"""JSON-file-backed config: Immich connection, selected album, and cursor
state (which photo /frame/image serves next)."""

from __future__ import annotations

import json
import os
from pathlib import Path
from threading import Lock

from pydantic import BaseModel

CONFIG_PATH = Path(os.environ.get("CONFIG_PATH", "/data/config.json"))

_lock = Lock()


class FrameConfig(BaseModel):
    immich_url: str = ""
    immich_api_key: str = ""
    management_token: str = ""  # gates the web UI (see main.py); empty = no gate, open on trusted LAN
    album_id: str = ""
    order: str = "sequential"  # or "shuffle"
    refresh_interval_s: int = 3600
    smart_crop_faces: bool = True

    # Current photo + upcoming queue (see app/photo_queue.py). current_asset_set_at
    # is what lets the server decide "has it been long enough to advance" on its
    # own clock, independent of how/why the device asked for a photo.
    current_asset_id: str = ""
    current_asset_set_at: float = 0.0
    queue: list[str] = []
    queue_cursor: int = 0  # internal bookkeeping for sequential queue top-up; not user-facing
    queue_target_len: int = 20  # how many upcoming photos to keep queued/shown in the web UI


def load() -> FrameConfig:
    with _lock:
        if not CONFIG_PATH.exists():
            cfg = FrameConfig()
        else:
            cfg = FrameConfig(**json.loads(CONFIG_PATH.read_text()))

    # IMMICH_URL/IMMICH_API_KEY/MANAGEMENT_TOKEN set in the environment
    # (e.g. docker-compose.yml, see docker-compose.yml.example) take
    # precedence over whatever's saved in CONFIG_PATH, so credentials never
    # need to go through the web UI.
    env_url = os.environ.get("IMMICH_URL")
    env_key = os.environ.get("IMMICH_API_KEY")
    env_token = os.environ.get("MANAGEMENT_TOKEN")
    if env_url:
        cfg.immich_url = env_url
    if env_key:
        cfg.immich_api_key = env_key
    if env_token:
        cfg.management_token = env_token

    return cfg


def save(cfg: FrameConfig) -> None:
    with _lock:
        CONFIG_PATH.parent.mkdir(parents=True, exist_ok=True)
        CONFIG_PATH.write_text(cfg.model_dump_json(indent=2))