"""方法G：暗色图形的连通域 + alpha 轮廓形状匹配实验。"""
from pathlib import Path
import cv2
import numpy as np

ROOT = Path(__file__).resolve().parent.parent
CAP = ROOT / "captchas"
OUT = ROOT / "try" / "out" / "G"
OUT.mkdir(parents=True, exist_ok=True)


def files_for(prefix):
    bigs = [p for p in CAP.glob(f"{prefix}*.jpeg") if "-mark" not in p.stem]
    if not bigs:
        return None, None
    big = bigs[0]
    return big, CAP / f"{big.stem}-mark.png"


def detect_components(gray):
    """用局部暗目标检测提取候选组件。"""
    blur = cv2.GaussianBlur(gray, (0, 0), 15)
    dark = np.clip(blur.astype(np.int16) - gray.astype(np.int16), 0, 255).astype(np.uint8)
    mask = (dark > 12).astype(np.uint8) * 255
    mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, np.ones((5, 5), np.uint8), iterations=2)
    mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, np.ones((3, 3), np.uint8))
    return mask


def process(prefix):
    big_path, mark_path = files_for(prefix)
    if big_path is None:
        return
    big = cv2.imread(str(big_path), cv2.IMREAD_COLOR)
    mark = cv2.imread(str(mark_path), cv2.IMREAD_UNCHANGED)
    if big is None or mark is None:
        return
    alpha = mark[..., 3] if mark.ndim == 3 and mark.shape[2] == 4 else np.full(mark.shape[:2], 255, np.uint8)
    m = (alpha > 128).astype(np.uint8) * 255
    mc, _ = cv2.findContours(m, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    mc = max(mc, key=cv2.contourArea)
    ma = max(cv2.contourArea(mc), 1)
    gray = cv2.cvtColor(big, cv2.COLOR_BGR2GRAY)
    mask = detect_components(gray)
    contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    vis = big.copy()
    found = []
    for c in contours:
        area = cv2.contourArea(c)
        x, y, w, h = cv2.boundingRect(c)
        if area < ma * 0.08 or area > ma * 3 or min(w, h) < 20 or max(w, h) > 180:
            continue
        score = cv2.matchShapes(mc, c, cv2.CONTOURS_MATCH_I1, 0)
        found.append((score, area, x, y, w, h))
    found.sort(key=lambda z: z[0])
    for i, (_, _, x, y, w, h) in enumerate(found[:5]):
        color = (0, 0, 255) if i == 0 else (255, 0, 0)
        cv2.rectangle(vis, (x, y), (x + w, y + h), color, 2)
        cv2.putText(vis, f"{i+1}", (x, max(14, y - 3)), cv2.FONT_HERSHEY_SIMPLEX, .5, color, 2)
    cv2.imwrite(str(OUT / f"{prefix}-components.png"), vis)
    line = "  ".join(f"#{i+1}:{s:.3f}@({x},{y},{w},{h})" for i,(s,_,x,y,w,h) in enumerate(found[:5]))
    print(prefix, line or "无候选")


def main():
    prefixes = sorted({p.name.split("~", 1)[0] for p in CAP.glob("*.jpeg") if "-mark" not in p.stem})
    for prefix in prefixes:
        process(prefix)


if __name__ == "__main__":
    main()