CardVideoSummary/app/services/video_service.py

import math
import os
import re
import uuid
from dataclasses import dataclass
from typing import Any, Optional

import cv2

from app.core.config import settings
from app.core.logger import get_logger
from app.schemas.models import CardInfoInput, CardInfoOutput

logger = get_logger("VideoService")


@dataclass
class FrameCandidate:
    """
    候选帧数据类：记录了从视频中抽取的某一帧的所有评分维度。
    使用 dataclass 让数据结构非常清晰。
    """
    frame: Any  # 原始图像矩阵 (OpenCV BGR)
    time_ms: int  # 该帧在视频中的时间戳 (毫秒)
    sharpness: float  # 拉普拉斯清晰度绝对值 (越大越清晰)
    time_weight: float  # 时间权重 (距离目标时间戳越近，权重越高)
    segmentation_used: bool = False  # 是否成功启用了分割模型
    has_card: bool = False  # 画面中是否出现了卡
    has_hand: bool = False  # 画面中是否出现了手
    card_area_ratio: float = 0.0  # 卡片占画面比例
    hand_area_ratio: float = 0.0  # 手占画面比例
    card_bbox: Optional[tuple[int, int, int, int]] = None  # (x, y, w, h) 卡片/手的聚焦边界框
    presence_score: float = 0.0  # 实体存在感得分 (卡和手面积越大，得分越高)
    sharpness_score: float = 0.0  # 归一化后的清晰度得分 (0~1)
    dwell_score: float = 0.0  # 停留得分 (连续出现的帧数越多得分越高，用于抗闪烁)
    base_score: float = 0.0  # 基础分 (不包含OCR)
    ocr_text: str = ""  # OCR识别出的文本
    ocr_score: float = 0.0  # OCR文本与预期卡片信息的匹配度得分 (0~1)
    final_score: float = 0.0  # 最终总分

    @property
    def is_present(self) -> bool:
        """只要有卡或者有手，就算该实体在画面中存在"""
        return self.has_card or self.has_hand


class VideoService:
    def __init__(self):
        # 高斯分布的 sigma，用于计算时间权重。10.0 表示对时间差容忍度较高
        self.weight_sigma = 10.0
        self.search_before_ms = settings.VIDEO_SEARCH_BEFORE_MS
        self.search_after_ms = settings.VIDEO_SEARCH_AFTER_MS
        self.analysis_fps = max(settings.VIDEO_ANALYSIS_FPS, 0.5)

        # 延迟加载组件，节省初始化时的内存占用
        self._ocr_engine = None
        self._ocr_disabled = False
        self._ocr_runtime_warning_sent = False

        self._seg_processor = None
        self._seg_model = None
        self._seg_torch = None
        self._seg_pil_image = None
        self._seg_disabled = False
        self._seg_runtime_warning_sent = False

    def time_str_to_ms(self, time_str: str) -> int:
        """将格式为 'HH:MM:SS' 或 'MM:SS' 的字符串转换为毫秒"""
        try:
            parts = list(map(int, time_str.split(":")))
            if len(parts) == 3:
                h, m, s = parts
                return (h * 3600 + m * 60 + s) * 1000
            if len(parts) == 2:
                m, s = parts
                return (m * 60 + s) * 1000
            return 0
        except ValueError:
            return 0

    def get_laplacian_sharpness(self, frame) -> float:
        """
        计算图像的拉普拉斯方差，这是业界最常用的无参考图像清晰度评估方法。
        方差越大，说明边缘信息越丰富（越不模糊）。
        """
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        return float(cv2.Laplacian(gray, cv2.CV_64F).var())

    def calculate_weight(self, current_time_ms: int, target_time_ms: int) -> float:
        """利用高斯函数计算时间权重。距离 target_time_ms 越近，返回值越接近 1.0"""
        diff_seconds = abs(current_time_ms - target_time_ms) / 1000.0
        return math.exp(-((diff_seconds ** 2) / (2 * self.weight_sigma ** 2)))

    def _analysis_stride(self, fps: float) -> int:
        """计算视频读取时的跳帧步长，确保处理速度匹配 VIDEO_ANALYSIS_FPS"""
        fps = fps if fps > 0 else 30.0
        return max(1, int(round(fps / self.analysis_fps)))

    def _ensure_ocr_engine(self):
        """单例模式懒加载 OCR 引擎 (RapidOCR)"""
        if self._ocr_disabled:
            return None
        if self._ocr_engine is not None:
            return self._ocr_engine

