<?php
/**
 * Plugin Name: Get The Image
 * Plugin URI: http://themehybrid.com/plugins/get-the-image
 * Description: This is a highly intuitive script that can grab an image by custom field input, post attachment, or extracting it from the post's content.
 * Version: 0.8
 * Author: Justin Tadlock
 * Author URI: http://justintadlock.com
 *
 * Get the Image - An advanced post image script for WordPress.
 *
 * Get the Image was created to be a highly-intuitive image script that displays post-specific images (an
 * image-based representation of a post).  The script handles old-style post images via custom fields for
 * backwards compatibility.  It also supports WordPress' built-in featured image functionality.  On top of
 * those things, it can automatically set attachment images as the post image or scan the post content for
 * the first image element used.  It can also fall back to a given default image.
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU
 * General Public License version 2, as published by the Free Software Foundation.  You may NOT assume
 * that you can use any other version of the GPL.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * @package GetTheImage
 * @version 0.8.0
 * @author Justin Tadlock <justin@justintadlock.com>
 * @copyright Copyright (c) 2008 - 2012, Justin Tadlock
 * @link http://justintadlock.com/archives/2008/05/27/get-the-image-wordpress-plugin
 * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 */

/* Adds theme support for WordPress 'featured images'. */
add_theme_support( 'post-thumbnails' );

/* Delete the cache when a post or post metadata is updated. */
add_action( 'save_post', 'get_the_image_delete_cache_by_post' );
add_action( 'deleted_post_meta', 'get_the_image_delete_cache_by_meta', 10, 2 );
add_action( 'updated_post_meta', 'get_the_image_delete_cache_by_meta', 10, 2 );
add_action( 'added_post_meta', 'get_the_image_delete_cache_by_meta', 10, 2 );

/**
 * The main image function for displaying an image.  It supports several arguments that allow developers to
 * customize how the script outputs the image.
 *
 * The image check order is important to note here.  If an image is found by any specific check, the script
 * will no longer look for images.  The check order is 'meta_key', 'the_post_thumbnail', 'attachment',
 * 'image_scan', 'callback', and 'default_image'.
 *
 * @since 0.1.0
 * @access public
 * @global $post The current post's database object.
 * @param array $args Arguments for how to load and display the image.
 * @return string|array The HTML for the image. | Image attributes in an array.
 */
function get_the_image( $args = array() ) {

    /* Set the default arguments. */
    $defaults = array(
        'meta_key' =>           array( 'Thumbnail', 'thumbnail' ), // array|string
        'post_id' =>            get_the_ID(),
        'attachment' =>         true,
        'the_post_thumbnail' => true, // WP 2.9+ image function
        'size' =>               'large',
        'default_image' =>      false,
        'order_of_image' =>     1,
        'link_to_post' =>       true,
        'image_class' =>        false,
        'image_scan' =>         true,
        'width' =>              false,
        'height' =>             false,
        'format' =>             'img',
        'meta_key_save' =>      false,
        'thumbnail_id_save' =>  false, // Set 'featured image'.
        'callback' =>           null,
        'cache' =>              false,
        'before' =>             '',
        'after' =>              '',
        'echo' =>               true,
        'custom_key' =>         null, // @deprecated 0.6. Use 'meta_key'.
        'default_size' =>       null, // @deprecated 0.5.  Use 'size'.
    );

    /* Allow plugins/themes to filter the arguments. */
    $args = apply_filters( 'get_the_image_args', $args );

    /* Merge the input arguments and the defaults. */
    $args = wp_parse_args( $args, $defaults );

    /* If $default_size is given, overwrite $size. */
    if ( !is_null( $args['default_size'] ) )
        $args['size'] = $args['default_size']; // Deprecated 0.5 in favor of $size

    /* If $custom_key is set, overwrite $meta_key. */
    if ( !is_null( $args['custom_key'] ) )
        $args['meta_key'] = $args['custom_key']; // Deprecated 0.6 in favor of $meta_key

    /* If $format is set to 'array', don't link to the post. */
    if ( 'array' == $args['format'] )
        $args['link_to_post'] = false;

    /* Extract the array to allow easy use of variables. */
    extract( $args );

    /* Get cache key based on $args. */
    $key = md5( serialize( compact( array_keys( $args ) ) ) );

    /* Check for a cached image. */
    $image_cache = wp_cache_get( $post_id, 'get_the_image' );

    if ( !is_array( $image_cache ) )
        $image_cache = array();

    /* Set up a default, empty $image_html variable. */
    $image_html = '';

    /* If there is no cached image, let's see if one exists. */
    if ( !isset( $image_cache[$key] ) || empty( $cache ) ) {

