# retoor <retoor@molodetz.nl>
import re
from functools import lru_cache

import mistune
from mistune.renderers.html import HTMLRenderer

from molodetz import config
from molodetz.rendering import normalize_dashes

PROSE_DIR = config.TEMPLATES_DIR / "docs" / "prose"

SECTIONS = ("Start here", "Building with the API", "Admin")

DOCS_PAGES = [
    {"slug": "welcome", "title": "Welcome", "section": "Start here", "file": "welcome.md"},
    {"slug": "writing", "title": "Writing on the roll", "section": "Start here", "file": "writing.md"},
    {"slug": "join", "title": "Joining", "section": "Start here", "file": "join.md"},
    {"slug": "legal", "title": "Terms and privacy", "section": "Start here", "file": "legal.md"},
    {"slug": "api", "title": "API and authentication", "section": "Building with the API", "file": "api.md"},
    {"slug": "content", "title": "Galleries and content", "section": "Start here", "file": "content.md"},
    {"slug": "admin", "title": "Admin and services", "section": "Admin", "file": "admin.md", "admin": True},
    {"slug": "operator", "title": "Operator runbook", "section": "Admin", "file": "operator.md", "admin": True},
    {"slug": "backups", "title": "Backups and maintenance", "section": "Admin", "file": "backups.md", "admin": True},
]


class ProseRenderer(HTMLRenderer):
    def heading(self, text, level, **attrs):
        anchor = re.sub(r"[^a-z0-9-]", "-", re.sub(r"<[^>]+>", "", text).lower())
        anchor = re.sub(r"-+", "-", anchor).strip("-")
        return f'<h{level} id="{anchor}"><a class="permalink" href="#{anchor}">{text}</a></h{level}>\n'


_prose_markdown = mistune.create_markdown(escape=False, hard_wrap=True, renderer=ProseRenderer(escape=False), plugins=["table", "strikethrough", "url"])


def visible_pages(viewer_is_admin):
    return [page for page in DOCS_PAGES if viewer_is_admin or not page.get("admin")]


def page_by_slug(slug):
    for page in DOCS_PAGES:
        if page["slug"] == slug:
            return page
    return None


@lru_cache(maxsize=64)
def page_source(slug):
    page = page_by_slug(slug)
    if page is None:
        return ""
    return normalize_dashes((PROSE_DIR / page["file"]).read_text(encoding="utf-8"))


@lru_cache(maxsize=64)
def render_page(slug):
    return _prose_markdown(page_source(slug))


def sidebar(viewer_is_admin):
    pages = visible_pages(viewer_is_admin)
    return [(section, [page for page in pages if page["section"] == section]) for section in SECTIONS]