foxhunt/ml/src/error_consolidated.rs

//! Consolidated error handling for the ML module using CommonError
//!
//! This module demonstrates the consolidated error handling pattern
//! using the common error system across all Foxhunt ML services.

use common::error::{CommonError, ErrorCategory, RetryStrategy, ErrorSeverity};

// NO TYPE ALIASES USING RE-EXPORTS - Define directly or import explicitly
// pub type MLResult<T> = CommonResult<T>;

/// ML module specific error extensions
/// For cases where we need domain-specific error information beyond CommonError
#[derive(Debug, thiserror::Error)]
pub enum MLServiceError {
    /// Common error with context
    #[error("ML service error: {0}")]
    Common(#[from] CommonError),

    /// Model training specific error with detailed context
    #[error("Model training error: {model_name} epoch {epoch} - {message}")]
    ModelTraining {
        model_name: String,
        epoch: u32,
        message: String,
    },

    /// Model inference specific error with model context
    #[error("Model inference error: {model_name} - {message}")]
    ModelInference {
        model_name: String,
        message: String,
    },

    /// GPU/Hardware specific error
    #[error("Hardware error: {device} - {message}")]
    Hardware {
        device: String,
        message: String,
    },

    /// Feature extraction error with feature context
    #[error("Feature extraction error: {feature_name} - {message}")]
    FeatureExtraction {
        feature_name: String,
        message: String,
    },

    /// Model validation error with metrics context
    #[error("Model validation error: {model_name} metric {metric} value {value} threshold {threshold}")]
    ModelValidation {
        model_name: String,
        metric: String,
        value: f64,
        threshold: f64,
    },

    /// Data preprocessing error
    #[error("Data preprocessing error: {stage} - {message}")]
    DataPreprocessing {
        stage: String,
        message: String,
    },
}

impl MLServiceError {
    /// Convert to CommonError for metrics and monitoring
    pub fn to_common_error(self) -> CommonError {
        match self {
            MLServiceError::Common(err) => err,
            MLServiceError::ModelTraining { model_name, epoch, message } => {
                CommonError::ml(
                    model_name,
                    format!("Training epoch {}: {}", epoch, message)
                )
            }
            MLServiceError::ModelInference { model_name, message } => {
                CommonError::ml(model_name, format!("Inference: {}", message))
            }
            MLServiceError::Hardware { device, message } => {
                CommonError::service(
                    ErrorCategory::System,
                    format!("Hardware {} error: {}", device, message)
                )
            }
            MLServiceError::FeatureExtraction { feature_name, message } => {
                CommonError::ml(
                    format!("feature_extractor_{}", feature_name),
                    message
                )
            }
            MLServiceError::ModelValidation { model_name, metric, value, threshold } => {
                CommonError::ml(
                    model_name,
                    format!("Validation failed: {} {} < {}", metric, value, threshold)
                )
            }
            MLServiceError::DataPreprocessing { stage, message } => {
                CommonError::service(
                    ErrorCategory::ML,
                    format!("Preprocessing stage {}: {}", stage, message)
                )
            }
        }
    }

    /// Get error category for metrics
    pub fn category(&self) -> ErrorCategory {
        match self {
            MLServiceError::Common(err) => err.category(),
            _ => ErrorCategory::ML,
        }
    }

    /// Get error severity
    pub fn severity(&self) -> ErrorSeverity {
        match self {
            MLServiceError::ModelValidation { .. } => ErrorSeverity::Critical,
            MLServiceError::Hardware { .. } => ErrorSeverity::Critical,
            MLServiceError::ModelTraining { .. } => ErrorSeverity::Error,
            MLServiceError::ModelInference { .. } => ErrorSeverity::Error,
            MLServiceError::FeatureExtraction { .. } => ErrorSeverity::Warn,
            MLServiceError::DataPreprocessing { .. } => ErrorSeverity::Warn,
            MLServiceError::Common(err) => err.severity(),
        }
    }

