<?php

namespace Gumlet;

use Exception;

/**
 * PHP class to resize and scale images
 */
class ImageResize
{
    const CROPTOP = 1;
    const CROPCENTRE = 2;
    const CROPCENTER = 2;
    const CROPBOTTOM = 3;
    const CROPLEFT = 4;
    const CROPRIGHT = 5;
    const CROPTOPCENTER = 6;
    const IMG_FLIP_HORIZONTAL = 0;
    const IMG_FLIP_VERTICAL = 1;
    const IMG_FLIP_BOTH = 2;

    public $quality_jpg = 85;
    public $quality_webp = 85;
    public $quality_png = 6;
    public $quality_truecolor = true;

    public $interlace = 1;

    public $source_type;

    protected $source_image;

    protected $original_w;
    protected $original_h;

    protected $dest_x = 0;
    protected $dest_y = 0;

    protected $source_x;
    protected $source_y;

    protected $dest_w;
    protected $dest_h;

    protected $source_w;
    protected $source_h;

    protected $source_info;


    protected $filters = [];

    /**
     * Create instance from a strng
     *
     * @param string $image_data
     * @return ImageResize
     * @throws ImageResizeException
     */
    public static function createFromString($image_data)
    {
        if (empty($image_data) || $image_data === null) {
            throw new ImageResizeException('image_data must not be empty');
        }
        $resize = new self('data://application/octet-stream;base64,' . base64_encode($image_data));
        return $resize;
    }


    /**
     * Add filter function for use right before save image to file.
     *
     * @param callable $filter
     * @return $this
     */
    public function addFilter(callable $filter)
    {
        $this->filters[] = $filter;
        return $this;
    }

    /**
     * Apply filters.
     *
     * @param $image resource an image resource identifier
     * @param $filterType filter type and default value is IMG_FILTER_NEGATE
     */
    protected function applyFilter($image, $filterType = IMG_FILTER_NEGATE)
    {
        foreach ($this->filters as $function) {
            $function($image, $filterType);
        }
    }

    /**
     * Loads image source and its properties to the instanciated object
     *
     * @param string $filename
     * @return ImageResize
     * @throws ImageResizeException
     */
    public function __construct($filename)
    {
        if (!defined('IMAGETYPE_WEBP')) {
            define('IMAGETYPE_WEBP', 18);
        }
        if ($filename === null || empty($filename) || (substr($filename, 0, 7) !== 'data://' && !is_file($filename))) {
            throw new ImageResizeException('File does not exist');
        }

        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        if (strstr(finfo_file($finfo, $filename), 'image') === false) {
            throw new ImageResizeException('Unsupported file type');
        }

        if (!$image_info = getimagesize($filename, $this->source_info)) {
            $image_info = getimagesize($filename);
        }

        if (!$image_info) {
            throw new ImageResizeException('Could not read file');
        }

        list(
            $this->original_w,
            $this->original_h,
            $this->source_type
        ) = $image_info;

        switch ($this->source_type) {
        case IMAGETYPE_GIF:
            $this->source_image = imagecreatefromgif($filename);
            break;

        case IMAGETYPE_JPEG:
            $this->source_image = $this->imageCreateJpegfromExif($filename);

            // set new width and height for image, maybe it has changed
            $this->original_w = imagesx($this->source_image);
            $this->original_h = imagesy($this->source_image);

            break;

        case IMAGETYPE_PNG:
            $this->source_image = imagecreatefrompng($filename);
            break;

        case IMAGETYPE_WEBP:
            if (version_compare(PHP_VERSION, '5.5.0', '<')) {
                throw new ImageResizeException('For WebP support PHP >= 5.5.0 is required');
            }
            $this->source_image = imagecreatefromwebp($filename);
            break;

        default:
            throw new ImageResizeException('Unsupported image type');
        }

        if (!$this->source_image) {
            throw new ImageResizeException('Could not load image');
        }

        return $this->resize($this->getSourceWidth(), $this->getSourceHeight());
    }

    // http://stackoverflow.com/a/28819866
    public function imageCreateJpegfromExif($filename)
    {
        $img = imagecreatefromjpeg($filename);

        if (!function_exists('exif_read_data') || !isset($this->source_info['APP1'])  || strpos($this->source_info['APP1'], 'Exif') !== 0) {
            return $img;
        }

        try {
            $exif = @exif_read_data($filename);
        } catch (Exception $e) {
            $exif = null;
        }

        if (!$exif || !isset($exif['Orientation'])) {
            return $img;
        }

        $orientation = $exif['Orientation'];

        if ($orientation === 6 || $orientation === 5) {
            $img = imagerotate($img, 270, null);
        } elseif ($orientation === 3 || $orientation === 4) {
            $img = imagerotate($img, 180, null);
        } elseif ($orientation === 8 || $orientation === 7) {
            $img = imagerotate($img, 90, null);
        }

