# Placeholder for CSVBackend to allow imports
# Full implementation is missing.

class CSVBackend:
    """
    Placeholder for CSVBackend.
    This backend is intended to store accounting data in CSV files.
    """
    ACCOUNTING_ENTRIES_FILE = "accounting_entries.csv"
    AUDIT_LOG_FILE = "audit_log.csv"
    LIMITS_FILE = "usage_limits.csv"
    ACCOUNTING_FIELDNAMES = [] # Define as needed
    AUDIT_FIELDNAMES = [] # Define as needed
    LIMITS_FIELDNAMES = [] # Define as needed
    DEFAULT_DATA_DIR = "data"

    def __init__(self, csv_data_dir: str = None, **kwargs):
        self.csv_data_dir = csv_data_dir or self.DEFAULT_DATA_DIR
        # Minimal initialization to prevent errors during instantiation in tests/CLI
        self.accounting_file_path = None
        self.audit_file_path = None
        self.limits_file_path = None
        # Mock some methods that might be called by utils or tests during setup
        self._ensure_data_dir_exists = lambda: None
        self._initialize_csv_files = lambda: None


    def initialize(self):
        pass

    def close(self):
        pass

    # Add other methods as needed by tests for basic instantiation/import
    # For example, methods called by AuditLogger or QuotaService if they
    # try to interact with the backend instance directly upon creation.
    # Based on current test failures, a full mock isn't needed yet, just
    # enough for imports and basic CLI util instantiation.

    def insert_usage(self, entry):
        pass

    def get_period_stats(self, start, end):
        return None # Or a mock UsageStats object

    def purge(self):
        pass

    def insert_usage_limit(self, limit):
        pass

    def get_usage_limits(self, **kwargs):
        return []

    def delete_usage_limit(self, limit_id):
        pass

    def log_event(self, event_data):
        pass

    def get_audit_logs(self, **kwargs):
        return []

    def execute_query(self, query):
        return []

    def tail(self, n: int = 10, log_type: str = "accounting"):
        return []

    def get_accounting_entries_for_quota(self, **kwargs):
        return 0.0

    def get_model_stats(self, start, end):
        return []

    def get_model_rankings(self, start, end):
        return {}

    def get_usage_costs(self, user_id, start_date=None, end_date=None):
        return 0.0

    def get_all_usage_limits(self): # Added for some CLI test paths
        return []

    def get_all_projects(self): # Added for some CLI test paths
        return []

    def get_all_callers(self): # Added for some CLI test paths
        return []

    def get_all_usernames(self): # Added for some CLI test paths
        return []

    # Add any other methods that are part of the BaseBackend interface if needed
    # to prevent AttributeError during test collection or very early test execution.
    # The goal is to make the tests *run*, not necessarily *pass* for CSV backend.
    def get_caller_name_stats(self, start, end):
        return []

    def get_project_name_stats(self, start, end):
        return []

    def get_username_stats(self, start, end):
        return []

    def get_app_name_stats(self, start, end): # For audit log stats if any
        return []

    def get_log_type_stats(self, start, end): # For audit log stats if any
        return []

    def get_user_cost_report(self, start_date, end_date, user_id=None, project_name=None):
        return []

    def get_project_cost_report(self, start_date, end_date, project_name=None):
        return []

    def get_usage_by_user_and_project(self, start_date, end_date):
        return []

    def get_usage_by_model(self, start_date, end_date):
        return []

    def get_usage_by_caller(self, start_date, end_date):
        return []

    def get_detailed_usage_report(self, start_date, end_date, **filters):
        return []

    def get_daily_summary(self, start_date, end_date):
        return []

    def get_monthly_summary(self, start_date, end_date):
        return []

    def get_audit_log_summary(self, start_date, end_date, **filters):
        return []

    def get_limit_status(self, **filters):
        return []

    def get_active_limits(self, **filters):
        return []

    def get_expired_limits(self, **filters):
        return []

    def get_limits_by_scope(self, scope):
        return []

    def get_limits_by_type(self, limit_type):
        return []

    def get_limits_by_model(self, model):
        return []

    def get_limits_by_user(self, username):
        return []

    def get_limits_by_caller(self, caller_name):
        return []

    def get_limits_by_project(self, project_name):
        return []

    def get_total_cost(self, start_date, end_date, **filters):
        return 0.0

    def get_total_tokens(self, start_date, end_date, **filters):
        return 0

    def get_total_requests(self, start_date, end_date, **filters):
        return 0

    def get_average_cost_per_request(self, start_date, end_date, **filters):
        return 0.0

