<?php

  class sml_data_waveforms extends mw_data{

    public $SOX_EXISTS;

    public function init_waveform_dirs(){
      $env = $this->env();
      $dir = $env->path("content")."tmp";
      if(!is_dir($dir)) @mkdir($dir);
      if(!is_dir($dir)) return false;
      $dir = $env->path("content")."waveforms";
      if(!is_dir($dir)) @mkdir($dir);
      if(!is_dir($dir)) return false;
      return true;
    }

    public function audio_to_png($params = array()){
      $env = $this->env();
      $audio_file = $params["audio_file"];
      if(!$audio_file) return false;
      if(!file_exists($audio_file)) return false;

      $png_file = $params["png_file"];
      if(!$png_file) return false;

      $width = isset($params["width"]) ? $params["width"] : "650";
      $height = isset($params["height"]) ? $params["height"] : "100";
      $background = isset($params["background"]) ? $params["background"] : "";
      $foreground = isset($params["foreground"]) ? $params["foreground"] : "#000000";
      $draw_flat = isset($params["draw_flat"]) ? $params["draw_flat"] : true;
      $DETAIL = isset($params["DETAIL"]) ? $params["DETAIL"] : 5;

      if(!is_dir($env->path("content")."waveforms")){
        @mkdir($env->path("content")."waveforms");
      }
      if(!is_dir($env->path("content")."waveforms")) return false;
      if(!is_dir($env->path("content")."tmp")){
        @mkdir($env->path("content")."tmp");
      }
      if(!is_dir($env->path("content")."tmp")) return false;

      if(
        !$this->audio_to_wav(
          $audio_file,
          $wav_file = $env->path("content")."tmp/".substr(md5(time()), 0, 10).".wav"
        )
      ) return false;

      $OK = true;
      if(
        !(
          $img = $this->wav_to_img(
            $wav_file,
            array(
              "width" => $width,
              "height" => $height,
              "background" => $background,
              "foreground" => $foreground,
              "draw_flat" => $draw_flat,
              "DETAIL" => $DETAIL
            )
          )
        )
      ){
        $OK = false;
      }
      unlink($wav_file);
      if(!$OK) return false;

      // want it resized?
      if ($width) {
        // resample the image to the proportions defined in the form
        $rimg = imagecreatetruecolor($width, $height);
        // save alpha from original image
        imagesavealpha($rimg, true);
        imagealphablending($rimg, false);
        // copy to resized
        imagecopyresampled($rimg, $img, 0, 0, 0, 0, $width, $height, imagesx($img), imagesy($img));
        $OK = @imagepng($rimg, $png_file);
        imagedestroy($rimg);
      } else {
        $OK = @imagepng($img, $png_file);
      }
      imagedestroy($img);
      if(!$OK) return false;
      return true;
    }

    // ----------------------------------------------------------------------------
    //                                                                  utilitaires
    //

    public function sox_command($audio_file, $wav_file){
      return "sox -V \"".$audio_file."\" -b 16 -r 8000 -c 1 \"".$wav_file."\"";
    }

    public function sox_exists(){
      if(isset($this->SOX_EXISTS)){
        return $this->SOX_EXISTS;
      }
      $command = "sox";
      $whereIsCommand = (PHP_OS == 'WINNT') ? 'where' : 'which';
      if(
        (
          $process = proc_open(
            "$whereIsCommand $command",
            array(
              0 => array("pipe", "r"), //STDIN
              1 => array("pipe", "w"), //STDOUT
              2 => array("pipe", "w"), //STDERR
            ),
            $pipes
          )
        ) === false
      ){
        $this->SOX_EXISTS = false;
      }
      else{
        $stdout = stream_get_contents($pipes[1]);
        $stderr = stream_get_contents($pipes[2]);
        fclose($pipes[1]);
        fclose($pipes[2]);
        proc_close($process);
        $this->SOX_EXISTS = $stdout != '';
      }
      return $this->SOX_EXISTS;
    }

    public function audio_to_wav($audio_file, $wav_file){
      if(!$this->sox_exists()){
        return false;
      }
      system($this->sox_command($audio_file, $wav_file));
      return file_exists($wav_file);
    }

    public function wav_to_img($wav_file, $params = array()){

      $width = isset($params["width"]) ? $params["width"] : "650";
      $height = isset($params["height"]) ? $params["height"] : "100";
      $background = isset($params["background"]) ? $params["background"] : "";
      $foreground = isset($params["foreground"]) ? $params["foreground"] : "#000000";
      $draw_flat = isset($params["draw_flat"]) ? $params["draw_flat"] : true;

