import logging
import os
from pathlib import Path
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError


logger = logging.getLogger(__name__)

PROJECT_ROOT = Path(__file__).resolve().parent.parent
ENV_FILE = PROJECT_ROOT / ".env"

TOKEN_ENV_NAME = "BOT_TOKEN"
PASSWORD_ENV_NAME = "ASSISTANT_PASSWORD"
DB_ENV_NAME = "ASSISTANT_DB"
MODE_ENV_NAME = "ASSISTANT_MODE"
OLLAMA_BASE_URL_ENV_NAME = "OLLAMA_BASE_URL"
OLLAMA_MODEL_ENV_NAME = "OLLAMA_MODEL"
YANDEX_CLOUD_FOLDER_ENV_NAME = "YANDEX_CLOUD_FOLDER"
YANDEX_CLOUD_MODEL_ENV_NAME = "YANDEX_CLOUD_MODEL"
YANDEX_STT_MODEL_ENV_NAME = "YANDEX_STT_MODEL"
YANDEX_STT_LANGUAGE_ENV_NAME = "YANDEX_STT_LANGUAGE"
TIMEZONE_ENV_NAME = "ASSISTANT_TIMEZONE"
WHISPER_MODEL_ENV_NAME = "WHISPER_MODEL"
WHISPER_DEVICE_ENV_NAME = "WHISPER_DEVICE"
WHISPER_COMPUTE_TYPE_ENV_NAME = "WHISPER_COMPUTE_TYPE"
WHISPER_LANGUAGE_ENV_NAME = "WHISPER_LANGUAGE"
VOICE_MAX_DURATION_ENV_NAME = "VOICE_MAX_DURATION_SECONDS"

DEFAULT_DB_FILE = PROJECT_ROOT / "assistant_data.sqlite3"
DEFAULT_MODE = "local"
DEFAULT_OLLAMA_BASE_URL = "http://localhost:11434"
DEFAULT_OLLAMA_MODEL = "qwen3.5:9b"
DEFAULT_YANDEX_CLOUD_MODEL = "yandexgpt/latest"
DEFAULT_YANDEX_STT_MODEL = "general"
DEFAULT_YANDEX_STT_LANGUAGE = "ru-RU"
DEFAULT_TIMEZONE = "Europe/Moscow"
DEFAULT_WHISPER_MODEL = "large-v3"
DEFAULT_WHISPER_DEVICE = "cuda"
DEFAULT_WHISPER_COMPUTE_TYPE = "int8"
DEFAULT_WHISPER_LANGUAGE = "ru"
DEFAULT_VOICE_MAX_DURATION_SECONDS = 120

REMINDER_POLL_SECONDS = 30
MAX_TELEGRAM_MESSAGE_LENGTH = 3900
MAX_AGENT_STEPS = 5
CONVERSATION_HISTORY_LIMIT = 12


def load_env_file(path: Path = ENV_FILE) -> None:
    if not path.exists():
        return

    for raw_line in path.read_text(encoding="utf-8").splitlines():
        line = raw_line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue

        key, value = line.split("=", 1)
        key = key.strip()
        value = value.strip()

        if not key or key in os.environ:
            continue

        if len(value) >= 2 and value[0] == value[-1] and value[0] in {'"', "'"}:
            value = value[1:-1]

        os.environ[key] = value


def get_bot_token() -> str:
    load_env_file()
    token = os.getenv(TOKEN_ENV_NAME)
    if not token:
        raise RuntimeError(f"Set {TOKEN_ENV_NAME} in environment or .env file.")
    return token


def get_assistant_password() -> str:
    load_env_file()
    password = os.getenv(PASSWORD_ENV_NAME, "").strip()
    if not password:
        raise RuntimeError(
            f"Set {PASSWORD_ENV_NAME} in environment or .env file."
        )
    return password


def get_db_path() -> Path:
    load_env_file()
    raw_path = os.getenv(DB_ENV_NAME)
    if not raw_path:
        return DEFAULT_DB_FILE

    path = Path(raw_path).expanduser()
    if path.is_absolute():
        return path
    return PROJECT_ROOT / path


