import os
from dataclasses import dataclass

from dotenv import load_dotenv

load_dotenv()

GOOGLE_SCOPES = (
    "https://www.googleapis.com/auth/gmail.modify",
    "https://www.googleapis.com/auth/gmail.send",
    "https://www.googleapis.com/auth/calendar.readonly",
)


@dataclass(frozen=True)
class Settings:
    google_client_secrets_file: str
    google_token_file: str
    gmail_scan_interval_minutes: int
    gmail_query: str
    agent_api_key: str
    llm_api_key: str
    llm_model: str
    llm_base_url: str | None
    llm_timeout_seconds: float
    llm_fallback_to_rules: bool
    unsubscribe_digest_interval_minutes: int
    unsubscribe_query: str
    unsubscribe_max_results: int
    unsubscribe_state_file: str
    unsubscribe_digest_recipient: str | None
    unsubscribe_send_empty_digest: bool
    log_level: str


def get_settings() -> Settings:
    llm_base_url = os.getenv("LLM_BASE_URL", "").strip()
    unsubscribe_digest_recipient = os.getenv("UNSUBSCRIBE_DIGEST_RECIPIENT", "").strip()
    return Settings(
        google_client_secrets_file=os.getenv("GOOGLE_CLIENT_SECRETS_FILE", "credentials.json"),
        google_token_file=os.getenv("GOOGLE_TOKEN_FILE", "token.json"),
        gmail_scan_interval_minutes=int(os.getenv("GMAIL_SCAN_INTERVAL_MINUTES", "5")),
        gmail_query=os.getenv(
            "GMAIL_QUERY", "in:inbox -label:AgentProcessed newer_than:7d"
        ),
        agent_api_key=os.getenv("AGENT_API_KEY", ""),
        llm_api_key=os.getenv("LLM_API_KEY", ""),
        llm_model=os.getenv("LLM_MODEL", "gpt-4.1-mini"),
        llm_base_url=llm_base_url or None,
        llm_timeout_seconds=float(os.getenv("LLM_TIMEOUT_SECONDS", "20")),
        llm_fallback_to_rules=_as_bool(os.getenv("LLM_FALLBACK_TO_RULES", "false")),
        unsubscribe_digest_interval_minutes=int(
            os.getenv("UNSUBSCRIBE_DIGEST_INTERVAL_MINUTES", "1440")
        ),
        unsubscribe_query=os.getenv("UNSUBSCRIBE_QUERY", "label:Advertising"),
        unsubscribe_max_results=int(os.getenv("UNSUBSCRIBE_MAX_RESULTS", "500")),
        unsubscribe_state_file=os.getenv(
            "UNSUBSCRIBE_STATE_FILE", "data/sent_unsubscribe_links.json"
        ),
        unsubscribe_digest_recipient=unsubscribe_digest_recipient or None,
        unsubscribe_send_empty_digest=_as_bool(
            os.getenv("UNSUBSCRIBE_SEND_EMPTY_DIGEST", "false")
        ),
        log_level=os.getenv("LOG_LEVEL", "INFO"),
    )


def _as_bool(value: str) -> bool:
    return value.strip().lower() in {"1", "true", "yes", "on"}