<?php
class ColorGradient
{
  public $pct;
  public $color;

  public static function RGB2HSV($R, $G, $B)    // RGB values:    0-255, 0-255, 0-255
  {                                // HSV values:    0-360, 0-100, 0-100
    // Convert the RGB byte-values to percentages
    $R = ($R / 255);
    $G = ($G / 255);
    $B = ($B / 255);

    // Calculate a few basic values, the maximum value of R,G,B, the
    //   minimum value, and the difference of the two (chroma).
    $maxRGB = max($R, $G, $B);
    $minRGB = min($R, $G, $B);
    $chroma = $maxRGB - $minRGB;

    // Value (also called Brightness) is the easiest component to calculate,
    //   and is simply the highest value among the R,G,B components.
    // We multiply by 100 to turn the decimal into a readable percent value.
    $computedV = 100 * $maxRGB;

    // Special case if hueless (equal parts RGB make black, white, or grays)
    // Note that Hue is technically undefined when chroma is zero, as
    //   attempting to calculate it would cause division by zero (see
    //   below), so most applications simply substitute a Hue of zero.
    // Saturation will always be zero in this case, see below for details.
    if ($chroma == 0)
        return array(0, 0, $computedV);

    // Saturation is also simple to compute, and is simply the chroma
    //   over the Value (or Brightness)
    // Again, multiplied by 100 to get a percentage.
    $computedS = 100 * ($chroma / $maxRGB);

    // Calculate Hue component
    // Hue is calculated on the "chromacity plane", which is represented
    //   as a 2D hexagon, divided into six 60-degree sectors. We calculate
    //   the bisecting angle as a value 0 <= x < 6, that represents which
    //   portion of which sector the line falls on.
    if ($R == $minRGB)
        $h = 3 - (($G - $B) / $chroma);
    elseif ($B == $minRGB)
        $h = 1 - (($R - $G) / $chroma);
    else // $G == $minRGB
        $h = 5 - (($B - $R) / $chroma);

    // After we have the sector position, we multiply it by the size of
    //   each sector's arc (60 degrees) to obtain the angle in degrees.
    $computedH = 60 * $h;

    return array($computedH, $computedS, $computedV);
  }

  public static function HSV2RGB($h, $s, $v)
  {
    $s /= 256.0;
    if ($s == 0.0) return array($v,$v,$v);
    $h /= (256.0 / 6.0);
    $i = floor($h);
    $f = $h - $i;
    $p = (integer)($v * (1.0 - $s));
    $q = (integer)($v * (1.0 - $s * $f));
    $t = (integer)($v * (1.0 - $s * (1.0 - $f)));
    switch($i) {
    case 0: return array($v,$t,$p);
    case 1: return array($q,$v,$p);
    case 2: return array($p,$v,$t);
    case 3: return array($p,$q,$v);
    case 4: return array($t,$p,$v);
    default: return array($v,$p,$q);
    }
  }

   public static function gradient($from_color, $to_color, $graduations = 10) 
   {
        $graduations--;
        $startcol = str_replace("#", "", $from_color);
        $endcol = str_replace("#", "", $to_color);
        $RedOrigin = hexdec(substr($startcol, 0, 2));
        $GrnOrigin = hexdec(substr($startcol, 2, 2));
        $BluOrigin = hexdec(substr($startcol, 4, 2));
        if ($graduations >= 2) { // for at least 3 colors
            $GradientSizeRed = (hexdec(substr($endcol, 0, 2)) - $RedOrigin) / $graduations; //Graduation Size Red
            $GradientSizeGrn = (hexdec(substr($endcol, 2, 2)) - $GrnOrigin) / $graduations;
            $GradientSizeBlu = (hexdec(substr($endcol, 4, 2)) - $BluOrigin) / $graduations;
            for ($i = 0; $i <= $graduations; $i++) {
                $RetVal[$i] = strtoupper("#" . str_pad(dechex($RedOrigin + ($GradientSizeRed * $i)), 2, '0', STR_PAD_LEFT) .
                        str_pad(dechex($GrnOrigin + ($GradientSizeGrn * $i)), 2, '0', STR_PAD_LEFT) .
                        str_pad(dechex($BluOrigin + ($GradientSizeBlu * $i)), 2, '0', STR_PAD_LEFT));
            }
        } elseif ($graduations == 1) { // exactlly 2 colors
            $RetVal[] = $from_color;
            $RetVal[] = $to_color;
        } else { // one color
            $RetVal[] = $from_color;
        }
        return $RetVal;
    }

