"""反向盤口移動（RLM）偵測模組。"""

from __future__ import annotations

from dataclasses import dataclass
from datetime import datetime


@dataclass(frozen=True)
class ReverseLineMovementAlert:
  match_id: str
  market_type: str
  selection: str
  opening_odds: float
  current_odds: float
  ticket_pct: float
  handle_pct: float
  odds_change_pct: float
  smart_money_to: str
  is_triggered: bool
  triggered_at: datetime
  rationale: str


def evaluate_reverse_line_movement(
  match_id: str,
  market_type: str,
  selection: str,
  *,
  opening_odds: float,
  current_odds: float,
  ticket_pct: float,
  handle_pct: float,
  ticket_threshold: float = 70.0,
  odds_change_threshold: float = 0.05,
) -> ReverseLineMovementAlert:
  """依條件判斷是否出現反向盤口。"""

  if opening_odds <= 0:
    odds_pct = 0.0
  else:
    odds_pct = round((current_odds - opening_odds) / opening_odds, 6)

  is_triggered = (
    ticket_pct > ticket_threshold
    and odds_pct > odds_change_threshold
    and handle_pct < ticket_pct
  )

  smart_money_to = selection if handle_pct > ticket_pct else '對側'
  rationale = (
    f'散戶 {ticket_pct:.1f}% 追捧卻資金 {handle_pct:.1f}%，\n'
    f'盤口由 {opening_odds:.2f} 上升到 {current_odds:.2f}'
  )

  return ReverseLineMovementAlert(
    match_id=match_id,
    market_type=market_type,
    selection=selection,
    opening_odds=opening_odds,
    current_odds=current_odds,
    ticket_pct=ticket_pct,
    handle_pct=handle_pct,
    odds_change_pct=round(odds_pct * 100, 4),
    smart_money_to=smart_money_to,
    is_triggered=is_triggered,
    triggered_at=datetime.utcnow(),
    rationale=rationale,
  )