"""
Behavioral tests for configuration patterns.

These tests verify the logic of configuration patterns like loading,
validation, merging, environment variables, and defaults
without making actual file system or environment calls.
"""

import re
from dataclasses import dataclass, field


class TestConfigurationLoading:
    """Tests for configuration loading patterns."""

    def test_merge_configs(self):
        """Test merging multiple configuration sources."""

        def merge_configs(*configs):
            result = {}
            for config in configs:
                for key, value in config.items():
                    if (
                        key in result
                        and isinstance(result[key], dict)
                        and isinstance(value, dict)
                    ):
                        result[key] = merge_configs(result[key], value)
                    else:
                        result[key] = value
            return result

        base = {"debug": False, "database": {"host": "localhost", "port": 5432}}
        override = {"debug": True, "database": {"host": "production.db"}}
        result = merge_configs(base, override)
        assert result["debug"] is True
        assert result["database"]["host"] == "production.db"
        assert result["database"]["port"] == 5432

    def test_load_with_defaults(self):
        """Test loading config with default values."""

        def load_with_defaults(config, defaults):
            result = defaults.copy()

            def deep_update(base, updates):
                for key, value in updates.items():
                    if (
                        isinstance(value, dict)
                        and key in base
                        and isinstance(base[key], dict)
                    ):
                        deep_update(base[key], value)
                    else:
                        base[key] = value

            deep_update(result, config)
            return result

        defaults = {"timeout": 30, "retries": 3, "log_level": "INFO"}
        config = {"timeout": 60}
        result = load_with_defaults(config, defaults)
        assert result["timeout"] == 60
        assert result["retries"] == 3

    def test_config_precedence(self):
        """Test configuration source precedence."""

        def resolve_config(sources):
            # Sources in order: defaults, file, env, cli
            result = {}
            for source in sources:
                result.update(source)
            return result

        defaults = {"debug": False, "port": 8080}
        file_config = {"port": 9000}
        env_config = {"port": 8000}
        cli_config = {}

        result = resolve_config([defaults, file_config, env_config, cli_config])
        assert result["port"] == 8000  # Env overrides file

    def test_parse_dotted_key(self):
        """Test parsing dotted notation keys."""

        def set_nested(config, dotted_key, value):
            keys = dotted_key.split(".")
            current = config
            for key in keys[:-1]:
                if key not in current:
                    current[key] = {}
                current = current[key]
            current[keys[-1]] = value
            return config

        config = {}
        set_nested(config, "database.host", "localhost")
        set_nested(config, "database.port", 5432)
        assert config["database"]["host"] == "localhost"
        assert config["database"]["port"] == 5432

    def test_get_nested_value(self):
        """Test getting nested config value."""

        def get_nested(config, dotted_key, default=None):
            keys = dotted_key.split(".")
            current = config
            for key in keys:
                if not isinstance(current, dict) or key not in current:
                    return default
                current = current[key]
            return current

        config = {"database": {"host": "localhost", "port": 5432}}
        assert get_nested(config, "database.host") == "localhost"
        assert get_nested(config, "database.missing", "default") == "default"
        assert get_nested(config, "missing.nested") is None


class TestEnvironmentVariables:
    """Tests for environment variable handling."""

    def test_parse_env_value(self):
        """Test parsing environment variable values."""

        def parse_env_value(value, value_type=str):
            if value_type is bool:
                return value.lower() in ("true", "1", "yes", "on")
            if value_type is int:
                return int(value)
            if value_type is float:
                return float(value)
            if value_type is list:
                return [v.strip() for v in value.split(",")]
            return value

        assert parse_env_value("true", bool) is True
        assert parse_env_value("false", bool) is False
        assert parse_env_value("42", int) == 42
        assert parse_env_value("3.14", float) == 3.14
        assert parse_env_value("a,b,c", list) == ["a", "b", "c"]

    def test_env_var_name_conversion(self):
        """Test converting config key to env var name."""

        def to_env_var_name(key, prefix=""):
            name = key.replace(".", "_").upper()
            if prefix:
                name = f"{prefix}_{name}"
            return name

        assert to_env_var_name("database.host") == "DATABASE_HOST"
        assert to_env_var_name("log_level", prefix="APP") == "APP_LOG_LEVEL"

    def test_expand_env_vars_in_string(self):
        """Test expanding environment variables in strings."""

