from dataclasses import dataclass

# COCO-17 keypoint indices
NOSE = 0
L_EYE, R_EYE, L_EAR, R_EAR = 1, 2, 3, 4
L_SHOULDER, R_SHOULDER = 5, 6
L_ELBOW, R_ELBOW, L_WRIST, R_WRIST = 7, 8, 9, 10
L_HIP, R_HIP = 11, 12
L_KNEE, R_KNEE, L_ANKLE, R_ANKLE = 13, 14, 15, 16
CORE_JOINTS = (L_SHOULDER, R_SHOULDER, L_HIP, R_HIP)


@dataclass(frozen=True)
class Keypoint:
    x: float
    y: float
    conf: float


@dataclass(frozen=True)
class BBox:
    x1: float
    y1: float
    x2: float
    y2: float

    @property
    def width(self) -> float:
        return self.x2 - self.x1

    @property
    def height(self) -> float:
        return self.y2 - self.y1

    @property
    def aspect(self) -> float:
        return self.width / self.height if self.height else 0.0

    @property
    def cx(self) -> float:
        return (self.x1 + self.x2) / 2

    @property
    def cy(self) -> float:
        return (self.y1 + self.y2) / 2


@dataclass(frozen=True)
class Person:
    bbox: BBox
    keypoints: list  # list[Keypoint], length 17