<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use LogicException;

/**
 * One entry in a poll's append-only ballot ledger. Holds no voter identity.
 * Entries are only ever inserted, through App\Polls\Ledger.
 */
class PollLedgerEntry extends Model
{
    public const CAST = 'cast';
    public const CHANGE = 'change';
    public const WITHDRAW = 'withdraw';
    public const SEAL = 'seal';

    protected $table = 'poll_ledger';

    public $timestamps = false;

    protected $fillable = [
        'poll_id', 'sequence', 'format_version', 'entry_type', 'fingerprint', 'refers_to_sequence',
        'payload', 'recorded_at', 'previous_hash', 'hash',
    ];

    protected $casts = [
        'sequence' => 'integer',
        'format_version' => 'integer',
        'refers_to_sequence' => 'integer',
        'payload' => 'array',
    ];

    protected static function booted(): void
    {
        static::updating(fn () => throw new LogicException('Poll ledger entries cannot be changed.'));
        static::deleting(fn () => throw new LogicException('Poll ledger entries cannot be deleted.'));
    }

    public function poll()
    {
        return $this->belongsTo(Poll::class);
    }

    public function isBallot(): bool
    {
        return in_array($this->entry_type, [self::CAST, self::CHANGE], true);
    }
}