"""Unit tests for the subscription evaluation engine's pure logic (no DB, no
network): trigger detection against a synthetic climatology and message wording."""
import datetime
import types

import numpy as np
import polars as pl

import notify


def _history() -> pl.DataFrame:
    start, end = datetime.date(1990, 1, 1), datetime.date(2020, 12, 31)
    dates = [start + datetime.timedelta(days=i) for i in range((end - start).days + 1)]
    rng = np.random.default_rng(1)
    n = len(dates)
    return pl.DataFrame({
        "date": dates,
        "doy": np.array([d.timetuple().tm_yday for d in dates], dtype="int16"),
        "tmax": 70 + rng.normal(0, 8, n),
        "tmin": 48 + rng.normal(0, 7, n),
        "precip": rng.exponential(0.05, n),
    })


def _sub(**kw):
    d = dict(metrics=["tmax"], threshold=95, two_sided=False, kind="observed",
             label="Testville", lat=1.0, lon=2.0)
    d.update(kw)
    return types.SimpleNamespace(**d)


def _row(date, **vals):
    r = {"date": datetime.date.fromisoformat(date)}
    r.update(vals)
    return r


def test_high_trigger():
    row = _row("2021-07-15", tmax=115.0, tmin=50.0, precip=0.0)
    hit = notify._first_trigger(_sub(metrics=["tmax"], threshold=95), [row], _history(), {})
    assert hit is not None
    _, metric, direction, g = hit
    assert metric == "tmax" and direction == "high" and g["percentile"] >= 95


def test_no_trigger_when_normal():
    row = _row("2021-07-15", tmax=70.0, tmin=48.0, precip=0.0)
    assert notify._first_trigger(_sub(metrics=["tmax"], threshold=95), [row], _history(), {}) is None


def test_low_trigger_only_when_two_sided():
    row = _row("2021-07-15", tmax=70.0, tmin=10.0, precip=0.0)   # extreme low overnight
    assert notify._first_trigger(
        _sub(metrics=["tmin"], threshold=95, two_sided=False), [row], _history(), {}) is None
    hit = notify._first_trigger(
        _sub(metrics=["tmin"], threshold=95, two_sided=True), [row], _history(), {})
    assert hit is not None and hit[1] == "tmin" and hit[2] == "low"


def test_precip_never_low_side():
    # A dry day has no rain-percentile, so a precip subscription never fires low
    # even when two-sided (rain is one-directional).
    row = _row("2021-07-15", tmax=70.0, precip=0.0)
    assert notify._first_trigger(
        _sub(metrics=["precip"], threshold=95, two_sided=True), [row], _history(), {}) is None


def test_compose_observed_wording():
    g = {"percentile": 99.0, "value": 115.0, "grade": "Near Record"}
    title, body = notify._compose(_sub(kind="observed", label="Phoenix"),
                                  "2026-07-14", "tmax", "high", g)
    assert title == "Phoenix: unusually hot day"
    assert body.startswith("On 2026-07-14")
    assert "99th percentile" in body and "Near Record" in body


def test_compose_forecast_wording():
    g = {"percentile": 2.0, "value": 5.0, "grade": "Near Record"}
    title, body = notify._compose(_sub(kind="forecast", label="Nome"),
                                  "2026-01-02", "tmin", "low", g)
    assert title == "Nome: unusually cold night"
    assert body.startswith("Forecast for 2026-01-02")