<?php

namespace App\Services;

use Carbon\Carbon;
use getID3;

class Mp3MetadataService
{
    /**
     * Extract tags and duration from a common audio file (MP3, WAV, OGG, FLAC, M4A, etc.).
     *
     * @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 = $this->preferredTags($info);

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

        $duration = isset($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,
        ];
    }

    /**
     * Pick the richest tag set getID3 found for this format.
     *
     * @param  array<string, mixed>  $info
     * @return array<string, mixed>
     */
    private function preferredTags(array $info): array
    {
        $priority = [
            'id3v2',
            'id3v1',
            'vorbiscomment',
            'quicktime',
            'riff',
            'asf',
            'ape',
            'matroska',
        ];

        foreach ($priority as $format) {
            if (! empty($info['tags'][$format]) && is_array($info['tags'][$format])) {
                return $info['tags'][$format];
            }
        }

        if (! empty($info['comments']) && is_array($info['comments'])) {
            return $info['comments'];
        }

        return [];
    }

    /**
     * @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;
    }
}