from __future__ import annotations

import copy

import pytest

from app.core.common.identifiers import new_governance_uid
from app.core.data_flow.dataflows import DataFlowService


class GraphResult:
    def __init__(self, record=None):
        self.record = record

    def single(self):
        return self.record


class GraphSession:
    def __init__(self, *, existing=None, conflict=False):
        self.existing = existing
        self.conflict = conflict
        self.calls = []

    def run(self, query, parameters=None, **kwargs):
        values = parameters or kwargs
        self.calls.append((query, values))
        if query.startswith("CREATE CONSTRAINT"):
            return GraphResult()
        if "WHERE n.uid IS NULL OR n.uid <> $uid" in query:
            return GraphResult({"uid": "other"}) if self.conflict else GraphResult()
        if query.startswith("MERGE"):
            node = copy.deepcopy(self.existing or values["properties"])
            self.existing = node
            return GraphResult({"n": node, "node_id": 73})
        raise AssertionError(query)

    def __enter__(self):
        return self

    def __exit__(self, *_args):
        return None


class GraphDriver:
    def __init__(self, session):
        self.graph_session = session

    def session(self):
        return self.graph_session

    def close(self):
        return None


def governed_node():
    return {
        "uid": new_governance_uid(),
        "name_zh": "客户治理生产线",
        "name_en": "customer_line",
        "script_type": "governed",
        "script_requirement": '{"dataflow_spec":{"schema_version":"2.0"}}',
        "script_path": "",
    }


def test_governed_graph_create_installs_constraint_and_reconciles_same_uid(
    monkeypatch,
):
    node = governed_node()
    graph = GraphSession()
    monkeypatch.setattr(
        "app.core.data_flow.dataflows.connect_graph",
        lambda: GraphDriver(graph),
    )

    first_id, first = DataFlowService._merge_governed_dataflow(node)
    second_id, second = DataFlowService._merge_governed_dataflow(node)

    assert first_id == second_id == 73
    assert first == second
    assert any(
        call[0]
        == "CREATE CONSTRAINT data_flow_uid IF NOT EXISTS "
        "FOR (n:DataFlow) REQUIRE n.uid IS UNIQUE"
        for call in graph.calls
    )
    assert sum(call[0].startswith("MERGE") for call in graph.calls) == 2


def test_governed_graph_reconcile_fails_closed_on_uid_or_name_conflict(
    monkeypatch,
):
    node = governed_node()
    graph = GraphSession(existing={**node, "name_zh": "被篡改的名称"})
    monkeypatch.setattr(
        "app.core.data_flow.dataflows.connect_graph",
        lambda: GraphDriver(graph),
    )
    with pytest.raises(ValueError, match="dataflow_uid_conflict"):
        DataFlowService._merge_governed_dataflow(node)

    name_conflict = GraphSession(conflict=True)
    monkeypatch.setattr(
        "app.core.data_flow.dataflows.connect_graph",
        lambda: GraphDriver(name_conflict),
    )
    with pytest.raises(ValueError, match="dataflow_uid_conflict"):
        DataFlowService._merge_governed_dataflow(node)


def test_completed_saga_replays_result_without_another_neo4j_write(monkeypatch):
    expected = {"id": 73, **governed_node()}

    class Repository:
        def load_published_assets(self, _flow):
            return {}, {}

        def begin_dataflow_create(self, _receipt, *, actor_uid):
            assert actor_uid
            return {
                "status": "completed",
                "dataflow_uid": expected["uid"],
                "result": expected,
            }

    flow = {
        "schema_version": "2.0",
        "dataflow_uid": expected["uid"],
        "name": "客户治理生产线",
        "input_schema_refs": ["bd:customer:v1"],
        "output_schema_ref": "bd:customer_clean:v1",
        "components": [],
    }
    # Use the project's validator fixture shape through the repository-level
    # contract; the replay must happen before any graph write.
    from tests.core.data_rules.test_contracts import valid_dataflow_spec

    flow = valid_dataflow_spec()
    flow["dataflow_uid"] = expected["uid"]
    envelope = {
        "dataflow_spec": flow,
        "dataset_edges": {
            "source_table": flow["input_schema_refs"],
            "target_table": flow["output_schema_ref"],
        },
        "migration_metadata": {
            "status": "migrated",
            "legacy_fields_present": False,
            "preserved_for_read_only": True,
            "governed_semantics": "dataflow_spec",
        },
    }
    monkeypatch.setattr(
        DataFlowService,
        "_merge_governed_dataflow",
        lambda _node: pytest.fail("Neo4j was called during completed replay"),
    )

    result = DataFlowService.create_dataflow(
        {
            "name_zh": "客户治理生产线",
            "describe": "响应丢失重试",
            "script_type": "governed",
            "script_requirement": envelope,
            "draft_reservation": {
                "reservation_id": new_governance_uid(),
                "dataflow_uid": expected["uid"],
                "nonce": "response-loss",
            },
        },
        repository=Repository(),
        actor_uid=new_governance_uid(),
    )
    assert result == expected


def test_graph_failure_is_persisted_but_finalize_failure_leaves_reconcilable_lease(
    monkeypatch,
):
    from tests.core.data_rules.test_contracts import valid_dataflow_spec
    from tests.test_legacy_governance_cutover import PublishedAssetRepository

    flow = valid_dataflow_spec()
    actor = new_governance_uid()

    def payload(repository):
        receipt = repository.reserve_dataflow_draft(actor_uid=actor)
        receipt["dataflow_uid"] = flow["dataflow_uid"]
        return {
            "name_zh": "故障注入生产线",
            "describe": "故障注入",
            "script_type": "governed",
            "script_requirement": {
                "dataflow_spec": flow,
                "dataset_edges": {
                    "source_table": flow["input_schema_refs"],
                    "target_table": flow["output_schema_ref"],
                },
                "migration_metadata": {
                    "status": "migrated",
                    "legacy_fields_present": False,
                    "preserved_for_read_only": True,
                    "governed_semantics": "dataflow_spec",
                },
            },
            "draft_reservation": {
                key: receipt[key]
                for key in ("reservation_id", "dataflow_uid", "nonce")
            },
        }

    graph_failure = PublishedAssetRepository()
    failures = []
    graph_failure.commit_dataflow_create_failure = (
        lambda **kwargs: failures.append(kwargs)
    )
    monkeypatch.setattr(
        DataFlowService,
        "_merge_governed_dataflow",
        lambda _node: (_ for _ in ()).throw(RuntimeError("neo4j unavailable")),
    )
    with pytest.raises(RuntimeError, match="neo4j unavailable"):
        DataFlowService.create_dataflow(
            payload(graph_failure), repository=graph_failure, actor_uid=actor
        )
    assert failures[0]["error_code"] == "neo4j_create_failed"

    finalize_failure = PublishedAssetRepository()
    monkeypatch.setattr(
        DataFlowService,
        "_merge_governed_dataflow",
        lambda node: (73, {**node, "id": 73}),
    )
    finalize_failure.complete_dataflow_create = (
        lambda **_kwargs: (_ for _ in ()).throw(
            RuntimeError("postgres finalize failed")
        )
    )
    with pytest.raises(RuntimeError, match="postgres finalize failed"):
        DataFlowService.create_dataflow(
            payload(finalize_failure),
            repository=finalize_failure,
            actor_uid=actor,
        )