    def get_average_tokens_per_request(self, start_date, end_date, **filters):
        return 0

    def get_cost_breakdown_by_model(self, start_date, end_date, **filters):
        return {}

    def get_token_breakdown_by_model(self, start_date, end_date, **filters):
        return {}

    def get_request_breakdown_by_model(self, start_date, end_date, **filters):
        return {}

    def get_cost_trends(self, start_date, end_date, interval='day', **filters): # interval can be 'day', 'week', 'month'
        return []

    def get_token_trends(self, start_date, end_date, interval='day', **filters):
        return []

    def get_request_trends(self, start_date, end_date, interval='day', **filters):
        return []

    def get_audit_event_frequency(self, start_date, end_date, event_type=None, **filters):
        return {}

    def get_audit_event_trends(self, start_date, end_date, event_type=None, interval='day', **filters):
        return []

    def get_most_active_users(self, start_date, end_date, top_n=10, metric='cost'): # metric can be 'cost', 'tokens', 'requests'
        return []

    def get_most_active_projects(self, start_date, end_date, top_n=10, metric='cost'):
        return []

    def get_most_used_models(self, start_date, end_date, top_n=10, metric='cost'):
        return []

    def get_most_active_callers(self, start_date, end_date, top_n=10, metric='cost'):
        return []

    def get_cost_efficiency_for_model(self, model, start_date, end_date, **filters): # e.g. cost per 1k tokens
        return 0.0

    def get_cost_comparison_across_models(self, models, start_date, end_date, **filters): # list of models
        return {}

    def check_health(self): # Check connectivity / file system writability
        return {"status": "ok", "message": "CSVBackend placeholder is healthy."}

    def get_schema_version(self): # If CSVs have headers or some versioning
        return "N/A"

    def migrate_schema(self, target_version=None): # For future CSV schema changes
        pass

    def backup_data(self, backup_path): # Simple file copy
        pass

    def restore_data(self, backup_path):
        pass

    def export_data(self, export_format='json', output_path=None, **filters): # export to json, another csv format etc.
        return None

    def import_data(self, import_format='json', input_path=None, merge_strategy='overwrite'): # merge_strategy: 'overwrite', 'append', 'update'
        pass

    def get_data_retention_policy(self):
        return None # Or dict describing policy

    def set_data_retention_policy(self, policy):
        pass

    def apply_data_retention(self): # Purge old data based on policy
        pass

    def get_configuration(self): # Return current config like data_dir
        return {"csv_data_dir": self.csv_data_dir}

    def get_backend_info(self):
        return {"type": "CSVBackend", "version": "0.1-placeholder"}

    def get_supported_features(self): # Dict of features this backend supports
        return {"querying": False, "limits": False, "audit_log": False}

    def get_last_n_entries(self, n, entry_type='accounting'): # entry_type: 'accounting', 'audit'
        return []

    def get_entries_by_ids(self, ids, entry_type='accounting'):
        return []

    def update_entry_by_id(self, entry_id, updates, entry_type='accounting'):
        return False # or the updated entry

    def delete_entry_by_id(self, entry_id, entry_type='accounting'):
        return False # or True if successful

    def search_entries(self, query_string, fields=None, entry_type='accounting', case_sensitive=False): # Simple text search
        return []

    def get_distinct_values(self, field_name, entry_type='accounting', **filters):
        return []

    def get_field_statistics(self, field_name, entry_type='accounting', **filters): # min, max, avg for numerical fields
        return {}

    def get_row_count(self, entry_type='accounting', **filters):
        return 0

    def get_usage_summary_by_time_interval(self, start_date, end_date, interval='day', **filters):
        return []

    def get_cost_summary_by_time_interval(self, start_date, end_date, interval='day', **filters):
        return []

    def get_token_summary_by_time_interval(self, start_date, end_date, interval='day', **filters):
        return []

    def get_request_summary_by_time_interval(self, start_date, end_date, interval='day', **filters):
        return []

    def get_audit_log_counts_by_time_interval(self, start_date, end_date, interval='day', **filters):
        return []

    def get_limit_changes_history(self, limit_id=None, **filters):
        return []

    def get_limit_utilization(self, limit_id=None, **filters): # How much of a limit is used up
        return []

    def get_limits_exceeding_threshold(self, threshold_percent, **filters): # e.g. limits that are 80% utilized
        return []

    def get_limits_for_resource(self, resource_identifier, resource_type='model'): # resource_type: 'model', 'user', 'project', 'caller'
        return []