    /// Get retry strategy
    pub fn retry_strategy(&self) -> RetryStrategy {
        match self {
            MLServiceError::ModelValidation { .. } => RetryStrategy::NoRetry, // Model validation failures are permanent
            MLServiceError::Hardware { .. } => RetryStrategy::NoRetry, // Hardware issues require manual intervention
            MLServiceError::ModelTraining { .. } => RetryStrategy::Linear { base_delay_ms: 5000 }, // Training can retry with delay
            MLServiceError::ModelInference { .. } => RetryStrategy::Immediate, // Inference can retry immediately
            MLServiceError::FeatureExtraction { .. } => RetryStrategy::Linear { base_delay_ms: 1000 },
            MLServiceError::DataPreprocessing { .. } => RetryStrategy::Linear { base_delay_ms: 2000 },
            MLServiceError::Common(err) => err.retry_strategy(),
        }
    }

    /// Check if error is retryable
    pub fn is_retryable(&self) -> bool {
        !matches!(self.retry_strategy(), RetryStrategy::NoRetry)
    }

    /// Get error code for monitoring
    pub fn error_code(&self) -> &'static str {
        match self {
            MLServiceError::Common(_) => "ML_COMMON_ERROR",
            MLServiceError::ModelTraining { .. } => "ML_MODEL_TRAINING_ERROR",
            MLServiceError::ModelInference { .. } => "ML_MODEL_INFERENCE_ERROR",
            MLServiceError::Hardware { .. } => "ML_HARDWARE_ERROR",
            MLServiceError::FeatureExtraction { .. } => "ML_FEATURE_EXTRACTION_ERROR",
            MLServiceError::ModelValidation { .. } => "ML_MODEL_VALIDATION_ERROR",
            MLServiceError::DataPreprocessing { .. } => "ML_DATA_PREPROCESSING_ERROR",
        }
    }
}

/// Convert standard errors to CommonError for consistent handling
impl From<candle_core::Error> for MLServiceError {
    fn from(err: candle_core::Error) -> Self {
        MLServiceError::Common(CommonError::ml("candle", format!("Candle error: {}", err)))
    }
}

impl From<std::io::Error> for MLServiceError {
    fn from(err: std::io::Error) -> Self {
        MLServiceError::Common(CommonError::network(format!("IO error: {}", err)))
    }
}

impl From<serde_json::Error> for MLServiceError {
    fn from(err: serde_json::Error) -> Self {
        MLServiceError::Common(CommonError::serialization(format!("JSON error: {}", err)))
    }
}

impl From<anyhow::Error> for MLServiceError {
    fn from(err: anyhow::Error) -> Self {
        MLServiceError::Common(CommonError::internal(format!("Anyhow error: {}", err)))
    }
}

/// Convenience functions for creating ML service errors
impl MLServiceError {
    /// Create model training error
    pub fn model_training<M: Into<String>, S: Into<String>>(model_name: M, epoch: u32, message: S) -> Self {
        Self::ModelTraining {
            model_name: model_name.into(),
            epoch,
            message: message.into(),
        }
    }

    /// Create model inference error
    pub fn model_inference<M: Into<String>, S: Into<String>>(model_name: M, message: S) -> Self {
        Self::ModelInference {
            model_name: model_name.into(),
            message: message.into(),
        }
    }

    /// Create hardware error
    pub fn hardware<D: Into<String>, M: Into<String>>(device: D, message: M) -> Self {
        Self::Hardware {
            device: device.into(),
            message: message.into(),
        }
    }

    /// Create feature extraction error
    pub fn feature_extraction<F: Into<String>, M: Into<String>>(feature_name: F, message: M) -> Self {
        Self::FeatureExtraction {
            feature_name: feature_name.into(),
            message: message.into(),
        }
    }

    /// Create model validation error
    pub fn model_validation<M: Into<String>, T: Into<String>>(
        model_name: M,
        metric: T,
        value: f64,
        threshold: f64,
    ) -> Self {
        Self::ModelValidation {
            model_name: model_name.into(),
            metric: metric.into(),
            value,
            threshold,
        }
    }