      // $DETAIL : how much detail we want. Larger number means less detail
      // (basically, how many bytes/frames to skip processing)
      // the lower the number means longer processing time
      $DETAIL = isset($params["DETAIL"]) ? $params["DETAIL"] : 5;

      list($r, $g, $b) = $this->html2rgb($foreground);

      if(!($handle = fopen($wav_file, "r"))) return false;

      // wav file header retrieval
      $heading[] = fread($handle, 4);
      $heading[] = bin2hex(fread($handle, 4));
      $heading[] = fread($handle, 4);
      $heading[] = fread($handle, 4);
      $heading[] = bin2hex(fread($handle, 4));
      $heading[] = bin2hex(fread($handle, 2));
      $heading[] = bin2hex(fread($handle, 2));
      $heading[] = bin2hex(fread($handle, 4));
      $heading[] = bin2hex(fread($handle, 4));
      $heading[] = bin2hex(fread($handle, 2));
      $heading[] = bin2hex(fread($handle, 2));
      $heading[] = fread($handle, 4);
      $heading[] = bin2hex(fread($handle, 4));

      // wav bitrate
      $peek = hexdec(substr($heading[10], 0, 2));
      $byte = $peek / 8;

      // checking whether a mono or stereo wav
      $channel = hexdec(substr($heading[6], 0, 2));

      $ratio = ($channel == 2 ? 40 : 80);

      // start putting together the initial canvas
      // $data_size = (size_of_file - header_bytes_read) / skipped_bytes + 1
      $data_size = floor((filesize($wav_file) - 44) / ($ratio + $byte) + 1);
      $data_point = 0;

      if($img = imagecreatetruecolor($data_size / $DETAIL, $height)){
        if($background == ""){
          imagesavealpha($img, true);
          $transparentColor = imagecolorallocatealpha($img, 0, 0, 0, 127);
          imagefill($img, 0, 0, $transparentColor);
        }
        else{
          list($br, $bg, $bb) = $this->html2rgb($background);
          imagefilledrectangle($img, 0, 0, (int) ($data_size / $DETAIL), $height, imagecolorallocate($img, $br, $bg, $bb));
        }
      }

      if($img) while(!feof($handle) && $data_point < $data_size){
        if ($data_point++ % $DETAIL == 0){
          $bytes = array();
          for ($i = 0; $i < $byte; $i++) $bytes[$i] = fgetc($handle);
          switch($byte){
            // get value for 8-bit wav
            case 1:
              $data = $this->findValues($bytes[0], $bytes[1]);
              break;
            // get value for 16-bit wav
            case 2:
              if(ord($bytes[1]) & 128)
                $temp = 0;
              else
                $temp = 128;
              $temp = chr((ord($bytes[1]) & 127) + $temp);
              $data = floor($this->findValues($bytes[0], $temp) / 256);
              break;
          }

          // skip bytes for memory optimization
          fseek($handle, $ratio, SEEK_CUR);
          // draw this data point
          // relative value based on height of image being generated
          // data values can range between 0 and 255
          $v = (int) ($data / 255 * $height);
          // don't print flat values on the canvas if not necessary
          if (!($v / $height == 0.5 && !$draw_flat))
            // draw the line on the image using the $v value and centering it vertically on the canvas
            imageline(
              $img,
              // x1
              (int) ($data_point / $DETAIL),
              // y1: height of the image minus $v as a percentage of the height for the wave amplitude
              $height - $v,
              // x2
              (int) ($data_point / $DETAIL),
              // y2: same as y1, but from the bottom of the image
              $height - ($height - $v),
              imagecolorallocate($img, $r, $g, $b)
            );

        } else {
          // skip this one due to lack of detail
          fseek($handle, $ratio + $byte, SEEK_CUR);
        }
      }
      fclose($handle);
      return $img;
    }

    public function findValues($byte1, $byte2){
      return hexdec(bin2hex($byte1)) + (hexdec(bin2hex($byte2)) * 256);
    }

    public function html2rgb($input){
      $input = $input[0] == "#" ? substr($input, 1, 6) : substr($input, 0, 6);
      return array(
       hexdec(substr($input, 0, 2)),
       hexdec(substr($input, 2, 2)),
       hexdec(substr($input, 4, 2))
      );
    }

  }