        try:
            from rapidocr import RapidOCR
            self._ocr_engine = RapidOCR()
        except Exception as exc:
            self._ocr_disabled = True
            logger.warning(f"OCR disabled: init failed: {exc}")
            return None

        return self._ocr_engine

    def _ensure_segmentation_model(self):
        """单例模式懒加载 HuggingFace Segformer 语义分割模型"""
        if self._seg_disabled:
            return None
        if self._seg_processor is not None and self._seg_model is not None:
            return self._seg_processor, self._seg_model

        model_dir = settings.VIDEO_SEG_MODEL_DIR
        if not model_dir or not os.path.exists(model_dir):
            self._seg_disabled = True
            logger.warning(f"Segmentation disabled: model dir not found: {model_dir}")
            return None

        try:
            import torch
            from PIL import Image
            from transformers import AutoImageProcessor, AutoModelForSemanticSegmentation

            self._seg_processor = AutoImageProcessor.from_pretrained(model_dir)
            self._seg_model = AutoModelForSemanticSegmentation.from_pretrained(model_dir)
            self._seg_model.eval()  # 开启评估模式

            # 自动分配到 GPU (如果可用) 以加速推理
            if torch.cuda.is_available():
                self._seg_model = self._seg_model.to("cuda")

            self._seg_torch = torch
            self._seg_pil_image = Image
        except Exception as exc:
            self._seg_disabled = True
            logger.warning(f"Segmentation disabled: model loading failed: {exc}")
            return None

        return self._seg_processor, self._seg_model

    def _largest_bbox(self, mask) -> Optional[tuple[int, int, int, int]]:
        """从二进制掩码 (Mask) 中提取面积最大的连通区域的外接矩形"""
        if mask is None or not mask.any():
            return None

        mask_uint8 = (mask.astype("uint8")) * 255
        contours, _ = cv2.findContours(mask_uint8, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
        if not contours:
            return None

        largest = max(contours, key=cv2.contourArea)
        x, y, w, h = cv2.boundingRect(largest)

        # 过滤掉噪点 (宽或高小于20像素的通常是识别错误)
        if w < 20 or h < 20:
            return None
        return x, y, w, h

    def _expand_bbox(
            self,
            bbox: Optional[tuple[int, int, int, int]],
            width: int,
            height: int,
            margin_ratio: float = 0.08,
    ) -> Optional[tuple[int, int, int, int]]:
        """适度扩大 Bounding Box (增加 margin_ratio)，防止目标边缘被裁掉，有利于后续 OCR"""
        if bbox is None:
            return None

        x, y, w, h = bbox
        margin_x = int(w * margin_ratio)
        margin_y = int(h * margin_ratio)

        x1 = max(0, x - margin_x)
        y1 = max(0, y - margin_y)
        x2 = min(width, x + w + margin_x)
        y2 = min(height, y + h + margin_y)
        return x1, y1, x2 - x1, y2 - y1

    def _focus_region(self, frame, bbox: Optional[tuple[int, int, int, int]]):
        """裁剪出关注区域。如果没有有效 BBox，则返回原图，作为容错机制。"""
        height, width = frame.shape[:2]
        expanded = self._expand_bbox(bbox, width, height)
        if expanded is None:
            return frame

        x, y, w, h = expanded
        if w < 24 or h < 24:
            return frame
        return frame[y: y + h, x: x + w]

    def _compute_presence_score(
            self,
            segmentation_used: bool,
            has_card: bool,
            has_hand: bool,
            card_area_ratio: float,
            hand_area_ratio: float,
    ) -> float:
        """根据卡片和手的面积占比计算"存在感得分" (0.0 ~ 1.0)"""
        if not segmentation_used:
            return 0.0

