1.php

<?php
namespace F3\Changelog;

use Composer\Semver\Semver;
use F3\Changelog\Exception\NoTagsFound;
use F3\Changelog\Exception\TagNotFound;

class ReleaseNotes
{
    /**
     * @var GitGateway
     */
    private $git;

    public function write(Printer $printer, string $tag = null)
    {
        $tags = $this->git->getTags();
        if (empty($tags)) {
            throw new NoTagsFound();
        }
        $tags = Semver::rsort($tags);
        $tag = $tag ?: reset($tags);
        $index = array_search($tag, $tags);
        if (false === $index) {
            throw new TagNotFound($tag);
        }
        if (++$index < count($tags)) {
            $release = new SubsequentRelease($this->git, $tags[$index], $tag);
        } else {
            $release = new Release($this->git, $tag);
        }
        $release->printHeader($printer);
        $release->printChanges($printer);
    }
}