    public static function hex2rgb($hex) { return sscanf($hex, "#%02x%02x%02x"); }

    // ---
    // --- Local fonctions
    // ---
    public static function rgb2hex($rgb) {
      $hex = "#";
      $hex .= str_pad(dechex($rgb[0]), 2, "0", STR_PAD_LEFT);
      $hex .= str_pad(dechex($rgb[1]), 2, "0", STR_PAD_LEFT);
      $hex .= str_pad(dechex($rgb[2]), 2, "0", STR_PAD_LEFT);

      return $hex; // returns the hex value including the number sign (#)
    }
}

class Plot 
{
  private $aCoords;
  function __construct(&$aCoords) 
  {
    $this->aCoords = &$aCoords;
  }

  public function drawLine($vImage, $vColor, $iPosX = 0, $imaxX = false) 
  {
    $maxX = $imaxX;
    if ($imaxX === false) $maxX = imagesx($vImage);

    reset($this->aCoords);
    list($iPrevX, $iPrevY) = each($this->aCoords);

    while (list ($x, $y) = each($this->aCoords)) 
    {
      $laCouleur = null;
      if (!is_array($vColor)) $laCouleur = $vColor;
      else
      {
        $s = count($vColor) - 1;
        $laCouleur = $vColor[$s]->color;
        $pct = $x / $maxX;
        while(($s>0)&&($pct < $vColor[$s]->pct))
        {
          $s -= 1;
          $laCouleur = $vColor[$s]->color;
        }
      }
      imageline($vImage, round($iPrevX), round($iPrevY), round($x), round($y), $laCouleur);
      $iPrevX = $x;
      $iPrevY = $y;
    }
  }

  public function drawDots($vImage, $vColor, $iPosX = 0, $iPosY = false, $iDotSize = 1) {
    if ($iPosY === false)
      $iPosY = imagesy($vImage);
    $vBorderColor = imagecolorallocate($vImage, 0, 0, 0);
    foreach ($this->aCoords as $x => $y) {
      imagefilledellipse($vImage, $iPosX + round($x), $iPosY - round($y), $iDotSize, $iDotSize, $vColor);
      imageellipse($vImage, $iPosX + round($x), $iPosY - round($y), $iDotSize, $iDotSize, $vBorderColor);
    }
  }

  public function drawAxis($vImage, $vColor, $iPosX = 0, $iPosY = false) {
    if ($iPosY === false) $iPosY = imagesy($vImage);
    $vImageWidth = imagesx($vImage);
    imageline($vImage, $iPosX, $iPosY, $iPosX, 0, $vColor);
    imageline($vImage, $iPosX, $iPosY, $vImageWidth, $iPosY, $vColor);
    imagefilledpolygon($vImage, array($iPosX, 0, $iPosX - 3, 5, $iPosX + 3, 5), 3, $vColor);
    imagefilledpolygon($vImage, array($vImageWidth, $iPosY, $vImageWidth - 5, $iPosY - 3, $vImageWidth - 5, $iPosY + 3), 3, $vColor);
  }
}

