# -*- coding: utf-8 -*-
"""
扫描 SRT 文件, 报告字幕质量指标 + 抽样, 帮你快速判断OCR字幕好不好。
纯标准库。

用法:
  python3 tools/检查srt质量.py ./srt              # 扫目录下所有 .srt
  python3 tools/检查srt质量.py a.srt b.srt         # 扫指定文件
  python3 tools/检查srt质量.py ./srt --sample 8     # 多抽几条看
"""
import argparse
import glob
import os
import re

CJK = re.compile(r'[一-鿿]')


def parse_srt(path):
    """返回 [(idx, start, end, text), ...]"""
    try:
        raw = open(path, encoding='utf-8', errors='ignore').read()
    except OSError:
        return []
    blocks = re.split(r'\n\s*\n', raw.strip())
    out = []
    for b in blocks:
        lines = [x for x in b.splitlines() if x.strip()]
        if len(lines) < 2:
            continue
        m = re.search(r'(\d+):(\d+):(\d+)[,.](\d+)\s*-->\s*(\d+):(\d+):(\d+)[,.](\d+)', b)
        if not m:
            continue
        g = list(map(int, m.groups()))
        st = g[0]*3600 + g[1]*60 + g[2] + g[3]/1000.0
        en = g[4]*3600 + g[5]*60 + g[6] + g[7]/1000.0
        ti = next((i for i, l in enumerate(lines) if '-->' in l), 0)
        text = ' '.join(lines[ti+1:]).strip()
        out.append((st, en, text))
    return out


def has_self_repeat(s, minlen=4):
    """检测整条里前半段==后半段这种自我重复(如 AABB → AB 重复)。"""
    n = len(s)
    if n < minlen * 2:
        return False
    h = n // 2
    return s[:h] == s[h:2*h] and len(s[:h]) >= minlen


def scan(paths, sample):
    files = []
    for p in paths:
        if os.path.isdir(p):
            files += glob.glob(os.path.join(p, '**', '*.srt'), recursive=True)
        elif p.endswith('.srt'):
            files.append(p)
    if not files:
        print("没找到 .srt")
        return

    tot_e = empty = dup = selfrep = tooshort = lowcjk = badtime = 0
    chars = 0
    samples = []
    for f in files:
        subs = parse_srt(f)
        prev = None
        for st, en, text in subs:
            tot_e += 1
            chars += len(text)
            if not text:
                empty += 1
            if prev is not None and text and text == prev:
                dup += 1
            if has_self_repeat(text):
                selfrep += 1
            if text and len(text) <= 1:
                tooshort += 1
            if text and len(CJK.findall(text)) < len(text) * 0.3 and len(text) > 4:
                lowcjk += 1            # 中文占比过低 → 可能乱码/纯符号
            if en <= st or (en - st) > 30:
                badtime += 1
            prev = text
        if subs and len(samples) < sample:
            mid = len(subs) // 2
            for s in subs[mid:mid+2]:
                samples.append((os.path.basename(f), s))

    print("=" * 58)
    print(f"SRT 文件 {len(files)} 个 | 字幕条目 {tot_e} 条 | 平均 {chars/max(tot_e,1):.1f} 字/条")
    print("-" * 58)
    def pct(x): return f"{x} ({x/max(tot_e,1)*100:.1f}%)"
    print(f"  空条目:            {pct(empty)}        <- 应≈0")
    print(f"  连续重复(同上条):  {pct(dup)}        <- 高=去重没做好")
    print(f"  自我重复(AABB):    {pct(selfrep)}        <- 高=自重复bug")
    print(f"  单字条目:          {pct(tooshort)}")
    print(f"  低中文占比(疑乱码):{pct(lowcjk)}        <- 高=OCR乱/纯符号")
    print(f"  时间轴异常:        {pct(badtime)}        <- 重叠/0时长/超30s")
    print("=" * 58)
    print("抽样字幕:")
    for fn, (st, en, text) in samples[:sample]:
        print(f"  [{st:6.1f}-{en:6.1f}] {text[:50]}   ({fn})")


if __name__ == '__main__':
    ap = argparse.ArgumentParser()
    ap.add_argument('paths', nargs='+')
    ap.add_argument('--sample', type=int, default=6)
    a = ap.parse_args()
    scan(a.paths, a.sample)