<?php

namespace TFGraphics\SmartImport\Search;

use TFGraphics\SmartImport\Domain\Search\SearchRequest;
use TFGraphics\SmartImport\Domain\Search\SearchResult;

final class SearchCache
{
    // Cache lineage: a schema or identity-policy change must receive a new
    // namespace so stale canonical products cannot bypass the current merge.
    // Build 0122 advances the positive-result namespace to v11.
    // Build 0096 used v8, the first 0097 candidate used v9 and bounded
    // multi-provider discovery used v10. Identifier enrichment now has a
    // stricter trust contract, so old cards must not bypass it from cache.
    private const TRANSIENT_PREFIX = 'tfsi_search_positive_v16_';
    private const DEFAULT_TTL_SECONDS = 900;

    private array $storage = [];
    private int $ttlSeconds;

    public function __construct(int $ttlSeconds = self::DEFAULT_TTL_SECONDS)
    {
        $this->ttlSeconds = max(60, $ttlSeconds);
    }

    public function createCacheKey(SearchRequest $request): string
    {
        $preferredProviders = implode(',', $request->getPreferredProviders());

        $diagnosticVersion = $request->getMediaType() === 'medicine' ? 'aifa_diag_0161|' : '';
        $identityPolicyVersion = $request->getMediaType() === 'medicine' ? '' : 'identity_media_conflict_v1|';
        $completionVersion = $request->isIdentifierSearch() && $request->getMediaType() !== 'medicine' ? 'identifier_source_recovery_v8|' : '';
        return sha1($completionVersion . $identityPolicyVersion . $diagnosticVersion . sprintf(
            '%s|%s|%s|%s|%s|%s|%s|%d|%d',
            $this->normalizeQuery($request),
            $request->getSearchType() ?? '',
            $request->getSearchIntent() ?? '',
            $request->getMediaType(),
            $this->normalizeBrand($request->getBrand()),
            $preferredProviders,
            $request->getExecutionMode(),
            $request->getLimit(),
            $request->getOffset()
        ));
    }

    public function has(string $key): bool
    {
        if (isset($this->storage[$key])) { return true; }
        if (! function_exists('get_transient')) { return false; }
        $cached = get_transient(self::TRANSIENT_PREFIX . $key);
        if (! $cached instanceof SearchResult) { return false; }
        $this->storage[$key] = $cached;
        return true;
    }

    public function get(string $key): SearchResult
    {
        $result = $this->storage[$key];
        $trace = $result->getProviderTrace();
        foreach ($trace as &$attempt) {
            if (! is_array($attempt)) { continue; }
            $attempt['cached_snapshot'] = true;
            $attempt['reason'] = '[historical provider snapshot] ' . (string) ($attempt['reason'] ?? '');
            $attempt['historical_response_time_ms'] = (float) ($attempt['response_time_ms'] ?? 0.0);
            $attempt['response_time_ms'] = 0.0;
        }
        unset($attempt);
        $trace[] = [
            'provider' => 'SearchCache',
            'status' => ProviderStatus::CACHED_POSITIVE,
            'result_count' => count($result->getItems()),
            'ttl_seconds' => $this->ttlSeconds,
            'cached_provider_attempts' => $result->getProviderAttempts(),
            'cached_provider_response_time_ms' => $result->getProviderResponseTimeMs(),
            'response_time_ms' => 0.0,
        ];

        return new SearchResult(
            $result->getItems(),
            $result->getTotal(),
            $result->getProviderUsed(),
            $result->getProviderFallbackFrom(),
            0,
            0.0,
            $trace,
            $result->getAppliedOffset(),
            $result->getRemoteTotal(),
            $result->getKnownQualifiedTotal(),
            $result->hasRemoteContinuation(),
            $result->getProviderContinuations()
        );
    }

    public function store(string $key, SearchResult $result): void
    {
        $this->storage[$key] = $result;
        if (function_exists('set_transient')) {
            set_transient(self::TRANSIENT_PREFIX . $key, $result, $this->ttlSeconds);
        }
    }

    private function normalizeQuery(SearchRequest $request): string
    {
        $query = trim($request->getQuery());
        if ($request->isIdentifierSearch()) {
            return strtoupper((string) preg_replace('/[^A-Z0-9]/i', '', $query));
        }
        $query = function_exists('mb_strtolower') ? mb_strtolower($query, 'UTF-8') : strtolower($query);
        return trim((string) preg_replace('/\s+/u', ' ', $query));
    }

    private function normalizeBrand(string $brand): string
    {
        $brand = function_exists('mb_strtolower') ? mb_strtolower(trim($brand), 'UTF-8') : strtolower(trim($brand));
        return trim((string) preg_replace('/\s+/u', ' ', $brand));
    }
}