        /* If a custom field key (array) is defined, check for images by custom field. */
        if ( !empty( $meta_key ) )
            $image = get_the_image_by_meta_key( $args );

        /* If no image found and $the_post_thumbnail is set to true, check for a post image (WP feature). */
        if ( empty( $image ) && !empty( $the_post_thumbnail ) ) {
            $image = get_the_image_by_post_thumbnail( $args );

             if (!isset($image['src'])) unset($image);

         }

        /* If no image found and $attachment is set to true, check for an image by attachment. */
        if ( empty( $image ) && !empty( $attachment ) )
            $image = get_the_image_by_attachment( $args );

        /* If no image found and $image_scan is set to true, scan the post for images. */
        if ( empty( $image ) && !empty( $image_scan ) ) {
            $image = get_the_image_by_scan( $args );
        }

        /* If no image found and a callback function was given. Callback function must pass back array of <img> attributes. */
        if ( empty( $image ) && !is_null( $callback ) && function_exists( $callback ) )
            $image = call_user_func( $callback, $args );

        /* If no image found and a $default_image is set, get the default image. */
        if ( empty( $image ) && !empty( $default_image ) )
            $image = get_the_image_by_default( $args );

        /* If an image was found. */
        if ( !empty( $image ) ) {

            /* If $meta_key_save was set, save the image to a custom field. */
            if ( !empty( $meta_key_save ) )
                get_the_image_meta_key_save( $args, $image['src'] );

            /* Format the image HTML. */
            $image_html = get_the_image_format( $args, $image );

            /* Set the image cache for the specific post. */
            $image_cache[$key] = $image_html;
            wp_cache_set( $post_id, $image_cache, 'get_the_image' );
        }
    }

    /* If an image was already cached for the post and arguments, use it. */
    else {
        $image_html = $image_cache[$key];
    }

    /* Allow plugins/theme to override the final output. */
    $image_html = apply_filters( 'get_the_image', $image_html );

    /* If $format is set to 'array', return an array of image attributes. */
    if ( 'array' == $format ) {

        /* Set up a default empty array. */
        $out = array();

        /* Get the image attributes. */
        $atts = wp_kses_hair( $image_html, array( 'http' ) );

        /* Loop through the image attributes and add them in key/value pairs for the return array. */
        foreach ( $atts as $att )
            $out[$att['name']] = $att['value'];

        if (isset($out['src'])) {
            $out['url'] = $out['src']; // @deprecated 0.5 Use 'src' instead of 'url'.
        }

        /* Return the array of attributes. */
        return $out;
    }

    /* Or, if $echo is set to false, return the formatted image. */
    elseif ( false === $echo ) {
        return $args['before'] . $image_html . $args['after'];
    }

    /* If there is a $post_thumbnail_id, do the actions associated with get_the_post_thumbnail(). */
    if ( isset( $image['post_thumbnail_id'] ) )
        do_action( 'begin_fetch_post_thumbnail_html', $post_id, $image['post_thumbnail_id'], $size );

    /* Display the image if we get to this point. */
    if ($image_html) {
        echo $args['before'] . $image_html . $args['after'];
    }

    /* If there is a $post_thumbnail_id, do the actions associated with get_the_post_thumbnail(). */
    if ( isset( $image['post_thumbnail_id'] ) )
        do_action( 'end_fetch_post_thumbnail_html', $post_id, $image['post_thumbnail_id'], $size );
}

/* Internal Functions */

/**
 * Calls images by custom field key.  Script loops through multiple custom field keys.  If that particular key
 * is found, $image is set and the loop breaks.  If an image is found, it is returned.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @return array|bool Array of image attributes. | False if no image is found.
 */
function get_the_image_by_meta_key( $args = array() ) {

    /* If $meta_key is not an array. */
    if ( !is_array( $args['meta_key'] ) )
        $args['meta_key'] = array( $args['meta_key'] );

    /* Loop through each of the given meta keys. */
    foreach ( $args['meta_key'] as $meta_key ) {

        /* Get the image URL by the current meta key in the loop. */
        $image = get_post_meta( $args['post_id'], $meta_key, true );

        /* If an image was found, break out of the loop. */
        if ( !empty( $image ) )
            break;
    }

    /* If a custom key value has been given for one of the keys, return the image URL. */
    if ( !empty( $image ) )
        return array( 'src' => $image );

    return false;
}

/**
 * Checks for images using a custom version of the WordPress 2.9+ get_the_post_thumbnail() function.
 * If an image is found, return it and the $post_thumbnail_id.  The WordPress function's other filters are
 * later added in the display_the_image() function.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @return array|bool Array of image attributes. | False if no image is found.
 */
function get_the_image_by_post_thumbnail( $args = array() ) {

