"""Durable weekly impact metrics (server/impact.py)."""
import importlib

import pytest

from server import impact


@pytest.fixture(autouse=True)
def _clean():
    impact.reset()
    yield
    impact.reset()


def test_record_and_read_roundtrip():
    impact.record_capture(3, conflicts_caught=1)
    w = impact.this_week()
    assert w["events_captured"] == 3
    assert w["conflicts_caught"] == 1
    # default estimate: 3*8 + 1*15
    assert w["minutes_saved"] == 3 * 8 + 1 * 15


def test_accumulates_across_calls():
    impact.record_capture(2)
    impact.record_capture(1, conflicts_caught=2)
    w = impact.this_week()
    assert w["events_captured"] == 3
    assert w["conflicts_caught"] == 2


def test_persists_across_restart():
    """this_week() reads from disk each call, so a fresh import sees prior data."""
    impact.record_capture(5)
    reloaded = importlib.reload(impact)
    assert reloaded.this_week()["events_captured"] == 5


def test_week_rollover_keeps_weeks_separate(monkeypatch):
    # one _week_key() call per record_capture / this_week
    weeks = iter(["2026-W23", "2026-W24"])
    monkeypatch.setattr(impact, "_week_key", lambda when=None: next(weeks))
    impact.record_capture(2)              # writes W23
    this = impact.this_week()             # reads W24 -> empty
    assert this["events_captured"] == 0
    # both weeks coexist in the file
    data = impact._load()
    assert data["2026-W23"]["events_captured"] == 2


def test_minutes_saved_env_override(monkeypatch):
    monkeypatch.setenv("IMPACT_MIN_PER_EVENT", "12")
    monkeypatch.setenv("IMPACT_MIN_PER_CONFLICT", "20")
    impact.record_capture(2, conflicts_caught=1)
    assert impact.this_week()["minutes_saved"] == 2 * 12 + 1 * 20


def test_this_week_defaults_to_zero():
    w = impact.this_week()
    assert w == {"events_captured": 0, "conflicts_caught": 0, "minutes_saved": 0}