from typing import Dict, List, Union, Optional, Any
from pathlib import Path
from enum import Enum
import os

from pydantic import BaseSettings, PyObject
import yaml

from soupjobs import SOUPJOBS, CONFIG_FILE_ENV_VAR, CONFIG_FILE_PLACEHOLDER


StrListOrStr = Union[str, List[str]]
TagAttrs = Dict[str, StrListOrStr]
OptInt = Optional[int]
OptStr = Optional[str]
OptPyObj = Optional[PyObject]


class OutputFormat(str, Enum):
    simple = 'simple'
    yaml = 'yaml'
    json = 'json'


class Settings(BaseSettings):
    _CONFIG_FILE: Optional[Path] = os.getenv(CONFIG_FILE_ENV_VAR, CONFIG_FILE_PLACEHOLDER)

    entry_urls: StrListOrStr = []  # test
    regex_mode: bool = False
    max_depth: int = 0
    max_pages: OptInt
    output_with_urls: bool = False
    output_format: OutputFormat = OutputFormat.simple

    # Target to extract:
    target_tag: OptStr
    target_text: OptStr
    target_attrs: TagAttrs = {}
    target_match_func: OptPyObj
    target_required: bool = False
    target_limit: OptInt
    target_extract_text: bool = True
    target_transform: OptPyObj

    # Link to next page:
    next_link_text: OptStr
    next_link_href: OptStr
    next_link_attrs: TagAttrs = {}
    next_link_match_func: OptPyObj
    next_link_limit: OptInt
    next_link_random: bool = True

    def has_target_filters(self) -> bool:
        return any([self.target_tag, self.target_text, self.target_attrs, self.target_match_func])

    class Config:
        validate_assignment = True
        env_prefix = SOUPJOBS + '_'
        env_file_encoding = 'utf-8'

        @classmethod
        def customise_sources(cls, init_settings, env_settings, file_secret_settings):
            return init_settings, env_settings, file_secret_settings, yaml_settings


def yaml_settings(settings_obj: Settings) -> Dict[str, Any]:
    try:
        with open(getattr(settings_obj, '_CONFIG_FILE'), 'r') as f:
            config = yaml.safe_load(f)
    except FileNotFoundError:
        return {}
    for section_name in ('target', 'next_link'):
        section = config.pop(section_name, {})
        for key, value in section.items():
            config.setdefault(f'{section_name}_{key}', value)
    return config


settings = Settings()