import json
import os
from configparser import ConfigParser
from pathlib import Path
from typing import Any

CONFIG_DEFAULTS = {
    'SQLALCHEMY_TRACK_MODIFICATIONS': False
}
CONFIG_PREFIXES = ['SMIDGEN_', 'SQLALCHEMY_']
STRIPPED_PREFIXES = ['SMIDGEN_']


def read_from_file() -> dict:
    """Read the configuration file and return the values in a dictionary"""
    config_file = Path(__file__).parent / '..' / 'codesmidgen.cfg'
    if not config_file.exists():
        return {}
    config_parser = ConfigParser()
    config_parser.read(config_file)
    config: dict[str, Any] = {}
    for option in config_parser.options('codesmidgen'):
        config[option.upper()] = config_parser.get('codesmidgen', option)
    return config


def read_from_envvars() -> dict:
    """Read the configuration from environment variables"""
    config: dict[str, Any] = {}
    for key in sorted(os.environ):
        if not any([key.startswith(prefix) for prefix in CONFIG_PREFIXES]):
            continue
        value = os.environ[key]
        try:
            value = json.loads(value)
        except Exception:
            # If the value is not JSON parseable, just leave it as a string
            pass
        for prefix in STRIPPED_PREFIXES:
            key = key.replace(prefix, '')
        # Check if there are any "nested" values
        if '__' not in key:
            config[key] = value
            continue
        # Navigate the nested values and build the structure
        *parents, child = key.split('__')
        item = config
        for parent in parents:
            if parent not in item:
                item[parent] = {}
            item = item[parent]
        item[child] = value
    return config


def get_config() -> dict:
    """Read configuration from files, environment variables, etc."""
    config = {}
    config.update(CONFIG_DEFAULTS)
    config.update(read_from_file())
    config.update(read_from_envvars())
    return config