"""Shared utilities for novoyuuparosk-auto-wiki pipelines."""

import html
import os
import re
import subprocess
from urllib.parse import urlparse

import mwclient

AUTO_BANNER_PREFIX = "{{Auto-generated"

# A ```columns fenced block is passed through Pandoc verbatim as
# <pre class="columns">…</pre>; columns within it are separated by a line of ===.
_COLUMNS_BLOCK_RE = re.compile(r'<pre class="columns">(.*?)</pre>', re.DOTALL)
_COLUMN_SEP_RE = re.compile(r"^\s*===\s*$", re.MULTILINE)

# Minimal Markdown emphasis → wikitext, for use inside a verbatim columns block
# (Pandoc doesn't process Markdown there). Asterisk style only, single line.
# Order matters: bold-italic (***) before bold (**) before italic (*).
_BOLD_ITALIC_RE = re.compile(r"\*\*\*(.+?)\*\*\*")
_BOLD_RE = re.compile(r"\*\*(.+?)\*\*")
_ITALIC_RE = re.compile(r"\*(.+?)\*")


def _md_emphasis_to_wikitext(text: str) -> str:
    text = _BOLD_ITALIC_RE.sub(r"'''''\1'''''", text)
    text = _BOLD_RE.sub(r"'''\1'''", text)
    text = _ITALIC_RE.sub(r"''\1''", text)
    return text


def strip_first_h1(text: str) -> str:
    """Remove the first '# Heading' line and any immediately following blank line."""
    lines = text.split("\n")
    for i, line in enumerate(lines):
        if line.strip().startswith("# "):
            del lines[i]
            if i < len(lines) and lines[i].strip() == "":
                del lines[i]
            break
    return "\n".join(lines)


def expand_columns(wikitext: str) -> str:
    """Expand ```columns fenced blocks into a flex row of <poem> columns.

    Authors write a fenced code block tagged ``columns``; Pandoc passes its body
    through verbatim as ``<pre class="columns">…</pre>`` (line breaks and blank
    lines preserved, inline markup entity-escaped). Columns within the block are
    separated by a line containing only ``===``. Each column is wrapped in
    <poem> so its line breaks survive MediaWiki parsing. Content is
    HTML-unescaped (so inline markup such as <b>…</b> renders rather than
    appearing as literal text) and Markdown emphasis (``*italic*``, ``**bold**``,
    ``***bold-italic***``) is converted to wikitext, since Pandoc does not
    process Markdown inside the verbatim block.
    """

    def render(match: re.Match) -> str:
        body = _md_emphasis_to_wikitext(html.unescape(match.group(1)))
        columns = _COLUMN_SEP_RE.split(body)
        poems = "".join("<poem>\n" + col.strip("\n") + "\n</poem>" for col in columns)
        return '<div style="display:flex; gap:3em; align-items:flex-start">' + poems + "</div>"

    return _COLUMNS_BLOCK_RE.sub(render, wikitext)


def markdown_to_wikitext(body: str) -> str:
    result = subprocess.run(
        ["pandoc", "-f", "markdown", "-t", "mediawiki"],
        input=body,
        capture_output=True,
        text=True,
    )
    if result.returncode != 0:
        raise RuntimeError(f"pandoc failed: {result.stderr.strip()}")
    return expand_columns(result.stdout)


def connect_wiki() -> mwclient.Site:
    api_url = os.environ["WIKI_API_URL"]
    parsed = urlparse(api_url)
    host = parsed.netloc
    path = parsed.path[: parsed.path.rfind("/") + 1] or "/"
    site = mwclient.Site(host, path=path, scheme=parsed.scheme)
    site.login(os.environ["WIKI_BOT_USER"], os.environ["WIKI_BOT_PASSWORD"])
    return site