<?php

declare(strict_types=1);

namespace App\Models;

use Illuminate\Database\Eloquent\Attributes\Fillable;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\MorphTo;

/**
 * One recorded change to one record.
 *
 * Keeps the author's name as well as the link to their account: people leave,
 * accounts get deleted, and "somebody published this in March" is worth less
 * than a name.
 */
#[Fillable(['user_id', 'user_name', 'event', 'changeset'])]
class Revision extends Model
{
    public const UPDATED_AT = null;

    protected function casts(): array
    {
        return ['changeset' => 'array'];
    }

    /**
     * @return MorphTo<Model, $this>
     */
    public function revisionable(): MorphTo
    {
        return $this->morphTo();
    }

    /**
     * @return BelongsTo<User, $this>
     */
    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function author(): string
    {
        // The live name when the account is at hand — people rename
        // themselves — and the recorded one otherwise, including once the
        // account is gone. Never a lazy load: this is read inside table rows.
        if ($this->relationLoaded('user') && $this->user !== null) {
            return $this->user->name;
        }

        return $this->user_name ?? __('panel.revisions.system');
    }

    /**
     * The attributes this revision touched.
     *
     * @return array<int, string>
     */
    public function fields(): array
    {
        return array_keys($this->changeset ?? []);
    }

    /**
     * What a given attribute looked like before and after.
     *
     * @return array{old: mixed, new: mixed}
     */
    public function diff(string $field): array
    {
        return [
            'old' => $this->changeset[$field]['old'] ?? null,
            'new' => $this->changeset[$field]['new'] ?? null,
        ];
    }

    /**
     * The values needed to put a record back the way it was.
     *
     * @return array<string, mixed>
     */
    public function previousValues(): array
    {
        return collect($this->changeset ?? [])
            ->map(fn (array $change) => $change['old'] ?? null)
            ->all();
    }
}