"""The manual page, which is generated from the settings table."""
import shutil
import subprocess
import sys
from pathlib import Path

import pytest

from bandsaunter import settings as st

GENERATOR = Path(__file__).resolve().parent.parent / "packaging" / "make-man.py"


@pytest.fixture(scope="module")
def page(tmp_path_factory):
    out = tmp_path_factory.mktemp("man") / "bandsaunter.1"
    subprocess.run([sys.executable, str(GENERATOR), str(out)],
                   check=True, capture_output=True)
    return out.read_text()


def test_every_setting_is_documented(page):
    """A setting the manual does not mention is one nobody can look up."""
    missing = [s.key for s in st.SETTINGS if s.key not in page]
    assert not missing, f"settings missing from the manual: {missing}"


def test_every_flag_is_documented(page):
    missing = [f for s in st.SETTINGS for f in s.flags + s.off_flags
               if f.replace("-", "\\-") not in page and f not in page]
    assert not missing, f"flags missing from the manual: {missing}"


def test_every_setting_explains_itself_in_plain_words(page):
    """The guidance is the point of the manual: what it is, when to change it."""
    for s in st.SETTINGS:
        assert s.guidance, f"{s.key} has no plain-language guidance"
        assert len(s.guidance) > 80, f"{s.key}'s guidance says too little"
        # The first sentence has to stand on its own for someone skimming.
        assert s.guidance.rstrip().endswith("."), s.key


def test_the_commands_and_the_keys_are_documented(page):
    for word in ("scan", "bands", "config", "transcribe", "devices",
                 "profiles", "analyze"):
        assert f".B {word}\n" in page, f"command {word} undocumented"
    for section in ("SYNOPSIS", "DESCRIPTION", "COMMANDS", "OPTIONS",
                    "SETTINGS", "FILES", "ENVIRONMENT", "EXAMPLES"):
        assert f".SH {section}" in page


@pytest.mark.skipif(not shutil.which("groff"), reason="groff not installed")
def test_it_renders_without_complaint(page, tmp_path):
    """Troff is unforgiving: an unescaped leading dot silently eats a line."""
    src = tmp_path / "bandsaunter.1"
    src.write_text(page)
    proc = subprocess.run(["groff", "-man", "-Tutf8", "-ww", "-z", str(src)],
                          capture_output=True, text=True)
    assert proc.returncode == 0, proc.stderr
    assert not proc.stderr.strip(), proc.stderr


@pytest.mark.skipif(not shutil.which("groff"), reason="groff not installed")
def test_the_guidance_survives_into_the_rendered_page(page, tmp_path):
    src = tmp_path / "bandsaunter.1"
    src.write_text(page)
    rendered = subprocess.run(["groff", "-man", "-Tutf8", str(src)],
                              capture_output=True, text=True).stdout
    flat = " ".join(rendered.replace("\b", "").split())
    # A sentence from one setting's guidance, chosen because it is the one a
    # newcomer most needs: what the squelch actually is.
    assert "This is the squelch knob." in flat