<?php
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * User OTP Model
 * Manages email-based one-time passwords for two-factor authentication
 */
class UserOtp_model extends MY_Model
{
    protected $tablename = "user_otp_codes";

    /**
     * Generate and store a new OTP code for a user
     * @param int $userId User ID
     * @param int $expiryMinutes Expiry time in minutes (default 10)
     * @return string The generated OTP code
     */
    public function generateOTP($userId, $expiryMinutes = 10)
    {
        // Generate 6-digit OTP
        $otpCode = str_pad(random_int(0, 999999), 6, '0', STR_PAD_LEFT);

        // Calculate expiry time
        $expiresAt = date('Y-m-d H:i:s', strtotime("+{$expiryMinutes} minutes"));

        // Store OTP in database
        $data = [
            'user_id' => $userId,
            'otp_code' => $otpCode,
            'expires_at' => $expiresAt,
            'used' => 'F'
        ];

        // Use direct insert since this table doesn't have audit columns
        $this->db->insert($this->tablename, $data);

        return $otpCode;
    }

    /**
     * Verify an OTP code for a user
     * @param int $userId User ID
     * @param string $otpCode The OTP code to verify
     * @return bool True if valid, false otherwise
     */
    public function verifyOTP($userId, $otpCode)
    {
        // Get the most recent unused OTP for this user
        $sql = "
            SELECT * FROM {$this->tablename}
            WHERE user_id = ?
            AND otp_code = ?
            AND used = 'F'
            AND expires_at > NOW()
            ORDER BY created_at DESC
            LIMIT 1
        ";

        $query = $this->db->query($sql, [$userId, $otpCode]);

        if ($query->num_rows() == 0) {
            return false;
        }

        $result = $query->row();

        // Mark OTP as used (use direct update since this table doesn't have audit columns)
        $this->db->where('id', $result->id);
        $this->db->update($this->tablename, ['used' => 'T']);

        return true;
    }

    /**
     * Clean up expired OTP codes
     * @return int Number of deleted records
     */
    public function cleanupExpiredOTPs()
    {
        $this->sql = "DELETE FROM {$this->tablename} WHERE expires_at < NOW() OR used = 'T'";
        $this->db->query($this->sql);

        return $this->db->affected_rows();
    }

    /**
     * Delete all OTP codes for a user
     * @param int $userId User ID
     */
    public function deleteUserOTPs($userId)
    {
        $this->db->where('user_id', $userId);
        $this->db->delete($this->tablename);
    }
}