"""pytest 公共夹具与合成关键点工具。"""
import os

import numpy as np
import pytest

FIXTURES = os.path.join(os.path.dirname(__file__), "fixtures")
OUTPUT = os.path.join(os.path.dirname(__file__), "output")
os.makedirs(OUTPUT, exist_ok=True)


def fixture(name):
    return os.path.join(FIXTURES, name)


class _LM:
    """模拟 MediaPipe landmark.x/.y/.z（归一化坐标）。"""
    def __init__(self, x, y, z=0.0):
        self.x, self.y, self.z = x, y, z


def build_synthetic_landmarks(px_per_cm=50.0, W=1000, H=1000):
    """按已知 cm 几何摆放关键点，返回 (landmarks_list, ground_truth_dict)。

    坐标与 px_per_cm 都由测试设定，故每段 cm/占比真值已知，测量数学应分毫不差。
    """
    cx = W / 2

    def Y(cm_from_top):
        return (cm_from_top * px_per_cm) / H

    def X(px):
        return px / W

    gt = {
        "top_court_cm": 4.0, "upper_court_cm": 5.0,
        "middle_court_cm": 6.0, "lower_court_cm": 5.0,
        "eye_width_cm": 3.0, "inter_eye_cm": 3.4, "face_width_cm": 14.0,
        "px_per_cm": px_per_cm,
    }
    y_hairtop = 2.0
    y_hairline = y_hairtop + gt["top_court_cm"]
    y_brow = y_hairline + gt["upper_court_cm"]
    y_nose = y_brow + gt["middle_court_cm"]
    y_chin = y_nose + gt["lower_court_cm"]

    lm = {i: _LM(X(cx), 0.0) for i in range(478)}
    # 纵向中轴点
    lm[9] = _LM(X(cx), Y(y_brow));  lm[151] = _LM(X(cx), Y(y_brow))
    lm[94] = _LM(X(cx), Y(y_nose))
    lm[152] = _LM(X(cx), Y(y_chin))
    # 七眼横向点
    ew = gt["eye_width_cm"] * px_per_cm
    ie = gt["inter_eye_cm"] * px_per_cm
    fw = gt["face_width_cm"] * px_per_cm
    eye_y = Y(y_brow + 2.0)
    lm[133] = _LM(X(cx - ie / 2), eye_y);      lm[33] = _LM(X(cx - ie / 2 - ew), eye_y)
    lm[362] = _LM(X(cx + ie / 2), eye_y);      lm[263] = _LM(X(cx + ie / 2 + ew), eye_y)
    lm[234] = _LM(X(cx - fw / 2), eye_y);      lm[454] = _LM(X(cx + fw / 2), eye_y)
    # 虹膜边缘点：直径 = 1.17cm * px_per_cm，使尺度可被精确反解
    d = 1.17 * px_per_cm
    lm[469] = _LM(X(cx - ie / 2 - ew / 2 - d / 2), eye_y)
    lm[471] = _LM(X(cx - ie / 2 - ew / 2 + d / 2), eye_y)
    lm[474] = _LM(X(cx + ie / 2 + ew / 2 - d / 2), eye_y)
    lm[476] = _LM(X(cx + ie / 2 + ew / 2 + d / 2), eye_y)
    return [lm[i] for i in range(478)], gt


@pytest.fixture
def oversize_file(tmp_path):
    """1006 用例：>1MB 的占位文件（无需合法图片，只看字节数）。"""
    p = tmp_path / "oversize.bin"
    p.write_bytes(b"\x00" * 1_100_000)
    return p