"""Tests for the canonical constants module (thechart.core.constants)."""

import os
import sys
from unittest.mock import patch


def _fresh_constants():
    """Import or reload the constants module and return it.

    Ensures a local binding exists in callers to avoid UnboundLocalError
    while supporting env var patching between tests.
    """
    import importlib

    mod_name = "thechart.core.constants"
    if mod_name in sys.modules:
        mod = sys.modules[mod_name]
        return importlib.reload(mod)
    import thechart.core.constants as constants
    return constants


class TestConstants:
    """Test cases for the canonical constants module."""

    def test_default_log_level(self):
        with patch.dict(os.environ, {}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_LEVEL == "INFO"

    def test_custom_log_level(self):
        with patch.dict(os.environ, {"LOG_LEVEL": "debug"}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_LEVEL == "DEBUG"

    def test_default_log_path(self):
        with patch.dict(os.environ, {}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_PATH == "/tmp/logs/thechart"

    def test_custom_log_path(self):
        with patch.dict(os.environ, {"LOG_PATH": "/custom/log/path"}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_PATH == "/custom/log/path"

    def test_default_log_clear(self):
        with patch.dict(os.environ, {}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_CLEAR == "False"

    def test_custom_log_clear_true(self):
        with patch.dict(os.environ, {"LOG_CLEAR": "true"}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_CLEAR == "True"

    def test_custom_log_clear_false(self):
        with patch.dict(os.environ, {"LOG_CLEAR": "false"}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_CLEAR == "False"

    def test_log_level_case_insensitive(self):
        with patch.dict(os.environ, {"LOG_LEVEL": "warning"}, clear=True):
            constants = _fresh_constants()
            assert constants.LOG_LEVEL == "WARNING"

    def test_dotenv_override(self):
        # This is a structural test since dotenv is loaded during import
        with patch("thechart.core.constants.load_dotenv") as mock_load_dotenv:
            import importlib

            name = "thechart.core.constants"
            if name in sys.modules:
                importlib.reload(sys.modules[name])
            else:
                import thechart.core.constants  # noqa: F401

            mock_load_dotenv.assert_called_once_with(override=True)

    def test_all_constants_are_strings(self):
        constants = _fresh_constants()
        assert isinstance(constants.LOG_LEVEL, str)
        assert isinstance(constants.LOG_PATH, str)
        assert isinstance(constants.LOG_CLEAR, str)

    def test_constants_not_empty(self):
        constants = _fresh_constants()
        assert constants.LOG_LEVEL != ""
        assert constants.LOG_PATH != ""
        assert constants.LOG_CLEAR != ""