"""Tests for backend.main_headless ready-event JSON format."""

import sys
from pathlib import Path

import pytest

# Ensure project root is on path
project_root = Path(__file__).resolve().parent.parent.parent
sys.path.insert(0, str(project_root))


def test_ready_event_reports_api_port_not_obs_port():
    """The ready JSON printed by main_headless must set ``port`` to
    ``obs_port + 1`` (the API port), not the OBS display port.

    From main_headless.py::

        obs_port = controller.actual_web_port or args.port
        api_port = obs_port + 1

        print(json.dumps({
            "event": "ready",
            "port": api_port,
            "obs_port": obs_port,
        }), flush=True)

    We verify this contract by reading the source and checking the
    structure directly (running main() would start a real server).
    """
    import ast
    import textwrap

    source_path = project_root / "backend" / "main_headless.py"
    source = source_path.read_text()

    # Verify the key relationships exist in the source:
    # 1. api_port = obs_port + 1
    assert "api_port = obs_port + 1" in source, (
        "Expected `api_port = obs_port + 1` in main_headless.py"
    )

    # 2. The ready event JSON uses api_port for "port", not obs_port
    assert '"port": api_port' in source or "'port': api_port" in source, (
        "The ready event should report api_port as 'port'"
    )

    # 3. obs_port is also included separately
    assert '"obs_port": obs_port' in source or "'obs_port': obs_port" in source, (
        "The ready event should also include 'obs_port'"
    )

    # 4. Verify the event name
    assert '"event": "ready"' in source or "'event': 'ready'" in source, (
        "The ready event should have event='ready'"
    )