new alarm mechanism

pi/alarm_scheduler.py

@@ -0,0 +1,114 @@
+"""Alarm scheduler — load config and check firing schedule."""
+
+import json
+import logging
+import re
+from datetime import datetime
+from pathlib import Path
+
+log = logging.getLogger(__name__)
+
+DEFAULT_CONFIG_PATH = Path(__file__).parent / "config" / "alarms.json"
+
+VALID_DAYS = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"}
+TIME_RE = re.compile(r"^([01]\d|2[0-3])[0-5]\d$")
+
+
+def load_config(path: Path) -> dict | None:
+    """Read and validate alarm config JSON.
+
+    Returns the config dict, or None if the file is missing, empty, or invalid.
+    Never raises — logs warnings and returns None on any problem.
+    """
+    try:
+        text = path.read_text(encoding="utf-8").strip()
+    except FileNotFoundError:
+        log.warning("Config file not found: %s", path)
+        return None
+    except OSError as e:
+        log.warning("Cannot read config %s: %s", path, e)
+        return None
+
+    if not text:
+        log.warning("Config file is empty: %s", path)
+        return None
+
+    try:
+        data = json.loads(text)
+    except json.JSONDecodeError as e:
+        log.warning("Invalid JSON in %s: %s", path, e)
+        return None
+
+    # Empty object or empty list means "no alarms"
+    if not data or (isinstance(data, list) and len(data) == 0):
+        log.info("Config is empty — no alarms configured")
+        return None
+
+    if not isinstance(data, dict):
+        log.warning("Config must be a JSON object, got %s", type(data).__name__)
+        return None
+
+    # Validate alarm_time (required)
+    alarm_time = data.get("alarm_time")
+    if alarm_time is None:
+        log.warning("Missing required field 'alarm_time'")
+        return None
+    if not isinstance(alarm_time, str) or not TIME_RE.match(alarm_time):
+        log.warning("Invalid alarm_time '%s' — must be 4-digit HHMM (e.g. '0730')", alarm_time)
+        return None
+
+    # Validate alarm_days (optional)
+    alarm_days = data.get("alarm_days")
+    if alarm_days is not None:
+        if not isinstance(alarm_days, list) or not all(isinstance(d, str) for d in alarm_days):
+            log.warning("alarm_days must be a list of strings")
+            return None
+        bad = [d for d in alarm_days if d not in VALID_DAYS]
+        if bad:
+            log.warning("Invalid day abbreviations in alarm_days: %s", bad)
+            return None
+
+    # Validate alarm_dates (optional)
+    alarm_dates = data.get("alarm_dates")
+    if alarm_dates is not None:
+        if not isinstance(alarm_dates, list) or not all(isinstance(d, str) for d in alarm_dates):
+            log.warning("alarm_dates must be a list of strings")
+            return None
+        date_re = re.compile(r"^(0[1-9]|1[0-2])/(0[1-9]|[12]\d|3[01])$")
+        bad = [d for d in alarm_dates if not date_re.match(d)]
+        if bad:
+            log.warning("Invalid date formats in alarm_dates (expected MM/DD): %s", bad)
+            return None
+
+    log.info("Alarm config loaded: time=%s days=%s", alarm_time, alarm_days or "(every day)")
+    return data
+
+
+def should_fire(config: dict) -> bool:
+    """Check if the alarm should fire right now based on config schedule.
+
+    Rules:
+    - alarm_time must match current HHMM
+    - If alarm_days is present, today's 3-letter abbreviation must be in the list
+    - If alarm_days is absent but alarm_dates is present, today's MM/DD must match
+    - If neither alarm_days nor alarm_dates is present, fires every day
+    - If both are present, alarm_days wins (alarm_dates ignored)
+    """
+    now = datetime.now()
+    current_hhmm = now.strftime("%H%M")
+
+    if config["alarm_time"] != current_hhmm:
+        return False
+
+    alarm_days = config.get("alarm_days")
+    alarm_dates = config.get("alarm_dates")
+
+    # alarm_days takes priority over alarm_dates
+    if alarm_days is not None:
+        return now.strftime("%a") in alarm_days
+
+    if alarm_dates is not None:
+        return now.strftime("%m/%d") in alarm_dates
+
+    # Neither specified — fire every day
+    return True