<?php

declare(strict_types=1);

namespace App\Agent;

use App\Commerce\ShopSearchService;
use App\Config\AgentRunnerConfig;
use App\Context\ContextService;
use App\Context\UrlAnalyzer;
use App\Infrastructure\OllamaClient;
use App\Intent\CommerceIntentLite;
use App\Knowledge\Retrieval\RetrieverInterface;
use Generator;
use Psr\Log\LoggerInterface;
use Throwable;

final readonly class AgentRunner
{
    private bool $systemMsgOn;

    public function __construct(
        private PromptBuilder      $promptBuilder,
        private ThinkSuppressor    $thinkSuppressor,
        private ContextService     $contextService,
        private UrlAnalyzer        $urlAnalyzer,
        private RetrieverInterface $retriever,
        private ShopSearchService  $shopSearchService,
        private CommerceIntentLite $commerceIntentLite,
        private OllamaClient       $ollamaClient,
        private LoggerInterface    $agentLogger,
        private AgentRunnerConfig  $agentRunnerConfig,
        private bool               $debug,
        private bool               $logPrompt,
        private bool               $logContext,
    )
    {
        $this->systemMsgOn = true;
    }

    public function run(string $prompt, string $userId, ?bool $includeFullContext = false): Generator
    {
        $prompt = trim($prompt);
        $swagFullOutPut = '';
        $firstThinkLoop = true;
        $shopResults = [];

        if ($prompt === '') {
            yield '❌ Empty prompt.';
            return;
        }

        $this->agentLogger->info('Agent run started', [
            'userId' => $userId,
        ]);

        try {
            // ---------------------------------------------------------
            // 1) Context strategy
            // ---------------------------------------------------------

            if ($includeFullContext) {
                //Coming soon
            }

            yield $this->systemMsg("Ich analysiere deine Anfrage...", "think");

            // ---------------------------------------------------------
            // 2) Extract URL content (if present)
            // ---------------------------------------------------------
            yield $this->systemMsg("Ich prüfe auf Internet Quellen...", "think");
            $urlContent = $this->urlAnalyzer->extractContentFromPrompt($prompt);

            // ---------------------------------------------------------
            // 3) Retrieve RAG knowledge
            // ---------------------------------------------------------
            yield $this->systemMsg("Ich hole relevante Daten aus meinem RAG Wissen...", "think");
            $knowledgeChunks = $this->retriever->retrieve($prompt);

            // ---------------------------------------------------------
            // 4) commerce/shop search
            // ---------------------------------------------------------

            $commerceMeta = $this->commerceIntentLite->detect($prompt);
            $commerceIntent = (string)($commerceMeta['intent'] ?? CommerceIntentLite::NONE);

            if ($commerceIntent === CommerceIntentLite::PRODUCT_SEARCH || $commerceIntent === CommerceIntentLite::ADVISORY_PRODUCT_SEARCH) {
                //PreOptimize swag search query
                $promptSwagSearch = $this->agentRunnerConfig->getShopPrompt($prompt);

                //Reset thinkSuppressor
                $this->thinkSuppressor->reset();

                yield $this->systemMsg("Ich optimere die Recherche...", "think");

                //Call ai for optimized swag query
                foreach ($this->ollamaClient->stream($promptSwagSearch) as $swagToken) {

                    if (!is_string($swagToken)) {
                        continue;
                    }

                    $swagCleanToken = $this->thinkSuppressor->filter($swagToken);

                    if ($swagCleanToken === '') {
                        continue;
                    }

                    $swagFullOutPut .= $swagCleanToken;
                }

                yield $this->systemMsg("Ich rufe Recherchedaten ab (type: " . $commerceIntent . ")", "think");

                //Search in swag by ai optimized query
                try {
                    $shopResults = $swagFullOutPut !== ''
                        ? $this->shopSearchService->search($swagFullOutPut, $commerceIntent)
                        : [];
                } catch (Throwable $e) {
                    $this->agentLogger->warning('Shop search failed, continuing without shop results', [
                        'userId' => $userId,
                        'exception' => $e,
                    ]);

