<?php

namespace alveolata\structures;


require_once(DIR_ALVEOLATA . '/structures/pair/functions.php');


/**
 * @template type_key
 * @template type_value
 */
class struct_subject_map
{
	
	/**
	 * @var array {list<&struct_subject_pair<§type_key,§type_value>>}
	 */
	public $pairs;
	
	
	/**
	 * @param array {list<&struct_subject_pair<§type_key,§type_value>>}
	 */
	public function __construct(
		array $pairs
	)
	{
		$this->pairs = $pairs;
	}
	
}


/**
 * @template type_key
 * @template type_value
 * @param array {list<record<key:§type_key,value:§type_value>>}
 * @return struct_subject_map<type_key,type_value>
 */
function map_make(
	array $pairs = []
)
{
	return (new struct_subject_map($pairs));
}


/**
 * @template type_key
 * @template type_value
 * @param struct_subject_map<type_key,type_value> $subject
 * @param type_key $key
 * @return bool
 */
function map_has(
	\Closure $collate_key,
	struct_subject_map $subject,
	$key
) : bool
{
	foreach ($subject->pairs as $pair) {
		if ($collate_key($key, $pair->first)) {
			return true;
		}
	}
	return false;
}


/**
 * @template type_key
 * @template type_value
 * @param struct_subject_map<type_key,type_value> $subject
 * @param type_key $key
 * @return type_value
 * @throws \Exception if not found
 */
function map_get(
	\Closure $collate_key,
	struct_subject_map $subject,
	$key
)
{
	foreach ($subject->pairs as $pair) {
		if ($collate_key($key, $pair->first)) {
			return $pair->second;
		}
	}
	throw (new \Exception('not found'));
}


/**
 * @template type_key
 * @template type_value
 * @param struct_subject_map<type_key,type_value> $subject
 * @param type_key $key
 * @param type_value $value
 */
function map_set(
	\Closure $collate_key,
	struct_subject_map $subject,
	$key, 
	$value
) : void
{
	$found = false;
	foreach ($subject->pairs as &$pair) {
		if ($collate_key($key, $pair->first)) {
			$pair->second = $value;
			$found = true;
			break;
		}
	}
	unset($pair);
	if (! $found) {
		$pair = \alveolata\structures\pair_make($key, $value);
		array_push($subject->pairs, $pair);
	}
}


/**
 * @template type_key
 * @template type_value
 * @param struct_subject_map<type_key,type_value> $subject
 * @param \Closure $procedure {function<§type_key,§type_value,void>}
 */
function map_iterate(
	struct_subject_map $subject,
	\Closure $procedure
) : void
{
	foreach ($subject->pairs as $pair) {
		$procedure($pair->first, $pair->second);
	}
}

 ?>