    /* Check for a post image ID (set by WP as a custom field). */
    $post_thumbnail_id = get_post_thumbnail_id( $args['post_id'] );

    /* If no post image ID is found, return false. */
    if ( empty( $post_thumbnail_id ) )
        return false;

    /* Apply filters on post_thumbnail_size because this is a default WP filter used with its image feature. */
    $size = apply_filters( 'post_thumbnail_size', $args['size'] );

    /* Get the attachment image source.  This should return an array. */
    $image = wp_get_attachment_image_src( $post_thumbnail_id, $size );

    /* Get the attachment excerpt to use as alt text. */
    $alt = trim( strip_tags( get_post_field( 'post_excerpt', $post_thumbnail_id ) ) );

    /* Return both the image URL and the post thumbnail ID. */
    return array( 'src' => $image[0], 'post_thumbnail_id' => $post_thumbnail_id, 'alt' => $alt );
}

/**
 * Check for attachment images.  Uses get_children() to check if the post has images attached.  If image
 * attachments are found, loop through each.  The loop only breaks once $order_of_image is reached.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @return array|bool Array of image attributes. | False if no image is found.
 */
function get_the_image_by_attachment( $args = array() ) {

    /* Get the post type of the current post. */
    $post_type = get_post_type( $args['post_id'] );

    /* Check if the post itself is an image attachment. */
    if ( 'attachment' == $post_type && wp_attachment_is_image( $args['post_id'] ) ) {
        $attachment_id = $args['post_id'];
    }

    /* If the post is not an attachment, check if it has any image attachments. */
    elseif ( 'attachment' !== $post_type ) {

        /* Get attachments for the inputted $post_id. */
        $attachments = get_children(
            array(
                'post_parent' => $args['post_id'],
                'post_status' => 'inherit',
                'post_type' => 'attachment',
                'post_mime_type' => 'image',
                'order' => 'ASC',
                'orderby' => 'menu_order ID',
                'suppress_filters' => true
            )
        );

        /* Check if any attachments were found. */
        if ( !empty( $attachments ) ) {

            /* Set the default iterator to 0. */
            $i = 0;

            /* Loop through each attachment. */
            foreach ( $attachments as $id => $attachment ) {

                /* Set the attachment ID as the current ID in the loop. */
                $attachment_id = $id;

                /* Break if/when we hit 'order_of_image'. */
                if ( ++$i == $args['order_of_image'] )
                    break;
            }
        }
    }

    /* Check if we have an attachment ID before proceeding. */
    if ( !empty( $attachment_id ) ) {

        /* Get the attachment image. */
        $image = wp_get_attachment_image_src( $id, $args['size'] );

        /* Get the attachment excerpt. */
        $alt = trim( strip_tags( get_post_field( 'post_excerpt', $id ) ) );

        /* Save the attachment as the 'featured image'. */
        if ( true === $args['thumbnail_id_save'] )
            set_post_thumbnail( $args['post_id'], $id );

        /* Return the image URL. */
        return array( 'src' => $image[0], 'alt' => $alt );
    }

    /* Return false for anything else. */
    return false;
}

/**
 * Scans the post for images within the content.  Not called by default with get_the_image().  Shouldn't use
 * if using large images within posts, better to use the other options.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @return array|bool Array of image attributes. | False if no image is found.
 */
function get_the_image_by_scan( $args = array() ) {

     global $wpdb;
    // check for an embed code to see if we can fetch an auto thumbnail
    $videocode = get_post_meta($args['post_id'], 'wpzoom_post_embed_code', true);

    if (function_exists('fetch_video_thumbnail_url')) {
         if(strlen($videocode) > 1 && false !== ($url = fetch_video_thumbnail_url($videocode))) {
         return array( 'src' => $url );
         }
    }

      /* Search the post's content for the <img /> tag and get its URL. */
    preg_match_all( '|<img.*?src=[\'"](.*?)[\'"].*?>|i', get_post_field( 'post_content', $args['post_id'] ), $matches );

    /* If there is a match for the image, return its URL. */
    if ( isset( $matches ) && isset($matches[1][0]) && $matches[1][0] )
        return array( 'src' => $matches[1][0] );

    return false;

}

/**
 * Used for setting a default image.  The function simply returns the image URL it was given in an array.
 * Not used with get_the_image() by default.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @return array|bool Array of image attributes. | False if no image is found.
 */
function get_the_image_by_default( $args = array() ) {
    return array( 'src' => $args['default_image'] );
}

