<?php

declare(strict_types=1);

namespace App\Intent;

use App\Config\IntentLightConfig;

/**
 * IntentLite
 *
 * Deterministic, LLM-agnostic intent detection.
 * Focus: LIST intent for retrieval control.
 *
 * IMPORTANT:
 * - Always call it with the ORIGINAL prompt.
 * - Not with the QueryCleaner result.
 */
final readonly class IntentLite
{

    public function __construct(
        private IntentLightConfig $config
    )
    {

    }

    public function detectList(string $originalPrompt): array
    {
        $p = $this->normalize($originalPrompt);

        $score = 0;
        $signals = [];

        // --------------------------------------------------------
        // 1. Starke explizite Listen-Trigger (hohes Gewicht)
        // --------------------------------------------------------
        $strongPatterns = $this->config->getStrongPatterns();

        foreach ($strongPatterns as $pattern) {
            if (preg_match($pattern, $p) === 1) {
                $score += 3;
                $signals[] = "strong:$pattern";
            }
        }

        // --------------------------------------------------------
        // 2. Mengen- / Mehrzahl-Indikatoren
        // --------------------------------------------------------
        $quantityWords = $this->config->getQuantityWords();

        foreach ($quantityWords as $word) {
            if (preg_match('/\b' . preg_quote($word, '/') . '\b/u', $p) === 1) {
                $score += 2;
                $signals[] = "quantity:$word";
            }
        }

        // --------------------------------------------------------
        // 3. Explizite Zahlen (z. B. "5 Vorteile")
        // --------------------------------------------------------
        if (preg_match('/\b\d+\b/u', $p) === 1) {
            $score += 2;
            $signals[] = 'number';
        }

        // --------------------------------------------------------
        // 4. Enumeration-Hinweise (1., -, *, etc.)
        // --------------------------------------------------------
        if (
            preg_match('/(^|\s)(\d+\)|\d+\.|-\s|\*\s)/u', $originalPrompt) === 1
        ) {
            $score += 1;
            $signals[] = 'enumeration_hint';
        }

        // --------------------------------------------------------
        // Entscheidung
        // --------------------------------------------------------
        $isList = $score >= IntentLightConfig::LIST_THRESHOLD;

        return [
            'is_list' => $isList,
            'score' => $score,
            'signals' => $signals,
        ];
    }

    public function isListQuery(string $originalPrompt): bool
    {
        return $this->detectList($originalPrompt)['is_list'];
    }

    // ------------------------------------------------------------
    // Interne Normalisierung (ohne Stopword-Entfernung!)
    // ------------------------------------------------------------
    private function normalize(string $s): string
    {
        $s = mb_strtolower($s);

        // Umlaute zusätzlich absichern (falls QueryCleaner das tut)
        $replacements = [
            'ä' => 'ae',
            'ö' => 'oe',
            'ü' => 'ue',
            'ß' => 'ss',
        ];

        // Nur als Zusatzform speichern (nicht ersetzen!)
        foreach ($replacements as $umlaut => $alt) {
            if (str_contains($s, $umlaut)) {
                $s .= ' ' . str_replace($umlaut, $alt, $s);
                break;
            }
        }

        return $s;
    }
}