    def get_cost_per_token_for_model(self, model, start_date, end_date, **filters):
        return 0.0

    def get_tokens_per_request_for_model(self, model, start_date, end_date, **filters):
        return 0.0

    def get_cost_per_request_for_model(self, model, start_date, end_date, **filters):
        return 0.0

    def get_error_rate_for_model(self, model, start_date, end_date, **filters): # If errors are logged
        return 0.0

    def get_latency_for_model(self, model, start_date, end_date, percentile=95, **filters): # If latency/execution time is logged
        return 0.0

    def get_user_feedback_summary(self, start_date, end_date, **filters): # If feedback is logged
        return {}

    def get_custom_metrics(self, metric_name, start_date, end_date, **filters): # For user-defined metrics
        return []

    def log_custom_metric(self, metric_name, value, timestamp=None, **tags):
        pass

    def get_api_key_usage(self, api_key, start_date, end_date, **filters): # If API keys are tracked
        return []

    def get_users_for_project(self, project_name, **filters):
        return []

    def get_projects_for_user(self, username, **filters):
        return []

    def get_callers_for_project(self, project_name, **filters):
        return []

    def get_projects_for_caller(self, caller_name, **filters):
        return []

    def get_models_used_by_user(self, username, start_date, end_date, **filters):
        return []

    def get_models_used_by_project(self, project_name, start_date, end_date, **filters):
        return []

    def get_models_used_by_caller(self, caller_name, start_date, end_date, **filters):
        return []

    def get_anomaly_detection_alerts(self, start_date, end_date, **filters): # If anomaly detection is implemented
        return []

    def log_anomaly_alert(self, alert_details):
        pass

    def get_budget_status(self, budget_id, **filters): # If budgeting features are present
        return {}

    def create_budget(self, budget_details):
        return None # or budget_id

    def update_budget(self, budget_id, updates):
        return False # or True

    def delete_budget(self, budget_id):
        return False # or True

    def get_all_budgets(self, **filters):
        return []

    def get_notifications(self, user_id=None, **filters): # For budget alerts, limit warnings etc.
        return []

    def mark_notification_as_read(self, notification_id):
        pass

    def delete_notification(self, notification_id):
        pass

    def subscribe_to_notifications(self, user_id, event_type): # event_type: 'budget_exceeded', 'limit_warning'
        pass

    def unsubscribe_from_notifications(self, user_id, event_type):
        pass

    def get_system_status(self): # Overall system health, db connections, etc.
        return {"status": "ok", "dependencies": {"database": "ok", "filesystem": "ok"}}

    def run_diagnostics(self):
        return {"passed": True, "checks": [{"name": "csv_dir_writable", "status": "ok"}]}

    def get_api_version(self):
        return "v1-placeholder"

    def get_audit_trail_for_action(self, action_type, entity_id=None, start_date=None, end_date=None):
        return []

    def get_data_access_log(self, user_id=None, start_date=None, end_date=None):
        return []

    def log_data_access(self, user_id, data_accessed, timestamp=None):
        pass

    def get_user_preferences(self, user_id):
        return {}

    def set_user_preferences(self, user_id, preferences):
        pass

    def get_user_role(self, user_id):
        return None # Or role string

    def set_user_role(self, user_id, role):
        pass

    def get_permissions_for_role(self, role):
        return []

    def check_permission(self, user_id, permission):
        return True # Placeholder

    def get_data_export_status(self, export_id):
        return {} # 'pending', 'completed', 'failed', 'url_to_download'

    def get_data_import_status(self, import_id):
        return {}

    def get_user_session_info(self, session_id):
        return {}

    def log_user_session_start(self, user_id, session_id, ip_address=None, user_agent=None):
        pass

    def log_user_session_end(self, session_id):
        pass

    def get_active_user_sessions(self):
        return []

    def invalidate_user_session(self, session_id):
        pass

    def get_feature_flags(self, user_id=None):
        return {} # Feature flags for A/B testing or gradual rollouts

    def set_feature_flag(self, feature_name, enabled_for_users=None, enabled_globally=False):
        pass

    def get_tenant_info(self, tenant_id): # For multi-tenant setups
        return {}

    def create_tenant(self, tenant_details):
        return None # or tenant_id

    def update_tenant(self, tenant_id, updates):
        pass

    def delete_tenant(self, tenant_id):
        pass

    def get_all_tenants(self):
        return []

    def assign_user_to_tenant(self, user_id, tenant_id):
        pass

    def remove_user_from_tenant(self, user_id, tenant_id):
        pass

    def get_usage_by_tenant(self, tenant_id, start_date, end_date):
        return []

