#!/usr/bin/env python3
r"""golden_compare.py — C 档黄金图对比（呈现层测试分级·渲染闸周期件）。

用法: python tools/golden_compare.py <黄金图目录> <新截图目录> [屏清单...]
默认屏清单 = shot_menu.png shot_camp.png shot_level.png shot_battle.png。

判据（容差口径，v1 冻结）:
  ① 四屏存在且尺寸一致（与黄金图逐屏比对）;
  ② 逐像素灰度差 >16 的像素占比 ≤2%（抗锯齿/微噪声容差带——结构级变化必超带）;
  ③ changed 占比 >2% 即 FAIL（视觉回归信号——逐屏列差异热区提示）。
基准冻结于 v3.5 视觉落码+营地终稿+分辨率案甲后;资产升档换代时显式重制基准。
退出码: 0 = 全过 / 1 = 有失败。
"""
import sys
from pathlib import Path

from PIL import Image, ImageChops

TOLERANCE = 16     # 灰度差容差（单通道）
FAIL_RATIO = 0.02  # changed 占比失败线


def compare(base: Path, curr: Path, name: str, failures: list) -> None:
    pb, pc = base / name, curr / name
    if not pb.exists():
        failures.append("%s: 黄金图缺失（基准未建）" % name)
        return
    if not pc.exists():
        failures.append("%s: 新截图缺失" % name)
        return
    a = Image.open(pb).convert("L")
    b = Image.open(pc).convert("L")
    if a.size != b.size:
        failures.append("%s: 尺寸 %s != 基准 %s" % (name, b.size, a.size))
        return
    diff = ImageChops.difference(a, b)
    hist = diff.histogram()
    total = a.size[0] * a.size[1]
    changed = sum(hist[TOLERANCE + 1:]) / total
    print("[golden] %s — changed=%.2f%%（容差 ≤%.0f 差/≤%.0f%%）%s" % (
        name, changed * 100, TOLERANCE, FAIL_RATIO * 100, "OK" if changed <= FAIL_RATIO else "FAIL"))
    if changed > FAIL_RATIO:
        failures.append("%s: changed %.2f%% > %.0f%%（视觉回归——核对热区后重制或修复）" % (name, changed * 100, FAIL_RATIO * 100))


def main() -> int:
    if len(sys.argv) < 3:
        print("用法: python tools/golden_compare.py <黄金图目录> <新截图目录> [屏清单...]")
        return 1
    base, curr = Path(sys.argv[1]), Path(sys.argv[2])
    shots = sys.argv[3:] or ["shot_menu.png", "shot_camp.png", "shot_level.png", "shot_battle.png"]
    failures = []
    for name in shots:
        compare(base, curr, name, failures)
    if failures:
        print("[golden] FAIL——")
        for f in failures:
            print("  - %s" % f)
        return 1
    print("[golden] PASS（%d 屏黄金图对比全过）" % len(shots))
    return 0


if __name__ == "__main__":
    sys.exit(main())