"""The shipped nginx template, checked against the code it fronts.

STD-06. `app/nginx.conf` proxied to `127.0.0.1:5000` — run.py's development
default — while `wsgi.py`, which is what actually serves production, binds
`PORT` with a default of 10000. Installing the file as shipped therefore
produced 502 Bad Gateway on every page, from a configuration that reads as
entirely reasonable and a server that is running perfectly well.

Nothing in the repository related the two numbers, so nothing could notice
they had diverged. That is what this file is: the relation, written down
somewhere that runs.

It deliberately checks only what can be wrong in a way that breaks the site
silently. The rest of the nginx configuration is the operator's.
"""

import pathlib
import re

import pytest

ROOT = pathlib.Path(__file__).resolve().parent.parent
NGINX_CONF = ROOT / 'app' / 'nginx.conf'
WSGI = ROOT / 'wsgi.py'


@pytest.fixture(scope='module')
def nginx_text():
    return NGINX_CONF.read_text(encoding='utf-8')


def _wsgi_default_port():
    """The port wsgi.py binds when PORT is unset."""
    match = re.search(r"os\.getenv\(\s*'PORT'\s*,\s*(\d+)\s*\)", WSGI.read_text(encoding='utf-8'))
    assert match, 'wsgi.py no longer reads PORT the way this test expects'
    return match.group(1)


class TestTheUpstreamPort:
    def test_the_wsgi_default_is_findable(self):
        """Premise: if the regex stopped matching, every test below would be
        comparing against nothing."""
        assert _wsgi_default_port().isdigit()

    def test_every_proxy_pass_targets_it(self, nginx_text):
        """Including the commented-out ones. A block someone uncomments a
        year from now carries whatever port it was written with."""
        expected = _wsgi_default_port()
        ports = re.findall(r'proxy_pass\s+http://127\.0\.0\.1:(\d+)', nginx_text)

        assert ports, 'no proxy_pass found; this test is no longer checking anything'
        assert set(ports) == {expected}, (
            f'nginx proxies to {sorted(set(ports))} but wsgi.py binds {expected}. '
            f'Installing this file would give 502 on every page.'
        )


class TestTheStaticAliasIsStillFlagged:
    """The /static/ alias is shipped with a guessed path, and the HANDOFF
    lists it as a node setting. This test does not know the right value —
    it makes sure the warning stays next to it."""

    def test_the_alias_says_it_must_be_checked(self, nginx_text):
        lines = nginx_text.splitlines()
        alias_lines = [i for i, line in enumerate(lines) if line.strip().startswith('alias ')]
        if not alias_lines:
            pytest.skip('no alias directive in this configuration')

        for index in alias_lines:
            preceding = '\n'.join(lines[max(0, index - 20) : index]).lower()
            assert any(word in preceding for word in ('adjust', 'check', 'guess', 'must match')), (
                f'line {index + 1}: the alias path is a guess about the deployment '
                f'layout; the note saying so must stay with it'
            )