<?php

/**
 * Servicio de WhatsApp - Envío de mensajes
 * Fecha: 13 de noviembre de 2025
 */

class WhatsAppService
{
    private $token;
    private $phoneNumberId;
    private $apiUrl;
    private $db;

    public function __construct()
    {
        // Obtener configuración desde base de datos
        $config = getWhatsAppConfigFromDB();
        
        $this->token = $config['token']; // Usar token de BD
        $this->phoneNumberId = $config['phone_number_id']; // Usar phone_number_id de BD
        $this->apiUrl = $config['api_url'] ?: 'https://graph.facebook.com/v22.0/'; // Usar api_url de BD
        $this->db = Database::getInstance();
    }

    /**
     * Enviar mensaje de texto
     */
    public function sendTextMessage($to, $message)
    {
        $data = [
            'messaging_product' => 'whatsapp',
            'to' => $this->formatPhoneNumber($to),
            'type' => 'text',
            'text' => [
                'body' => $message
            ]
        ];

        return $this->sendMessage($data);
    }

    /**
     * Enviar mensaje con template
     */
    public function sendTemplateMessage(
        $to,
        $templateName,
        $language = 'es',
        $bodyParameters = [],
        $headerParameters = []
    ) {
        $components = [];

        if (!empty($headerParameters)) {
            $components[] = [
                'type' => 'header',
                'parameters' => $headerParameters
            ];
        }

        if (!empty($bodyParameters)) {
            $components[] = [
                'type' => 'body',
                'parameters' => $bodyParameters
            ];
        }

        $template = [
            'name' => $templateName,
            'language' => [
                'code' => $language
            ]
        ];

        if (!empty($components)) {
            $template['components'] = $components;
        }

        $data = [
            'messaging_product' => 'whatsapp',
            'to' => $this->formatPhoneNumber($to),
            'type' => 'template',
            'template' => $template
        ];

        return $this->sendMessage($data);
    }

    /**
     * Enviar mensaje con botones interactivos
     */
    public function sendInteractiveMessage($to, $bodyText, $buttons, $header = null, $footer = null)
    {
        $interactive = [
            'type' => 'button',
            'body' => [
                'text' => $bodyText
            ],
            'action' => [
                'buttons' => $buttons
            ]
        ];

        if ($header) {
            $interactive['header'] = [
                'type' => 'text',
                'text' => $header
            ];
        }

        if ($footer) {
            $interactive['footer'] = [
                'text' => $footer
            ];
        }

        $data = [
            'messaging_product' => 'whatsapp',
            'recipient_type' => 'individual',
            'to' => $this->formatPhoneNumber($to),
            'type' => 'interactive',
            'interactive' => $interactive
        ];

        return $this->sendMessage($data);
    }

    /**
     * Enviar mensaje con lista
     */
    public function sendListMessage($to, $bodyText, $buttonText, $sections, $header = null, $footer = null)
    {
        $interactive = [
            'type' => 'list',
            'body' => [
                'text' => $bodyText
            ],
            'action' => [
                'button' => $buttonText,
                'sections' => $sections
            ]
        ];

        if ($header) {
            $interactive['header'] = [
                'type' => 'text',
                'text' => $header
            ];
        }

        if ($footer) {
            $interactive['footer'] = [
                'text' => $footer
            ];
        }

        $data = [
            'messaging_product' => 'whatsapp',
            'recipient_type' => 'individual',
            'to' => $this->formatPhoneNumber($to),
            'type' => 'interactive',
            'interactive' => $interactive
        ];

        return $this->sendMessage($data);
    }

    /**
     * Marcar mensaje como leído
     */
    public function markAsRead($messageId)
    {
        $data = [
            'messaging_product' => 'whatsapp',
            'status' => 'read',
            'message_id' => $messageId
        ];

        $url = $this->apiUrl . $this->phoneNumberId . '/messages';
        return $this->makeRequest('POST', $url, $data);
    }

    /**
     * Enviar mensaje principal
     */
    private function sendMessage($data)
    {
        // Construir URL correctamente
        $url = rtrim($this->apiUrl, '/') . '/' . $this->phoneNumberId . '/messages';
        
        // Debug log
        error_log("WhatsApp API URL: " . $url);
        error_log("WhatsApp Token length: " . strlen($this->token));
        error_log("WhatsApp Data: " . json_encode($data));
        
        $response = $this->makeRequest('POST', $url, $data);

        // Guardar mensaje enviado en la base de datos
        if ($response && isset($response['messages'][0]['id'])) {
            $this->saveOutgoingMessage($data, $response);
        }

        return $response;
    }

    /**
     * Realizar petición HTTP
     */
    private function makeRequest($method, $url, $data = null)
    {
        $ch = curl_init();

