from __future__ import annotations

from dataclasses import dataclass, field

from app.config import Settings

# The exact phrase required in LIVE_CONFIRMATION before live trading starts.
LIVE_CONFIRMATION_PHRASE = "I UNDERSTAND THE RISK"


@dataclass(slots=True)
class LiveCheck:
    """Result of the go-live preflight."""

    ok: bool
    mode: str
    # Each failure is a human-readable reason live trading is blocked.
    blockers: list[str] = field(default_factory=list)

    def as_dict(self) -> dict:
        return {"ok": self.ok, "mode": self.mode, "blockers": self.blockers}


def check_live_ready(settings: Settings, starting_balance: float | None = None) -> LiveCheck:
    """Validate that the configuration is safe enough to trade real money.

    Paper mode always passes. Live mode must satisfy every guard; the point is
    that ``MODE=live`` alone is not sufficient to start live trading.
    """
    if settings.mode != "live":
        return LiveCheck(ok=True, mode=settings.mode)

    blockers: list[str] = []

    has_limit = (
        settings.max_daily_loss > 0
        or settings.max_drawdown_pct > 0
        or settings.max_trades_per_day > 0
    )
    if not has_limit:
        blockers.append(
            "no active risk limit: set MAX_DAILY_LOSS, MAX_DRAWDOWN_PCT or MAX_TRADES_PER_DAY"
        )

    if settings.max_position_pct >= 1.0:
        blockers.append(
            "MAX_POSITION_PCT must be below 1.0 so a single position cannot be the whole account"
        )

    if settings.live_confirmation != LIVE_CONFIRMATION_PHRASE:
        blockers.append(f'LIVE_CONFIRMATION must be exactly "{LIVE_CONFIRMATION_PHRASE}"')

    balance = starting_balance if starting_balance is not None else settings.starting_balance
    if balance < settings.min_live_balance:
        blockers.append(
            f"starting balance {balance:g} is below MIN_LIVE_BALANCE {settings.min_live_balance:g}"
        )

    if not settings.exchange_api_key or not settings.exchange_api_secret:
        blockers.append("EXCHANGE_API_KEY and EXCHANGE_API_SECRET are required for live")

    return LiveCheck(ok=not blockers, mode=settings.mode, blockers=blockers)