class CubicSplines 
{
  protected $aCoords;
  protected $aCrdX;
  protected $aCrdY;
  protected $aSplines = array();
  protected $iMinX;
  protected $iMaxX;
  protected $iStep;
  protected function prepareCoords(&$aCoords, $iStep, $iMinX = -1, $iMaxX = -1) {
    $this->aCrdX = array();
    $this->aCrdY = array();
    $this->aCoords = array();
    ksort($aCoords);
    foreach ($aCoords as $x => $y) {
      $this->aCrdX[] = $x;
      $this->aCrdY[] = $y;
    }
    $this->iMinX = $iMinX;
    $this->iMaxX = $iMaxX;
    if ($this->iMinX == -1)
      $this->iMinX = min($this->aCrdX);
    if ($this->iMaxX == -1)
      $this->iMaxX = max($this->aCrdX);
    $this->iStep = $iStep;
  }
  public function setInitCoords(&$aCoords, $iStep = 1, $iMinX = -1, $iMaxX = -1) {
    $this->aSplines = array();
    if (count($aCoords) < 4) {
      return false;
    }
    $this->prepareCoords($aCoords, $iStep, $iMinX, $iMaxX);
    $this->buildSpline($this->aCrdX, $this->aCrdY, count($this->aCrdX));
  }
  public function processCoords() {
    for ($x = $this->iMinX; $x <= $this->iMaxX; $x += $this->iStep) {
      $this->aCoords[$x] = $this->funcInterp($x);
    }
    return $this->aCoords;
  }
  private function buildSpline($x, $y, $n) {
    for ($i = 0; $i < $n; ++$i) {
      $this->aSplines[$i]['x'] = $x[$i];
      $this->aSplines[$i]['a'] = $y[$i];
    }
    $this->aSplines[0]['c'] = $this->aSplines[$n - 1]['c'] = 0;
    $alpha[0] = $beta[0] = 0;
    for ($i = 1; $i < $n - 1; ++$i) {
      $h_i = $x[$i] - $x[$i - 1];
      $h_i1 = $x[$i + 1] - $x[$i];
      $A = $h_i;
      $C = 2.0 * ($h_i + $h_i1);
      $B = $h_i1;
      $F = 6.0 * (($y[$i + 1] - $y[$i]) / $h_i1 - ($y[$i] - $y[$i - 1]) / $h_i);
      $z = ($A * $alpha[$i - 1] + $C);
      $alpha[$i] = - $B / $z;
      $beta[$i] = ($F - $A * $beta[$i - 1]) / $z;
    }
    for ($i = $n - 2; $i > 0; --$i) {
      $this->aSplines[$i]['c'] = $alpha[$i] * $this->aSplines[$i + 1]['c'] + $beta[$i];
    }
    for ($i = $n - 1; $i > 0; --$i) {
      $h_i = $x[$i] - $x[$i - 1];
      $this->aSplines[$i]['d'] = ($this->aSplines[$i]['c'] - $this->aSplines[$i - 1]['c']) / $h_i;
      $this->aSplines[$i]['b'] = $h_i * (2.0 * $this->aSplines[$i]['c'] + $this->aSplines[$i - 1]['c']) / 6.0 + ($y[$i] - $y[$i - 1]) / $h_i;
    }
  }
  private function funcInterp($x) {
    $n = count($this->aSplines);
    if ($x <= $this->aSplines[0]['x'])  {
      $s = $this->aSplines[1];
    } else {
      if ($x >= $this->aSplines[$n - 1]['x']) {
        $s = $this->aSplines[$n - 1];
      } else {
        $i = 0;
        $j = $n - 1;
        while ($i + 1 < $j) {
          $k = $i + ($j - $i) / 2;
          if ($x <= $this->aSplines[$k]['x']) {
            $j = $k;
          } else {
            $i = $k;
          }
        }
        $s = $this->aSplines[$j];
      }
    }
    $dx = ($x - $s['x']);
    return $s['a'] + ($s['b'] + ($s['c'] / 2.0 + $s['d'] * $dx / 6.0) * $dx) * $dx;
  }
}

class topisto_spline
{
  public static function DefaultDrawBlock($the_block, $vImage, $x, $y, $graph_width, $graph_height, $type=1)
  {
    topisto_spline::DrawBlock($the_block, $vImage, $x, $y, $graph_width, $graph_height, 3.5, 1, $type);
    topisto_spline::DrawBlock($the_block, $vImage, $x, $y, $graph_width, $graph_height, 5, 30, $type);
  }

  //
  // modes
  //    - 0   : une droite de couleur uniforme
  //    - 1   : une droite en dégradé de couleur
  //    - 2   : une spline en dégradé de couleur passant les valeurs du hash de la transaction
  //    - 3   : la spline dessinée en 2 est atténuée à gauche et amplifiée à droite
  //    - 3.5 : idem mode 3, mais avec de la transparence
  //    - 4   : $iterations splines oscillants autour de la spline dessinée en 2
  //    - 4.5 : les splines sont desssinées en transparence
  //
  public static function DrawBlock($the_block, $vImage, $x, $y, $graph_width, $graph_height, $mode, $iterations, $type=1)
  {
    $somme = 0;
    $min   =-1;
    $max   = 0;
    $data  = blockchain::getTransactionData($the_block, $type);
    $local_iterations = $iterations;
    $n_data = count($data);

    $vBgColor = imagecolorallocate($vImage, 10, 10, 10);
    imagefilledrectangle($vImage, $x, $y, $x+$graph_width, $y+$graph_height, $vBgColor);

    // Calcul des min max
    foreach($data as $v)
    {
      if ($v['value'] > $max) $max = $v['value'];
      if (($v['value'] < $min)||($min == -1)) $min = $v['value'];
      $somme += $v['value'];
    }
    if ($min == $max) $max = $min + 1;
    if ($somme == 0) return;

    // --- 
    // --- On se limite à 40 000 traits
    // ---    Pour des questions de performance
    // ---
    while(($n_data * $local_iterations)>40000) $local_iterations--;

    $vColor     = array();

    // Gestion de la transparence
    $alpha = 125;
    if ($mode < 4.5)  $alpha = 0;
    if ($mode == 3.5) $alpha = 100;

    // On choisit des couleurs au hasard
    $hex_val = array(
      ColorGradient::rgb2hex([rand(0,255),rand(0,255),rand(0,255)]),
      ColorGradient::rgb2hex([rand(0,255),rand(0,255),rand(0,255)]),
      ColorGradient::rgb2hex([rand(0,255),rand(0,255),rand(0,255)])
    );
    // dan sla moitié des cas, on s'en tient au "dégradé de feu"
    if (rand(0,100) > 50) $hex_val = array('#D2691E', '#FF8C00', '#EEEEEE');