        # 对占比进行归一化，最大不超过 1.0
        card_ratio = min(card_area_ratio / max(settings.VIDEO_MIN_CARD_AREA_RATIO, 1e-6), 1.0)
        hand_ratio = min(hand_area_ratio / max(settings.VIDEO_MIN_HAND_AREA_RATIO, 1e-6), 1.0)

        score = 0.0
        if has_card:
            score += 0.70 * max(card_ratio, 0.35)  # 卡片权重占 70%
        if has_hand:
            score += 0.30 * max(hand_ratio, 0.25)  # 手的权重占 30%
        if has_card and has_hand:
            score += 0.10  # 卡和手同框，给予额外 10% 奖励分

        return min(score, 1.0)

    def _analyze_segmentation(self, frame) -> dict[str, Any]:
        """对单帧图像进行语义分割分析，寻找卡片和手的区域"""
        if self._ensure_segmentation_model() is None:
            return {
                "segmentation_used": False,
                "has_card": False,
                "has_hand": False,
                "card_area_ratio": 0.0,
                "hand_area_ratio": 0.0,
                "card_bbox": None,
            }

        try:
            # OpenCV (BGR) 转换为 PIL 所需的 RGB
            rgb_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
            image = self._seg_pil_image.fromarray(rgb_frame)

            # 推理所需的数据需放到和模型同一设备上 (CPU or CUDA)
            device = next(self._seg_model.parameters()).device
            inputs = self._seg_processor(images=image, return_tensors="pt").to(device)

            with self._seg_torch.no_grad():
                outputs = self._seg_model(**inputs)

            logits = outputs.logits

            # 上采样回原始分辨率
            pred = self._seg_torch.nn.functional.interpolate(
                logits,
                size=image.size[::-1],
                mode="bilinear",
                align_corners=False,
            ).argmax(dim=1)[0].cpu().numpy()

            card_mask = pred == settings.VIDEO_CARD_LABEL_ID
            hand_mask = pred == settings.VIDEO_HAND_LABEL_ID

            card_area_ratio = float(card_mask.mean()) if card_mask.size else 0.0
            hand_area_ratio = float(hand_mask.mean()) if hand_mask.size else 0.0

            # [核心改进]: 提取两个 bbox
            card_bbox = self._largest_bbox(card_mask)
            hand_bbox = self._largest_bbox(hand_mask)

            has_card = card_area_ratio >= settings.VIDEO_MIN_CARD_AREA_RATIO
            has_hand = hand_area_ratio >= settings.VIDEO_MIN_HAND_AREA_RATIO

            # [核心改进]: 如果卡片太小/没切出来，但有手，把 focus box 降级到手的区域
            # 因为手大概率握着卡片，对“手”周边做 OCR 也能有效提取卡面信息
            focus_bbox = card_bbox if card_bbox is not None else hand_bbox

            # [核心改进]: 主动清理张量内存，防止长视频导致显存/内存溢出
            del inputs, outputs, logits, pred
            if self._seg_torch.cuda.is_available():
                self._seg_torch.cuda.empty_cache()

            return {
                "segmentation_used": True,
                "has_card": has_card,
                "has_hand": has_hand,
                "card_area_ratio": card_area_ratio,
                "hand_area_ratio": hand_area_ratio,
                "card_bbox": focus_bbox,  # 返回 fallback 后的 bbox
            }
        except Exception as exc:
            if not self._seg_runtime_warning_sent:
                logger.warning(f"Segmentation runtime failure, fallback enabled: {exc}")
                self._seg_runtime_warning_sent = True

            return {
                "segmentation_used": False,
                "has_card": False,
                "has_hand": False,
                "card_area_ratio": 0.0,
                "hand_area_ratio": 0.0,
                "card_bbox": None,
            }

    def _build_candidate(self, frame, current_time_ms: int, target_time_ms: int) -> FrameCandidate:
        """整合单帧的所有基础分析数据（分割、清晰度、存在感等），构建候选对象"""
        seg_result = self._analyze_segmentation(frame)

        # 对裁剪后的有效区域求清晰度，比算全图清晰度更准确，抗背景干扰
        focus_region = self._focus_region(frame, seg_result["card_bbox"])
        sharpness = self.get_laplacian_sharpness(focus_region)

        presence_score = self._compute_presence_score(
            segmentation_used=seg_result["segmentation_used"],
            has_card=seg_result["has_card"],
            has_hand=seg_result["has_hand"],
            card_area_ratio=seg_result["card_area_ratio"],
            hand_area_ratio=seg_result["hand_area_ratio"],
        )

        return FrameCandidate(
            frame=frame.copy(),
            time_ms=int(current_time_ms),
            sharpness=sharpness,
            time_weight=self.calculate_weight(current_time_ms, target_time_ms),
            segmentation_used=seg_result["segmentation_used"],
            has_card=seg_result["has_card"],
            has_hand=seg_result["has_hand"],
            card_area_ratio=seg_result["card_area_ratio"],
            hand_area_ratio=seg_result["hand_area_ratio"],
            card_bbox=seg_result["card_bbox"],
            presence_score=presence_score,
        )

    def _collect_candidates(
            self,
            cap: cv2.VideoCapture,
            start_time_ms: int,
            end_time_ms: int,
            target_time_ms: int,
            fps: float,
    ) -> list[FrameCandidate]:
        """在指定时间窗口内滑动，按步长收集视频帧作为候选"""
        candidates: list[FrameCandidate] = []
        analysis_stride = self._analysis_stride(fps)

