<?php

namespace App\Services\Runware;

use App\Models\RunwareModel;

/**
 * Pre-flight cost estimation used by BudgetGuard before a Runware call is
 * made. Deliberately conservative — the real cost is always reconciled
 * afterward from Runware's response `cost` field (or, for text, `usage.cost`).
 */
class CostEstimator
{
    protected const DEFAULT_VIDEO_DURATION_SECONDS = 5;

    protected const DEFAULT_TEXT_TOKEN_BUDGET = 2048;

    public function estimateUsd(RunwareModel $model, array $params): float
    {
        return match ($model->unit) {
            'per_image' => (float) $model->price_usd * (int) ($params['numberResults'] ?? 1),
            'per_second' => (float) $model->price_usd * (int) ($params['duration'] ?? self::DEFAULT_VIDEO_DURATION_SECONDS),
            'per_million_tokens' => (float) $model->price_usd
                * (((int) ($params['max_completion_tokens'] ?? self::DEFAULT_TEXT_TOKEN_BUDGET)) / 1_000_000),
        };
    }
}