"""Persistent mapping between Telegram topics and Tracker projects."""

import json
import logging
from pathlib import Path

logger = logging.getLogger(__name__)

MAP_FILE = Path(__file__).parent / "data" / "topic_map.json"


class TopicMap:
    """Bidirectional mapping: topic_id <-> project_uuid."""

    def __init__(self):
        self._by_topic: dict[int, str] = {}    # topic_id -> project_uuid
        self._by_project: dict[str, int] = {}  # project_uuid -> topic_id
        self._load()

    def _load(self):
        if MAP_FILE.exists():
            data = json.loads(MAP_FILE.read_text())
            for tid_str, puuid in data.items():
                tid = int(tid_str)
                self._by_topic[tid] = puuid
                self._by_project[puuid] = tid
            logger.info("Loaded %d topic mappings", len(self._by_topic))

    def _save(self):
        MAP_FILE.parent.mkdir(parents=True, exist_ok=True)
        data = {str(tid): puuid for tid, puuid in self._by_topic.items()}
        MAP_FILE.write_text(json.dumps(data, indent=2))

    def set(self, topic_id: int, project_uuid: str):
        self._by_topic[topic_id] = project_uuid
        self._by_project[project_uuid] = topic_id
        self._save()

    def get_project(self, topic_id: int) -> str | None:
        return self._by_topic.get(topic_id)

    def get_topic(self, project_uuid: str) -> int | None:
        return self._by_project.get(project_uuid)

    def remove_by_topic(self, topic_id: int):
        puuid = self._by_topic.pop(topic_id, None)
        if puuid:
            self._by_project.pop(puuid, None)
            self._save()

    def all(self) -> dict[int, str]:
        return dict(self._by_topic)