        if ($orientation === 5 || $orientation === 4 || $orientation === 7) {
            if(function_exists('imageflip')) {
                imageflip($img, IMG_FLIP_HORIZONTAL);
            } else {
                $this->imageFlip($img, IMG_FLIP_HORIZONTAL);
            }
        }

        return $img;
    }

    /**
     * Saves new image
     *
     * @param string $filename
     * @param string $image_type
     * @param integer $quality
     * @param integer $permissions
     * @return static
     */
    public function save($filename, $image_type = null, $quality = null, $permissions = null)
    {
        $image_type = $image_type ?: $this->source_type;
        $quality = is_numeric($quality) ? (int) abs($quality) : null;

        switch ($image_type) {
        case IMAGETYPE_GIF:
            $dest_image = imagecreatetruecolor($this->getDestWidth(), $this->getDestHeight());

            $background = imagecolorallocatealpha($dest_image, 255, 255, 255, 1);
            imagecolortransparent($dest_image, $background);
            imagefill($dest_image, 0, 0, $background);
            imagesavealpha($dest_image, true);
            break;

        case IMAGETYPE_JPEG:
            $dest_image = imagecreatetruecolor($this->getDestWidth(), $this->getDestHeight());

            $background = imagecolorallocate($dest_image, 255, 255, 255);
            imagefilledrectangle($dest_image, 0, 0, $this->getDestWidth(), $this->getDestHeight(), $background);
            break;

        case IMAGETYPE_WEBP:
            if (version_compare(PHP_VERSION, '5.5.0', '<')) {
                throw new ImageResizeException('For WebP support PHP >= 5.5.0 is required');
            }
            $dest_image = imagecreatetruecolor($this->getDestWidth(), $this->getDestHeight());

            $background = imagecolorallocate($dest_image, 255, 255, 255);
            imagefilledrectangle($dest_image, 0, 0, $this->getDestWidth(), $this->getDestHeight(), $background);
            break;

        case IMAGETYPE_PNG:
            if (!$this->quality_truecolor && !imageistruecolor($this->source_image)) {
                $dest_image = imagecreate($this->getDestWidth(), $this->getDestHeight());

                $background = imagecolorallocatealpha($dest_image, 255, 255, 255, 1);
                imagecolortransparent($dest_image, $background);
                imagefill($dest_image, 0, 0, $background);
            } else {
                $dest_image = imagecreatetruecolor($this->getDestWidth(), $this->getDestHeight());
            }

            imagealphablending($dest_image, false);
            imagesavealpha($dest_image, true);
            break;
        }

        imageinterlace($dest_image, $this->interlace);
        
        imagegammacorrect($this->source_image, 2.2, 1.0);
        
        imagecopyresampled(
            $dest_image,
            $this->source_image,
            $this->dest_x,
            $this->dest_y,
            $this->source_x,
            $this->source_y,
            $this->getDestWidth(),
            $this->getDestHeight(),
            $this->source_w,
            $this->source_h
        );
        
        imagegammacorrect($dest_image, 1.0, 2.2);


        $this->applyFilter($dest_image);

        switch ($image_type) {
        case IMAGETYPE_GIF:
            imagegif($dest_image, $filename);
            break;

        case IMAGETYPE_JPEG:
            if ($quality === null || $quality > 100) {
                $quality = $this->quality_jpg;
            }

            imagejpeg($dest_image, $filename, $quality);
            break;

        case IMAGETYPE_WEBP:
            if (version_compare(PHP_VERSION, '5.5.0', '<')) {
                throw new ImageResizeException('For WebP support PHP >= 5.5.0 is required');
            }
            if ($quality === null) {
                $quality = $this->quality_webp;
            }

            imagewebp($dest_image, $filename, $quality);
            break;

        case IMAGETYPE_PNG:
            if ($quality === null || $quality > 9) {
                $quality = $this->quality_png;
            }

            imagepng($dest_image, $filename, $quality);
            break;
        }

        if ($permissions) {
            chmod($filename, $permissions);
        }

        imagedestroy($dest_image);

        return $this;
    }

    /**
     * Convert the image to string
     *
     * @param int $image_type
     * @param int $quality
     * @return string
     */
    public function getImageAsString($image_type = null, $quality = null)
    {
        $string_temp = tempnam(sys_get_temp_dir(), '');

        $this->save($string_temp, $image_type, $quality);

        $string = file_get_contents($string_temp);

        unlink($string_temp);

        return $string;
    }

    /**
     * Convert the image to string with the current settings
     *
     * @return string
     */
    public function __toString()
    {
        return $this->getImageAsString();
    }

