import json
import os
from dataclasses import dataclass, field
from typing import List


@dataclass
class Config:
    token: str
    friend_id: int
    emoji: str
    days_back: int
    db_path: str
    log_level: str
    manual_guild_ids: List[int] = field(default_factory=list)
    verify_reactions: bool = True


def load_config(path: str = "config.json") -> Config:
    if not os.path.exists(path):
        raise FileNotFoundError(
            f"Config file not found: {path}. Copy config.example.json to config.json and fill it in."
        )

    with open(path, "r", encoding="utf-8") as f:
        data = json.load(f)

    required = ["token", "friend_id", "emoji"]
    missing = [key for key in required if not data.get(key)]
    if missing:
        raise ValueError(f"Missing required config fields: {missing}")

    return Config(
        token=data["token"],
        friend_id=int(data["friend_id"]),
        emoji=data["emoji"],
        days_back=int(data.get("days_back", 10)),
        db_path=data.get("db_path", "reactions.sqlite3"),
        log_level=data.get("log_level", "INFO"),
        manual_guild_ids=[int(g) for g in data.get("manual_guild_ids", [])],
        verify_reactions=bool(data.get("verify_reactions", True)),
    )