//! Machine Learning Format Implementations
//!
//! This module provides serialization support for machine learning formats,
//! particularly ONNX (Open Neural Network Exchange) for ML model interoperability.

// Imports needed by both real implementations and stubs
#[allow(unused_imports)]
use super::common::{SerializationFormat, SerializationOptions, TensorMetadata};
#[allow(unused_imports)]
use crate::{Tensor, TensorElement};
#[allow(unused_imports)]
use std::path::Path;
#[allow(unused_imports)]
use torsh_core::error::{Result, TorshError};

/// ONNX format implementation
#[cfg(feature = "serialize-onnx")]
pub mod onnx {
    use super::*;

    /// Serialize tensor to ONNX format
    ///
    /// Creates an ONNX model file containing the tensor data.
    /// Used for ML model interoperability between frameworks.
    ///
    /// # Arguments
    /// * `tensor` - Tensor to serialize
    /// * `path` - Output file path
    /// * `options` - Serialization options
    ///
    /// # Returns
    /// * `Result<()>` - Ok if successful, error otherwise
    pub fn serialize_onnx<T: TensorElement>(
        tensor: &Tensor<T>,
        _path: &Path,
        options: &SerializationOptions,
    ) -> Result<()> {
        // TODO: Implement ONNX serialization using onnx-rs crate
        let _metadata = TensorMetadata::from_tensor(
            tensor,
            options,
            SerializationFormat::Onnx,
            tensor.numel() * std::mem::size_of::<T>(),
        );

        Err(TorshError::SerializationError(
            "ONNX serialization not yet implemented".to_string(),
        ))
    }

    /// Deserialize tensor from ONNX format
    ///
    /// # Arguments
    /// * `path` - Input file path
    ///
    /// # Returns
    /// * `Result<Tensor<T>>` - Deserialized tensor or error
    pub fn deserialize_onnx<T: TensorElement>(path: &Path) -> Result<Tensor<T>> {
        let _ = path;
        Err(TorshError::SerializationError(
            "ONNX deserialization not yet implemented".to_string(),
        ))
    }
}

/// Stub implementation when ONNX feature is not enabled
#[cfg(not(feature = "serialize-onnx"))]
pub mod onnx {
    use super::*;

    pub fn serialize_onnx<T: TensorElement>(
        _tensor: &Tensor<T>,
        _path: &Path,
        _options: &SerializationOptions,
    ) -> Result<()> {
        Err(TorshError::SerializationError(
            "ONNX serialization requires the 'serialize-onnx' feature to be enabled".to_string(),
        ))
    }

    pub fn deserialize_onnx<T: TensorElement>(_path: &Path) -> Result<Tensor<T>> {
        Err(TorshError::SerializationError(
            "ONNX deserialization requires the 'serialize-onnx' feature to be enabled".to_string(),
        ))
    }
}
