<?php

namespace App\Services;

use App\Http\Controllers\Admin\ProductController;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;

class PriceBroadcastService
{
    private const LAST_HASH_KEY = 'ws_broadcast:last_hash';

    private const LIST_HASH_KEY = 'ws_broadcast:list_hash';

    /**
     * montzar فقط trigger «price_update» را به کلاینت‌ها relay می‌کند.
     *
     * @param array<string, mixed>|null $lastPayload
     */
    public function broadcastAfterPriceUpdate(?array $lastPayload = null, bool $force = false): void
    {
        $ws = app(WebsocketBroadcastService::class);
        if (! $ws->isEnabled()) {
            return;
        }

        if ($force) {
            $ws->sendEvent('price_update', []);

            return;
        }

        if ($lastPayload === null) {
            $cache = app(LivePriceCacheService::class);
            $lastPayload = $cache->get() ?? $cache->buildFromDatabase();
        }

        $lastChanged = is_array($lastPayload) && $lastPayload !== []
            && $this->rememberHashIfChanged(self::LAST_HASH_KEY, $lastPayload);

        $listPayload = $this->buildProductListPayload();
        $listChanged = $listPayload !== null
            && $this->rememberHashIfChanged(self::LIST_HASH_KEY, $listPayload);

        if ($lastChanged || $listChanged) {
            $ws->sendEvent('price_update', []);
        }
    }

    /**
     * @param array<string, mixed>|array<int, mixed> $payload
     */
    private function rememberHashIfChanged(string $cacheKey, array $payload): bool
    {
        $hash = md5(json_encode($payload, JSON_UNESCAPED_UNICODE));
        if (Cache::get($cacheKey) === $hash) {
            return false;
        }

        Cache::put($cacheKey, $hash, now()->addHour());

        return true;
    }

    /**
     * @return array<int, mixed>|null
     */
    private function buildProductListPayload(): ?array
    {
        $request = Request::create('/customer/product/list', 'GET');
        app()->instance('request', $request);

        $response = app(ProductController::class)->listProduct();
        $decoded = json_decode($response->getContent(), true);

        return is_array($decoded) ? $decoded : null;
    }
}