<?php
/**
 * The account's maps as picker options a person can tell apart.
 *
 * @package Mapsemble
 */

namespace Mapsemble;

/**
 * Pure: no WordPress. The caller supplies the date formatter so the unit
 * suite can run without wp_date().
 *
 * Accounts accumulate same-named maps — every starter-kit map starts as "New
 * Map from Starter Kit" — so a label alone does not identify a map. Map ids
 * are UUIDv7, whose first 48 bits are the creation time in milliseconds: the
 * date comes free, with no API change. The short id breaks ties within a day.
 */
final class MapChoices {

	/**
	 * Builds picker options, newest first.
	 *
	 * @param array<array-key, mixed> $maps        Remote maps keyed by id, in Mapsemble's order (oldest first).
	 * @param callable(int): string   $format_date Formats a unix timestamp for display.
	 * @return list<array{value: string, label: string, name: string}> `label` is what the picker shows; `name` is the plain label, for naming a chosen map.
	 */
	public static function options( array $maps, callable $format_date ): array {
		$counts = array();
		foreach ( $maps as $id => $map ) {
			$label            = self::label( (string) $id, $map );
			$counts[ $label ] = ( $counts[ $label ] ?? 0 ) + 1;
		}

		$options = array();
		foreach ( array_reverse( $maps, true ) as $id => $map ) {
			$id    = (string) $id;
			$name  = self::label( $id, $map );
			$label = $name;
			if ( $counts[ $name ] > 1 ) {
				$created = self::created_at( $id );
				$label  .= ' · ' . ( null !== $created ? $format_date( $created ) . ' · ' : '' ) . substr( $id, -4 );
			}
			$options[] = array(
				'value' => $id,
				'label' => $label,
				'name'  => $name,
			);
		}
		return $options;
	}

	/**
	 * The creation time of a map, read from its UUIDv7 id.
	 *
	 * @param string $id Map id.
	 * @return int|null Unix seconds, or null for an id that is not a UUIDv7.
	 */
	public static function created_at( string $id ): ?int {
		$hex = str_replace( '-', '', strtolower( $id ) );
		if ( 32 !== strlen( $hex ) || ! ctype_xdigit( $hex ) || '7' !== $hex[12] ) {
			return null;
		}
		// 48 bits overflow a 32-bit int, so hexdec() returns a float there; a double holds them exactly.
		return (int) floor( hexdec( substr( $hex, 0, 12 ) ) / 1000 );
	}

	/**
	 * A map id short enough to sit in a table cell: its first and last four
	 * characters. Ids of nine characters or fewer are shown whole — shortening
	 * them would save nothing. Counted in characters, not bytes, so a
	 * non-ASCII id is never cut mid-character.
	 *
	 * @param string $id Map id.
	 */
	public static function short_id( string $id ): string {
		return mb_strlen( $id, 'UTF-8' ) > 9
			? mb_substr( $id, 0, 4, 'UTF-8' ) . '…' . mb_substr( $id, -4, null, 'UTF-8' )
			: $id;
	}

	/**
	 * A map's display label: its trimmed label, or its id when it has none.
	 *
	 * @param string $id  Map id.
	 * @param mixed  $map Remote map payload (anything: the API is not trusted to send an array).
	 * @return string
	 */
	public static function label( string $id, $map ): string {
		$raw   = is_array( $map ) ? ( $map['label'] ?? '' ) : '';
		$label = is_scalar( $raw ) ? trim( (string) $raw ) : '';
		return '' !== $label ? $label : $id;
	}
}