        # 预估最大读取次数，防止视频结尾卡死死循环
        max_reads = int((end_time_ms - start_time_ms) / 1000.0 * fps) + analysis_stride + 10

        # 跳转到起始时间 (注意: OpenCV 的 POS_MSEC 某些视频源上可能不精准)
        cap.set(cv2.CAP_PROP_POS_MSEC, start_time_ms)

        read_count = 0
        while read_count < max_reads:
            ret, frame = cap.read()
            if not ret:
                break

            current_time_ms = cap.get(cv2.CAP_PROP_POS_MSEC)
            if current_time_ms > end_time_ms:
                break

            # 按计算好的步长 (analysis_stride) 进行抽帧分析
            if read_count % analysis_stride == 0:
                candidates.append(self._build_candidate(frame, int(current_time_ms), target_time_ms))

            read_count += 1

        return candidates

    def _assign_dwell_scores(self, candidates: list[FrameCandidate]) -> None:
        """
        计算"停留得分" (Dwell Score):
        如果一个人抽到卡通常会停留展示一段时间。连续在帧中被检测到的实体，其停留得分会更高。
        这能有效过滤掉发牌时一晃而过的模糊残影。
        """
        if not candidates or not any(candidate.segmentation_used for candidate in candidates):
            return

        target_frames = max(1, int(round(settings.VIDEO_DWELL_TARGET_SECONDS * self.analysis_fps)))
        index = 0

        while index < len(candidates):
            if not candidates[index].is_present:
                index += 1
                continue

            # 寻找连续出现(is_present = True)的片段
            run_end = index
            while run_end + 1 < len(candidates) and candidates[run_end + 1].is_present:
                run_end += 1

            run_length = run_end - index + 1
            dwell_score = min(run_length / target_frames, 1.0)

            # 为这段连续的帧赋相同的停留分
            for pos in range(index, run_end + 1):
                candidates[pos].dwell_score = dwell_score

            index = run_end + 1

    def _normalize_sharpness(self, sharpness: float, max_sharpness: float) -> float:
        """对清晰度进行对数归一化处理。使用 log 防止极值（超锐化噪点）拉爆分数池"""
        if sharpness <= 0 or max_sharpness <= 0:
            return 0.0

        denominator = math.log1p(max_sharpness)
        if denominator <= 0:
            return 0.0
        return min(math.log1p(sharpness) / denominator, 1.0)

    def _normalize_text(self, text: str) -> str:
        """清洗文本：去点，全大写，仅保留英文、数字、中文字符"""
        if not text:
            return ""
        cleaned = text.replace(".", "")
        cleaned = re.sub(r"[^0-9A-Za-z\u4e00-\u9fff]+", " ", cleaned.upper())
        return re.sub(r"\s+", " ", cleaned).strip()

    def _tokenize_text(self, text: str) -> list[str]:
        """将文本拆分为分词列表，去重去单字母（除非是数字）"""
        normalized = self._normalize_text(text)
        if not normalized:
            return []

        tokens: list[str] = []
        seen: set[str] = set()
        for token in normalized.split():
            if len(token) == 1 and not token.isdigit():
                continue
            if token in seen:
                continue
            seen.add(token)
            tokens.append(token)
        return tokens

    def _build_expected_text(self, card: CardInfoOutput) -> dict[str, Any]:
        """从输入的 json 信息中提取期望的卡片名字、系列号、编号等，作为 OCR 的对比基准"""
        name_tokens = self._tokenize_text(card.card_name_en or "")
        if not name_tokens and card.card_name_cn:
            name_tokens = self._tokenize_text(card.card_name_cn)

        all_series_tokens = self._tokenize_text(card.series or "")
        number_tokens = [token for token in all_series_tokens if token.isdigit()][:3]
        series_tokens = [token for token in all_series_tokens if not token.isdigit()]
        series_tokens.sort(key=len, reverse=True)

