//! Dictionary update algorithms

use scirs2_core::ndarray::Array2;
#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};
use sklears_core::{error::Result, types::Float};

/// Update algorithms
#[derive(Debug, Clone, Copy)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum UpdateAlgorithm {
    SVD,
    GradientDescent,
    Newton,
}

/// Update configuration
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct UpdateConfig {
    pub algorithm: UpdateAlgorithm,
    pub learning_rate: Float,
}

impl Default for UpdateConfig {
    fn default() -> Self {
        Self {
            algorithm: UpdateAlgorithm::SVD,
            learning_rate: 0.01,
        }
    }
}

/// Dictionary update result
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct DictionaryUpdateResult {
    pub updated_dictionary: Array2<Float>,
    pub convergence_error: Float,
}

/// Dictionary updater
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct DictionaryUpdater {
    config: UpdateConfig,
}

/// Atom updater utility
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct AtomUpdater;

impl DictionaryUpdater {
    pub fn new(config: UpdateConfig) -> Self {
        Self { config }
    }

    pub fn update(
        &self,
        dictionary: &Array2<Float>,
        _data: &Array2<Float>,
        _codes: &Array2<Float>,
    ) -> Result<DictionaryUpdateResult> {
        let updated_dictionary = dictionary.clone();
        let convergence_error = 0.0;

        Ok(DictionaryUpdateResult {
            updated_dictionary,
            convergence_error,
        })
    }
}
