"""Small integration test: compute_party_coords vs centroids code-path used in trajectories tab.

Builds a tiny synthetic positions_by_window and party_map and asserts that the centroids
returned by compute_party_coords (x and y) match the centroids computed by the
build_trajectories_tab logic (the same mean computations).
"""

from explorer_helpers import compute_party_coords


def test_compass_vs_trajectory_centroids_match():
    # synthetic positions_by_window: two windows W1 and W2
    positions_by_window = {
        "W1": {
            "A": (0.1, 0.2),
            "B": (0.3, 0.4),
            "C": (-0.2, 0.0),
        },
        "W2": {
            "A": (0.15, 0.25),
            "B": (0.35, 0.45),
            "C": (-0.25, 0.05),
        },
    }
    party_map = {"A": "P1", "B": "P1", "C": "P2"}

    # compute party centroids via helper for W2
    party_coords, fallback = compute_party_coords(positions_by_window, party_map, "W2")

    # compute centroids the same way trajectories tab does:
    per_party = {}
    for ent, (x, y) in positions_by_window["W2"].items():
        p = party_map.get(ent)
        per_party.setdefault(p, []).append((x, y))
    centroids = {}
    for p, coords in per_party.items():
        xs = [c[0] for c in coords]
        ys = [c[1] for c in coords]
        centroids[p] = (sum(xs) / len(xs), sum(ys) / len(ys))

    assert party_coords == centroids
    assert not fallback