<?php
namespace App\Services\Catalog;

use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;
use RuntimeException;

class AmazonCreatorsApiService
{
    public function isConfigured(): bool
    {
        return (bool) config('services.amazon.creators_enabled', false)
            && $this->credentialId() !== ''
            && $this->credentialSecret() !== ''
            && $this->tokenUrl() !== ''
            && $this->apiBaseUrl() !== '';
    }

    public function getMarketplace(): string
    {
        return trim((string) config('services.amazon.marketplace', 'www.amazon.it')) ?: 'www.amazon.it';
    }

    public function getAssociateTag(): ?string
    {
        $tag = trim((string) config('services.amazon.referral_tag', ''));

        return $tag !== '' ? $tag : null;
    }

    /** @return array<string, mixed> */
    public function searchItems(string $keywords, array $parameters = []): array
    {
        $keywords = trim($keywords);
        if ($keywords === '') {
            throw new RuntimeException('Keywords Amazon vuote.');
        }

        return $this->requestOperation('searchItems', array_filter(array_replace([
            'keywords'    => $keywords,
            'marketplace' => $this->getMarketplace(),
            'partnerTag'  => $this->getAssociateTag(),
        ], $parameters), static fn(mixed $value): bool => $value !== null && $value !== ''));
    }

    /** @param array<int, string> $identifiers
     *  @return array<string, mixed>
     */
    public function getItems(array $identifiers, array $parameters = []): array
    {
        $identifiers = array_values(array_filter(array_map(
            static fn(mixed $value): string => trim((string) $value),
            $identifiers
        ), static fn(string $value): bool => $value !== ''));

        if ($identifiers === []) {
            throw new RuntimeException('Specificare almeno un ASIN Amazon.');
        }

        return $this->requestOperation('getItems', array_filter(array_replace([
            'itemIds'     => $identifiers,
            'marketplace' => $this->getMarketplace(),
            'partnerTag'  => $this->getAssociateTag(),
        ], $parameters), static fn(mixed $value): bool => $value !== null && $value !== ''));
    }

    private function credentialId(): string
    {
        return trim((string) config('services.amazon.creators_credential_id', ''));
    }

    private function credentialSecret(): string
    {
        return trim((string) config('services.amazon.creators_credential_secret', ''));
    }

    private function tokenUrl(): string
    {
        return trim((string) config('services.amazon.creators_token_url', ''));
    }

    private function apiBaseUrl(): string
    {
        return rtrim(trim((string) config('services.amazon.creators_api_base_url', '')), '/');
    }

    /** @return array<string, mixed> */
    private function requestOperation(string $operation, array $payload): array
    {
        if (! $this->isConfigured()) {
            throw new RuntimeException('Amazon Creators API non configurata: valorizza le variabili AMAZON_CREATORS_* in ambiente.');
        }

        $path = trim((string) Arr::get(config('services.amazon.creators_paths', []), $operation, ''), '/');
        if ($path === '') {
            throw new RuntimeException('Percorso Creators API mancante per l\'operazione ' . $operation . '.');
        }

        $response = Http::timeout(max(5, (int) config('services.amazon.creators_timeout', 20)))
            ->acceptJson()
            ->asJson()
            ->withToken($this->getAccessToken())
            ->post($this->apiBaseUrl() . '/' . $path, $payload);

        if (! $response->successful()) {
            throw new RuntimeException('Amazon Creators API ' . $operation . ' ha risposto con HTTP ' . $response->status() . ': ' . substr(trim($response->body()), 0, 400));
        }

        $json = $response->json();
        if (! is_array($json)) {
            throw new RuntimeException('Risposta Creators API non valida per ' . $operation . '.');
        }

        return $json;
    }

    private function getAccessToken(): string
    {
        $cacheKey = 'amazon-creators-api-token:' . sha1($this->credentialId() . '|' . $this->tokenUrl());
        $cached   = Cache::get($cacheKey);
        if (is_string($cached) && trim($cached) !== '') {
            return $cached;
        }

        $response = Http::timeout(max(5, (int) config('services.amazon.creators_timeout', 20)))
            ->asForm()
            ->post($this->tokenUrl(), [
                'grant_type'    => 'client_credentials',
                'client_id'     => $this->credentialId(),
                'client_secret' => $this->credentialSecret(),
                'version'       => trim((string) config('services.amazon.creators_credential_version', 'v3.2')) ?: 'v3.2',
            ]);

        if (! $response->successful()) {
            throw new RuntimeException('Token Creators API non ottenuto: HTTP ' . $response->status() . ' ' . substr(trim($response->body()), 0, 300));
        }

        $json = $response->json();
        if (! is_array($json)) {
            throw new RuntimeException('Token Creators API non valido.');
        }

        $token = trim((string) ($json['access_token'] ?? $json['token'] ?? ''));
        if ($token === '') {
            throw new RuntimeException('Risposta token Creators API senza access_token.');
        }

        $expiresIn = max(60, (int) ($json['expires_in'] ?? 3600));
        Cache::put($cacheKey, $token, now()->addSeconds(max(60, $expiresIn - 60)));

        return $token;
    }
}