                    $shopResults = [];
                    yield $this->systemMsg('Shopdaten konnten nicht geladen werden, ich antworte mit Wissensbasis weiter...', 'think');
                }
            }

            if ($commerceIntent === CommerceIntentLite::PRODUCT_SEARCH) {
                $knowledgeChunks = array_slice($knowledgeChunks, 0, 2);
            } elseif ($commerceIntent === CommerceIntentLite::ADVISORY_PRODUCT_SEARCH) {
                $knowledgeChunks = array_slice($knowledgeChunks, 0, 3);
            }

            yield $this->systemMsg("Ich analysiere alle Informationen...", "think");

            // ---------------------------------------------------------
            // 5) Build final prompt
            // ---------------------------------------------------------
            $finalPrompt = $this->promptBuilder->build(
                prompt: $prompt,
                userId: $userId,
                urlContent: $urlContent,
                knowledgeChunks: $knowledgeChunks,
                shopResults: $shopResults,
                fullContext: $includeFullContext,
                swagFullOutPut: $swagFullOutPut
            );

            if ($this->debug && $this->logPrompt) {
                $this->agentLogger->debug($finalPrompt);
            }

            if ($this->debug && $this->logContext) {
                $this->agentLogger->debug('Conversation context snapshot', [
                    'context' => $this->contextService->buildUserContext(
                        $userId,
                        $includeFullContext
                    ),
                ]);
            }

            // ---------------------------------------------------------
            // 6) Stream tokens from the LLM backend (chunked streaming)
            // ---------------------------------------------------------
            $fullOutput = '';
            $chunker = new StreamChunker();
            $chunker->flush();
            $this->thinkSuppressor->reset();

            foreach ($this->ollamaClient->stream($finalPrompt) as $token) {

                if (!is_string($token)) {
                    continue;
                }

                $cleanToken = $this->thinkSuppressor->filter((string)$token);

                if ($cleanToken === '') {
                    if ($firstThinkLoop) {
                        yield $this->systemMsg("Denke nach...", "think");
                        $firstThinkLoop = false;
                    }
                    continue;
                }

                // Vollständige Antwort weiter sammeln (für History)
                $fullOutput .= $cleanToken;

                // ⬇️ Token in Chunker geben
                $chunk = $chunker->push($cleanToken);
                if ($chunk !== null) {
                    yield $this->systemMsg($chunk, 'answer');
                }
            }

            // ⬇️ Rest flushen
            $finalChunk = $chunker->flush();
            if ($finalChunk !== null) {
                yield $this->systemMsg($finalChunk, 'answer');
            } elseif ($fullOutput === '') {
                yield $this->systemMsg('❌ Es wurden keine Daten vom LLM empfangen.', 'err');
            }

            // ---------------------------------------------------------
            // 7) Persist conversation history
            // ---------------------------------------------------------
            $this->contextService->appendHistory(
                $userId,
                $prompt,
                $fullOutput
            );

            $this->agentLogger->info('Agent run finished', [
                'userId' => $userId,
                'outputLength' => mb_strlen($fullOutput),
                'contextMode' => 'recent',
                'commerceIntent' => $commerceIntent,
                'shopResultsCount' => count($shopResults),
            ]);
        } catch (Throwable $e) {
            $this->agentLogger->error('Agent run failed', [
                'userId' => $userId,
                'exception' => $e,
            ]);

            yield $this->systemMsg("\n❌ An internal error occurred while processing the request. \nError: " . $e->getMessage(), 'err');
        }
    }

    private function systemMsg(string $msg, string $type = ''): string
    {
        if (!$this->systemMsgOn) {
            return '';
        }

        return match ($type) {
            'answer' => '' . $msg,
            'err' => '<span class="text-danger">' . $msg . "</span>\n<hr>\n",
            'think' => '<span class="text-info think">' . $msg . "</span>\n"
        };
    }
}