<?php
declare(strict_types=1);

namespace Esun\Reward\Model;

class TierResolver
{
    public function __construct(private readonly Config $config) {}

    public function resolve(float $lifetimeSpend, ?int $storeId = null): array
    {
        $tiers = $this->config->tiers($storeId);
        $current = $tiers[0];
        $nextThreshold = null;

        foreach ($tiers as $tier) {
            if ($lifetimeSpend >= $tier['threshold']) {
                $current = $tier;
                continue;
            }
            $nextThreshold = $tier['threshold'];
            break;
        }

        return [
            'code' => $current['code'],
            'label' => $current['label'],
            'multiplier' => $current['multiplier'],
            'next_threshold' => $nextThreshold,
        ];
    }

    public function resolveEffective(string $savedTierCode, float $lifetimeSpend, ?int $storeId = null): array
    {
        $tiers = $this->config->tiers($storeId);
        $computed = $this->resolve($lifetimeSpend, $storeId);
        $byCode = [];
        foreach ($tiers as $position => $tier) {
            $byCode[$tier['code']] = ['position' => $position, 'tier' => $tier];
        }
        if (!isset($byCode[$savedTierCode])) {
            return $computed;
        }
        $saved = $byCode[$savedTierCode];
        $computedPosition = $byCode[$computed['code']]['position'] ?? 0;
        if ($saved['position'] <= $computedPosition) {
            return $computed;
        }
        $nextThreshold = $tiers[$saved['position'] + 1]['threshold'] ?? null;
        return [
            'code' => $saved['tier']['code'],
            'label' => $saved['tier']['label'],
            'multiplier' => $saved['tier']['multiplier'],
            'next_threshold' => $nextThreshold,
        ];
    }
}