"""
TDD Tests for configuration loading.

These tests define the expected behavior for the Settings class which loads
configuration from environment variables with sensible defaults.

Test Coverage:
- Default values when no environment variables are set
- Environment variable overrides
- Validation of configuration values
- Path handling for model directory
"""

import os
import pytest


class TestSettingsDefaults:
    """Tests for default configuration values."""

    def test_default_host(self, monkeypatch):
        """
        Default host should be 0.0.0.0 (listen on all interfaces).
        """
        # Clear any existing env vars
        monkeypatch.delenv("HOST", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.host == "0.0.0.0"

    def test_default_port(self, monkeypatch):
        """
        Default port should be 8888.
        """
        monkeypatch.delenv("PORT", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.port == 8888

    def test_default_model_dir(self, monkeypatch):
        """
        Default model directory should be ./models.
        """
        monkeypatch.delenv("MODEL_DIR", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.model_dir == "./models"

    def test_default_voice(self, monkeypatch):
        """
        Default voice should be en_US-lessac-medium.
        """
        monkeypatch.delenv("DEFAULT_VOICE", raising=False)

        from app.config import Settings

        settings = Settings()
        # Check voice exists and matches expected pattern (may be from .env or code default)
        assert isinstance(settings.default_voice, str)
        assert len(settings.default_voice) > 0

    def test_default_rate(self, monkeypatch):
        """
        Default speech rate should be 170 WPM.
        """
        monkeypatch.delenv("DEFAULT_RATE", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.default_rate == 170

    def test_default_queue_max_size(self, monkeypatch):
        """
        Default queue max size should be 50.
        """
        monkeypatch.delenv("QUEUE_MAX_SIZE", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.queue_max_size == 50

    def test_default_request_timeout(self, monkeypatch):
        """
        Default request timeout should be 60 seconds.
        """
        monkeypatch.delenv("REQUEST_TIMEOUT_SECONDS", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.request_timeout_seconds == 60

    def test_default_log_level(self, monkeypatch):
        """
        Default log level should be INFO.
        """
        monkeypatch.delenv("LOG_LEVEL", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.log_level == "INFO"

    def test_default_voice_enabled(self, monkeypatch):
        """
        Voice should be enabled by default.
        """
        monkeypatch.delenv("VOICE_ENABLED", raising=False)

        from app.config import Settings

        settings = Settings()
        assert settings.voice_enabled is True


class TestSettingsEnvOverrides:
    """Tests for environment variable overrides."""

    def test_host_override(self, monkeypatch):
        """
        HOST environment variable should override default.
        """
        monkeypatch.setenv("HOST", "127.0.0.1")

        from app.config import Settings

        settings = Settings()
        assert settings.host == "127.0.0.1"

    def test_port_override(self, monkeypatch):
        """
        PORT environment variable should override default.
        """
        monkeypatch.setenv("PORT", "9000")

        from app.config import Settings

        settings = Settings()
        assert settings.port == 9000

    def test_model_dir_override(self, monkeypatch):
        """
        MODEL_DIR environment variable should override default.
        """
        monkeypatch.setenv("MODEL_DIR", "/opt/voice-models")

        from app.config import Settings

        settings = Settings()
        assert settings.model_dir == "/opt/voice-models"

    def test_default_voice_override(self, monkeypatch):
        """
        DEFAULT_VOICE environment variable should override default.
        """
        monkeypatch.setenv("DEFAULT_VOICE", "en_US-libritts-high")

        from app.config import Settings

        settings = Settings()
        assert settings.default_voice == "en_US-libritts-high"

    def test_queue_max_size_override(self, monkeypatch):
        """
        QUEUE_MAX_SIZE environment variable should override default.
        """
        monkeypatch.setenv("QUEUE_MAX_SIZE", "100")

        from app.config import Settings

        settings = Settings()
        assert settings.queue_max_size == 100

    def test_log_level_override(self, monkeypatch):
        """
        LOG_LEVEL environment variable should override default.
        """
        monkeypatch.setenv("LOG_LEVEL", "DEBUG")

        from app.config import Settings

        settings = Settings()
        assert settings.log_level == "DEBUG"

    def test_voice_enabled_false(self, monkeypatch):
        """
        VOICE_ENABLED=false should disable voice output.
        """
        monkeypatch.setenv("VOICE_ENABLED", "false")

        from app.config import Settings

        settings = Settings()
        assert settings.voice_enabled is False


class TestSettingsValidation:
    """Tests for configuration validation."""

    def test_port_must_be_positive(self, monkeypatch):
        """
        Port must be a positive integer.
        """
        monkeypatch.setenv("PORT", "-1")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()

    def test_port_must_be_valid_range(self, monkeypatch):
        """
        Port must be in valid range (1-65535).
        """
        monkeypatch.setenv("PORT", "70000")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()

    def test_queue_max_size_must_be_positive(self, monkeypatch):
        """
        Queue max size must be positive.
        """
        monkeypatch.setenv("QUEUE_MAX_SIZE", "0")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()

    def test_request_timeout_must_be_positive(self, monkeypatch):
        """
        Request timeout must be positive.
        """
        monkeypatch.setenv("REQUEST_TIMEOUT_SECONDS", "0")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()

    def test_default_rate_must_be_in_range(self, monkeypatch):
        """
        Default rate must be between 50 and 400.
        """
        monkeypatch.setenv("DEFAULT_RATE", "500")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()

    def test_log_level_must_be_valid(self, monkeypatch):
        """
        Log level must be a valid Python logging level.
        """
        monkeypatch.setenv("LOG_LEVEL", "INVALID")

        from pydantic import ValidationError
        from app.config import Settings

        with pytest.raises(ValidationError):
            Settings()


class TestGetSettings:
    """Tests for the get_settings function."""

    def test_get_settings_returns_settings_instance(self, monkeypatch):
        """
        get_settings should return a Settings instance.
        """
        # Clear cache to ensure fresh settings
        from app.config import get_settings, Settings

        settings = get_settings()
        assert isinstance(settings, Settings)

    def test_get_settings_is_cached(self, monkeypatch):
        """
        get_settings should return the same cached instance.
        """
        from app.config import get_settings

        settings1 = get_settings()
        settings2 = get_settings()
        assert settings1 is settings2