"""Environment configuration; production fails closed without upload authentication."""
import os
from dataclasses import dataclass
from functools import lru_cache
from pathlib import Path

@dataclass(frozen=True)
class Settings:
    environment: str
    database_url: str
    storage_dir: Path
    api_key: str
    public_url: str
    max_upload_bytes: int
    parse_timeout: int
    link_ttl: int
    max_pending: int
    s3_bucket: str
    s3_endpoint: str | None
    s3_region: str

@lru_cache
def settings():
    root = Path(os.getenv('STORAGE_DIR', './data')).resolve()
    config = Settings(
        environment=os.getenv('APP_ENV', 'development'),
        database_url=os.getenv('DATABASE_URL', f'sqlite:///{root}/jobs.db'),
        storage_dir=root,
        api_key=os.getenv('API_KEY', ''),
        public_url=os.getenv('PUBLIC_BASE_URL', 'http://127.0.0.1:8000').rstrip('/'),
        max_upload_bytes=int(os.getenv('MAX_UPLOAD_BYTES', str(32 * 1024 * 1024))),
        parse_timeout=int(os.getenv('PARSE_TIMEOUT_SECONDS', '60')),
        link_ttl=int(os.getenv('LINK_TTL_SECONDS', '604800')),
        max_pending=int(os.getenv('MAX_PENDING_JOBS', '100')),
        s3_bucket=os.getenv('S3_BUCKET', ''),
        s3_endpoint=os.getenv('S3_ENDPOINT_URL') or None,
        s3_region=os.getenv('AWS_DEFAULT_REGION', 'us-east-1'),
    )
    if config.environment == 'production' and len(config.api_key) < 32:
        raise RuntimeError('Production requires API_KEY with at least 32 characters')
    if config.environment == 'production' and not config.public_url.startswith('https://'):
        raise RuntimeError('Production requires an HTTPS PUBLIC_BASE_URL')
    if min(config.max_upload_bytes, config.parse_timeout, config.link_ttl, config.max_pending) <= 0:
        raise RuntimeError('Upload, parse, expiry and queue limits must be positive')
    root.mkdir(parents=True, exist_ok=True, mode=0o700)
    return config