<?php
/**
 * Blood glucose threshold storage and sanitisation.
 *
 * @package SugarCalc
 */

declare(strict_types=1);

namespace SugarCalc;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Manages the sugarcalc_thresholds option: clinical defaults, retrieval, sanitisation, and persistence.
 */
class Thresholds {

	public const OPTION_KEY = 'sugarcalc_thresholds';

	/**
	 * Return evidence-based default threshold values.
	 *
	 * @return array<string, float|string>
	 */
	public static function defaults(): array {
		return array(
			// Critical high — aligned with 2024 ICR consensus (Umpierrez et al.).
			'ketoacidosis_threshold'    => 11.1,

			// Type 1 — NICE NG17 2022.
			'type1_fasting_min'         => 4.0,
			'type1_fasting_max'         => 7.0,
			'type1_post_meal_min'       => 5.0,
			'type1_post_meal_max'       => 9.0,

			// Type 2 — ADA 2024 (upper); universal hypo floor (lower).
			'type2_fasting_min'         => 4.0,
			'type2_fasting_max'         => 7.2,
			'type2_post_meal_min'       => 5.0,
			'type2_post_meal_max'       => 10.0,

			// Gestational — NICE NG3 / ADA 2024 (stored; not yet used by Calculator widget).
			'gestational_fasting_min'   => 4.0,
			'gestational_fasting_max'   => 5.3,
			'gestational_post_meal_min' => 4.0,
			'gestational_post_meal_max' => 7.8,

			'default_diabetes_type'     => 'type1',
			'default_meal_timing'       => 'fasting',
		);
	}

	/**
	 * Return the active thresholds, merged over defaults.
	 *
	 * @return array<string, float|string>
	 */
	public static function get(): array {
		$saved = get_option( self::OPTION_KEY, array() );
		if ( ! is_array( $saved ) ) {
			$saved = array();
		}

		return array_merge( self::defaults(), $saved );
	}

	/**
	 * Sanitise raw POST data into a clean thresholds array with range clamping.
	 *
	 * @param array<string, mixed> $data Raw input data to sanitise.
	 * @return array<string, float|string>
	 */
	public static function sanitise( array $data ): array {
		$defaults = self::defaults();
		$clean    = array();

		$float_keys = array(
			'ketoacidosis_threshold',
			'type1_fasting_min',
			'type1_fasting_max',
			'type1_post_meal_min',
			'type1_post_meal_max',
			'type2_fasting_min',
			'type2_fasting_max',
			'type2_post_meal_min',
			'type2_post_meal_max',
			'gestational_fasting_min',
			'gestational_fasting_max',
			'gestational_post_meal_min',
			'gestational_post_meal_max',
		);

		foreach ( $float_keys as $key ) {
			$val           = (float) ( $data[ $key ] ?? $defaults[ $key ] );
			$clean[ $key ] = max( 0.1, min( 50.0, $val ) );
		}

		$clean['default_diabetes_type'] = in_array( $data['default_diabetes_type'] ?? '', array( 'type1', 'type2' ), true )
			? (string) $data['default_diabetes_type']
			: (string) $defaults['default_diabetes_type'];

		$clean['default_meal_timing'] = in_array( $data['default_meal_timing'] ?? '', array( 'fasting', 'postMeal' ), true )
			? (string) $data['default_meal_timing']
			: (string) $defaults['default_meal_timing'];

		return $clean;
	}

	/**
	 * Sanitise and persist thresholds to the database.
	 *
	 * @param array<string, mixed> $data Raw input data to sanitise and save.
	 */
	public static function save( array $data ): void {
		update_option( self::OPTION_KEY, self::sanitise( $data ) );
	}
}