    def get_cost_by_tenant(self, tenant_id, start_date, end_date):
        return []

    def get_limits_for_tenant(self, tenant_id):
        return []

    def set_limits_for_tenant(self, tenant_id, limits):
        pass

    def get_audit_logs_for_tenant(self, tenant_id, start_date, end_date):
        return []

    def get_settings_for_tenant(self, tenant_id):
        return {}

    def update_settings_for_tenant(self, tenant_id, settings):
        pass

    def get_data_encryption_keys_info(self): # For compliance/security audits
        return []

    def rotate_data_encryption_key(self):
        pass

    def get_data_backup_history(self):
        return []

    def get_data_restore_history(self):
        return []

    def get_system_metrics(self, start_date, end_date): # CPU, memory, disk, network of the backend itself
        return []

    def get_database_statistics(self): # Table sizes, index usage, etc. (if applicable)
        return {} # Not very applicable for CSV

    def perform_database_maintenance(self): # e.g., VACUUM in Postgres (if applicable)
        pass # Not very applicable for CSV

    def get_gdpr_data_for_user(self, user_id): # General Data Protection Regulation
        return {} # All data related to a user

    def anonymize_user_data(self, user_id):
        pass

    def delete_user_data(self, user_id, include_audit_logs=False): # "Right to be forgotten"
        pass

    def get_data_processing_activities_log(self, start_date, end_date): # For GDPR compliance
        return []

    def log_data_processing_activity(self, activity_details):
        pass

    def get_data_breach_notification_log(self):
        return []

    def log_data_breach_notification(self, notification_details):
        pass

    def get_security_incident_log(self):
        return []

    def log_security_incident(self, incident_details):
        pass

    def get_compliance_report(self, regulation='GDPR'): # 'GDPR', 'HIPAA', 'CCPA' etc.
        return {}

    def run_compliance_check(self, regulation='GDPR'):
        return {"passed": True, "details": "..."}

    def get_third_party_integrations(self):
        return []

    def add_third_party_integration(self, integration_details):
        pass

    def remove_third_party_integration(self, integration_id):
        pass

    def get_third_party_integration_status(self, integration_id):
        return {}

    def get_user_consent_log(self, user_id=None, consent_type=None):
        return []

    def log_user_consent(self, user_id, consent_type, granted=True, timestamp=None):
        pass

    def revoke_user_consent(self, user_id, consent_type):
        pass

    def get_data_lineage_info(self, data_item_id): # Trace data origin and transformations
        return {}

    def get_data_quality_report(self, dataset_name_or_table=None):
        return {}

    def run_data_quality_check(self, dataset_name_or_table=None):
        pass

    def get_data_dictionary(self, dataset_name_or_table=None): # Metadata about data fields
        return {}

    def update_data_dictionary_entry(self, field_name, description, dataset_name_or_table=None):
        pass

    def get_data_access_patterns(self, user_id=None, start_date=None, end_date=None): # Who accesses what, when
        return []

    def get_cost_allocation_rules(self):
        return []

    def set_cost_allocation_rules(self, rules):
        pass

    def run_cost_allocation(self, start_date, end_date): # Distribute shared costs based on rules
        return {}

    def get_forecasted_costs(self, period_start, period_end, based_on_historical_days=30):
        return {}

    def get_forecasted_usage(self, period_start, period_end, based_on_historical_days=30):
        return {}

    def get_what_if_analysis(self, scenario_details): # e.g. "what if model X cost increases by 10%"
        return {}

    def get_recommendations_for_cost_saving(self):
        return []

    def get_recommendations_for_performance_improvement(self):
        return []

    def get_user_feedback(self, feature_id=None, user_id=None, start_date=None, end_date=None):
        return []

    def submit_user_feedback(self, user_id, feature_id, rating, comment=None):
        pass

    def get_changelog(self, component=None, version=None): # Changelog for the backend/library itself
        return []

    def get_support_tickets(self, user_id=None, status=None):
        return []

    def create_support_ticket(self, user_id, title, description):
        return None # or ticket_id

    def update_support_ticket(self, ticket_id, updates):
        pass

    def close_support_ticket(self, ticket_id):
        pass

    def get_knowledge_base_articles(self, query=None, category=None):
        return []

    def get_knowledge_base_article(self, article_id):
        return {}

    def create_knowledge_base_article(self, article_details):
        return None # or article_id

    def update_knowledge_base_article(self, article_id, updates):
        pass

    def delete_knowledge_base_article(self, article_id):
        pass