    /**
     * Outputs image to browser
     * @param string $image_type
     * @param integer $quality
     */
    public function output($image_type = null, $quality = null)
    {
        $image_type = $image_type ?: $this->source_type;

        header('Content-Type: ' . image_type_to_mime_type($image_type));

        $this->save(null, $image_type, $quality);
    }

    /**
     * Resizes image according to the given short side (short side proportional)
     *
     * @param integer $max_short
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resizeToShortSide($max_short, $allow_enlarge = false)
    {
        if ($this->getSourceHeight() < $this->getSourceWidth()) {
            $ratio = $max_short / $this->getSourceHeight();
            $long = $this->getSourceWidth() * $ratio;

            $this->resize($long, $max_short, $allow_enlarge);
        } else {
            $ratio = $max_short / $this->getSourceWidth();
            $long = $this->getSourceHeight() * $ratio;

            $this->resize($max_short, $long, $allow_enlarge);
        }

        return $this;
    }

    /**
     * Resizes image according to the given long side (short side proportional)
     *
     * @param integer $max_long
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resizeToLongSide($max_long, $allow_enlarge = false)
    {
        if ($this->getSourceHeight() > $this->getSourceWidth()) {
            $ratio = $max_long / $this->getSourceHeight();
            $short = $this->getSourceWidth() * $ratio;

            $this->resize($short, $max_long, $allow_enlarge);
        } else {
            $ratio = $max_long / $this->getSourceWidth();
            $short = $this->getSourceHeight() * $ratio;

            $this->resize($max_long, $short, $allow_enlarge);
        }

        return $this;
    }

    /**
     * Resizes image according to the given height (width proportional)
     *
     * @param integer $height
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resizeToHeight($height, $allow_enlarge = false)
    {
        $ratio = $height / $this->getSourceHeight();
        $width = $this->getSourceWidth() * $ratio;

        $this->resize($width, $height, $allow_enlarge);

        return $this;
    }

    /**
     * Resizes image according to the given width (height proportional)
     *
     * @param integer $width
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resizeToWidth($width, $allow_enlarge = false)
    {
        $ratio  = $width / $this->getSourceWidth();
        $height = $this->getSourceHeight() * $ratio;

        $this->resize($width, $height, $allow_enlarge);

        return $this;
    }

    /**
     * Resizes image to best fit inside the given dimensions
     *
     * @param integer $max_width
     * @param integer $max_height
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resizeToBestFit($max_width, $max_height, $allow_enlarge = false)
    {
        if ($this->getSourceWidth() <= $max_width && $this->getSourceHeight() <= $max_height && $allow_enlarge === false) {
            return $this;
        }

        $ratio  = $this->getSourceHeight() / $this->getSourceWidth();
        $width = $max_width;
        $height = $width * $ratio;

        if ($height > $max_height) {
            $height = $max_height;
            $width = $height / $ratio;
        }

        return $this->resize($width, $height, $allow_enlarge);
    }

    /**
     * Resizes image according to given scale (proportionally)
     *
     * @param integer|float $scale
     * @return static
     */
    public function scale($scale)
    {
        $width  = $this->getSourceWidth() * $scale / 100;
        $height = $this->getSourceHeight() * $scale / 100;

        $this->resize($width, $height, true);

        return $this;
    }

    /**
     * Resizes image according to the given width and height
     *
     * @param integer $width
     * @param integer $height
     * @param boolean $allow_enlarge
     * @return static
     */
    public function resize($width, $height, $allow_enlarge = false)
    {
        if (!$allow_enlarge) {
            // if the user hasn't explicitly allowed enlarging,
            // but either of the dimensions are larger then the original,
            // then just use original dimensions - this logic may need rethinking

            if ($width > $this->getSourceWidth() || $height > $this->getSourceHeight()) {
                $width  = $this->getSourceWidth();
                $height = $this->getSourceHeight();
            }
        }

        $this->source_x = 0;
        $this->source_y = 0;

        $this->dest_w = $width;
        $this->dest_h = $height;

        $this->source_w = $this->getSourceWidth();
        $this->source_h = $this->getSourceHeight();

        return $this;
    }

    /**
     * Crops image according to the given width, height and crop position
     *
     * @param integer $width
     * @param integer $height
     * @param boolean $allow_enlarge
     * @param integer $position
     * @return static
     */
    public function crop($width, $height, $allow_enlarge = false, $position = self::CROPCENTER)
    {
        if (!$allow_enlarge) {
            // this logic is slightly different to resize(),
            // it will only reset dimensions to the original
            // if that particular dimenstion is larger

            if ($width > $this->getSourceWidth()) {
                $width  = $this->getSourceWidth();
            }

            if ($height > $this->getSourceHeight()) {
                $height = $this->getSourceHeight();
            }
        }

