from app.models.habit import ALL_WEEKDAYS_MASK
from app.services.log_service import MILESTONE_STREAKS

_DAY_LABELS = ["월", "화", "수", "목", "금", "토", "일"]


def is_milestone_streak(streak: int) -> bool:
    return streak in MILESTONE_STREAKS


def weekday_label(mask: int) -> str:
    if mask == ALL_WEEKDAYS_MASK:
        return "매일"
    days = [label for i, label in enumerate(_DAY_LABELS) if mask & (1 << i)]
    return ", ".join(days) if days else "선택된 요일 없음"


def heatmap_opacity(checked_count: int, scheduled_count: int) -> float:
    """월별 캘린더 히트맵 셀의 배경 투명도(0~0.9)를 계산한다."""
    if not scheduled_count:
        return 0.0
    ratio = checked_count / scheduled_count
    if ratio <= 0:
        return 0.0
    return round(0.12 + ratio * 0.78, 2)