#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""OTSL 归一化：把任意来源的表格标注统一成 **PaddleOCR-VL 1.6 的原生 OTSL 约定**。

为什么必须统一(2026-10-21 实测)
------------------------------
手上有三套互不兼容的 OTSL 约定：

| 来源 | rowspan 怎么写 | 行尾 | 词表 |
|---|---|---|---|
| 数据集自带(PubTables-1M/PubTabNet/tablet/ccocr/omnidocbench) | `<fcel><ulcel>NMES1` 同行塞标记，续接行直接少一格 | 补 `<ecel>` 到固定列数 | 含 `<ulcel>` |
| 我们自己的 html_to_otsl | `<fcel>` + `<ulcel>`*(rs-1) 拼在**同一行** | 不补 | 含 `<ulcel>` |
| **PaddleOCR-VL 1.6 原生** | 续接格是**独立的行**，内容为纯 `<ucel>` | 不补(ragged) | fcel/ecel/lcel/ucel/xcel/nl |

问题：
1. `<ulcel>` **不在 1.6 词表里**(模型吐不出来)，而评测器 `canonical_teds.py` 的
   `OTSL_KNOWN_FOREIGN` 也没收录它 → 被**当成单元格正文**吞掉
   (`<fcel><ulcel><ulcel>characteristic` → 文本 "<ulcel><ulcel>characteristic")。
   实测带 `<ulcel>` 的 GT 行占比：pubtables1m 37%、ccocr 33%、omnidocbench16 25%、
   pubtabnet 23%、tablet 22%、omnidocbench15 20%、ocrbenchv2 17%。
2. 源约定"续接行少一格"，而 1.6 解析器要求续接格占位 → 结构对不上。
3. 源约定每行补 `<ecel>`，模型输出是 ragged → 每行都被算成结构编辑
   (这正是之前"加倍"口径的问题)。

本模块按 1.6 官方语义(paddlex `paddleocr_vl/uilts.py::otsl_parse_texts`)重建：
  - 单元格起点: `<fcel>`(有文字) / `<ecel>`(无文字)
  - colspan 续接: **同一行**右侧连续 `<lcel>`
  - rowspan 续接: **下方行**同列连续 `<ucel>`
  - 同时向上和向左合并: `<xcel>`
  - 行尾不补空格(ragged)，行内按列对齐(空槽 `<ecel>`)
  - 文字: 去首尾空白 + 内部连续空白压成单空格

对外接口:
  html_to_otsl(html)        -> 规范 OTSL
  otsl_stats(otsl)          -> (行数, 槽位数, span 数) 便于对齐统计
  has_foreign(otsl)         -> 是否含 `<ulcel>` 等非法 token
"""
from __future__ import annotations

import re
from html.parser import HTMLParser

OTSL_NL = "<nl>"
OTSL_FCEL = "<fcel>"
OTSL_ECEL = "<ecel>"
OTSL_LCEL = "<lcel>"
OTSL_UCEL = "<ucel>"
OTSL_XCEL = "<xcel>"

_WS = re.compile(r"\s+")
_TOK = re.compile(r"(<fcel>|<ecel>|<lcel>|<ucel>|<xcel>|<nl>)")
_SPAN = ("<ucel>", "<lcel>", "<xcel>")
_FOREIGN = ("<ulcel>", "<ccel>", "<ched>", "<frow>", "<lrow>", "<ncol>",
            "<ccol>", "<xrow>", "<xcol>", "<fc>", "<lc>", "<ec>", "<oc>")


def _norm_text(s: str) -> str:
    return _WS.sub(" ", s or "").strip()


