<?php

declare(strict_types=1);

namespace Infrastructure\Persistence;

// @responsibility: CRUD-Operationen für Text-Chunks aus Dokumenten

use Domain\Repository\ChunkRepositoryInterface;
use PDO;

final class ChunkRepository implements ChunkRepositoryInterface
{
    private PDO $db;

    public function __construct()
    {
        $this->db = DatabaseFactory::content();
    }

    /**
     * {@inheritDoc}
     */
    public function getStats(): array
    {
        $result = $this->db->query(
            'SELECT
                COUNT(*) as total,
                COALESCE(SUM(token_count), 0) as tokens,
                SUM(CASE WHEN qdrant_id IS NOT NULL THEN 1 ELSE 0 END) as embedded
             FROM chunks'
        )->fetch();

        return $result !== false ? $result : ['total' => 0, 'tokens' => 0, 'embedded' => 0];
    }

    /**
     * {@inheritDoc}
     */
    public function findRecent(int $limit = 5): array
    {
        $stmt = $this->db->prepare(
            'SELECT c.id, c.content, c.token_count, c.created_at, c.qdrant_id, d.filename
             FROM chunks c
             JOIN documents d ON c.document_id = d.id
             ORDER BY c.created_at DESC
             LIMIT :limit'
        );
        $stmt->bindValue(':limit', $limit, PDO::PARAM_INT);
        $stmt->execute();

        return $stmt->fetchAll();
    }

    /**
     * {@inheritDoc}
     */
    public function findByDocument(int $documentId): array
    {
        $stmt = $this->db->prepare(
            'SELECT c.id, c.chunk_index, c.content, c.token_count, c.heading_path,
                    c.metadata, c.qdrant_id, c.created_at
             FROM chunks c
             WHERE c.document_id = :id
             ORDER BY c.chunk_index'
        );
        $stmt->execute(['id' => $documentId]);

        return $stmt->fetchAll();
    }

    /**
     * {@inheritDoc}
     */
    public function findFiltered(string $search = '', string $embedded = '', int $limit = 50, int $offset = 0): array
    {
        $sql = 'SELECT c.id, c.chunk_index, c.content, c.token_count, c.qdrant_id, c.created_at,
                       d.filename, d.id as document_id
                FROM chunks c
                JOIN documents d ON c.document_id = d.id
                WHERE 1=1';

        $params = [];

        if ($search !== '') {
            $sql .= ' AND c.content LIKE :search';
            $params['search'] = '%' . $search . '%';
        }

        if ($embedded === 'yes') {
            $sql .= ' AND c.qdrant_id IS NOT NULL';
        } elseif ($embedded === 'no') {
            $sql .= ' AND c.qdrant_id IS NULL';
        }

        $sql .= ' ORDER BY c.created_at DESC LIMIT ' . $limit . ' OFFSET ' . $offset;

        $stmt = $this->db->prepare($sql);
        $stmt->execute($params);

        return $stmt->fetchAll();
    }

    /**
     * {@inheritDoc}
     */
    public function count(string $search = '', string $embedded = ''): int
    {
        $sql = 'SELECT COUNT(*) FROM chunks c
                JOIN documents d ON c.document_id = d.id
                WHERE 1=1';

        $params = [];

        if ($search !== '') {
            $sql .= ' AND c.content LIKE :search';
            $params['search'] = '%' . $search . '%';
        }

        if ($embedded === 'yes') {
            $sql .= ' AND c.qdrant_id IS NOT NULL';
        } elseif ($embedded === 'no') {
            $sql .= ' AND c.qdrant_id IS NULL';
        }

        $stmt = $this->db->prepare($sql);
        $stmt->execute($params);

        return (int) $stmt->fetchColumn();
    }

    /**
     * {@inheritDoc}
     */
    public function find(int $id): ?array
    {
        $stmt = $this->db->prepare(
            'SELECT c.*, d.filename, d.source_path, d.id as document_id
             FROM chunks c
             JOIN documents d ON c.document_id = d.id
             WHERE c.id = :id'
        );
        $stmt->execute(['id' => $id]);
        $result = $stmt->fetch();

        return $result === false ? null : $result;
    }

    /**
     * {@inheritDoc}
     */
    public function findByDocumentAndIndex(int $documentId, int $chunkIndex): ?array
    {
        $stmt = $this->db->prepare(
            'SELECT id, chunk_index FROM chunks
             WHERE document_id = :doc_id AND chunk_index = :idx'
        );
        $stmt->execute(['doc_id' => $documentId, 'idx' => $chunkIndex]);
        $result = $stmt->fetch();

        return $result === false ? null : $result;
    }
}