        return {
            "name_tokens": name_tokens[:4],
            "series_tokens": series_tokens[:6],
            "number_tokens": number_tokens,
            "has_expectation": bool(name_tokens or series_tokens or number_tokens),
        }

    def _extract_ocr_text(self, ocr_result: Any) -> str:
        """递归解析 RapidOCR 返回的复杂嵌套结构，将所有识别出的文本段落拼装成一个大字符串"""
        texts: list[str] = []

        def visit(node: Any) -> None:
            if node is None:
                return
            if isinstance(node, str):
                stripped = node.strip()
                if stripped:
                    texts.append(stripped)
                return
            if hasattr(node, "txts"):
                visit(getattr(node, "txts"))
                return
            if hasattr(node, "ocr_res"):
                visit(getattr(node, "ocr_res"))
                return
            if isinstance(node, dict):
                for value in node.values():
                    visit(value)
                return
            if isinstance(node, (list, tuple)):
                if len(node) >= 2 and isinstance(node[1], str):
                    visit(node[1])
                    return
                for item in node:
                    visit(item)

        visit(ocr_result)

        deduped: list[str] = []
        seen: set[str] = set()
        for text in texts:
            if text in seen:
                continue
            seen.add(text)
            deduped.append(text)
        return " ".join(deduped)

    def _token_overlap_score(self, expected_tokens: list[str], ocr_tokens: list[str]) -> float:
        """计算期望 Token 和 OCR 识别 Token 之间的重叠得分，包含对子串（部分匹配）的兼容分"""
        if not expected_tokens or not ocr_tokens:
            return 0.0

        score = 0.0
        ocr_set = set(ocr_tokens)
        for token in expected_tokens:
            if token in ocr_set:
                score += 1.0  # 完全命中给 1 分
                continue

            # 兼容：如果目标 token 是 OCR结果的子串，或者 OCR结果是 token的子串 (例如 "PIKACHU" 匹配出 "PIKACH")
            partial_match = any(
                len(other) >= 2 and (token in other or other in token)
                for other in ocr_set
            )
            if partial_match:
                score += 0.6  # 部分匹配给 0.6 分

        return min(score / len(expected_tokens), 1.0)

    def _score_ocr_match(self, ocr_text: str, expected: dict[str, Any]) -> float:
        """综合评判 OCR 识别文本与目标 JSON 信息的多维度匹配程度"""
        if not ocr_text or not expected["has_expectation"]:
            return 0.0

        normalized_text = self._normalize_text(ocr_text)
        ocr_tokens = self._tokenize_text(ocr_text)
        if not ocr_tokens:
            return 0.0

        name_tokens = expected["name_tokens"]
        series_tokens = expected["series_tokens"]
        number_tokens = expected["number_tokens"]

        name_score = self._token_overlap_score(name_tokens, ocr_tokens)
        if name_tokens:
            joined_name = " ".join(name_tokens)
            if joined_name and joined_name in normalized_text:
                name_score = 1.0  # 名字完全作为整体匹配上，直接满分

        series_score = self._token_overlap_score(series_tokens, ocr_tokens)
        number_score = self._token_overlap_score(number_tokens, ocr_tokens)

        # 加权混合：卡片名字(60%) > 系列名(25%) > 卡片编号(15%)
        if name_tokens:
            return min(0.60 * name_score + 0.25 * series_score + 0.15 * number_score, 1.0)
        return min(0.65 * series_score + 0.35 * number_score, 1.0)

    def _run_ocr(self, frame, bbox: Optional[tuple[int, int, int, int]]) -> str:
        """调用 OCR 引擎对关注区域进行文本识别，加入抗弹幕干扰的分块策略"""
        engine = self._ensure_ocr_engine()
        if engine is None:
            return ""

        focus_region = self._focus_region(frame, bbox)
        if focus_region is None or focus_region.shape[0] == 0 or focus_region.shape[1] == 0:
            return ""

        texts: list[str] = []

        # 1. 常规全图 OCR (可能被中间的弹幕压制，但能提取出分散的编号等)
        try:
            result_full = engine(focus_region)
            texts.append(self._extract_ocr_text(result_full))
        except Exception as exc:
            if not self._ocr_runtime_warning_sent:
                logger.warning(f"OCR full region failure: {exc}")
                self._ocr_runtime_warning_sent = True

