Add time-of-day system with tests

src/mudlib/timeofday.py

@@ -0,0 +1,70 @@
+"""Time-of-day periods and atmospheric descriptions."""
+
+from __future__ import annotations
+
+
+def get_time_period(hour: int) -> str:
+    """Map a game hour (0-23) to a time period.
+
+    Args:
+        hour: Game hour (0-23)
+
+    Returns:
+        Time period: "dawn", "day", "dusk", or "night"
+    """
+    if 5 <= hour <= 6:
+        return "dawn"
+    elif 7 <= hour <= 17:
+        return "day"
+    elif 18 <= hour <= 19:
+        return "dusk"
+    else:
+        return "night"
+
+
+def get_sky_description(hour: int) -> str:
+    """Return an atmospheric one-liner for the current time of day.
+
+    Args:
+        hour: Game hour (0-23)
+
+    Returns:
+        Short atmospheric description based on time of day
+    """
+    period = get_time_period(hour)
+
+    # multiple variants per period, pick based on hour for determinism
+    descriptions = {
+        "dawn": [
+            "pale light seeps across the horizon",
+            "the first rays of dawn touch the sky",
+        ],
+        "day": [
+            "the sun hangs high overhead",
+            "bright daylight illuminates everything",
+            "warm light fills the air",
+            "midday light is at its strongest",
+            "golden afternoon light slants across the land",
+            "the day is bright and warm",
+            "light glints off distant surfaces",
+            "the sun begins its slow descent",
+            "late afternoon shadows grow longer",
+            "the sun drifts toward the western horizon",
+            "the day's light begins to soften",
+        ],
+        "dusk": [
+            "the sky burns orange and violet",
+            "twilight deepens across the landscape",
+        ],
+        "night": [
+            "stars wheel slowly overhead",
+            "darkness blankets the world",
+            "the night is deep and still",
+            "moonlight casts pale shadows",
+            "the hours before dawn stretch long and dark",
+        ],
+    }
+
+    variants = descriptions[period]
+    # use hour to pick variant deterministically
+    return variants[hour % len(variants)]

tests/test_timeofday.py

@@ -0,0 +1,56 @@
+"""Tests for time-of-day system."""
+
+from mudlib.timeofday import get_sky_description, get_time_period
+
+
+def test_get_time_period_dawn():
+    assert get_time_period(5) == "dawn"
+    assert get_time_period(6) == "dawn"
+
+
+def test_get_time_period_day():
+    assert get_time_period(7) == "day"
+    assert get_time_period(12) == "day"
+    assert get_time_period(17) == "day"
+
+
+def test_get_time_period_dusk():
+    assert get_time_period(18) == "dusk"
+    assert get_time_period(19) == "dusk"
+
+
+def test_get_time_period_night():
+    assert get_time_period(20) == "night"
+    assert get_time_period(21) == "night"
+    assert get_time_period(23) == "night"
+    assert get_time_period(0) == "night"
+    assert get_time_period(1) == "night"
+    assert get_time_period(4) == "night"
+
+
+def test_get_sky_description_returns_non_empty():
+    for hour in range(24):
+        desc = get_sky_description(hour)
+        assert desc, f"hour {hour} returned empty description"
+        assert isinstance(desc, str)
+
+
+def test_get_sky_description_differs_by_period():
+    dawn_desc = get_sky_description(5)
+    day_desc = get_sky_description(12)
+    dusk_desc = get_sky_description(18)
+    night_desc = get_sky_description(0)
+
+    # each period should have different descriptions
+    descriptions = {dawn_desc, day_desc, dusk_desc, night_desc}
+    assert len(descriptions) == 4, "periods should have distinct descriptions"
+
+
+def test_get_sky_description_edge_cases():
+    # boundaries between periods
+    assert get_sky_description(0)  # night start
+    assert get_sky_description(5)  # dawn start
+    assert get_sky_description(7)  # day start
+    assert get_sky_description(18)  # dusk start
+    assert get_sky_description(20)  # night start
+    assert get_sky_description(23)  # night end