        def expand_env_vars(value, env_vars):
            pattern = r"\$\{(\w+)\}"
            matches = re.findall(pattern, value)
            for var_name in matches:
                if var_name in env_vars:
                    value = value.replace(
                        f"${{{var_name}}}", env_vars[var_name]
                    )
            return value

        env = {"HOST": "localhost", "PORT": "5432"}
        template = "postgres://user@${HOST}:${PORT}/db"
        result = expand_env_vars(template, env)
        assert result == "postgres://user@localhost:5432/db"

    def test_env_var_with_default(self):
        """Test environment variable with default value."""

        def get_env_with_default(env_vars, key, default=None):
            return env_vars.get(key, default)

        env = {"DEBUG": "true"}
        assert get_env_with_default(env, "DEBUG", "false") == "true"
        assert get_env_with_default(env, "MISSING", "default") == "default"

    def test_required_env_var(self):
        """Test required environment variable validation."""

        def validate_required_env(env_vars, required_vars):
            missing = [var for var in required_vars if var not in env_vars]
            return missing

        env = {"DB_HOST": "localhost"}
        required = ["DB_HOST", "DB_PASSWORD", "SECRET_KEY"]
        missing = validate_required_env(env, required)
        assert "DB_PASSWORD" in missing
        assert "SECRET_KEY" in missing
        assert "DB_HOST" not in missing


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

    def test_validate_required_fields(self):
        """Test validating required configuration fields."""

        def validate_required(config, required_fields):
            errors = []
            for field_name in required_fields:
                parts = field_name.split(".")
                current = config
                for part in parts:
                    if not isinstance(current, dict) or part not in current:
                        errors.append(f"Missing required field: {field_name}")
                        break
                    current = current[part]
            return errors

        config = {"database": {"host": "localhost"}}
        required = ["database.host", "database.port", "api_key"]
        errors = validate_required(config, required)
        assert "Missing required field: database.port" in errors
        assert "Missing required field: api_key" in errors

    def test_validate_type(self):
        """Test validating configuration value types."""

        def validate_types(config, type_spec):
            errors = []
            for key, expected_type in type_spec.items():
                if key in config:
                    value = config[key]
                    if not isinstance(value, expected_type):
                        errors.append(
                            f"{key}: expected {expected_type.__name__}, got {type(value).__name__}"
                        )
            return errors

        config = {"port": "8080", "debug": True, "workers": 4}
        type_spec = {"port": int, "debug": bool, "workers": int}
        errors = validate_types(config, type_spec)
        assert "port: expected int, got str" in errors

    def test_validate_range(self):
        """Test validating numeric range."""

        def validate_range(value, min_val=None, max_val=None):
            if min_val is not None and value < min_val:
                return f"Value {value} is below minimum {min_val}"
            if max_val is not None and value > max_val:
                return f"Value {value} is above maximum {max_val}"
            return None

        assert validate_range(5, min_val=1, max_val=10) is None
        assert validate_range(0, min_val=1) is not None
        assert validate_range(15, max_val=10) is not None

    def test_validate_enum(self):
        """Test validating enum values."""

        def validate_enum(value, allowed_values):
            if value not in allowed_values:
                return (
                    f"Value '{value}' not in allowed values: {allowed_values}"
                )
            return None

        assert validate_enum("DEBUG", ["DEBUG", "INFO", "WARNING"]) is None
        assert validate_enum("TRACE", ["DEBUG", "INFO", "WARNING"]) is not None

    def test_validate_pattern(self):
        """Test validating string patterns."""

        def validate_pattern(value, pattern):
            if not re.match(pattern, value):
                return f"Value '{value}' does not match pattern '{pattern}'"
            return None

        email_pattern = r"^[\w.-]+@[\w.-]+\.\w+$"
        assert validate_pattern("user@example.com", email_pattern) is None
        assert validate_pattern("invalid", email_pattern) is not None


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

    def test_apply_defaults(self):
        """Test applying default values."""

        def apply_defaults(config, defaults):
            result = {}
            for key, default_value in defaults.items():
                if key in config:
                    if isinstance(default_value, dict) and isinstance(
                        config[key], dict
                    ):
                        result[key] = apply_defaults(config[key], default_value)
                    else:
                        result[key] = config[key]
                else:
                    result[key] = default_value
            # Include any keys not in defaults
            for key in config:
                if key not in result:
                    result[key] = config[key]
            return result

        defaults = {"timeout": 30, "retries": 3, "options": {"verbose": False}}
        config = {"timeout": 60, "extra": "value"}
        result = apply_defaults(config, defaults)
        assert result["timeout"] == 60
        assert result["retries"] == 3
        assert result["extra"] == "value"

    def test_lazy_defaults(self):
        """Test lazy default value evaluation."""