        # 2. 分块特写 OCR，避开中心弹幕区，降低识别阈值
        h, w = focus_region.shape[:2]
        if h > 60 and w > 60:
            # A. 专门识别底部 40% (绝大多数球星卡球员名字、宝可梦卡信息在底部)
            try:
                bottom_half = focus_region[int(h * 0.6):h, :]
                result_bottom = engine(bottom_half)
                texts.append(self._extract_ocr_text(result_bottom))
            except Exception:
                pass

            # B. 专门识别顶部 40% (通常有 Bowman 1st 标志、帕尼尼系列名、或宝可梦名字)
            try:
                top_half = focus_region[0:int(h * 0.4), :]
                result_top = engine(top_half)
                texts.append(self._extract_ocr_text(result_top))
            except Exception:
                pass

        # 将全图、顶部、底部的识别结果合并（后续的 token_overlap_score 会自动处理去重）
        combined_text = " ".join(texts)

        # 3. 正则剔除常见的直播间高频干扰词 (防止误匹配)
        # 这里的词汇通常是海外拆卡直播间(Whatnot/TikTok)经常出现的系统提示语
        ignore_words = r"(?i)\b(bought|break|hobby|jumbo|box|close|spot|nice|snack|packs)\b"
        combined_text = re.sub(ignore_words, " ", combined_text)

        return combined_text

    def _score_candidates(
            self,
            candidates: list[FrameCandidate],
            card_output: CardInfoOutput,
    ) -> None:
        """
        核心打分中枢：结合之前计算的各个单项分，得出最终排名分。
        采用二次打分机制：先通过 Base Score 选出 Top K，再让 Top K 过一遍耗时的 OCR，得出 Final Score。
        """
        if not candidates:
            return

        self._assign_dwell_scores(candidates)

        # 只对画面里确认有卡/手的帧进行打分
        scoring_candidates = [candidate for candidate in candidates if candidate.is_present]
        if not scoring_candidates:
            scoring_candidates = candidates

        # 找准当前窗口期的相对最大清晰度作为归一化基准
        max_sharpness = max(candidate.sharpness for candidate in scoring_candidates) if scoring_candidates else 0.0
        segmentation_used = any(candidate.segmentation_used for candidate in candidates)

        expected = self._build_expected_text(card_output)
        ocr_enabled = self._ensure_ocr_engine() is not None and expected["has_expectation"]

        # 1. 粗排：计算 Base Score
        for candidate in scoring_candidates:
            candidate.sharpness_score = self._normalize_sharpness(candidate.sharpness, max_sharpness)
            if segmentation_used:
                # 若启用了图像分割：存在感(40%) + 清晰度(25%) + 离目标时间点的近度(20%) + 画面稳定性(15%)
                candidate.base_score = (
                        0.40 * candidate.presence_score
                        + 0.25 * candidate.sharpness_score
                        + 0.20 * candidate.time_weight
                        + 0.15 * candidate.dwell_score
                )
            else:
                # fallback: 没有分割模型，只能靠清晰度和时间权重
                candidate.base_score = (
                        0.55 * candidate.sharpness_score
                        + 0.35 * candidate.time_weight
                        + 0.10 * candidate.dwell_score
                )

        # 2. 精排：使用 OCR 计算 Final Score
        if ocr_enabled:
            # 只有 Base Score 排名前 K 的优胜者才会执行 OCR（性能优化）
            top_candidates = sorted(
                scoring_candidates,
                key=lambda item: item.base_score,
                reverse=True,
            )[: max(1, settings.VIDEO_OCR_TOP_K)]

            for candidate in top_candidates:
                candidate.ocr_text = self._run_ocr(candidate.frame, candidate.card_bbox)
                candidate.ocr_score = self._score_ocr_match(candidate.ocr_text, expected)

            # 更新所有入围帧的 Final Score
            for candidate in scoring_candidates:
                if segmentation_used:
                    # OCR占核心大头(40%)，配合其他物理指标
                    candidate.final_score = (
                            0.40 * candidate.ocr_score
                            + 0.25 * candidate.presence_score
                            + 0.20 * candidate.sharpness_score
                            + 0.10 * candidate.time_weight
                            + 0.05 * candidate.dwell_score
                    )
                else:
                    candidate.final_score = (
                            0.45 * candidate.ocr_score
                            + 0.30 * candidate.sharpness_score
                            + 0.20 * candidate.time_weight
                            + 0.05 * candidate.dwell_score
                    )
        else:
            # 如果 OCR 不可用或没配置预期，则直接用 Base Score 作为终局分数
            for candidate in scoring_candidates:
                candidate.final_score = candidate.base_score

    def _select_best_candidate(
            self,
            candidates: list[FrameCandidate],
            target_time_ms: int,
    ) -> Optional[FrameCandidate]:
        """选出最终最能代表"高光时刻"的帧"""
        if not candidates:
            return None

