import asyncio
from contextlib import asynccontextmanager, contextmanager
from datetime import datetime, timezone

from app.infra.db.timescaledb.repositories.realtime import RealtimeRepository


class _FakeCursor:
    def __init__(self):
        self.calls: list[tuple[str, tuple]] = []

    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type, exc, tb):
        return False

    async def execute(self, query, params):
        self.calls.append((str(query), params))

    async def fetchall(self):
        return []


class _FakeConnection:
    def __init__(self):
        self.cursor_instance = _FakeCursor()

    def cursor(self):
        return self.cursor_instance


def test_get_links_by_time_range_normalizes_inputs_to_utc():
    conn = _FakeConnection()

    asyncio.run(
        RealtimeRepository.get_links_by_time_range(
            conn,
            datetime.fromisoformat("2026-06-01T08:00:00+08:00"),
            datetime.fromisoformat("2026-06-01T09:00:00+08:00"),
        )
    )

    assert len(conn.cursor_instance.calls) == 1
    _, params = conn.cursor_instance.calls[0]
    assert params == (
        datetime(2026, 6, 1, 0, 0, tzinfo=timezone.utc),
        datetime(2026, 6, 1, 1, 0, tzinfo=timezone.utc),
    )


def test_get_nodes_by_time_range_normalizes_inputs_to_utc():
    conn = _FakeConnection()

    asyncio.run(
        RealtimeRepository.get_nodes_by_time_range(
            conn,
            datetime.fromisoformat("2026-06-01T08:00:00+08:00"),
            datetime.fromisoformat("2026-06-01T09:00:00+08:00"),
        )
    )

    assert len(conn.cursor_instance.calls) == 1
    _, params = conn.cursor_instance.calls[0]
    assert params == (
        datetime(2026, 6, 1, 0, 0, tzinfo=timezone.utc),
        datetime(2026, 6, 1, 1, 0, tzinfo=timezone.utc),
    )


class _SyncTransactionConnection:
    def __init__(self):
        self.transactions = 0
        self.calls: list[tuple[str, tuple]] = []

    @contextmanager
    def transaction(self):
        self.transactions += 1
        yield

    @contextmanager
    def cursor(self):
        connection = self

        class Cursor:
            def execute(self, query, params):
                connection.calls.append((query, params))

        yield Cursor()


def test_realtime_node_and_link_replacement_share_outer_transaction(monkeypatch):
    conn = _SyncTransactionConnection()
    calls: list[str] = []
    monkeypatch.setattr(
        RealtimeRepository,
        "_copy_nodes_sync",
        lambda _cur, _data, _time: calls.append("nodes"),
    )
    monkeypatch.setattr(
        RealtimeRepository,
        "_copy_links_sync",
        lambda _cur, _data, _time: calls.append("links"),
    )

    RealtimeRepository.store_realtime_simulation_result_sync(
        conn,
        [{"node": "N1", "result": [{"pressure": 1.0}]}],
        [{"link": "L1", "result": [{"flow": 2.0}]}],
        "2026-06-01T00:00:00Z",
    )

    assert conn.transactions == 1
    assert calls == ["nodes", "links"]
    assert [query for query, _params in conn.calls] == [
        "SELECT pg_advisory_xact_lock(hashtextextended(%s::text, 1))",
        "DELETE FROM realtime.node_results WHERE time = %s",
        "DELETE FROM realtime.link_results WHERE time = %s",
    ]


def test_realtime_batch_rejects_multiple_timestamps_before_writing():
    data = [
        {"time": "2026-06-01T00:00:00Z", "id": "N1"},
        {"time": "2026-06-01T00:15:00Z", "id": "N2"},
    ]

    try:
        RealtimeRepository.insert_nodes_batch_sync(object(), data)
    except ValueError as exc:
        assert str(exc) == "Realtime batch must contain exactly one timestamp"
    else:
        raise AssertionError("multiple realtime timestamps were accepted")


class _AsyncEmptySnapshotConnection:
    def __init__(self):
        self.calls: list[tuple[str, tuple]] = []

    @asynccontextmanager
    async def transaction(self):
        yield

    def cursor(self):
        connection = self

        class Cursor:
            async def __aenter__(self):
                return self

            async def __aexit__(self, *_args):
                return False

            async def execute(self, query, params):
                connection.calls.append((query, params))

        return Cursor()


def test_empty_realtime_side_is_deleted_as_part_of_snapshot_replacement():
    conn = _AsyncEmptySnapshotConnection()

    asyncio.run(
        RealtimeRepository.store_realtime_simulation_result(
            conn,
            node_result_list=[],
            link_result_list=[],
            result_start_time="2026-06-01T00:00:00Z",
        )
    )

    assert [query for query, _params in conn.calls] == [
        "SELECT pg_advisory_xact_lock(hashtextextended(%s::text, 1))",
        "DELETE FROM realtime.node_results WHERE time = %s",
        "DELETE FROM realtime.link_results WHERE time = %s",
    ]