surrealml-core 0.1.12

//! Defines the constructing and storing of normalisers.
use std::fmt;

use super::traits::Normaliser;
use super::utils::{extract_label, extract_two_numbers};
use super::{clipping, linear_scaling, log_scale, z_score};
use crate::errors::error::{SurrealError, SurrealErrorStatus};
use crate::safe_eject_option;

/// A wrapper for all different types of normalisers.
///
/// # Arguments
/// * `LinearScaling` - A linear scaling normaliser.
/// * `Clipping` - A clipping normaliser.
/// * `LogScaling` - A log scaling normaliser.
/// * `ZScore` - A z-score normaliser.
#[derive(Debug, PartialEq)]
pub enum NormaliserType {
	LinearScaling(linear_scaling::LinearScaling),
	Clipping(clipping::Clipping),
	LogScaling(log_scale::LogScaling),
	ZScore(z_score::ZScore),
}

impl NormaliserType {
	/// Constructs a new normaliser.
	///
	/// # Arguments
	/// * `label` - The label of the normaliser.
	/// * `one` - The first parameter of the normaliser.
	/// * `two` - The second parameter of the normaliser.
	///
	/// # Returns
	/// A new normaliser.
	pub fn new(label: String, one: f32, two: f32) -> Self {
		match label.as_str() {
			"linear_scaling" => NormaliserType::LinearScaling(linear_scaling::LinearScaling {
				min: one,
				max: two,
			}),
			"clipping" => NormaliserType::Clipping(clipping::Clipping {
				min: Some(one),
				max: Some(two),
			}),
			"log_scaling" => NormaliserType::LogScaling(log_scale::LogScaling {
				base: one,
				min: two,
			}),
			"z_score" => NormaliserType::ZScore(z_score::ZScore {
				mean: one,
				std_dev: two,
			}),
			_ => panic!("Invalid normaliser label: {}", label),
		}
	}

	/// Unpacks a normaliser from a string.
	///
	/// # Arguments
	/// * `normaliser_data` - A string containing the normaliser data.
	///
	/// # Returns
	/// (type of normaliser, [normaliser parameters], column name)
	pub fn unpack_normaliser_data(
		normaliser_data: &str,
	) -> Result<(String, [f32; 2], String), SurrealError> {
		let mut normaliser_buffer = normaliser_data.split("=>");

		let column_name = safe_eject_option!(normaliser_buffer.next());
		let normaliser_type = safe_eject_option!(normaliser_buffer.next()).to_string();

		let label = extract_label(&normaliser_type)?;
		let numbers = extract_two_numbers(&normaliser_type)?;
		Ok((label, numbers, column_name.to_string()))
	}

	/// Constructs a normaliser from a string.
	///
	/// # Arguments
	/// * `data` - A string containing the normaliser data.
	///
	/// # Returns
	/// (normaliser, column name)
	pub fn from_string(data: String) -> Result<(Self, String), SurrealError> {
		let (label, numbers, column_name) = Self::unpack_normaliser_data(&data)?;
		let normaliser = match label.as_str() {
			"linear_scaling" => {
				let min = numbers[0];
				let max = numbers[1];
				NormaliserType::LinearScaling(linear_scaling::LinearScaling {
					min,
					max,
				})
			}
			"clipping" => {
				let min = numbers[0];
				let max = numbers[1];
				NormaliserType::Clipping(clipping::Clipping {
					min: Some(min),
					max: Some(max),
				})
			}
			"log_scaling" => {
				let base = numbers[0];
				let min = numbers[1];
				NormaliserType::LogScaling(log_scale::LogScaling {
					base,
					min,
				})
			}
			"z_score" => {
				let mean = numbers[0];
				let std_dev = numbers[1];
				NormaliserType::ZScore(z_score::ZScore {
					mean,
					std_dev,
				})
			}
			_ => {
				let error = SurrealError::new(
					format!("Unknown normaliser type: {}", label).to_string(),
					SurrealErrorStatus::Unknown,
				);
				return Err(error);
			}
		};
		Ok((normaliser, column_name))
	}

	/// Normalises a value.
	///
	/// # Arguments
	/// * `value` - The value to normalise.
	///
	/// # Returns
	/// The normalised value.
	pub fn normalise(&self, value: f32) -> f32 {
		match self {
			NormaliserType::LinearScaling(normaliser) => normaliser.normalise(value),
			NormaliserType::Clipping(normaliser) => normaliser.normalise(value),
			NormaliserType::LogScaling(normaliser) => normaliser.normalise(value),
			NormaliserType::ZScore(normaliser) => normaliser.normalise(value),
		}
	}

	/// Inverse normalises a value.
	///
	/// # Arguments
	/// * `value` - The value to inverse normalise.
	///
	/// # Returns
	/// The inverse normalised value.
	pub fn inverse_normalise(&self, value: f32) -> f32 {
		match self {
			NormaliserType::LinearScaling(normaliser) => normaliser.inverse_normalise(value),
			NormaliserType::Clipping(normaliser) => normaliser.inverse_normalise(value),
			NormaliserType::LogScaling(normaliser) => normaliser.inverse_normalise(value),
			NormaliserType::ZScore(normaliser) => normaliser.inverse_normalise(value),
		}
	}
}

impl fmt::Display for NormaliserType {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
			NormaliserType::LinearScaling(normaliser) => {
				write!(f, "linear_scaling({},{})", normaliser.min, normaliser.max)
			}
			NormaliserType::Clipping(normaliser) => {
				let min = normaliser.min.unwrap_or_default();
				let max = normaliser.max.unwrap_or_default();
				write!(f, "clipping({},{})", min, max)
			}
			NormaliserType::LogScaling(normaliser) => {
				write!(f, "log_scaling({},{})", normaliser.base, normaliser.min)
			}
			NormaliserType::ZScore(normaliser) => {
				write!(f, "z_score({},{})", normaliser.mean, normaliser.std_dev)
			}
		}
	}
}

#[cfg(test)]
mod tests {

	use super::*;

	pub fn generate_string() -> String {
		let normaliser = NormaliserType::LinearScaling(linear_scaling::LinearScaling {
			min: 0.0,
			max: 1.0,
		});
		let column_name = "column_name".to_string();
		format!("{}=>{}", column_name, normaliser)
	}

	#[test]
	fn test_normaliser_type_to_string() {
		let normaliser = NormaliserType::LinearScaling(linear_scaling::LinearScaling {
			min: 0.0,
			max: 1.0,
		});
		assert_eq!(normaliser.to_string(), "linear_scaling(0,1)");
	}

	#[test]
	fn test_normaliser_type_from_string() {
		let normaliser_string = generate_string();
		let (normaliser, column_name) = NormaliserType::from_string(normaliser_string).unwrap();
		assert_eq!(
			normaliser,
			NormaliserType::LinearScaling(linear_scaling::LinearScaling {
				min: 0.0,
				max: 1.0
			})
		);
		assert_eq!(column_name, "column_name");
	}
}