from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path
from typing import Dict, Optional

from dotenv import load_dotenv

load_dotenv()

DEFAULT_CLIENT_COOLDOWN_SECONDS = 5.0


@dataclass(frozen=True)
class Config:
    bot_token: str
    manager_group_id: int
    database_path: Path
    # Optional per-language overrides for i18n keys (lang -> text).
    welcome_text: Dict[str, str]
    ack_text: Dict[str, str]
    cooldown_text: Dict[str, str]
    client_cooldown_seconds: float


def _optional_env(name: str) -> Optional[str]:
    raw = os.getenv(name)
    if raw is None:
        return None
    value = raw.strip()
    return value or None


def _text_overrides_for(key: str) -> Dict[str, str]:
    """Load per-language text overrides.

    Supported env vars (example for welcome):
      WELCOME_TEXT_RU / WELCOME_TEXT_UK — language-specific
      WELCOME_TEXT — legacy; applies only to default language (ru), so UK
      keeps its catalog string and the services button stays consistent.
    """
    from bot.i18n import DEFAULT_LANGUAGE, SUPPORTED_LANGUAGES

    overrides: Dict[str, str] = {}
    legacy = _optional_env(key)
    if legacy is not None:
        overrides[DEFAULT_LANGUAGE] = legacy

    for lang in SUPPORTED_LANGUAGES:
        specific = _optional_env(f"{key}_{lang.upper()}")
        if specific is not None:
            overrides[lang] = specific
    return overrides


def load_config() -> Config:
    token = os.getenv("BOT_TOKEN", "").strip()
    if not token:
        raise RuntimeError("BOT_TOKEN is not set")

    group_raw = os.getenv("MANAGER_GROUP_ID", "").strip()
    if not group_raw:
        raise RuntimeError("MANAGER_GROUP_ID is not set")

    try:
        manager_group_id = int(group_raw)
    except ValueError as exc:
        raise RuntimeError("MANAGER_GROUP_ID must be an integer") from exc

    db_path = Path(os.getenv("DATABASE_PATH", "data/bot.db")).expanduser()

    cooldown_raw = os.getenv("CLIENT_COOLDOWN_SECONDS", str(DEFAULT_CLIENT_COOLDOWN_SECONDS))
    try:
        client_cooldown_seconds = float(cooldown_raw)
    except ValueError as exc:
        raise RuntimeError("CLIENT_COOLDOWN_SECONDS must be a number") from exc
    if client_cooldown_seconds < 0:
        raise RuntimeError("CLIENT_COOLDOWN_SECONDS must be >= 0")

    return Config(
        bot_token=token,
        manager_group_id=manager_group_id,
        database_path=db_path,
        welcome_text=_text_overrides_for("WELCOME_TEXT"),
        ack_text=_text_overrides_for("ACK_TEXT"),
        cooldown_text=_text_overrides_for("COOLDOWN_TEXT"),
        client_cooldown_seconds=client_cooldown_seconds,
    )


def apply_text_overrides(config: Config) -> None:
    """Apply optional env text overrides into the i18n catalog (per language)."""
    from bot.i18n import TEXTS

    for lang, text in config.welcome_text.items():
        if lang in TEXTS:
            TEXTS[lang]["welcome"] = text
    for lang, text in config.ack_text.items():
        if lang in TEXTS:
            TEXTS[lang]["ack"] = text
    for lang, text in config.cooldown_text.items():
        if lang in TEXTS:
            TEXTS[lang]["cooldown"] = text