<?php

namespace App\Models;

use App\Enums\EntryType;
use Illuminate\Database\Eloquent\Factories\HasFactory;

/**
 * transaction_entries — DOUBLE-ENTRY LEDGER
 *
 * Every transaction MUST have exactly 2 entries (debit + credit).
 * balance_after_minor is the wallet balance snapshot after this entry.
 * This table is the source of truth for all balance calculations.
 *
 * @property int $transaction_id
 * @property int $wallet_id
 * @property string $entry_type     debit/credit
 * @property int $amount_minor      BIGINT
 * @property int $balance_after_minor  BIGINT — snapshot after this entry
 */
class TransactionEntry extends BaseModel
{
    use HasFactory;

    protected $fillable = [
        'transaction_id',
        'wallet_id',
        'entry_type',
        'amount_minor',
        'balance_after_minor',
    ];

    protected $casts = [
        'entry_type'          => EntryType::class,
        'amount_minor'        => 'integer',
        'balance_after_minor' => 'integer',
    ];

    public $timestamps = false; // created_at only, set via useCurrent()

    // ── Relationships ──

    public function transaction()
    {
        return $this->belongsTo(Transaction::class);
    }

    public function wallet()
    {
        return $this->belongsTo(Wallet::class);
    }

    // ── Scopes ──

    public function scopeDebits($query)
    {
        return $query->where('entry_type', EntryType::DEBIT);
    }

    public function scopeCredits($query)
    {
        return $query->where('entry_type', EntryType::CREDIT);
    }

    public function scopeForWallet($query, int $walletId)
    {
        return $query->where('wallet_id', $walletId);
    }

    // ── Reconciliation helper ──

    /**
     * Verify double-entry integrity: SUM(debits) must equal SUM(credits)
     * for the given transaction_id.
     */
    public static function verifyIntegrity(int $transactionId): bool
    {
        $debits  = self::where('transaction_id', $transactionId)->debits()->sum('amount_minor');
        $credits = self::where('transaction_id', $transactionId)->credits()->sum('amount_minor');

        return $debits === $credits && $debits > 0;
    }
}