<?php

namespace App\Services;

use Carbon\Carbon;
use getID3;

class Mp3MetadataService
{
    /**
     * Extract ID3 and audio metadata from an MP3 file on disk.
     *
     * @return array{
     *     title: ?string,
     *     artist: ?string,
     *     album: ?string,
     *     duration_seconds: ?int,
     *     recorded_at: ?string
     * }
     */
    public function extract(string $absolutePath): array
    {
        $analyzer = new getID3;
        $info = $analyzer->analyze($absolutePath);

        $tags = [];
        if (isset($info['tags']['id3v2'])) {
            $tags = $info['tags']['id3v2'];
        } elseif (isset($info['tags']['id3v1'])) {
            $tags = $info['tags']['id3v1'];
        }

        $title = $this->firstTag($tags, 'title');
        $artist = $this->firstTag($tags, 'artist');
        $album = $this->firstTag($tags, 'album');
        $year = $this->firstTag($tags, 'year') ?? $this->firstTag($tags, 'recording_time');

        $duration = isset($info['playtime_seconds'])
            ? (int) round((float) $info['playtime_seconds'])
            : null;

        $recordedAt = null;
        if (filled($year) && preg_match('/^\d{4}/', $year)) {
            try {
                $recordedAt = Carbon::parse($year)->toDateTimeString();
            } catch (\Throwable) {
                $recordedAt = null;
            }
        }

        return [
            'title' => $title,
            'artist' => $artist,
            'album' => $album,
            'duration_seconds' => $duration,
            'recorded_at' => $recordedAt,
        ];
    }

    /**
     * @param  array<string, mixed>  $tags
     */
    private function firstTag(array $tags, string $key): ?string
    {
        if (! isset($tags[$key])) {
            return null;
        }

        $value = $tags[$key];

        if (is_array($value)) {
            $value = $value[0] ?? null;
        }

        return filled($value) ? (string) $value : null;
    }
}