"""Tests for yt_untertitel.py; yt-dlp is always replaced by fakes (no network)."""
import json
import subprocess
import sys
from pathlib import Path

import pytest

import yt_untertitel as yt

URL = "https://www.youtube.com/watch?v=abc123"

AUTO_ONLY = {
    "id": "abc123",
    "title": "Eine Rede",
    "subtitles": {},
    "automatic_captions": {"de-orig": [], "de": [], "en": []},
}


def fake_yt_dlp(info, write=True, fail_download=False):
    """Stand-in for subprocess.run: answers the info request, writes the VTT file."""
    calls = []

    def run(command, capture_output, text):
        calls.append(command)
        if "--dump-single-json" in command:
            return subprocess.CompletedProcess(command, 0, json.dumps(info), "")
        if fail_download:
            return subprocess.CompletedProcess(command, 1, "", "HTTP Error 429")
        track = command[command.index("--sub-langs") + 1]
        template = command[command.index("-o") + 1]
        if write:
            Path(template.replace("%(ext)s", f"{track}.vtt")).write_text(
                "WEBVTT\n", encoding="utf-8"
            )
        return subprocess.CompletedProcess(command, 0, "", "")

    run.calls = calls
    return run


@pytest.fixture(autouse=True)
def yt_dlp_installed(monkeypatch):
    monkeypatch.setattr(yt.shutil, "which", lambda name: f"/usr/bin/{name}")


def run_main(monkeypatch, *args):
    monkeypatch.setattr(sys, "argv", ["yt_untertitel.py", *map(str, args)])
    yt.main()


# === Track selection ===

@pytest.mark.parametrize("info, lang, expected", [
    ({"subtitles": {"de": []}, "automatic_captions": {"de-orig": []}}, "de", ("de", False)),
    (AUTO_ONLY, "de", ("de-orig", True)),
    # "en" exists only as machine translation of the German original
    (AUTO_ONLY, "en", None),
    ({"subtitles": None, "automatic_captions": None}, "de", None),
])
def test_choose_track(info, lang, expected):
    assert yt.choose_track(info, lang) == expected


def test_available_tracks():
    info = {"subtitles": {"fr": []}, "automatic_captions": {"de-orig": [], "de": []}}
    assert yt.available_tracks(info) == (["fr"], ["de"])


# === Command line ===

def test_main_downloads_auto_original(tmp_path, monkeypatch, capsys):
    run = fake_yt_dlp(AUTO_ONLY)
    monkeypatch.setattr(yt.subprocess, "run", run)
    run_main(monkeypatch, "-u", URL, "-n", "Rede", "-d", tmp_path / "neu")

    assert (tmp_path / "neu" / "Rede.de-orig.vtt").is_file()
    download = run.calls[1]
    assert "--write-auto-subs" in download and "--write-subs" not in download
    assert download[-1] == URL
    out = capsys.readouterr().out
    assert "automatische Untertitel „de-orig“" in out
    assert "vtt2txt.py -i" in out


def test_main_prefers_manual_and_defaults_to_video_id(tmp_path, monkeypatch):
    info = dict(AUTO_ONLY, subtitles={"de": []})
    run = fake_yt_dlp(info)
    monkeypatch.setattr(yt.subprocess, "run", run)
    run_main(monkeypatch, "-u", URL, "-d", tmp_path)

    assert (tmp_path / "abc123.de.vtt").is_file()
    assert "--write-subs" in run.calls[1]


def test_main_no_matching_track(tmp_path, monkeypatch):
    monkeypatch.setattr(yt.subprocess, "run", fake_yt_dlp(AUTO_ONLY))
    with pytest.raises(SystemExit, match="Automatisch \\(Originalsprache\\): de"):
        run_main(monkeypatch, "-u", URL, "-l", "en", "-d", tmp_path)


def test_main_info_error(tmp_path, monkeypatch):
    def run(command, capture_output, text):
        return subprocess.CompletedProcess(command, 1, "", "ERROR: Video unavailable")

    monkeypatch.setattr(yt.subprocess, "run", run)
    with pytest.raises(SystemExit, match="Video unavailable"):
        run_main(monkeypatch, "-u", URL, "-d", tmp_path)


@pytest.mark.parametrize("kwargs, message", [
    ({"fail_download": True}, "HTTP Error 429"),
    ({"write": False}, "keine Datei"),
])
def test_main_download_errors(tmp_path, monkeypatch, kwargs, message):
    monkeypatch.setattr(yt.subprocess, "run", fake_yt_dlp(AUTO_ONLY, **kwargs))
    with pytest.raises(SystemExit, match=message):
        run_main(monkeypatch, "-u", URL, "-d", tmp_path)


@pytest.mark.parametrize("args, message", [
    ([], "required"),
    (["-u", URL, "-n", "sub/Rede"], "ohne Verzeichnis"),
    (["-u", URL, "-n", ""], "ohne Verzeichnis"),
])
def test_cli_errors(monkeypatch, capsys, args, message):
    with pytest.raises(SystemExit) as exc:
        run_main(monkeypatch, *args)
    assert exc.value.code == 2
    assert message in capsys.readouterr().err


def test_cli_without_yt_dlp(monkeypatch, capsys):
    monkeypatch.setattr(yt.shutil, "which", lambda name: None)
    with pytest.raises(SystemExit):
        run_main(monkeypatch, "-u", URL)
    assert "pip install yt-dlp" in capsys.readouterr().err