"""Tests for backend/services/ffmpeg_utils.py — Phase 1 Wave 3 (issue #76).

Covers :func:`resolve_ffprobe`'s env-first / PATH-fallback cascade and the
legacy-name alias (``FFPROBE_PATH`` still works, ``OMNIVOICE_FFPROBE_PATH``
takes precedence).
"""
import os

import pytest


@pytest.fixture(autouse=True)
def _clean_env(monkeypatch):
    """Strip both ffprobe env vars before each test so we control the cascade."""
    monkeypatch.delenv("OMNIVOICE_FFPROBE_PATH", raising=False)
    monkeypatch.delenv("FFPROBE_PATH", raising=False)


def test_resolve_ffprobe_prefers_omnivoice_env_var(monkeypatch, tmp_path):
    """OMNIVOICE_FFPROBE_PATH set to a real file → that path wins."""
    from services import ffmpeg_utils

    fake = tmp_path / "ffprobe"
    fake.write_text("#!/bin/sh\necho 1\n")
    fake.chmod(0o755)
    monkeypatch.setenv("OMNIVOICE_FFPROBE_PATH", str(fake))

    assert ffmpeg_utils.resolve_ffprobe() == str(fake)


def test_resolve_ffprobe_falls_back_to_legacy_FFPROBE_PATH(monkeypatch, tmp_path):
    """OMNIVOICE_FFPROBE_PATH absent but legacy FFPROBE_PATH set → legacy used."""
    from services import ffmpeg_utils

    fake = tmp_path / "ffprobe-legacy"
    fake.write_text("#!/bin/sh\necho 1\n")
    fake.chmod(0o755)
    monkeypatch.setenv("FFPROBE_PATH", str(fake))

    assert ffmpeg_utils.resolve_ffprobe() == str(fake)


def test_resolve_ffprobe_omnivoice_path_takes_precedence_over_legacy(
    monkeypatch, tmp_path,
):
    """Both env vars set → OMNIVOICE_FFPROBE_PATH wins."""
    from services import ffmpeg_utils

    canonical = tmp_path / "ffprobe-canonical"
    legacy = tmp_path / "ffprobe-legacy"
    for f in (canonical, legacy):
        f.write_text("#!/bin/sh\necho 1\n")
        f.chmod(0o755)

    monkeypatch.setenv("OMNIVOICE_FFPROBE_PATH", str(canonical))
    monkeypatch.setenv("FFPROBE_PATH", str(legacy))

    assert ffmpeg_utils.resolve_ffprobe() == str(canonical)


def test_resolve_ffprobe_falls_back_to_PATH(monkeypatch, tmp_path):
    """No env var → shutil.which result is returned."""
    from services import ffmpeg_utils

    # Stub shutil.which inside the module so we do not depend on the host PATH.
    fake = "/fake/path/from/system/ffprobe"

    def _fake_which(name):
        if name == "ffprobe":
            return fake
        return None

    monkeypatch.setattr(ffmpeg_utils, "shutil", _ShutilStub(_fake_which))
    assert ffmpeg_utils.resolve_ffprobe() == fake


def test_resolve_ffprobe_returns_None_when_nothing_resolves(monkeypatch):
    """No env, no PATH → returns None (no crash)."""
    from services import ffmpeg_utils

    monkeypatch.setattr(ffmpeg_utils, "shutil", _ShutilStub(lambda _name: None))
    assert ffmpeg_utils.resolve_ffprobe() is None


def test_resolve_ffprobe_env_var_with_command_name_resolves_via_which(
    monkeypatch, tmp_path,
):
    """Legacy shape: env var set to a bare command name (not a path) — resolve
    via shutil.which so older Tauri shells that set FFPROBE_PATH=ffprobe still
    work."""
    from services import ffmpeg_utils

    fake = tmp_path / "ffprobe"
    fake.write_text("#!/bin/sh\necho 1\n")
    fake.chmod(0o755)

    def _fake_which(name):
        if name == "ffprobe":
            return str(fake)
        return None

    monkeypatch.setattr(ffmpeg_utils, "shutil", _ShutilStub(_fake_which))
    monkeypatch.setenv("OMNIVOICE_FFPROBE_PATH", "ffprobe")

    assert ffmpeg_utils.resolve_ffprobe() == str(fake)


class _ShutilStub:
    """A tiny shim that mimics the parts of shutil ffmpeg_utils touches.

    monkeypatching the whole module avoids pulling in real PATH lookups while
    keeping the existing `import shutil` call sites untouched.
    """

    def __init__(self, which_impl):
        self._which = which_impl

    def which(self, name):
        return self._which(name)