"""Every page below a top-level section shows its trail back up (rule 134).

The breadcrumb block is empty by default, so a nested page that forgets it
ships with no way back up and nothing says so. Every full page (one that
extends base.html) must fill the block, unless it is a section's own top
page, a logged-out page or an error page: those are named below, so adding
one is a decision someone makes in this file.
"""
import re

from tests._templates import REPO, template_files

TOP_LEVEL = {
    "steward/templates/dashboard/index.html",
    "steward/templates/hosts/list.html",
    "steward/templates/monitors/index.html",
    "steward/templates/alerts/list.html",
    "steward/templates/ansible/index.html",
    "steward/templates/audit/list.html",
    "steward/templates/ai_access/index.html",
    "plugins/docker/templates/docker/index.html",
    "plugins/snmp/templates/snmp/index.html",
    "plugins/traefik/templates/traefik/index.html",
    "plugins/unifi/templates/unifi/index.html",
    # Logged out, or no page to go back up from.
    "steward/templates/auth/login.html",
    "steward/templates/auth/setup.html",
    "steward/templates/errors/404.html",
    "steward/templates/errors/500.html",
    "steward/templates/errors/database_unavailable.html",
}

_EXTENDS_BASE = re.compile(r"""\{%-?\s*extends\s+["']base\.html["']""")
_BLOCK = re.compile(r"\{%-?\s*block\s+breadcrumb\s*-?%\}(.*?)\{%-?\s*endblock", re.S)


def needs_crumbs_and_lacks_them(text: str) -> bool:
    block = _BLOCK.search(text)
    return bool(_EXTENDS_BASE.search(text)) and not (block and "crumbs(" in block.group(1))


def test_the_guard_can_fail():
    assert needs_crumbs_and_lacks_them('{% extends "base.html" %}{% block content %}x{% endblock %}')
    assert needs_crumbs_and_lacks_them('{% extends "base.html" %}{% block breadcrumb %}{% endblock %}')
    assert not needs_crumbs_and_lacks_them(
        '{% extends "base.html" %}{% block breadcrumb %}{{ crumbs([("Hosts", "/hosts/"), ("x", "")]) }}{% endblock %}')
    assert not needs_crumbs_and_lacks_them("<tr><td>a fragment</td></tr>")


def test_every_nested_page_has_a_trail():
    pages = {str(p.relative_to(REPO)): p for p in template_files()}
    assert TOP_LEVEL <= set(pages), sorted(TOP_LEVEL - set(pages))  # a renamed page leaves no stale entry
    missing = sorted(name for name, p in pages.items()
                     if name not in TOP_LEVEL and needs_crumbs_and_lacks_them(p.read_text()))
    assert not missing, f"add {{% block breadcrumb %}}{{{{ crumbs([...]) }}}} (rule 134): {missing}"