from datetime import datetime, timedelta
from unittest.mock import Mock

import pytest

from app.services import simulation


START = datetime.fromisoformat("2026-10-08T12:00:00+08:00")


def test_online_simulation_uses_realtime_steps_and_returns_requested_samples(monkeypatch):
    calls = []
    mappings = object()
    monkeypatch.setattr(simulation, "get_time", lambda _: {"HYDRAULIC TIMESTEP": "0:15:00"})
    monkeypatch.setattr(simulation, "query_corresponding_element_id_and_query_id", lambda _: mappings)

    def run(**kwargs):
        calls.append(kwargs)
        return {
            "units": {"pressure": "MTR", "flow": "LPS"},
            "node_results": [{"node": "123422", "result": [{"pressure": len(calls)}]}, {"node": "other", "result": [{}]}],
            "link_results": [{"link": "540672", "result": [{"flow": len(calls)}]}],
        }

    monkeypatch.setattr(simulation, "run_simulation", run)
    result = simulation.run_online_simulation("online", START, 3600, output_node_ids=["123422"], output_link_ids=["540672"])
    assert calls == [{
        "name": "online", "simulation_type": "realtime",
        "modify_pattern_start_time": (START + timedelta(minutes=15 * index)).isoformat(timespec="seconds"),
        "scada_mappings": mappings,
    } for index in range(4)]
    assert result["node_results"] == [{"node": "123422", "result": [{"pressure": index} for index in range(1, 5)]}]
    assert result["link_results"] == [{"link": "540672", "result": [{"flow": index} for index in range(1, 5)]}]
    assert result["times"]["num_periods"] == 4
    assert result["times"]["report_step"] == 900
    assert result["times"]["sample_times"][-1] == "2026-10-08T12:45:00+08:00"


def test_online_simulation_rejects_invalid_step_before_calculating(monkeypatch):
    monkeypatch.setattr(simulation, "get_time", lambda _: {"HYDRAULIC TIMESTEP": "0:00:00"})
    run = Mock()
    monkeypatch.setattr(simulation, "run_simulation", run)
    with pytest.raises(ValueError, match="HYDRAULIC TIMESTEP"):
        simulation.run_online_simulation("online", START, 3600)
    run.assert_not_called()


def test_mcp_online_simulation_does_not_copy_a_database(monkeypatch):
    from app.mcp.scenario_service import calculate_scenario

    def reject_copy(*_):
        pytest.fail("Online simulation must not clone the project database")

    run = Mock(return_value={"node_results": [], "link_results": [], "times": {}, "units": {}})
    monkeypatch.setattr("app.native.wndb.core.projects.temporary_project_database", reject_copy)
    monkeypatch.setattr(simulation, "run_online_simulation", run, raising=False)
    result = calculate_scenario("run_simulation", {
        "start_time": START, "duration": 3600,
        "output_node_ids": ["123422", "123425"], "output_link_ids": ["540672"],
    }, network="online", username="actor")
    run.assert_called_once_with("online", START, 3600, output_node_ids=["123422", "123425"], output_link_ids=["540672"])
    assert result["input_source"] == "online_model_simulation"
    assert result["persisted_baseline"] is True
    assert result["persisted_scheme"] is False