    $rgbval = ColorGradient::hex2rgb($hex_val[0]);

    $n = 0;
    $vColor[$n] = new ColorGradient();
    $vColor[$n]->pct   = 0;
    $vColor[$n]->color = imagecolorallocatealpha($vImage, $rgbval[0], $rgbval[1], $rgbval[2], $alpha);

    $n += 1;
    $vColor[$n] = new ColorGradient();
    $vColor[$n]->pct   = 0.1;
    $vColor[$n]->color = imagecolorallocatealpha($vImage, $rgbval[0], $rgbval[1], $rgbval[2], $alpha);

    if ($mode > 0)
    {
      $gradient = ColorGradient::gradient($hex_val[0], $hex_val[1], 60);
      for($i=0;$i<60;$i++)
      {
        $rgbval = ColorGradient::hex2rgb($gradient[$i]);
        $n += 1;
        $vColor[$n] = new ColorGradient();
        $vColor[$n]->pct   = (10+$i) / 100.0;
        $vColor[$n]->color = imagecolorallocatealpha($vImage, $rgbval[0], $rgbval[1], $rgbval[2], $alpha);
      }

      $gradient = ColorGradient::gradient($hex_val[1], $hex_val[2],30);
      for($i=0;$i<30;$i++)
      {
        $rgbval = ColorGradient::hex2rgb($gradient[$i]);
        $n += 1;
        $vColor[$n] = new ColorGradient();
        $vColor[$n]->pct   = (70+$i) / 100.0;
        $vColor[$n]->color = imagecolorallocatealpha($vImage, $rgbval[0], $rgbval[1], $rgbval[2], $alpha);
      }
    }

    //////////
    $oCurve = new CubicSplines();

    $marge_x = 10;
    $marge_y = 20;

    $coef    = ($graph_height - (2*$marge_y)) / $somme;
    $dx      = $graph_width;
    if ($mode > 0) $dx = round($dx / (TX_HASH_LEN+1));

    //$limite_x = $x + ($graph_width - $marge_x);
    $limite_x = $x + $graph_width - $marge_x;

    $h0 = 0;
    $hauteur = $y + $marge_y;
    $special_draw = (count($data) == 1);

    foreach($data as $transaction)
    {
      //
      // La nouvelle hauteur : cumule des montants de transaction
      //
      $hauteur += $coef * $transaction['value'];

      //
      // Cas des blocks qui n'ont qu'une seule transaction
      // 
      if ($special_draw) $hauteur = $y + ($graph_height / 2);

      //
      // Ne pas tracer 2 lignes à la même hauteur
      //
      if ((floor($hauteur)-$h0)<2) continue;
      $h0 = floor($hauteur);

      //
      // On va faire des itérations sur la transaction courante.
      // A chaque itération, on va s'appuyer sur le hash de la transaction
      // mais en introduisant du bruit.
      // On va donc statistiquement tracer une courbe représentant le hash
      // 
      for($j=0;$j<$local_iterations;$j++)
      {
        //
        // On recommence en début de ligne
        //
        $x0 = $x + $marge_x;

        //
        // La première partie est une ligne droite
        //
        imageline($vImage, $x0, $h0, $x0+$dx, $h0, $vColor[0]->color);
        $x0 += $dx;

        //
        // Le mode 0 consiste à tracer une droite de couleur uniforme
        //
        if (($mode == 0)||($x0 >= $limite_x))  continue;

        $aCoords  = array();
        $facteur = 1;

        if ($mode > 2) $facteur = 0.04;

        //
        // On découpe la ligne en fonction du nombre de DIGIT 
        //         dans le hash des transactions
        //
        $aCoords[$x0] = $h0;
        for ($i = 0; $i < (TX_HASH_LEN-1); $i++) 
        {
          $y0 = $h0;
          if ($mode > 1)
          {
            $y0 += (hexdec($transaction['hash'][$i]) - 8) * $facteur;
            $valeur = rand(-16, 16) * $facteur;
            if ($mode > 2) $facteur += 0.02;
            if ($mode > 3) $y0 += $valeur;
          }
          $x0 += $dx;
          $aCoords[$x0] = $y0;
        }
        if ($oCurve) 
        {
          $oCurve->setInitCoords($aCoords);
          $r = $oCurve->processCoords();
          if ($r)
          {
            $curveGraph = new Plot($r);
            $curveGraph->drawLine($vImage, $vColor, $x0, $limite_x);
          }
        }
      }
    }
  }
}
?>