mock_db_client):
        with self.assertRaisesRegex(
            ValueError, r"^Invalid Gitea change plan status transition$"
        ):
            await server.transition_gitea_change_plan_status(
                plan_id="plan-123",
                expected_status=server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                next_status=server.GITEA_CHANGE_PLAN_STATUS_APPLIED,
            )
        mock_db_client.assert_not_called()

    @patch("google.cloud.firestore.AsyncClient")
    async def test_rejects_status_in_updates_before_firestore(self, mock_db_client):
        with self.assertRaisesRegex(
            ValueError, r"^Gitea change plan updates cannot include status$"
        ):
            await server.transition_gitea_change_plan_status(
                plan_id="plan-123",
                expected_status=server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                next_status=server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
                updates={"status": server.GITEA_CHANGE_PLAN_STATUS_REJECTED},
            )
        mock_db_client.assert_not_called()

    @patch("server.get_gitea_change_plan", new_callable=AsyncMock)
    @patch("google.cloud.firestore.async_transactional")
    @patch("google.cloud.firestore.AsyncClient")
    async def test_transitions_matching_status_and_returns_refetched_plan(
        self, mock_db_client, mock_transactional, mock_get_plan
    ):
        def transactional_side_effect(callback):
            async def wrapped(transaction):
                return await callback(transaction)
            return wrapped
        mock_transactional.side_effect = transactional_side_effect

        mock_transaction = MagicMock()
        mock_transaction.update = MagicMock()
        mock_db_client.return_value.transaction.return_value = mock_transaction

        snapshot = MagicMock()
        snapshot.exists = True
        snapshot.get.return_value = server.GITEA_CHANGE_PLAN_STATUS_PENDING

        mock_plan_ref = MagicMock()
        mock_plan_ref.get = AsyncMock(return_value=snapshot)
        mock_db_client.return_value.collection.return_value.document.return_value = mock_plan_ref

        final_plan = server.GiteaChangePlan(
            status=server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            repo="o/r", branch="b", path="p", base_sha="a"*40,
            content_hash="c"*64, commit_message="m", unified_diff="d",
            approved_by="admin@example.com"
        )
        mock_get_plan.return_value = final_plan

        updates = {"approved_by": "admin@example.com"}
        result = await server.transition_gitea_change_plan_status(
            plan_id="plan-123",
            expected_status=server.GITEA_CHANGE_PLAN_STATUS_PENDING,
            next_status=server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            updates=updates,
        )

        mock_transaction.update.assert_called_once_with(
            mock_plan_ref,
            {
                "approved_by": "admin@example.com",
                "status": server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            },
        )
        self.assertEqual(updates, {"approved_by": "admin@example.com"})
        mock_get_plan.assert_awaited_once_with("plan-123")
        self.assertIs(result, final_plan)

    @patch("server.get_gitea_change_plan", new_callable=AsyncMock)
    @patch("google.cloud.firestore.async_transactional")
    @patch("google.cloud.firestore.AsyncClient")
    async def test_rejects_stale_status_inside_transaction(
        self, mock_db_client, mock_transactional, mock_get_plan
    ):
        def transactional_side_effect(callback):
            async def wrapped(transaction):
                return await callback(transaction)
            return wrapped
        mock_transactional.side_effect = transactional_side_effect

        mock_transaction = MagicMock()
        mock_transaction.update = MagicMock()
        mock_db_client.return_value.transaction.return_value = mock_transaction

        snapshot = MagicMock()
        snapshot.exists = True
        snapshot.get.return_value = server.GITEA_CHANGE_PLAN_STATUS_APPROVED

        mock_plan_ref = MagicMock()
        mock_plan_ref.get = AsyncMock(return_value=snapshot)
        mock_db_client.return_value.collection.return_value.document.return_value = mock_plan_ref

        with self.assertRaisesRegex(ValueError, r"^Gitea change plan status changed$"):
            await server.transition_gitea_change_plan_status(
                plan_id="plan-123",
                expected_status=server.GITEA_CHANGE_PLAN_STATUS_PENDING,
                next_status=server.GITEA_CHANGE_PLAN_STATUS_APPROVED,
            )

        mock_transaction.update.assert_not_called()
        mock_get_plan.assert_not_awaited()


if __name__ == "__main__":
    unittest.main()