from __future__ import annotations

from app.exercises.dead_bug.types import DeadBugMetrics, Point


def has_required_visibility(landmarks: list[Point], required_indices: tuple[int, ...], visibility_threshold: float) -> bool:
    """检查所有必需关键点的可见度是否高于阈值"""
    return all(landmarks[i].visibility >= visibility_threshold for i in required_indices)


def detect_diagonal_extension(metrics: DeadBugMetrics) -> str | None:
    """检测是否存在对角伸展（左臂+右腿 或 右臂+左腿）"""
    if metrics.left_leg_extended and metrics.right_leg_extended:
        return None

    if metrics.right_leg_extended and metrics.left_arm_extended:
        return "left_arm_right_leg"
    if metrics.left_leg_extended and metrics.right_arm_extended:
        return "right_arm_left_leg"
    return None


def is_ready_position(metrics: DeadBugMetrics) -> bool:
    """判断是否处于准备姿态（膝盖弯曲且四肢未伸展）"""
    knees_bent = metrics.left_knee_angle <= 140 and metrics.right_knee_angle <= 140
    legs_not_extended = not metrics.left_leg_extended and not metrics.right_leg_extended
    return knees_bent and legs_not_extended and detect_diagonal_extension(metrics) is None