from types import SimpleNamespace

import pytest

from app.algorithms.pressure_sensor_placement.kmeans_placement import (
    optimize_sensor_placement,
)


class FakeNetwork:
    junction_name_list = ["J1", "J2", "J3"]
    pipe_name_list = ["P1", "P2"]

    def __init__(self):
        self._nodes = {
            "J1": SimpleNamespace(coordinates=(0.0, 0.0)),
            "J2": SimpleNamespace(coordinates=(1.0, 0.0)),
            "J3": SimpleNamespace(coordinates=(2.0, 0.0)),
        }
        self._links = {
            "P1": SimpleNamespace(
                diameter=0.4, start_node_name="J1", end_node_name="J2"
            ),
            "P2": SimpleNamespace(
                diameter=0.1, start_node_name="J2", end_node_name="J3"
            ),
        }

    def get_node(self, node_id):
        return self._nodes[node_id]

    def get_link(self, link_id):
        return self._links[link_id]


class DuplicateNearestNodeNetwork:
    junction_name_list = ["J1", "J2", "J3", "J4"]
    pipe_name_list = ["P1", "P2", "P3"]

    def __init__(self):
        self._nodes = {
            "J1": SimpleNamespace(
                coordinates=(-0.2967811321994103, 0.4867937179527957)
            ),
            "J2": SimpleNamespace(
                coordinates=(1.8589649622870763, -1.0070372175769569)
            ),
            "J3": SimpleNamespace(
                coordinates=(-1.4882734126175363, -1.6220731365802619)
            ),
            "J4": SimpleNamespace(
                coordinates=(1.203441836600899, 2.2320704059758474)
            ),
        }
        self._links = {
            "P1": SimpleNamespace(
                diameter=0.4, start_node_name="J1", end_node_name="J2"
            ),
            "P2": SimpleNamespace(
                diameter=0.4, start_node_name="J2", end_node_name="J3"
            ),
            "P3": SimpleNamespace(
                diameter=0.4, start_node_name="J3", end_node_name="J4"
            ),
        }

    def get_node(self, node_id):
        return self._nodes[node_id]

    def get_link(self, link_id):
        return self._links[link_id]


def test_kmeans_filters_candidates_by_minimum_pipe_diameter():
    selected = optimize_sensor_placement(
        FakeNetwork(), sensor_count=2, min_diameter_mm=300
    )

    assert set(selected) == {"J1", "J2"}


def test_kmeans_rejects_sensor_count_above_eligible_candidates():
    with pytest.raises(ValueError, match="候选节点数量"):
        optimize_sensor_placement(
            FakeNetwork(), sensor_count=3, min_diameter_mm=300
        )


def test_kmeans_returns_unique_monitoring_nodes():
    selected = optimize_sensor_placement(
        DuplicateNearestNodeNetwork(), sensor_count=2, min_diameter_mm=300
    )

    assert len(selected) == 2
    assert len(set(selected)) == 2