<?php
/*
* Resize images dynamically using wp built in functions
* Victor Teixeira
*
* php 5.2+
*
* @param int $attach_id
* @param string $img_url
* @param int $width
* @param int $height
* @param bool $crop
* @return array
*/
if ( ! function_exists( 'vt_resize' ) ) {
	function vt_resize( $attach_id = null, $img_url = null, $width, $height, $crop = false ) {

		// Cast $width and $height to integer
		$width = intval( $width );
		$height = intval( $height );

		// this is an attachment, so we have the ID
		if ( $attach_id ) {
			$image_src = wp_get_attachment_image_src( $attach_id, 'full' );
			$file_path = get_attached_file( $attach_id );
		// this is not an attachment, let's use the image url
		} else if ( $img_url ) {
			$upload_dir = wp_upload_dir();
			$file_path = explode($upload_dir['baseurl'],$img_url);
			$file_path = $upload_dir['basedir'] . $file_path['1'];

			//$file_path = ltrim( $file_path['path'], '/' );
			//$file_path = rtrim( ABSPATH, '/' ).$file_path['path'];

			$orig_size = getimagesize( $file_path );

			$image_src[0] = $img_url;
			$image_src[1] = $orig_size[0];
			$image_src[2] = $orig_size[1];
		}

		$file_info = pathinfo( $file_path );

		// check if file exists
		if ( empty( $file_info['dirname'] ) && empty( $file_info['filename'] ) && empty( $file_info['extension'] )  )
			return;
		
		$base_file = $file_info['dirname'].'/'.$file_info['filename'].'.'.$file_info['extension'];
		if ( !file_exists($base_file) )
			return;

		$extension = '.'. $file_info['extension'];

		// the image path without the extension
		$no_ext_path = $file_info['dirname'].'/'.$file_info['filename'];

		$cropped_img_path = $no_ext_path.'-'.$width.'x'.$height.$extension;

		// checking if the file size is larger than the target size
		// if it is smaller or the same size, stop right here and return
		if ( $image_src[1] > $width ) {
			// the file is larger, check if the resized version already exists (for $crop = true but will also work for $crop = false if the sizes match)
			if ( file_exists( $cropped_img_path ) ) {
				$cropped_img_url = str_replace( basename( $image_src[0] ), basename( $cropped_img_path ), $image_src[0] );

				$vt_image = array (
					'url' => $cropped_img_url,
					'width' => $width,
					'height' => $height
				);
				return $vt_image;
			}

			// $crop = false or no height set
			if ( $crop == false OR !$height ) {
				// calculate the size proportionally
				$proportional_size = wp_constrain_dimensions( $image_src[1], $image_src[2], $width, $height );
				$resized_img_path = $no_ext_path.'-'.$proportional_size[0].'x'.$proportional_size[1].$extension;

				// checking if the file already exists
				if ( file_exists( $resized_img_path ) ) {
					$resized_img_url = str_replace( basename( $image_src[0] ), basename( $resized_img_path ), $image_src[0] );

					$vt_image = array (
						'url' => $resized_img_url,
						'width' => $proportional_size[0],
						'height' => $proportional_size[1]
					);
					return $vt_image;
				}
			}

			// check if image width is smaller than set width
			$img_size = getimagesize( $file_path );
			if ( $img_size[0] <= $width ) $width = $img_size[0];
			
			// Check if GD Library installed
			if ( ! function_exists ( 'imagecreatetruecolor' ) ) {
			    echo 'GD Library Error: imagecreatetruecolor does not exist - please contact your web host and ask them to install the GD library';
			    return;
			}

			// no cache files - let's finally resize it
			if ( function_exists( 'wp_get_image_editor' ) ) {
				$image = wp_get_image_editor( $file_path );
				if ( ! is_wp_error( $image ) ) {
					$image->resize( $width, $height, $crop );
					$save_data = $image->save();
					if ( isset( $save_data['path'] ) ) $new_img_path = $save_data['path'];
				}
			} else {
				$new_img_path = wp_get_image_editor( $file_path, $width, $height, $crop );
			}		
			
			$new_img_size = getimagesize( $new_img_path );
			$new_img = str_replace( basename( $image_src[0] ), basename( $new_img_path ), $image_src[0] );

			// resized output
			$vt_image = array (
				'url' => $new_img,
				'width' => $new_img_size[0],
				'height' => $new_img_size[1]
			);

			return $vt_image;
		}

		// default output - without resizing
		$vt_image = array (
			'url' => $image_src[0],
			'width' => $width,
			'height' => $height
		);

		return $vt_image;
	}
}