# ==========================================================================
# HTML -> 网格 -> 规范 OTSL
# ==========================================================================
class _TblParser(HTMLParser):
    def __init__(self):
        super().__init__(convert_charrefs=True)
        self.rows = []
        self.cur = None
        self.buf = None
        self.attrs = None
        self.depth = 0

    def handle_starttag(self, tag, attrs):
        if tag == "table":
            self.depth += 1
            return
        if self.depth > 1:
            return
        if tag == "tr":
            self.cur = []
        elif tag in ("td", "th"):
            if self.cur is None:
                self.cur = []
            a = dict(attrs)

            def _i(k):
                try:
                    return max(1, int(a.get(k, 1) or 1))
                except Exception:
                    return 1
            self.attrs = (_i("colspan"), _i("rowspan"))
            self.buf = []

    def handle_data(self, data):
        if self.buf is not None:
            self.buf.append(data)

    def handle_endtag(self, tag):
        if tag == "table":
            self.depth = max(0, self.depth - 1)
            return
        if self.depth > 1:
            return
        if tag in ("td", "th") and self.buf is not None:
            txt = _norm_text("".join(self.buf))
            cs, rs = self.attrs or (1, 1)
            self.cur.append((txt, cs, rs))
            self.buf = None
            self.attrs = None
        elif tag == "tr" and self.cur is not None:
            self.rows.append(self.cur)
            self.cur = None


class _Cell:
    __slots__ = ("text", "cs", "rs", "kind")   # kind: origin|col|up|both

    def __init__(self, text, cs, rs, kind):
        self.text, self.cs, self.rs, self.kind = text, cs, rs, kind


def _build_grid(rows):
    grid = []
    for r, rcells in enumerate(rows):
        while len(grid) <= r:
            grid.append([])
        row = grid[r]
        c = 0
        for (txt, cs, rs) in rcells:
            while c < len(row) and row[c] is not None:
                c += 1
            while len(row) < c + cs:
                row.append(None)
            row[c] = _Cell(txt, cs, rs, "origin")
            for dc in range(1, cs):
                row[c + dc] = _Cell("", cs, rs, "col")
            for dr in range(1, rs):
                rr = r + dr
                while len(grid) <= rr:
                    grid.append([])
                rrow = grid[rr]
                while len(rrow) < c + cs:
                    rrow.append(None)
                rrow[c] = _Cell("", cs, rs, "up")
                for dc in range(1, cs):
                    rrow[c + dc] = _Cell("", cs, rs, "both")
            c += cs
    return grid


def _grid_to_otsl(grid):
    out = []
    for row in grid:
        last = len(row) - 1
        while last >= 0 and row[last] is None:
            last -= 1
        if last < 0:
            continue
        parts = []
        for c in range(last + 1):
            cell = row[c]
            if cell is None:
                parts.append(OTSL_ECEL)
            elif cell.kind == "origin":
                parts.append(OTSL_FCEL + cell.text if cell.text else OTSL_ECEL)
            elif cell.kind == "col":
                parts.append(OTSL_LCEL)
            elif cell.kind == "up":
                parts.append(OTSL_UCEL)
            else:
                parts.append(OTSL_XCEL)
        out.append("".join(parts))
    return OTSL_NL.join(out)


def html_to_otsl(html: str) -> str:
    """HTML -> 规范 OTSL(1.6 约定)"""
    if not html or "<table" not in html.lower():
        return ""
    p = _TblParser()
    try:
        p.feed(html)
        p.close()
    except Exception:
        return ""
    if not p.rows:
        return ""
    return _grid_to_otsl(_build_grid(p.rows))


# ==========================================================================
# 统计/体检
# ==========================================================================
def otsl_stats(otsl: str):
    """-> (行数, 槽位数, span token 数, 含非法 token 数)"""
    if not otsl:
        return (0, 0, 0, 0)
    rows = [r for r in otsl.split(OTSL_NL) if r.strip()]
    slots = 0
    spans = 0
    for r in rows:
        toks = _TOK.findall(r)
        slots += len(toks)
        spans += sum(1 for t in toks if t in _SPAN)
    foreign = sum(otsl.count(t) for t in _FOREIGN)
    return (len(rows), slots, spans, foreign)


def has_foreign(otsl: str) -> bool:
    return any(t in (otsl or "") for t in _FOREIGN)


if __name__ == "__main__":
    demo = ("<table>"
            "<tr><td rowspan=\"2\">A</td><td colspan=\"2\">B</td></tr>"
            "<tr><td>C</td><td>D</td></tr>"
            "<tr><td>E</td><td>F</td><td>G</td></tr>"
            "</table>")
    o = html_to_otsl(demo)
    print(o)
    for i, r in enumerate(o.split("<nl>")):
        print(f"  行{i}: {r}")
    print("stats:", otsl_stats(o))