        def get_with_lazy_default(config, key, default_fn):
            if key in config:
                return config[key]
            return default_fn()

        config = {"name": "John"}
        # Default function is only called if key is missing
        call_count = {"count": 0}

        def expensive_default():
            call_count["count"] += 1
            return "computed"

        result1 = get_with_lazy_default(config, "name", expensive_default)
        assert result1 == "John"
        assert call_count["count"] == 0  # Not called

        result2 = get_with_lazy_default(config, "missing", expensive_default)
        assert result2 == "computed"
        assert call_count["count"] == 1

    def test_conditional_defaults(self):
        """Test conditional default values."""

        def get_conditional_default(config, env):
            defaults = {
                "development": {"debug": True, "log_level": "DEBUG"},
                "production": {"debug": False, "log_level": "WARNING"},
            }
            return defaults.get(env, defaults["development"])

        dev_defaults = get_conditional_default({}, "development")
        assert dev_defaults["debug"] is True

        prod_defaults = get_conditional_default({}, "production")
        assert prod_defaults["debug"] is False

    def test_default_factory(self):
        """Test default value factory functions."""

        @dataclass
        class Config:
            name: str = "default"
            tags: list = field(default_factory=list)
            settings: dict = field(default_factory=dict)

        config1 = Config()
        config2 = Config()

        # Factory creates new instances
        config1.tags.append("test")
        assert config2.tags == []  # Not affected

    def test_inherit_defaults(self):
        """Test inheriting defaults from parent config."""

        def inherit_defaults(child, parent):
            result = parent.copy()
            result.update(child)
            return result

        parent = {"timeout": 30, "retries": 3}
        child = {"timeout": 60, "custom": True}
        result = inherit_defaults(child, parent)
        assert result["timeout"] == 60
        assert result["retries"] == 3
        assert result["custom"] is True


class TestConfigProfiles:
    """Tests for configuration profiles/environments."""

    def test_load_profile(self):
        """Test loading configuration profile."""

        def load_profile(configs, profile_name):
            base = configs.get("base", {})
            profile = configs.get(profile_name, {})
            return {**base, **profile}

        configs = {
            "base": {"app_name": "MyApp", "debug": False},
            "development": {"debug": True, "database": "dev.db"},
            "production": {"database": "prod.db"},
        }

        dev_config = load_profile(configs, "development")
        assert dev_config["debug"] is True
        assert dev_config["app_name"] == "MyApp"

        prod_config = load_profile(configs, "production")
        assert prod_config["debug"] is False

    def test_detect_environment(self):
        """Test detecting current environment."""

        def detect_environment(env_vars, default="development"):
            env_names = ["ENV", "ENVIRONMENT", "NODE_ENV", "APP_ENV"]
            for name in env_names:
                if name in env_vars:
                    return env_vars[name]
            return default

        assert detect_environment({"ENV": "production"}) == "production"
        assert detect_environment({"NODE_ENV": "test"}) == "test"
        assert detect_environment({}) == "development"

    def test_profile_override(self):
        """Test overriding specific profile settings."""

        def apply_override(config, overrides, env):
            # Apply base config
            result = config.get("base", {}).copy()
            # Apply environment-specific
            result.update(config.get(env, {}))
            # Apply overrides
            result.update(overrides)
            return result

        config = {
            "base": {"debug": False, "port": 8080},
            "development": {"debug": True},
        }
        overrides = {"port": 9000}
        result = apply_override(config, overrides, "development")
        assert result["debug"] is True
        assert result["port"] == 9000

    def test_feature_flags(self):
        """Test feature flag configuration."""

        def is_feature_enabled(features, feature_name, default=False):
            return features.get(feature_name, default)

        features = {"new_ui": True, "beta_api": False}
        assert is_feature_enabled(features, "new_ui") is True
        assert is_feature_enabled(features, "beta_api") is False
        assert is_feature_enabled(features, "missing", default=True) is True

    def test_toggle_features_by_env(self):
        """Test toggling features by environment."""

        def get_features(env):
            features = {
                "development": {"debug_toolbar": True, "mock_api": True},
                "production": {"debug_toolbar": False, "mock_api": False},
            }
            return features.get(env, features["production"])

        dev_features = get_features("development")
        assert dev_features["debug_toolbar"] is True

        prod_features = get_features("production")
        assert prod_features["debug_toolbar"] is False


class TestConfigSecrets:
    """Tests for handling sensitive configuration."""

    def test_mask_secret_values(self):
        """Test masking secret values in output."""

