"""Unit tests for the hameter.discovery module."""

import threading
from unittest.mock import MagicMock, patch

import pytest

from hameter.discovery import run_discovery_for_web
from hameter.config import GeneralConfig
from hameter.state import AppState, PipelineStatus


VALID_LINE_1 = '{"Time":"2026-03-05T10:00:00Z","Type":"SCM","Message":{"ID":12345,"Consumption":50000}}'
VALID_LINE_2 = '{"Time":"2026-03-05T10:00:05Z","Type":"SCM","Message":{"ID":67890,"Consumption":12000}}'
VALID_LINE_3 = '{"Time":"2026-03-05T10:00:10Z","Type":"SCM","Message":{"ID":12345,"Consumption":50100}}'


@pytest.fixture
def config():
    return GeneralConfig()


@pytest.fixture
def shutdown_event():
    return threading.Event()


@pytest.fixture
def app_state():
    return AppState()


@patch("hameter.discovery.SubprocessManager")
def test_run_discovery_for_web_records_results(
    mock_spm_cls, config, shutdown_event, app_state
):
    """Parsed meter readings are recorded via app_state."""
    mock_proc = MagicMock()
    mock_spm_cls.return_value = mock_proc
    mock_proc.start_discovery_mode.return_value = True

    calls = [0]

    def get_line(timeout=1.0):
        calls[0] += 1
        lines = [VALID_LINE_1, VALID_LINE_2, VALID_LINE_3]
        if calls[0] <= len(lines):
            return lines[calls[0] - 1]
        shutdown_event.set()
        return None

    mock_proc.get_line.side_effect = get_line

    run_discovery_for_web(
        config, shutdown_event, app_state,
        duration=300, stop_event=None,
    )

    results = app_state.get_discovery_results()
    assert 12345 in results
    assert 67890 in results
    assert results[12345]["count"] >= 2
    mock_proc.stop.assert_called_once()


@patch("hameter.discovery.SubprocessManager")
def test_run_discovery_for_web_start_failure(
    mock_spm_cls, config, shutdown_event, app_state
):
    """Start failure sets ERROR status."""
    mock_proc = MagicMock()
    mock_spm_cls.return_value = mock_proc
    mock_proc.start_discovery_mode.return_value = False

    run_discovery_for_web(
        config, shutdown_event, app_state,
        duration=120, stop_event=None,
    )

    assert app_state.status == PipelineStatus.ERROR
    mock_proc.get_line.assert_not_called()


@patch("hameter.discovery.SubprocessManager")
def test_run_discovery_for_web_respects_stop_event(
    mock_spm_cls, config, shutdown_event, app_state
):
    """stop_event causes early exit."""
    mock_proc = MagicMock()
    mock_spm_cls.return_value = mock_proc
    mock_proc.start_discovery_mode.return_value = True

    stop_event = threading.Event()
    stop_event.set()

    mock_proc.get_line.return_value = VALID_LINE_1

    run_discovery_for_web(
        config, shutdown_event, app_state,
        duration=300, stop_event=stop_event,
    )

    mock_proc.stop.assert_called_once()


@patch("hameter.discovery.SubprocessManager")
def test_run_discovery_for_web_handles_invalid_json(
    mock_spm_cls, config, shutdown_event, app_state
):
    """Invalid lines are skipped without crashing."""
    mock_proc = MagicMock()
    mock_spm_cls.return_value = mock_proc
    mock_proc.start_discovery_mode.return_value = True

    calls = [0]
    lines = [
        "not json",
        "{malformed{{",
        "",
        VALID_LINE_1,
    ]

    def get_line(timeout=1.0):
        calls[0] += 1
        if calls[0] <= len(lines):
            return lines[calls[0] - 1]
        shutdown_event.set()
        return None

    mock_proc.get_line.side_effect = get_line

    run_discovery_for_web(
        config, shutdown_event, app_state,
        duration=300, stop_event=None,
    )

    results = app_state.get_discovery_results()
    assert 12345 in results
    assert len(results) == 1
    mock_proc.stop.assert_called_once()