# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: OpenMDW-1.1

"""Decode known rich inline commands for the legacy tabular fallback.

Used only after strict rich-grid parsing fails. This preserves unknown commands
and malformed arguments; it never invents cell contents or repairs table spans.
"""
import html
import re
try:
    from .hybrid_cleanup import decode_styles
except ImportError:
    from hybrid_cleanup import decode_styles

try:
    from .rich_table_reader import TAGS, LITERALS, argument
except ImportError:
    from rich_table_reader import TAGS, LITERALS, argument


def decode_known_inline(text, _depth=0):
    """Decode balanced, recognized inline arguments without exposing delimiters."""
    if _depth > 64:
        return text
    out = []
    i = 0
    known = set(TAGS) | set(LITERALS) | {'thead', 'linebreak', 'mbox', 'hl', 'colorbox'}
    while i < len(text):
        # Preserve escaped literal characters. In particular, an escaped
        # backslash followed by 'thead' must not become a formatting command.
        if text[i] == '\\' and i + 1 < len(text) and not text[i + 1].isalpha():
            literal = text[i + 1]
            out.append('\\&#' + str(ord(literal)) + ';' if literal in '&%$#_*{}' else text[i:i + 2])
            i += 2
            continue
        match = re.match(r'\\([A-Za-z]+)\{', text[i:])
        if not match or match[1] not in known:
            out.append(text[i])
            i += 1
            continue
        command = match[1]
        try:
            body, end = argument(text, i + len(command) + 1)
        except ValueError:
            out.append(text[i])
            i += 1
            continue
        if command in {'hl', 'colorbox'}:
            try:
                from .semantic_styles import mark_open
            except ImportError:
                from semantic_styles import mark_open
            from bs4 import BeautifulSoup
            node = BeautifulSoup('<mark></mark>', 'html.parser').mark
            if command == 'colorbox':
                node['background'] = body
                try:body, end = argument(text, end)
                except ValueError:
                    out.append(text[i:end]); i = end; continue
            out.append(mark_open(node) + decode_known_inline(body, _depth + 1) + '</mark>')
        elif command in TAGS or command == 'thead':
            inner = decode_known_inline(body, _depth + 1)
            tag = 'nvp-header-cell' if command == 'thead' else TAGS[command]
            out.append('<' + tag + '>' + inner + '</' + tag + '>')
        elif command in LITERALS and not body:
            # Entities cannot be mistaken for LaTeX row/column delimiters.
            out.append('\\&#' + str(ord(LITERALS[command])) + ';')
        elif command == 'linebreak' and not body:
            out.append('<nvp-line-break></nvp-line-break>')
        elif command == 'mbox' and not body:
            pass
        else:
            out.append(text[i:end])
        i = end
    return decode_styles(''.join(out))


def restore_header_cells(html_text):
    from bs4 import BeautifulSoup
    # Restore explicit breaks after legacy whitespace normalization, which
    # otherwise collapses consecutive linebreak commands.
    html_text = html_text.replace('<nvp-line-break></nvp-line-break>', '<br>')
    if '<nvp-header-cell>' not in html_text:
        return html_text
    soup = BeautifulSoup(html_text, 'html.parser')
    for cell in soup.find_all(['td', 'th']):
        markers = cell.find_all('nvp-header-cell')
        if markers:
            cell.name = 'th'
            for marker in markers:
                marker.unwrap()
    return str(soup)