<?php

namespace app\components;

use Exception;

class Whatsapp {

  private $_access_token = "";
  public $base_url = "https://graph.facebook.com/%s/%s/%s";
  public $components = [];
  public $language_code = "es_MX";
  public $message_product = "whatsapp";
  public $_from = "";
  public $_to = "";
  public $version = "v14.0";
  public $template_name = "";

  public function __construct() {
    $this->_access_token = "";
    $this->_from = "";
    $this->_to = "";
    $this->template_name = "";
    $this->components = [];
  }

  public function set_access_token($token) {
    $this->_access_token = $token;
    return $this;
  }

  public function msg_from($number = "") {
    if (trim($number) == "") {
      throw new Exception("From is required");
    }

    $this->_from = $number;
    return $this;
  }

  public function msg_to($number = "") {
    if (trim($number) == "") {
      throw new Exception("To is required");
    }

    $this->_to = $number;
    return $this;
  }

  public function template($name) {
    if (trim($name) == "") {
      // throw error
      return;
    }

    $this->template_name = $name;
    return $this;
  }

  public function add_component($type, $params = []) {
    $this->components[$type] = $params;
    return $this;
  }

  public function add_body_param($text, $type = "text") {
    if (!isset($this->components["body"])) {
      $this->components["body"] = [];
    }

    $dict = [
      "type" => $type,
      "text" => $text
    ];
    $this->components["body"][] = $dict;
    return $this;
  }

  public function send_template_message() {
    if (!$this->_to) {
      throw new Exception("To is not defined");
    }

    if (!$this->_from) {
      throw new Exception("From is not defined");
    }

    if (!$this->template_name) {
      throw new Exception("Template Name is not defined");
    }

    $url = sprintf($this->base_url, $this->version, $this->_from, "messages");
    $headers = [
      'Authorization: Bearer ' . $this->_access_token,
      'Content-Type: application/json'
    ];

    $components = [];
    if (isset($this->components['header'])) {
      $components[] = [
        "type" => "header",
        "parameters" => $this->components["header"]
      ];
    }

    if (isset($this->components['body'])) {
      $components[] = [
        "type" => "body",
        "parameters" => $this->components["body"]
      ];
    }

    if (isset($this->components['footer'])) {
      $components[] = [
        "type" => "footer",
        "parameters" => $this->components["footer"]
      ];
    }

    $body = [
      "messaging_product" => $this->message_product,
      "to" => $this->_to,
      "type" => "template",
      "template" => [
        "name" => $this->template_name,
        "language" => [
          "code" => $this->language_code
        ],
        "components" => $components
      ]
    ];

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($body));
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $resultado = curl_exec($ch);
    curl_close($ch);

    try {
      $json = json_decode($resultado);
      return $json;
    } catch(Exception $e) {
      return null;
    }
  }
}