        $headers = [
            'Authorization: Bearer ' . $this->token,
            'Content-Type: application/json',
            'User-Agent: WhatsApp-Bot/1.0'
        ];

        curl_setopt_array($ch, [
            CURLOPT_URL => $url,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_HTTPHEADER => $headers,
            CURLOPT_TIMEOUT => 30,
            CURLOPT_CONNECTTIMEOUT => 10,
            CURLOPT_SSL_VERIFYPEER => true,
            CURLOPT_SSL_VERIFYHOST => 2,
            CURLOPT_FOLLOWLOCATION => true,
            CURLOPT_MAXREDIRS => 3
        ]);

        if ($method === 'POST' && $data) {
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
        }

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $error = curl_error($ch);
        curl_close($ch);

        if ($error) {
            error_log("cURL Error: " . $error);
            throw new Exception("Error de comunicación con WhatsApp: " . $error);
        }

        $decoded = json_decode($response, true);

        if ($httpCode >= 400) {
            $errorMsg = isset($decoded['error']['message']) ? $decoded['error']['message'] : 'Error desconocido';
            
            // Debug detallado
            error_log("WhatsApp API Error Details:");
            error_log("- URL: " . $url);
            error_log("- HTTP Code: " . $httpCode);
            error_log("- Response: " . $response);
            error_log("- Token (first 20 chars): " . substr($this->token, 0, 20) . "...");
            
            throw new Exception("Error de WhatsApp API: " . $errorMsg);
        }

        return $decoded;
    }

    /**
     * Formatear número de teléfono
     */
    private function formatPhoneNumber($phone)
    {
        // Remover caracteres especiales
        $phone = preg_replace('/[^0-9]/', '', $phone);

        // Si empieza con +57 (Colombia), mantenerlo
        if (substr($phone, 0, 2) === '57' && strlen($phone) >= 12) {
            return $phone;
        }

        // Si es número colombiano sin código de país
        if (strlen($phone) === 10 && substr($phone, 0, 1) === '3') {
            return '57' . $phone;
        }

        return $phone;
    }

    /**
     * Guardar mensaje enviado en BD
     */
    private function saveOutgoingMessage($data, $response)
    {
        try {
            $user = $this->getUserByPhone($data['to']);
            if ($user) {
                $messageData = [
                    'user_id' => $user['id'],
                    'message_id' => $response['messages'][0]['id'],
                    'direction' => 'outgoing',
                    'message_type' => $data['type'],
                    'content' => $this->extractMessageContent($data),
                    'status' => 'sent',
                    'created_at' => date('Y-m-d H:i:s')
                ];

                $this->db->insert('conversations', $messageData);
            }
        } catch (Exception $e) {
            error_log("Error saving outgoing message: " . $e->getMessage());
        }
    }

    /**
     * Extraer contenido del mensaje para guardar
     */
    private function extractMessageContent($data)
    {
        switch ($data['type']) {
            case 'text':
                return $data['text']['body'];
            case 'template':
                return 'Template: ' . $data['template']['name'];
            case 'interactive':
                if (isset($data['interactive']['body']['text'])) {
                    return $data['interactive']['body']['text'];
                }
                break;
        }
        return json_encode($data);
    }

    /**
     * Obtener usuario por teléfono
     */
    private function getUserByPhone($phone)
    {
        return $this->db->fetch(
            "SELECT * FROM users WHERE phone_number = :phone",
            ['phone' => $phone]
        );
    }

    /**
     * Descargar archivo multimedia
     */
    public function downloadMedia($mediaId)
    {
        $url = $this->apiUrl . $mediaId;

        // Primero obtener información del archivo
        $mediaInfo = $this->makeRequest('GET', $url);

        if (!$mediaInfo || !isset($mediaInfo['url'])) {
            throw new Exception("No se pudo obtener información del archivo");
        }

        // Descargar el archivo
        $fileUrl = $mediaInfo['url'];
        $ch = curl_init();

        curl_setopt_array($ch, [
            CURLOPT_URL => $fileUrl,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_HTTPHEADER => [
                'Authorization: Bearer ' . $this->token
            ],
            CURLOPT_TIMEOUT => 60,
            CURLOPT_FOLLOWLOCATION => true
        ]);

        $fileContent = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode !== 200) {
            throw new Exception("Error descargando archivo multimedia");
        }

        return [
            'content' => $fileContent,
            'mime_type' => $mediaInfo['mime_type'] ?? 'application/octet-stream',
            'file_size' => $mediaInfo['file_size'] ?? strlen($fileContent)
        ];
    }
}