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01abcac8f2
Implement HF radiofax decoding with custom Python DSP pipeline (rtl_fm USB → Goertzel/Hilbert demodulation), 33-station database with broadcast schedules, audio waveform scope, live image preview, and decoded image gallery. Amber/gold UI theme for HF distinction. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
90 lines
2.6 KiB
Python
90 lines
2.6 KiB
Python
"""WeFax station database loader.
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Loads and caches station data from data/wefax_stations.json. Provides
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lookup by callsign and current-broadcast filtering based on UTC time.
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"""
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from __future__ import annotations
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import json
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from datetime import datetime, timezone
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from pathlib import Path
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_stations_cache: list[dict] | None = None
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_stations_by_callsign: dict[str, dict] = {}
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_STATIONS_PATH = Path(__file__).resolve().parent.parent / 'data' / 'wefax_stations.json'
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def load_stations() -> list[dict]:
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"""Load all WeFax stations from JSON, caching on first call."""
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global _stations_cache, _stations_by_callsign
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if _stations_cache is not None:
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return _stations_cache
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with open(_STATIONS_PATH) as f:
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data = json.load(f)
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_stations_cache = data.get('stations', [])
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_stations_by_callsign = {s['callsign']: s for s in _stations_cache}
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return _stations_cache
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def get_station(callsign: str) -> dict | None:
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"""Get a single station by callsign."""
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load_stations()
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return _stations_by_callsign.get(callsign.upper())
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def get_current_broadcasts(callsign: str) -> list[dict]:
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"""Return schedule entries closest to the current UTC time.
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Returns up to 3 entries: the most recent past broadcast and the
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next two upcoming ones, annotated with ``minutes_until`` or
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``minutes_ago`` relative to now.
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"""
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station = get_station(callsign)
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if not station:
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return []
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now = datetime.now(timezone.utc)
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current_minutes = now.hour * 60 + now.minute
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schedule = station.get('schedule', [])
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if not schedule:
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return []
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# Convert schedule times to minutes-since-midnight for comparison
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entries: list[tuple[int, dict]] = []
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for entry in schedule:
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parts = entry['utc'].split(':')
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mins = int(parts[0]) * 60 + int(parts[1])
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entries.append((mins, entry))
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entries.sort(key=lambda x: x[0])
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# Find closest entries relative to now
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results = []
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for mins, entry in entries:
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diff = mins - current_minutes
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# Wrap around midnight
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if diff < -720:
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diff += 1440
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elif diff > 720:
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diff -= 1440
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annotated = dict(entry)
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if diff >= 0:
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annotated['minutes_until'] = diff
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else:
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annotated['minutes_ago'] = abs(diff)
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annotated['_sort_key'] = abs(diff)
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results.append(annotated)
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results.sort(key=lambda x: x['_sort_key'])
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# Return 3 nearest entries, clean up sort key
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for r in results:
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r.pop('_sort_key', None)
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return results[:3]
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