        # 核心逻辑：主比对 final_score；如果最终分一样(比如都为0)，看清晰度；再一样，看谁离打点时间最近。
        return max(
            candidates,
            key=lambda item: (
                item.final_score,
                item.sharpness_score,
                -abs(item.time_ms - target_time_ms),
            ),
        )

    def capture_frames(self, video_path: str, cards: list[CardInfoInput]) -> list[CardInfoOutput]:
        """业务主干：传入视频与目标卡片打点列表，输出高光图片及匹配信息"""
        if not os.path.exists(video_path):
            logger.error(f"Video file not found: {video_path}")
            raise FileNotFoundError(f"Video file not found: {video_path}")

        logger.info(f"Open video: {video_path}")
        logger.info(f"Cards to process: {len(cards)}")

        cap = cv2.VideoCapture(video_path)
        fps = cap.get(cv2.CAP_PROP_FPS)
        if fps <= 0:
            fps = 30.0

        output_list: list[CardInfoOutput] = []
        success_count = 0
        filtered_count = 0

        for idx, card_input in enumerate(cards):
            card_output = CardInfoOutput(**card_input.dict())
            target_time_ms = self.time_str_to_ms(card_output.time)

            # 以打点时间戳为锚，建立一个[过去几s 到 未来 几s] 的搜索窗口
            start_time_ms = max(0, target_time_ms - self.search_before_ms)
            end_time_ms = target_time_ms + self.search_after_ms

            logger.info(
                f"[{idx + 1}/{len(cards)}] analyze {card_output.time} "
                f"for {card_output.card_name_cn or card_output.card_name_en or 'unknown'}"
            )
            logger.info(f"  search window: [{start_time_ms}ms ~ {end_time_ms}ms]")

            # 1. 在窗口内收集所有候选帧
            candidates = self._collect_candidates(
                cap=cap,
                start_time_ms=start_time_ms,
                end_time_ms=end_time_ms,
                target_time_ms=target_time_ms,
                fps=fps,
            )

            if not candidates:
                logger.warning("  no frames sampled in the target window")
                continue

            segmentation_used = any(candidate.segmentation_used for candidate in candidates)
            present_candidates = [candidate for candidate in candidates if candidate.is_present]

            # [需求点 1]: 如果使用了分割模型且这片窗口内完全找不到手/卡，直接判定无效数据
            if segmentation_used and not present_candidates:
                filtered_count += 1
                logger.info("  filtered out: no card/hand found around the timestamp")
                continue

            scoring_candidates = present_candidates if present_candidates else candidates

            # 2. 调用多维度评分枢纽给各个候选帧打分
            self._score_candidates(candidates, card_output)

            # 3. 选出最匹配、最清晰的一张
            best_candidate = self._select_best_candidate(scoring_candidates, target_time_ms)

            if best_candidate is None:
                logger.warning("  no usable candidate after scoring")
                continue

            # 4. 保存为 JPG，构造业务输出数据
            filename = f"{uuid.uuid4()}_{best_candidate.time_ms}.jpg"
            save_path = os.path.join(settings.FRAMES_DIR, filename)

            try:
                cv2.imwrite(save_path, best_candidate.frame)
                image_url = f"{settings.BASE_URL}/static/frames/{filename}"
                card_output.frame_image_path = image_url
                output_list.append(card_output)
                success_count += 1

                time_diff = (best_candidate.time_ms - target_time_ms) / 1000.0
                logger.info(
                    f"  saved {filename} "
                    f"(offset={time_diff:+.2f}s, sharpness={best_candidate.sharpness:.1f}, "
                    f"presence={best_candidate.presence_score:.2f}, "
                    f"ocr={best_candidate.ocr_score:.2f}, score={best_candidate.final_score:.2f})"
                )
            except Exception as exc:
                logger.error(f"  failed to save frame: {exc}")

        # 务必释放 OpenCV 句柄，避免被视频文件死锁
        cap.release()
        logger.info(
            f"Frame capture finished. saved={success_count}, "
            f"filtered={filtered_count}, total={len(cards)}"
        )
        return output_list