<?php

namespace App\Core\Database;

use PDO;
use PDOException;

/**
 * NovaCore Database Connection
 * PDO database wrapper
 */
class Connection
{
    private PDO $pdo;
    private array $config;

    public function __construct(array $config)
    {
        $this->config = $config;
        $this->connect();
    }

    /**
     * Establish database connection
     */
    private function connect(): void
    {
        try {
            $dsn = $this->buildDsn();

            if ($this->config['driver'] === 'sqlite') {
                $this->pdo = new PDO($dsn);
            } else {
                $this->pdo = new PDO(
                    $dsn,
                    $this->config['username'],
                    $this->config['password'],
                    $this->config['options'] ?? []
                );
            }
        } catch (PDOException $e) {
            throw new \Exception("Database connection failed: " . $e->getMessage());
        }
    }

    /**
     * Build DSN string
     */
    private function buildDsn(): string
    {
        $driver = $this->config['driver'];

        switch ($driver) {
            case 'mysql':
                $host = $this->config['host'];
                $port = $this->config['port'] ?? null;
                $database = $this->config['database'];
                $charset = $this->config['charset'] ?? 'utf8';
                return "mysql:host={$host};port={$port};dbname={$database};charset={$charset}";
            case 'pgsql':
                $host = $this->config['host'];
                $port = $this->config['port'] ?? null;
                $database = $this->config['database'];
                return "pgsql:host={$host};port={$port};dbname={$database}";
            case 'sqlite':
                $database = $this->config['database'];
                return "sqlite:{$database}";
            default:
                throw new \Exception("Unsupported database driver: {$driver}");
        }
    }

    /**
     * Get PDO instance
     */
    public function getPdo(): PDO
    {
        return $this->pdo;
    }

    /**
     * Execute query
     */
    public function query(string $sql, array $params = []): \PDOStatement
    {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }

    /**
     * Execute query and return all results
     */
    public function fetchAll(string $sql, array $params = []): array
    {
        $stmt = $this->query($sql, $params);
        return $stmt->fetchAll();
    }

    /**
     * Execute query and return single result
     */
    public function fetch(string $sql, array $params = []): ?array
    {
        $stmt = $this->query($sql, $params);
        $result = $stmt->fetch();
        return $result ?: null;
    }

    /**
     * Execute query and return single value
     */
    public function fetchColumn(string $sql, array $params = [])
    {
        $stmt = $this->query($sql, $params);
        return $stmt->fetchColumn();
    }

    /**
     * Execute query and return affected rows
     */
    public function execute(string $sql, array $params = []): int
    {
        $stmt = $this->query($sql, $params);
        return $stmt->rowCount();
    }

    /**
     * Begin transaction
     */
    public function beginTransaction(): bool
    {
        return $this->pdo->beginTransaction();
    }

    /**
     * Commit transaction
     */
    public function commit(): bool
    {
        return $this->pdo->commit();
    }

    /**
     * Rollback transaction
     */
    public function rollback(): bool
    {
        return $this->pdo->rollBack();
    }

    /**
     * Get last insert ID
     */
    public function lastInsertId(): string
    {
        return $this->pdo->lastInsertId();
    }

    /**
     * Check if connected
     */
    public function isConnected(): bool
    {
        try {
            $this->pdo->query('SELECT 1');
            return true;
        } catch (PDOException $e) {
            return false;
        }
    }
}