"""Tier 1 — 合成真值，精确验证测量数学（误差仅来自浮点，< 1e-6）。"""
from conftest import build_synthetic_landmarks

from face_analysis.calibration import estimate_scale_factor
from face_analysis.measure import measure_seven_eyes, estimate_vertical_landmarks


def test_scale_factor_exact():
    lm, gt = build_synthetic_landmarks(px_per_cm=50.0)
    assert abs(estimate_scale_factor(lm, 1000, 1000) - gt["px_per_cm"]) < 1e-6


def test_scale_factor_exact_other_scale():
    lm, gt = build_synthetic_landmarks(px_per_cm=73.0)
    assert abs(estimate_scale_factor(lm, 1000, 1000) - gt["px_per_cm"]) < 1e-6


def test_seven_eyes_exact():
    lm, gt = build_synthetic_landmarks()
    r = measure_seven_eyes(lm, 1000, 1000)
    pc = gt["px_per_cm"]
    assert abs(r["eye_width_px"] / pc - gt["eye_width_cm"]) < 1e-6
    assert abs(r["face_width_px"] / pc - gt["face_width_cm"]) < 1e-6
    assert abs(r["inter_eye_distance_px"] / pc - gt["inter_eye_cm"]) < 1e-6


def test_measured_courts_exact():
    """中庭、下庭为实测，应与真值分毫不差。"""
    lm, gt = build_synthetic_landmarks()
    v = estimate_vertical_landmarks(lm, 1000, 1000)
    pc = gt["px_per_cm"]
    assert abs(v["middle_court_px"] / pc - gt["middle_court_cm"]) < 1e-6
    assert abs(v["lower_court_px"] / pc - gt["lower_court_cm"]) < 1e-6


def test_method_a_ratio_formula():
    """方案 A 推算：上/顶庭应严格按既定比例（相对中下庭均值）执行。

    注意这只验证「公式按比例正确执行」，不验证贴近真实脸（方案 A 固有局限）。
    """
    lm, _ = build_synthetic_landmarks()
    v = estimate_vertical_landmarks(lm, 1000, 1000)
    one_unit = (v["middle_court_px"] + v["lower_court_px"]) / 2
    assert abs(v["upper_court_px"] - one_unit * (0.25 / 0.265)) < 1e-6
    assert abs(v["top_court_px"] - one_unit * (0.22 / 0.28)) < 1e-6