"""Read local configuration without changing the process environment or storage."""

import os
from pathlib import Path


ROOT_DIR = Path(__file__).resolve().parents[1]
ALLOWED_EXT = {'.png', '.jpg', '.jpeg', '.gif', '.webp', '.pdf', '.txt', '.csv'}
MAX_UPLOAD_MB = 10


def default_config():
    from dotenv import dotenv_values

    local_config = dotenv_values(ROOT_DIR / '.env', encoding='utf-8-sig', interpolate=False)
    api_key = os.environ.get('DEEPSEEK_API_KEY', local_config.get('DEEPSEEK_API_KEY'))
    return {
        'DATABASE': ROOT_DIR / 'history.db',
        'UPLOAD_DIR': ROOT_DIR / 'uploads',
        'BACKUP_DIR': ROOT_DIR / 'backups',
        'LOG_DIR': ROOT_DIR / 'logs',
        'DEEPSEEK_API_KEY': (api_key or '').strip(),
        'ORDER_DATA_TENANT_ID': str(os.environ.get('ORDER_DATA_TENANT_ID', local_config.get('ORDER_DATA_TENANT_ID')) or '').strip(),
        'MODEL_URL': 'https://api.deepseek.com/v1/chat/completions',
        'MODEL_NAME': 'deepseek-chat',
        'MAX_CONTEXT': 4,
        'MAX_ANSWER_CHARS': 800,
        'MAX_ANSWER_CHARS_EN': 1400,
        'RATE_LIMIT_PER_MIN': 60,
        'ALLOWED_EXT': set(ALLOWED_EXT),
        'MAX_UPLOAD_MB': MAX_UPLOAD_MB,
        'HOST': '0.0.0.0',
        'PORT': 5000,
        'INITIALIZE_RUNTIME': True,
    }


def get_setting(name):
    try:
        from flask import current_app, has_app_context
    except ImportError:
        return default_config()[name]
    if has_app_context():
        return current_app.config[name]
    return default_config()[name]