        def mask_secrets(config, secret_keys):
            result = {}
            for key, value in config.items():
                if key in secret_keys:
                    result[key] = "***MASKED***"
                elif isinstance(value, dict):
                    result[key] = mask_secrets(value, secret_keys)
                else:
                    result[key] = value
            return result

        config = {
            "database": {"host": "localhost", "password": "secret123"},
            "api_key": "abc123",
        }
        masked = mask_secrets(config, {"password", "api_key"})
        assert masked["database"]["password"] == "***MASKED***"
        assert masked["api_key"] == "***MASKED***"
        assert masked["database"]["host"] == "localhost"

    def test_detect_secrets_in_config(self):
        """Test detecting potential secrets in config."""

        def detect_secrets(config, secret_patterns):
            findings = []
            for key, value in config.items():
                if isinstance(value, dict):
                    findings.extend(detect_secrets(value, secret_patterns))
                elif isinstance(value, str):
                    for pattern in secret_patterns:
                        if re.match(pattern, key, re.IGNORECASE):
                            findings.append(key)
                            break
            return findings

        patterns = [
            r".*password.*",
            r".*secret.*",
            r".*api_key.*",
            r".*token.*",
        ]
        config = {
            "db_password": "secret",
            "user_name": "john",
            "api_token": "abc123",
        }
        secrets = detect_secrets(config, patterns)
        assert "db_password" in secrets
        assert "api_token" in secrets
        assert "user_name" not in secrets

    def test_validate_secret_strength(self):
        """Test validating secret strength."""

        def validate_secret_strength(secret, min_length=8):
            errors = []
            if len(secret) < min_length:
                errors.append(f"Must be at least {min_length} characters")
            if not re.search(r"[A-Z]", secret):
                errors.append("Must contain uppercase letter")
            if not re.search(r"[a-z]", secret):
                errors.append("Must contain lowercase letter")
            if not re.search(r"\d", secret):
                errors.append("Must contain digit")
            return errors

        errors = validate_secret_strength("weak")
        assert len(errors) > 0

        errors = validate_secret_strength("StrongPass123")
        assert len(errors) == 0

    def test_rotate_secret_check(self):
        """Test checking if secret needs rotation."""
        import time

        def needs_rotation(secret_metadata, max_age_days=90):
            created_at = secret_metadata.get("created_at", 0)
            age_days = (time.time() - created_at) / (24 * 3600)
            return age_days > max_age_days

        old_secret = {"created_at": time.time() - (100 * 24 * 3600)}
        new_secret = {"created_at": time.time()}

        assert needs_rotation(old_secret) is True
        assert needs_rotation(new_secret) is False


class TestConfigSchema:
    """Tests for configuration schema validation."""

    def test_schema_definition(self):
        """Test defining configuration schema."""

        schema = {
            "type": "object",
            "properties": {
                "name": {"type": "string", "required": True},
                "port": {"type": "integer", "min": 1, "max": 65535},
                "debug": {"type": "boolean", "default": False},
            },
        }

        def validate_property(value, prop_schema):
            prop_type = prop_schema.get("type")
            if prop_type == "string" and not isinstance(value, str):
                return f"Expected string, got {type(value).__name__}"
            if prop_type == "integer" and not isinstance(value, int):
                return f"Expected integer, got {type(value).__name__}"
            if prop_type == "boolean" and not isinstance(value, bool):
                return f"Expected boolean, got {type(value).__name__}"
            if "min" in prop_schema and value < prop_schema["min"]:
                return f"Value {value} below minimum {prop_schema['min']}"
            if "max" in prop_schema and value > prop_schema["max"]:
                return f"Value {value} above maximum {prop_schema['max']}"
            return None

        assert validate_property("test", schema["properties"]["name"]) is None
        assert validate_property(8080, schema["properties"]["port"]) is None
        assert (
            validate_property(70000, schema["properties"]["port"]) is not None
        )

    def test_nested_schema_validation(self):
        """Test nested schema validation."""

        def validate_nested(config, schema):
            errors = []
            for key, value in config.items():
                if key not in schema:
                    continue
                prop_schema = schema[key]
                if prop_schema.get("type") == "object" and isinstance(
                    value, dict
                ):
                    nested_errors = validate_nested(
                        value, prop_schema.get("properties", {})
                    )
                    errors.extend([f"{key}.{e}" for e in nested_errors])
                elif prop_schema.get("type") == "string" and not isinstance(
                    value, str
                ):
                    errors.append(f"{key}: expected string")
                elif prop_schema.get("type") == "integer" and not isinstance(
                    value, int
                ):
                    errors.append(f"{key}: expected integer")
            return errors

        schema = {
            "database": {
                "type": "object",
                "properties": {
                    "host": {"type": "string"},
                    "port": {"type": "integer"},
                },
            }
        }
        config = {
            "database": {"host": "localhost", "port": "5432"}
        }  # port is string
        errors = validate_nested(config, schema)
        assert "database.port: expected integer" in errors

    def test_array_schema_validation(self):
        """Test array schema validation."""