    /// Create data preprocessing error
    pub fn data_preprocessing<S: Into<String>, M: Into<String>>(stage: S, message: M) -> Self {
        Self::DataPreprocessing {
            stage: stage.into(),
            message: message.into(),
        }
    }

    /// Create network error using CommonError
    pub fn network<M: Into<String>>(message: M) -> Self {
        Self::Common(CommonError::network(message))
    }

    /// Create configuration error using CommonError
    pub fn configuration<M: Into<String>>(message: M) -> Self {
        Self::Common(CommonError::config(message))
    }

    /// Create validation error using CommonError
    pub fn validation<F: Into<String>, M: Into<String>>(field: F, message: M) -> Self {
        Self::Common(CommonError::validation(format!("{}: {}", field.into(), message.into())))
    }

    /// Create timeout error using CommonError
    pub fn timeout(actual_ms: u64, max_ms: u64) -> Self {
        Self::Common(CommonError::timeout(actual_ms, max_ms))
    }

    /// Create resource exhausted error using CommonError
    pub fn resource_exhausted<R: Into<String>>(resource: R) -> Self {
        Self::Common(CommonError::resource_exhausted(resource))
    }

    /// Create internal error using CommonError
    pub fn internal<M: Into<String>>(message: M) -> Self {
        Self::Common(CommonError::internal(message))
    }
}

/// Convert to CommonError automatically for interop
impl From<MLServiceError> for CommonError {
    fn from(err: MLServiceError) -> Self {
        err.to_common_error()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_ml_service_error_categorization() {
        let training_error = MLServiceError::model_training("MAMBA-2", 42, "Loss diverged");
        assert_eq!(training_error.category(), ErrorCategory::ML);
        assert_eq!(training_error.error_code(), "ML_MODEL_TRAINING_ERROR");
        assert_eq!(training_error.severity(), ErrorSeverity::Error);

        let validation_error = MLServiceError::model_validation("TFT", "accuracy", 0.75, 0.85);
        assert_eq!(validation_error.severity(), ErrorSeverity::Critical);
        assert!(!validation_error.is_retryable());
    }

    #[test]
    fn test_retry_strategies() {
        let inference_error = MLServiceError::model_inference("TLOB_TRANSFORMER", "CUDA OOM");
        assert!(inference_error.is_retryable());
        assert_eq!(inference_error.retry_strategy(), RetryStrategy::Immediate);

        let hardware_error = MLServiceError::hardware("GPU_0", "Memory allocation failed");
        assert!(!hardware_error.is_retryable());
        assert_eq!(hardware_error.retry_strategy(), RetryStrategy::NoRetry);
    }

    #[test]
    fn test_common_error_integration() {
        let config_error = MLServiceError::configuration("Missing model path");
        let common_error: CommonError = config_error.into();
        
        assert_eq!(common_error.category(), ErrorCategory::Configuration);
        assert_eq!(common_error.severity(), ErrorSeverity::Critical);
        assert!(!common_error.is_retryable());
    }

    #[test]
    fn test_feature_extraction_error() {
        let feature_error = MLServiceError::feature_extraction("TLOB_features", "Invalid orderbook depth");
        assert_eq!(feature_error.category(), ErrorCategory::ML);
        assert_eq!(feature_error.severity(), ErrorSeverity::Warn);
        assert!(feature_error.is_retryable());
        
        match feature_error.retry_strategy() {
            RetryStrategy::Linear { base_delay_ms } => assert_eq!(base_delay_ms, 1000),
            _ => panic!("Expected linear backoff for feature extraction"),
        }
    }

    #[test]
    fn test_error_conversion_chain() {
        let candle_error = candle_core::Error::Msg("Tensor dimension mismatch".to_string());
        let ml_error: MLServiceError = candle_error.into();
        let common_error: CommonError = ml_error.into();
        
        assert_eq!(common_error.category(), ErrorCategory::ML);
        assert!(common_error.to_string().contains("Candle error"));
    }
}