"""Lightweight image quality checks for generated game assets."""

from collections import deque


def _as_rgba_image(image_or_path):
    from PIL import Image

    if isinstance(image_or_path, str):
        return Image.open(image_or_path).convert("RGBA")
    return image_or_path.convert("RGBA")


def alpha_component_report(image_or_path, max_size=320, threshold=24):
    """Return connected-component stats for non-transparent pixels."""
    img = _as_rgba_image(image_or_path)
    if max(img.size) > max_size:
        scale = max_size / max(img.size)
        img = img.resize((max(1, int(img.width * scale)), max(1, int(img.height * scale))))
    alpha = img.getchannel("A")
    data = bytearray(1 if v > threshold else 0 for v in alpha.getdata())
    w, h = img.size
    opaque = sum(data)
    if opaque == 0:
        return {
            "ok": False,
            "reason": "empty_alpha",
            "size": [w, h],
            "opaque": 0,
            "components": [],
            "significantComponents": [],
            "largestShare": 0,
        }

    visited = bytearray(w * h)
    components = []
    for start, is_opaque in enumerate(data):
        if not is_opaque or visited[start]:
            continue
        q = deque([start])
        visited[start] = 1
        count = 0
        min_x = w
        min_y = h
        max_x = 0
        max_y = 0
        while q:
            idx = q.popleft()
            y, x = divmod(idx, w)
            count += 1
            min_x = min(min_x, x)
            min_y = min(min_y, y)
            max_x = max(max_x, x)
            max_y = max(max_y, y)
            for nx, ny in ((x - 1, y), (x + 1, y), (x, y - 1), (x, y + 1)):
                if nx < 0 or ny < 0 or nx >= w or ny >= h:
                    continue
                nidx = ny * w + nx
                if data[nidx] and not visited[nidx]:
                    visited[nidx] = 1
                    q.append(nidx)
        components.append({
            "pixels": count,
            "share": round(count / max(1, opaque), 4),
            "bbox": [min_x, min_y, max_x + 1, max_y + 1],
        })

    components.sort(key=lambda c: c["pixels"], reverse=True)
    significant = [
        c for c in components
        if c["pixels"] >= max(60, int(opaque * 0.06))
    ]
    return {
        "ok": True,
        "size": [w, h],
        "opaque": opaque,
        "opaqueRatio": round(opaque / max(1, w * h), 4),
        "components": components[:12],
        "significantComponents": significant,
        "largestShare": round(components[0]["pixels"] / max(1, opaque), 4),
        "secondShare": round(components[1]["pixels"] / max(1, opaque), 4) if len(components) > 1 else 0,
    }


def boss_preview_quality(image_or_path):
    """Check whether a boss preview reads as one assembled character."""
    report = alpha_component_report(image_or_path)
    if not report.get("ok"):
        return False, "预览图没有有效 Alpha 主体。", report

    sig_count = len(report["significantComponents"])
    largest = report["largestShare"]
    second = report["secondShare"]
    opaque_ratio = report["opaqueRatio"]
    if opaque_ratio < 0.035:
        return False, "关主体量太小，预览图主体不清晰。", report
    if sig_count >= 3:
        return False, f"关主被拆成 {sig_count} 个明显分离的大块，无法识别为完整角色。", report
    if sig_count >= 2 and second >= 0.12:
        return False, "关主存在明显分离的大部件，像拆件表而不是完整角色。", report
    if largest < 0.74:
        return False, "关主最大主体占比过低，整体轮廓不完整。", report
    return True, "关主预览主体连贯。", report


def boss_part_quality(part_id, image_or_path):
    """Check an individual rigging part for obvious sheet bleed or bad crops."""
    report = alpha_component_report(image_or_path)
    if not report.get("ok"):
        return False, "拆件没有有效 Alpha 内容。", report

    pid = (part_id or "").lower()
    allow_multi = any(token in pid for token in (
        "splash", "burst", "crack", "coin", "spark", "debris", "fragment", "shadow"
    ))
    if allow_multi:
        return True, "特效/碎片类拆件允许多块主体。", report

    second = report.get("secondShare", 0)
    sig_count = len(report.get("significantComponents", []))
    if sig_count >= 2 and second >= 0.04:
        return False, f"拆件包含 {sig_count} 个明显分离主体，疑似切进了相邻部件。", report

    w, h = report.get("size") or [0, 0]
    small_part = any(token in pid for token in (
        "head", "horn", "arm", "leg", "hand", "boot", "weapon", "sword"
    ))
    if small_part and max(w, h) >= 620 and min(w, h) >= 420:
        return False, "拆件尺寸接近完整角色，疑似把主图生成到了单个部件里。", report

    return True, "拆件主体干净。", report