<?php

namespace App\Services;

use Closure;
use Illuminate\Support\Facades\Cache;
use RuntimeException;
use Throwable;

/**
 * Read-through cache for slow third-party API calls.
 *
 * Fresh entries are served instantly, expired entries fall back to the last good value if the
 * upstream call fails, and a short failure cooldown stops every page load waiting on a dead API.
 * The scheduled `integrations:refresh` command runs with $forceRefresh enabled to keep it warm.
 */
class IntegrationCache
{
    private const RETAIN_SECONDS = 86400;

    private const FAILURE_COOLDOWN_SECONDS = 30;

    public bool $forceRefresh = false;

    /**
     * @template TValue
     *
     * @param  Closure(): TValue  $fetch
     * @return TValue
     */
    public function remember(string $key, int $freshSeconds, Closure $fetch, bool $fresh = false): mixed
    {
        $cacheKey = 'integration:'.$key;
        $entry = Cache::get($cacheKey);
        $bypass = $fresh || $this->forceRefresh;

        if (! $bypass && is_array($entry) && time() < $entry['fetched_at'] + $freshSeconds) {
            return $entry['value'];
        }
        if (! $bypass && ! is_array($entry) && ($failure = Cache::get($cacheKey.':failed'))) {
            throw new RuntimeException((string) $failure);
        }

        try {
            $value = $fetch();
        } catch (Throwable $exception) {
            if (is_array($entry)) {
                report($exception);

                return $entry['value'];
            }
            Cache::put($cacheKey.':failed', $exception->getMessage(), self::FAILURE_COOLDOWN_SECONDS);

            throw $exception;
        }

        Cache::put($cacheKey, ['value' => $value, 'fetched_at' => time()], self::RETAIN_SECONDS);
        Cache::forget($cacheKey.':failed');

        return $value;
    }

    public function forget(string $key): void
    {
        Cache::forget('integration:'.$key);
        Cache::forget('integration:'.$key.':failed');
    }
}