"""FlowDeck — Wiki-links & page mentions (v5.11.0).

Inline references live inside plain-text block content as tokens::

    [[fdpage:123]]   link to page id 123, label resolved at render time
    [[fddate:2026-10-01]]   date chip (static label)

The page token stores only the id, so renaming a page propagates everywhere
(the label is resolved through the DB / the titles endpoint at render time).
Backlinks keep working because the server renderer emits ``/pages/<id>``
anchors, and the backlink scanner also matches the raw token.

Pure-stdlib helpers shared by the public renderer and the block export.
"""
from __future__ import annotations

import html as _html
import re

WIKI_PAGE_RE = re.compile(r"\[\[fdpage:(\d+)\]\]")
WIKI_DATE_RE = re.compile(r"\[\[fddate:(\d{4}-\d{2}-\d{2})(?:T[0-9:]{5,8})?\]\]")
_DATE_LABELS = {0: "Mon", 1: "Tue", 2: "Wed", 3: "Thu", 4: "Fri", 5: "Sat", 6: "Sun"}
_MONTHS = ["Jan", "Feb", "Mar", "Apr", "May", "Jun",
           "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]


def extract_page_ids(text: str) -> list[int]:
    """All page ids referenced by wiki tokens in a content string."""
    return sorted({int(m) for m in WIKI_PAGE_RE.findall(text or "")})


def _date_label(iso: str) -> str:
    try:
        parts = iso.split("-")
        y, m, d = int(parts[0]), int(parts[1]), int(parts[2])
        import datetime as _dt
        wd = _dt.date(y, m, d).weekday()
        return f"{_DATE_LABELS[wd]} {d} {_MONTHS[m-1]} {y}"
    except (ValueError, IndexError):
        return iso


def token_labels(conn, content: str) -> dict[str, str]:
    """Map every token in ``content`` to its display label (page title)."""
    out: dict[str, str] = {}
    ids = extract_page_ids(content)
    if ids:
        placeholders = ",".join("?" * len(ids))
        rows = conn.execute(
            f"SELECT id, title, page_icon FROM pages WHERE id IN ({placeholders})", ids,
        ).fetchall()
        by_id = {str(r["id"]): (r["title"] or "Untitled", r["page_icon"] or "") for r in rows}
        for token_id in ids:
            title, icon = by_id.get(str(token_id), ("Deleted page", ""))
            out[f"[[fdpage:{token_id}]]"] = f"{icon + ' ' if icon else ''}{title}"
    for m in WIKI_DATE_RE.finditer(content or ""):
        iso = m.group(1)
        out[f"[[fddate:{iso}]]"] = _date_label(iso)
    return out


def resolve_tokens_html(content: str, titles: dict[str, str]) -> str:
    """Escape plain-text content then turn wiki tokens into HTML chips/links.

    ``titles`` maps token → label (from :func:`token_labels`). Used by the
    public page renderer and any server-side HTML output of block content.
    """
    s = _html.escape(content or "")

    def _page(m: re.Match) -> str:
        pid = m.group(1)
        label = titles.get(m.group(0)) or "Deleted page"
        return (f'<a class="fd-wiki-link" href="/pages/{pid}" '
                f'data-pid="{pid}" title="{_html.escape(label)}">{_html.escape(label)}</a>')

    def _date(m: re.Match) -> str:
        iso = m.group(1)
        label = titles.get(f"[[fddate:{iso}]]") or iso
        return f'<span class="fd-wiki-date" title="{_html.escape(iso)}">{_html.escape(label)}</span>'

    s = WIKI_PAGE_RE.sub(_page, s)
    s = WIKI_DATE_RE.sub(_date, s)
    return s