def get_assistant_mode() -> str:
    load_env_file()
    mode = os.getenv(MODE_ENV_NAME, DEFAULT_MODE).strip().lower()
    if mode not in {"local", "yandex"}:
        raise RuntimeError(
            f"{MODE_ENV_NAME} must be either 'local' or 'yandex', got {mode!r}."
        )
    return mode


def get_ollama_base_url() -> str:
    load_env_file()
    return os.getenv(OLLAMA_BASE_URL_ENV_NAME, DEFAULT_OLLAMA_BASE_URL).rstrip("/")


def get_default_ollama_model() -> str:
    load_env_file()
    return os.getenv(OLLAMA_MODEL_ENV_NAME, DEFAULT_OLLAMA_MODEL)


def get_yandex_cloud_folder() -> str:
    load_env_file()
    folder = os.getenv(YANDEX_CLOUD_FOLDER_ENV_NAME, "").strip()
    if not folder or folder == "":
        raise RuntimeError(
            f"Set {YANDEX_CLOUD_FOLDER_ENV_NAME} in environment or .env file."
        )
    return folder.strip("/")


def get_yandex_cloud_model() -> str:
    load_env_file()
    model = os.getenv(
        YANDEX_CLOUD_MODEL_ENV_NAME,
        DEFAULT_YANDEX_CLOUD_MODEL,
    ).strip()
    return model.strip("/") or DEFAULT_YANDEX_CLOUD_MODEL


def get_default_yandex_model() -> str:
    return f"gpt://{get_yandex_cloud_folder()}/{get_yandex_cloud_model()}"


def get_default_model(provider: str) -> str:
    if provider == "local":
        return get_default_ollama_model()
    if provider == "yandex":
        return get_default_yandex_model()
    raise ValueError(f"Unknown AI provider: {provider}")


def get_yandex_stt_model() -> str:
    load_env_file()
    return os.getenv(YANDEX_STT_MODEL_ENV_NAME, DEFAULT_YANDEX_STT_MODEL).strip()


def get_yandex_stt_language() -> str:
    load_env_file()
    return os.getenv(
        YANDEX_STT_LANGUAGE_ENV_NAME,
        DEFAULT_YANDEX_STT_LANGUAGE,
    ).strip()


def get_local_timezone() -> ZoneInfo:
    load_env_file()
    timezone_name = os.getenv(TIMEZONE_ENV_NAME, DEFAULT_TIMEZONE)
    try:
        return ZoneInfo(timezone_name)
    except ZoneInfoNotFoundError:
        logger.warning("Unknown timezone %s, falling back to UTC", timezone_name)
        return ZoneInfo("UTC")


def get_whisper_model() -> str:
    load_env_file()
    return os.getenv(WHISPER_MODEL_ENV_NAME, DEFAULT_WHISPER_MODEL).strip()


def get_whisper_device() -> str:
    load_env_file()
    return os.getenv(WHISPER_DEVICE_ENV_NAME, DEFAULT_WHISPER_DEVICE).strip()


def get_whisper_compute_type() -> str:
    load_env_file()
    return os.getenv(
        WHISPER_COMPUTE_TYPE_ENV_NAME,
        DEFAULT_WHISPER_COMPUTE_TYPE,
    ).strip()


def get_whisper_language() -> str | None:
    load_env_file()
    language = os.getenv(
        WHISPER_LANGUAGE_ENV_NAME,
        DEFAULT_WHISPER_LANGUAGE,
    ).strip()
    return None if language.lower() == "auto" else language or None


def get_voice_max_duration_seconds() -> int:
    load_env_file()
    raw_value = os.getenv(
        VOICE_MAX_DURATION_ENV_NAME,
        str(DEFAULT_VOICE_MAX_DURATION_SECONDS),
    )
    try:
        value = int(raw_value)
    except ValueError:
        value = 0
    if value <= 0:
        logger.warning(
            "%s must be a positive integer, using %s",
            VOICE_MAX_DURATION_ENV_NAME,
            DEFAULT_VOICE_MAX_DURATION_SECONDS,
        )
        return DEFAULT_VOICE_MAX_DURATION_SECONDS
    return value