<?php
namespace ATF;

use Exception;
use Amp;

interface IMChan
{
  function post(string $message, array $fields = array()) : array;
  function updatePost(string $thread_id, array $fields = array());
  function postFile(string $title, string $mime_type, string $file_path, array $fields = array()) : array;
  function postPNG(string $title, string $png_file, array $fields = array()) : array;
  function getPermalink(string $id) : string;
}

class NullMessenger implements IMChan
{
  function post(string $message, array $fields = array()) : array
  {
    return array('ok' => true, 'id' => 1);
  }

  function updatePost(string $id, array $fields = array()) : array
  {
    return array('ok' => true);
  }

  function postFile(string $title, string $mime_type, string $file_path, array $fields = array()) : array
  {
    return array('ok' => true);
  }

  function postPNG(string $title, string $png_file, array $fields = array()) : array
  {
    return array('ok' => true);
  }

  function getPermalink(string $id) : string
  {
    return "https://fake/$id";
  }
}

class MattermostChan implements IMChan
{
  private string $server;
  private string $token;
  private string $team;
  private string $chan;

  function __construct(string $server, string $token, string $team, string $chan)
  {
    $this->server = $server;
    $this->token = $token;
    $this->team = $team;
    $this->chan = $chan;
  }

  function post(string $message, array $fields = array()) : array
  {
    return mm_post($this->server, $this->token, $this->chan, $message, $fields);
  }

  function updatePost(string $id, array $fields = array()) : array
  {
    return mm_update($this->server, $this->token, $id, $fields);
  }

  function postFile(string $title, string $mime_type, string $file_path, array $fields = array()) : array
  {
    return mm_post_file($this->server, $this->token, $this->chan, $title, $mime_type, $file_path, $fields);
  }

  function postPNG(string $title, string $png_file, array $fields = array()) : array
  {
    return mm_post_png($this->server, $this->token, $this->chan, $title, $png_file, $fields);
  }

  function getPermalink(string $id) : string
  {
    return mm_get_permalink($this->server, $this->team, $id);
  }
}

function mm_post(string $server, string $token, string $chan, string $message, $fields = array())
{
  $ch = _mm_post_curl($server, $token, $chan, $message, $fields);
  $result = curl_exec($ch);
  curl_close($ch);

  $json = json_decode($result, true);
  if(!$json)
    return array('ok' => false, 'id' => 0);
  return array('ok' => true, 'id' => $json['id']);
}

function mm_post_async(string $server, string $token, string $chan, string $message, $fields = array()) : Amp\Promise
{
  return Amp\call(function() use($server, $token, $chan, $message, $fields) {

  $ch = _mm_post_curl($server, $token, $chan, $message, $fields);
  $result = yield _multi_curl_async($ch, true);
  curl_close($ch);

  $json = json_decode($result, true);
  if(!$json)
    return array('ok' => false, 'id' => 0);
  return array('ok' => true, 'id' => $json['id']);
  });
}

function mm_update(string $server, string $token, string $id, array $fields)
{
  $ch = curl_init("$server/api/v4/posts/$id");

  $headers = array(
   'Content-Type: application/json',
   'Authorization: Bearer ' . $token
  );

  $fields["post_id"] = $id;
  $fields["id"] = $id;
  
  curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

  $result = curl_exec($ch);
  curl_close($ch);

  return json_decode($result, true);
}

function mm_post_file(
  string $server, string $token, string $chan, 
  string $title, string $mime_type, string $file_path, 
  $msg_fields = array()
)
{
  $headers = array(
    'Content-Type: multipart/form-data',
    'Authorization: Bearer ' . $token
  );

  $file = new \CurlFile(realpath($file_path), $mime_type, basename($file_path));

  $fields = array();
  $fields['channel_id'] = $chan;
  $fields['files'] =  $file;

  $ch = curl_init("$server/api/v4/files");
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

  $result = curl_exec($ch);
  $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  curl_close($ch);

  if($status != 201)
    throw new Exception("File failed with status: " . $status .", result: " . var_export($result, true));

  $result = json_decode($result, true);
  $file_id = $result['file_infos'][0]['id'];

  $msg_fields['file_ids'] = array($file_id);

  return mm_post($server, $token, $chan, $title, $msg_fields);
}

function mm_post_png(
  string $server, string $token, string $chan, 
  string $title, string $png_file, 
  $msg_fields = array()
)
{
  $headers = array(
    'Content-Type: multipart/form-data',
    'Authorization: Bearer ' . $token
  );

  $file = new \CurlFile(realpath($png_file), 'image/png', basename($png_file));

  $fields = array();
  $fields['channel_id'] = $chan;
  $fields['files'] =  $file;

  $ch = curl_init("$server/api/v4/files");
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

  $result = curl_exec($ch);
  $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  curl_close($ch);

  if($status != 201)
    throw new Exception("File failed with status: " . $status .", result: " . $result);

  $result = json_decode($result, true);
  $file_id = $result['file_infos'][0]['id'];

  $msg_fields['file_ids'] = array($file_id);

  return mm_post($server, $token, $chan, $title, $msg_fields);
}

function mm_get_permalink(string $server, string $team, string $msg_id)
{
  return "$server/$team/pl/$msg_id";
}

function _mm_post_curl(string $server, string $token, string $chan, string $message, $fields = array())
{
  $ch = curl_init("$server/api/v4/posts");

  $headers = array(
   'Content-Type: application/json',
   'Authorization: Bearer ' . $token
  );

  if(!isset($fields['channel_id']))
    $fields['channel_id'] = $chan;
  $fields['message'] = $message;
  
  curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

  return $ch;
}