        $ratio_source = $this->getSourceWidth() / $this->getSourceHeight();
        $ratio_dest = $width / $height;

        if ($ratio_dest < $ratio_source) {
            $this->resizeToHeight($height, $allow_enlarge);

            $excess_width = ($this->getDestWidth() - $width) / $this->getDestWidth() * $this->getSourceWidth();

            $this->source_w = $this->getSourceWidth() - $excess_width;
            $this->source_x = $this->getCropPosition($excess_width, $position);

            $this->dest_w = $width;
        } else {
            $this->resizeToWidth($width, $allow_enlarge);

            $excess_height = ($this->getDestHeight() - $height) / $this->getDestHeight() * $this->getSourceHeight();

            $this->source_h = $this->getSourceHeight() - $excess_height;
            $this->source_y = $this->getCropPosition($excess_height, $position);

            $this->dest_h = $height;
        }

        return $this;
    }

    /**
     * Crops image according to the given width, height, x and y
     *
     * @param integer $width
     * @param integer $height
     * @param integer $x
     * @param integer $y
     * @return static
     */
    public function freecrop($width, $height, $x = false, $y = false)
    {
        if ($x === false || $y === false) {
            return $this->crop($width, $height);
        }
        $this->source_x = $x;
        $this->source_y = $y;
        if ($width > $this->getSourceWidth() - $x) {
            $this->source_w = $this->getSourceWidth() - $x;
        } else {
            $this->source_w = $width;
        }

        if ($height > $this->getSourceHeight() - $y) {
            $this->source_h = $this->getSourceHeight() - $y;
        } else {
            $this->source_h = $height;
        }

        $this->dest_w = $width;
        $this->dest_h = $height;

        return $this;
    }

    /**
     * Gets source width
     *
     * @return integer
     */
    public function getSourceWidth()
    {
        return $this->original_w;
    }

    /**
     * Gets source height
     *
     * @return integer
     */
    public function getSourceHeight()
    {
        return $this->original_h;
    }

    /**
     * Gets width of the destination image
     *
     * @return integer
     */
    public function getDestWidth()
    {
        return $this->dest_w;
    }

    /**
     * Gets height of the destination image
     * @return integer
     */
    public function getDestHeight()
    {
        return $this->dest_h;
    }

    /**
     * Gets crop position (X or Y) according to the given position
     *
     * @param integer $expectedSize
     * @param integer $position
     * @return float|integer
     */
    protected function getCropPosition($expectedSize, $position = self::CROPCENTER)
    {
        $size = 0;
        switch ($position) {
        case self::CROPBOTTOM:
        case self::CROPRIGHT:
            $size = $expectedSize;
            break;
        case self::CROPCENTER:
        case self::CROPCENTRE:
            $size = $expectedSize / 2;
            break;
        case self::CROPTOPCENTER:
            $size = $expectedSize / 4;
            break;
        }
        return $size;
    }

    /**
     *  Flips an image using a given mode if PHP version is lower than 5.5
     *
     * @param  resource $image
     * @param  integer  $mode
     * @return null
     */
    public function imageFlip($image, $mode)
    {
        switch($mode) {
            case self::IMG_FLIP_HORIZONTAL: {
                $max_x = imagesx($image) - 1;
                $half_x = $max_x / 2;
                $sy = imagesy($image);
                $temp_image = imageistruecolor($image)? imagecreatetruecolor(1, $sy): imagecreate(1, $sy);
                for ($x = 0; $x < $half_x; ++$x) {
                    imagecopy($temp_image, $image, 0, 0, $x, 0, 1, $sy);
                    imagecopy($image, $image, $x, 0, $max_x - $x, 0, 1, $sy);
                    imagecopy($image, $temp_image, $max_x - $x, 0, 0, 0, 1, $sy);
                }
                break;
            }
            case self::IMG_FLIP_VERTICAL: {
                $sx = imagesx($image);
                $max_y = imagesy($image) - 1;
                $half_y = $max_y / 2;
                $temp_image = imageistruecolor($image)? imagecreatetruecolor($sx, 1): imagecreate($sx, 1);
                for ($y = 0; $y < $half_y; ++$y) {
                    imagecopy($temp_image, $image, 0, 0, 0, $y, $sx, 1);
                    imagecopy($image, $image, 0, $y, 0, $max_y - $y, $sx, 1);
                    imagecopy($image, $temp_image, 0, $max_y - $y, 0, 0, $sx, 1);
                }
                break;
            }
            case self::IMG_FLIP_BOTH: {
                $sx = imagesx($image);
                $sy = imagesy($image);
                $temp_image = imagerotate($image, 180, 0);
                imagecopy($image, $temp_image, 0, 0, 0, 0, $sx, $sy);
                break;
            }
            default:
                return null;
        }
        imagedestroy($temp_image);
    }
}
