<?php

namespace Shikiryu\WebGobbler\Assembler;

use Imagick;
use Shikiryu\WebGobbler\Assembler;
use Shikiryu\WebGobbler\Config;
use Shikiryu\WebGobbler\Pool;

class Superpose extends Assembler
{
    /**
     * @var Imagick
     */
    private $current_image;

    private $base_image;

    /**
     * Superpose constructor.
     *
     * @param \Shikiryu\WebGobbler\Pool   $pool
     * @param \Shikiryu\WebGobbler\Config $config
     * @param string                      $from_file
     */
    public function __construct(Pool $pool, Config $config, $from_file = null)
    {
        $this->base_image = $from_file;

        parent::__construct($pool, $config);
    }

    /**
     * @param string $file
     *
     * @return void
     * @throws \ImagickException
     * @throws \Exception
     */
    public function saveTo($file)
    {
        $this->prepareImage();
        $this->current_image->writeImage($file);
    }

    /**
     *
     */
    public function display()
    {
        try {
            $this->prepareImage();

            header('Content-type: image/jpeg');
            echo $this->current_image;
        } catch (\ImagickException $e) {
            echo $e->getMessage();
        }
    }

    /**
     * @return \Imagick
     * @throws \ImagickException
     */
    public function superpose()
    {
        $file = $this->pool->getImage();
        $this->files[] = $file;

        return $this->superposeOneImage($this->current_image, new \Imagick($file));
    }

    /**
     * Superposes one image in the current image.
     * This method must only be called by the assembler_superpose thread !
     *
     * @param \Imagick $current_image
     * @param \Imagick $image_to_superpose
     *
     * @return \Imagick
     * @throws \Exception
     */
    private function superposeOneImage($current_image, $image_to_superpose)
    {
        if ($this->config->get('assembler.superpose.variante', 0) === 1) {
            $current_image->brightnessContrastImage(0.99, 1);
        }
        if ($image_to_superpose->getColorspace() !== \Imagick::COLORSPACE_RGB) {
            $image_to_superpose->setColorspace(\Imagick::COLORSPACE_RGB);
        }

        # If the image is bigger than current image, scale it down to 1/2 of final picture dimensions
        # (while keeping its ratio)
        $image_x = $image_to_superpose->getImageWidth();
        $image_y = $image_to_superpose->getImageHeight();
        if ($image_x < 32 || $image_y < 32) {
            throw new \Exception('Image too small.');
        }

        if ($image_x > $this->config->get('assembler.sizex') || $image_y > $this->config->get('assembler.sizey')) {
            try {
                $image_to_superpose->scaleImage($this->config->get('assembler.sizex') / 2, $this->config->get('assembler.sizey') / 2, true);
            } catch (\ImagickException $e) {
            }
        }

        # Scale down/up image if required.
        $scale_value = $this->config->get('assembler.superpose.scale', 1);
        if ($scale_value !== 1) {
            $image_to_superpose->thumbnailImage($image_x * $scale_value, $image_y * $scale_value);
        }
        $image_x = $image_to_superpose->getImageWidth();
        $image_y = $image_to_superpose->getImageHeight();

        # Some image are too white.
        # For example, the photo of a coin on a white background.
        # These picture degrad the quality of the final image.
        # We try to dectect them by summing the value of the pixels
        # on the borders.
        # If the image is considered "white", we invert it.
        $pixel_count = 1; // to prevent divide by zero error.
        $value_count = 0;
        for ($x = 0; $x < $image_x; $x += 20) {
            $pixel = $image_to_superpose->getImagePixelColor($x, 5);
            $value_count += array_sum($pixel->getColor());
            $pixel = $image_to_superpose->getImagePixelColor($x, $image_y - 5);
            $value_count += array_sum($pixel->getColor());
            $pixel_count += 2;
        }
        for ($y = 0; $y < $image_y; $y += 20) {
            $pixel = $image_to_superpose->getImagePixelColor(5, $y);
            $value_count += array_sum($pixel->getColor());
            $pixel = $image_to_superpose->getImagePixelColor($image_x - 5, $y);
            $value_count += array_sum($pixel->getColor());
            $pixel_count += 2;
        }
        # If the average r+g+b of the border pixels exceed this value,
        # we consider the image is too white, and we invert it.
        if (100 * $value_count / (255 * 3) / $pixel_count > 60) {
            $image_to_superpose->negateImage(false);
        }

        $paste_coords_x = random_int(-($image_x/2), max(0, $this->config->get('assembler.sizex')-$image_x));
        $paste_coords_y = random_int(-($image_y/2), max(0, $this->config->get('assembler.sizey')-$image_y));

        # Darken image borders
        $image_to_superpose = $this->darkenImageBorder($image_to_superpose);

        if ($this->config->get('assembler.superpose.randomrotation', false)) {
            $image_to_superpose->rotateImage('none', random_int(0, 359));
            $image_to_superpose = $this->darkenImageBorder($image_to_superpose);
        }

        // help for mask : https://phpimagick.com/Tutorial/backgroundMasking
        $image_to_superpose->setImageMatte(true);
        $mask_image = clone $image_to_superpose;
        $mask_image->setImageType(Imagick::IMGTYPE_GRAYSCALE);
        $mask_image->transformImageColorSpace(Imagick::COLORSPACE_GRAY);

        # Invert the transparency of 5% of the images (Except if we are in variante 1 mode)
        if ($this->config->get('assembler.superpose.variante') === 1 && random_int(0, 100) < 5) {
            $mask_image->negateImage(true);
        }

        $image_to_superpose->compositeImage($mask_image, \Imagick::COMPOSITE_COPYOPACITY, 0, 0);
        $current_image->compositeImage($image_to_superpose, \Imagick::COMPOSITE_DEFAULT, $paste_coords_x, $paste_coords_y);

        if ($this->config->get('assembler.superpose.variante') === 0) {
            $current_image->equalizeImage();
        } else {
            $current_image->autoLevelImage();
        }

        return $current_image;
    }

    /**
     * @param \Imagick $image
     * @param int|null     $border_size
     *
     * @return \Imagick
     */
    private function darkenImageBorder(Imagick $image, $border_size = null)
    {
        if (null === $border_size) {
            $border_size = $this->config->get('assembler.superpose.bordersmooth');
        }

        $image_x = $image->getImageWidth();
        $image_y = $image->getImageHeight();

        for ($i = 0; $i < $border_size; $i++) {
            $draw = new \ImagickDraw();
            $draw->setStrokeOpacity(($border_size-$i)/$border_size);
            $draw->setStrokeWidth(1);
            $draw->setStrokeColor('black');
            $draw->setFillColor('none');
            $draw->rectangle($i, $i, $image_x - $i, $image_y - $i);
            $image->drawImage($draw);
        }

        return $image;
    }

    /**
     * @throws \ImagickException
     */
    private function prepareImage()
    {
        $this->current_image = null === $this->base_image ? new \Imagick() : new \Imagick($this->base_image);
        $this->current_image->setSize($this->config->get('assembler.sizex'), $this->config->get('assembler.sizey'));
        $this->current_image->newImage($this->config->get('assembler.sizex'), $this->config->get('assembler.sizey'), 'none');

        $nb_images = $this->config->get('assembler.superpose.min_num_images', 5);
        for ($i = 0; $i < $nb_images; $i++) {
            $this->current_image = $this->superpose();
        }
    }
}