"""Loads the scraped events JSON file and keeps it in memory.

The file is treated as read-only. Call ``reload()`` to pick up a fresh
scrape without restarting the server.
"""

import json
import os
from datetime import date
from pathlib import Path
from threading import Lock
from typing import List, Optional

from models import Event

# Default: the fundi-scraped-output.json sitting in the repo root, one
# directory above this file. Override with the DATA_FILE env var.
_DEFAULT_DATA_FILE = Path(__file__).resolve().parent.parent / "fundi-scraped-output.json"


class EventStore:
    def __init__(self, path: Optional[os.PathLike] = None):
        self.path = Path(path or os.environ.get("DATA_FILE") or _DEFAULT_DATA_FILE)
        self._lock = Lock()
        self._events: List[Event] = []
        self.reload()

    def reload(self) -> int:
        """Re-read the JSON file from disk. Returns the number of events loaded."""
        if not self.path.exists():
            raise FileNotFoundError(f"Data file not found: {self.path}")
        with self.path.open(encoding="utf-8") as fh:
            raw = json.load(fh)
        events = [Event.model_validate(item) for item in raw]
        with self._lock:
            self._events = events
        return len(events)

    def all(self) -> List[Event]:
        with self._lock:
            return list(self._events)

    def get(self, index: int) -> Optional[Event]:
        with self._lock:
            if 0 <= index < len(self._events):
                return self._events[index]
        return None


def parse_event_date(value: str) -> Optional[date]:
    """Parse the scraper's ``dd.mm.yy`` date strings. Returns None if unparseable."""
    try:
        day, month, year = (int(part) for part in value.strip().split("."))
    except (ValueError, AttributeError):
        return None
    if year < 100:
        year += 2000
    try:
        return date(year, month, day)
    except ValueError:
        return None


def iter_artist_names(event: Event):
    for group in event.event_artists:
        for artist in group:
            if artist.artist_name:
                yield artist.artist_name