import asyncio
from datetime import datetime, timezone
import importlib.util
from pathlib import Path


def _load_scada_repository():
    module_path = (
        Path(__file__).resolve().parents[2]
        / "app"
        / "infra"
        / "db"
        / "timescaledb"
        / "repositories"
        / "scada.py"
    )
    spec = importlib.util.spec_from_file_location("tests_scada_repo_under_test", module_path)
    module = importlib.util.module_from_spec(spec)
    assert spec and spec.loader
    spec.loader.exec_module(module)
    return module.ScadaRepository


class _FakeCursor:
    def __init__(self, initial_rowcount: int):
        self.initial_rowcount = initial_rowcount
        self.rowcount = 0
        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))
        if len(self.calls) == 1:
            self.rowcount = self.initial_rowcount
        else:
            self.rowcount = 1


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

    def cursor(self):
        return self.cursor_instance


def test_update_scada_field_inserts_when_update_hits_no_rows():
    ScadaRepository = _load_scada_repository()
    conn = _FakeConnection(initial_rowcount=0)
    point_time = datetime(2026, 1, 1, 0, 0, tzinfo=timezone.utc)

    asyncio.run(
        ScadaRepository.update_scada_field(
            conn,
            point_time,
            "170490",
            "cleaned_value",
            26.5,
        )
    )

    assert len(conn.cursor_instance.calls) == 2
    assert "UPDATE scada.scada_data SET" in conn.cursor_instance.calls[0][0]
    assert "INSERT INTO scada.scada_data" in conn.cursor_instance.calls[1][0]


def test_update_scada_field_skips_insert_when_update_succeeds():
    ScadaRepository = _load_scada_repository()
    conn = _FakeConnection(initial_rowcount=1)
    point_time = datetime(2026, 1, 1, 0, 0, tzinfo=timezone.utc)

    asyncio.run(
        ScadaRepository.update_scada_field(
            conn,
            point_time,
            "170490",
            "cleaned_value",
            26.5,
        )
    )

    assert len(conn.cursor_instance.calls) == 1
    assert "UPDATE scada.scada_data SET" in conn.cursor_instance.calls[0][0]