        def validate_array(value, item_schema):
            if not isinstance(value, list):
                return "Expected array"
            errors = []
            for i, item in enumerate(value):
                if item_schema.get("type") == "string" and not isinstance(
                    item, str
                ):
                    errors.append(f"Item {i}: expected string")
                if item_schema.get("type") == "integer" and not isinstance(
                    item, int
                ):
                    errors.append(f"Item {i}: expected integer")
            return errors if errors else None

        assert validate_array(["a", "b", "c"], {"type": "string"}) is None
        errors = validate_array(["a", 1, "c"], {"type": "string"})
        assert "Item 1: expected string" in errors

    def test_apply_schema_defaults(self):
        """Test applying schema defaults."""

        def apply_schema_defaults(config, schema):
            result = config.copy()
            for key, prop_schema in schema.items():
                if key not in result and "default" in prop_schema:
                    result[key] = prop_schema["default"]
                elif prop_schema.get("type") == "object" and key in result:
                    result[key] = apply_schema_defaults(
                        result[key], prop_schema.get("properties", {})
                    )
            return result

        schema = {
            "debug": {"type": "boolean", "default": False},
            "timeout": {"type": "integer", "default": 30},
        }
        config = {"debug": True}
        result = apply_schema_defaults(config, schema)
        assert result["debug"] is True
        assert result["timeout"] == 30


class TestConfigurationWatch:
    """Tests for configuration watching/reloading."""

    def test_detect_config_changes(self):
        """Test detecting configuration changes."""

        def has_changed(old_config, new_config):
            return old_config != new_config

        old = {"debug": True, "port": 8080}
        new_same = {"debug": True, "port": 8080}
        new_different = {"debug": True, "port": 9000}

        assert has_changed(old, new_same) is False
        assert has_changed(old, new_different) is True

    def test_diff_configs(self):
        """Test getting differences between configs."""

        def diff_configs(old_config, new_config):
            changes = {"added": {}, "removed": {}, "modified": {}}
            all_keys = set(old_config.keys()) | set(new_config.keys())

            for key in all_keys:
                if key not in old_config:
                    changes["added"][key] = new_config[key]
                elif key not in new_config:
                    changes["removed"][key] = old_config[key]
                elif old_config[key] != new_config[key]:
                    changes["modified"][key] = {
                        "old": old_config[key],
                        "new": new_config[key],
                    }
            return changes

        old = {"a": 1, "b": 2, "c": 3}
        new = {"a": 1, "b": 5, "d": 4}
        diff = diff_configs(old, new)
        assert "d" in diff["added"]
        assert "c" in diff["removed"]
        assert "b" in diff["modified"]

    def test_notify_config_change(self):
        """Test notifying on config change."""

        class ConfigWatcher:
            def __init__(self):
                self.callbacks = []

            def on_change(self, callback):
                self.callbacks.append(callback)

            def notify(self, old_config, new_config):
                for callback in self.callbacks:
                    callback(old_config, new_config)

        watcher = ConfigWatcher()
        changes = []
        watcher.on_change(lambda old, new: changes.append((old, new)))

        watcher.notify({"a": 1}, {"a": 2})
        assert len(changes) == 1
        assert changes[0] == ({"a": 1}, {"a": 2})

    def test_hot_reload_safety(self):
        """Test safe hot reload validation."""

        def can_hot_reload(changed_keys, hot_reloadable_keys):
            # Check if all changed keys can be hot reloaded
            return all(key in hot_reloadable_keys for key in changed_keys)

        hot_reloadable = {"log_level", "cache_ttl", "feature_flags"}
        assert can_hot_reload(["log_level"], hot_reloadable) is True
        assert can_hot_reload(["database_url"], hot_reloadable) is False

    def test_config_version(self):
        """Test configuration versioning."""

        def bump_version(config):
            version = config.get("_version", 0)
            return {**config, "_version": version + 1}

        config = {"debug": True}
        v1 = bump_version(config)
        v2 = bump_version(v1)
        assert v1["_version"] == 1
        assert v2["_version"] == 2
