"""Generate an example config.json showing all available options with their defaults.

Produces a merged document: dataclass defaults provide the full key schema,
the bundled config.json supplies the real values (wins on conflict).

Usage:
  python scripts/gen_example_config.py
  python scripts/gen_example_config.py > docs/example_config.json
"""
import dataclasses
import json
import sys
from importlib.resources import files

sys.path.insert(0, str(__import__('pathlib').Path(__file__).parent.parent))

from room_cal._utils import CalendarEntry, Config, ServiceConfig, _deep_merge


def _strip_none(obj):
  """Recursively remove keys whose value is None."""
  if isinstance(obj, dict):
    return {k: _strip_none(v) for k, v in obj.items() if v is not None}
  if isinstance(obj, list):
    return [_strip_none(i) for i in obj]
  return obj


def _defaults_dict() -> dict:
  raw = dataclasses.asdict(Config())
  raw['global'] = raw.pop('global_')
  raw.pop('api_url', None)
  raw.pop('services', None)
  raw.pop('calendars', None)
  raw['rules'].pop('pipelines', None)
  return _strip_none(raw)


def _expand_service(key: str, d: dict) -> dict:
  """Round-trip a service dict through ServiceConfig so all dataclass fields appear."""
  full = dataclasses.asdict(ServiceConfig.from_dict(key, d))
  full.pop('key', None)
  return _strip_none(full)


def generate() -> str:
  defaults = _defaults_dict()
  stock = json.loads(files('room_cal').joinpath('config.json').read_text(encoding='utf-8'))
  merged = _deep_merge(defaults, stock)
  merged['services'] = {k: _expand_service(k, v) for k, v in merged.get('services', {}).items()}
  merged['calendars'] = [dataclasses.asdict(CalendarEntry.from_dict(e)) for e in merged.get('calendars', [])]
  return json.dumps(merged, indent=2)


def main():
  print(generate())


if __name__ == '__main__':
  main()