<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

class ExchangeRateHistory extends Model
{
    protected $table = 'exchange_rate_history';

    protected $fillable = [
        'currency_from',
        'currency_to',
        'old_rate',
        'new_rate',
        'change_percent',
        'change_source',
        'changed_by',
        'api_source',
        'notes',
    ];

    protected $casts = [
        'old_rate' => 'decimal:2',
        'new_rate' => 'decimal:2',
        'change_percent' => 'decimal:4',
    ];

    public function changedBy(): BelongsTo
    {
        return $this->belongsTo(User::class, 'changed_by');
    }

    // Helper برای محاسبه درصد تغییر
    public static function calculateChangePercent($old, $new): ?float
    {
        if (!$old || $old == 0) return null;
        return round((($new - $old) / $old) * 100, 4);
    }

    // Helper برای ثبت تغییر
    public static function recordChange(
        string $from,
        string $to,
        float $oldRate,
        float $newRate,
        string $source = 'manual',
        ?int $userId = null,
        ?string $apiSource = null,
        ?string $notes = null
    ): self {
        return self::create([
            'currency_from' => $from,
            'currency_to' => $to,
            'old_rate' => $oldRate,
            'new_rate' => $newRate,
            'change_percent' => self::calculateChangePercent($oldRate, $newRate),
            'change_source' => $source,
            'changed_by' => $userId,
            'api_source' => $apiSource,
            'notes' => $notes,
        ]);
    }

    // Scope برای آخرین تغییر
    public function scopeLatest($query, string $from = 'AED', string $to = 'IRR')
    {
        return $query->where('currency_from', $from)
                     ->where('currency_to', $to)
                     ->orderBy('created_at', 'desc');
    }
}