/**
 * Formats an image with appropriate alt text and class.  Adds a link to the post if argument is set.  Should
 * only be called if there is an image to display, but will handle it if not.
 *
 * @since 0.7.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @param array $image Array of image attributes ($image, $classes, $alt, $caption).
 * @return string $image Formatted image (w/link to post if the option is set).
 */
function get_the_image_format( $args = array(), $image = false ) {

    /* If there is no image URL, return false. */
    if ( empty( $image['src'] ) )
        return false;

    /* Extract the arguments for easy-to-use variables. */
    extract( $args );

    /* If there is alt text, set it.  Otherwise, default to the post title. */
    $image_alt = ( ( !empty( $image['alt'] ) ) ? $image['alt'] : apply_filters( 'the_title', get_post_field( 'post_title', $post_id ) ) );

    /* If there is a width or height, set them as HMTL-ready attributes. */
    $width = ( ( $width ) ? ' width="' . esc_attr( $width ) . '"' : '' );
    $height = ( ( $height ) ? ' height="' . esc_attr( $height ) . '"' : '' );

    /* Loop through the custom field keys and add them as classes. */
    if ( is_array( $meta_key ) ) {
        foreach ( $meta_key as $key )
            $classes[] = sanitize_html_class( $key );
    }

    /* Add the $size and any user-added $image_class to the class. */
    $classes[] = sanitize_html_class( $size );
    $classes[] = sanitize_html_class( $image_class );

    /* Join all the classes into a single string and make sure there are no duplicates. */
    $class = join( ' ', array_unique( $classes ) );

    /* Add the image attributes to the <img /> element. */
    $html = '<img src="' . $image['src'] . '" alt="' . esc_attr( strip_tags( $image_alt ) ) . '" class="' . esc_attr( $class ) . '"' . $width . $height . ' />';

    /* If $link_to_post is set to true, link the image to its post. */
    if ( $link_to_post )
        $html = '<a href="' . get_permalink( $post_id ) . '" title="' . esc_attr( apply_filters( 'the_title', get_post_field( 'post_title', $post_id ) ) ) . '">' . $html . '</a>';

    /* If there is a $post_thumbnail_id, apply the WP filters normally associated with get_the_post_thumbnail(). */
    if ( !empty( $image['post_thumbnail_id'] ) )
        $html = apply_filters( 'post_thumbnail_html', $html, $post_id, $image['post_thumbnail_id'], $size, '' );

    return $html;
}

/**
 * Saves the image URL as the value of the meta key provided.  This allows users to set a custom meta key
 * for their image.  By doing this, users can trim off database queries when grabbing attachments or get rid
 * of expensive scans of the content when using the image scan feature.
 *
 * @since 0.6.0
 * @access private
 * @param array $args Arguments for how to load and display the image.
 * @param array $image Array of image attributes ($image, $classes, $alt, $caption).
 */
function get_the_image_meta_key_save( $args = array(), $image = array() ) {

    /* If the $meta_key_save argument is empty or there is no image $url given, return. */
    if ( empty( $args['meta_key_save'] ) || empty( $image['src'] ) )
        return;

    /* Get the current value of the meta key. */
    $meta = get_post_meta( $args['post_id'], $args['meta_key_save'], true );

    /* If there is no value for the meta key, set a new value with the image $url. */
    if ( empty( $meta ) )
        add_post_meta( $args['post_id'], $args['meta_key_save'], $image['src'] );

    /* If the current value doesn't match the image $url, update it. */
    elseif ( $meta !== $image['src'] )
        update_post_meta( $args['post_id'], $args['meta_key_save'], $image['src'], $meta );
}

/**
 * Deletes the image cache for the specific post when the 'save_post' hook is fired.
 *
 * @since 0.7.0
 * @access private
 * @param int $post_id The ID of the post to delete the cache for.
 * @return void
 */
function get_the_image_delete_cache_by_post( $post_id ) {
    wp_cache_delete( $post_id, 'get_the_image' );
}

/**
 * Deletes the image cache for a specific post when the 'added_post_meta', 'deleted_post_meta',
 * or 'updated_post_meta' hooks are called.
 *
 * @since 0.7.0
 * @access private
 * @param int $meta_id The ID of the metadata being updated.
 * @param int $post_id The ID of the post to delete the cache for.
 * @return void
 */
function get_the_image_delete_cache_by_meta( $meta_id, $post_id ) {
    wp_cache_delete( $post_id, 'get_the_image' );
}

/**
 * @since 0.1.0
 * @deprecated 0.3.0
 */
function get_the_image_link( $deprecated = '', $deprecated_2 = '', $deprecated_3 = '' ) {
    get_the_image();
}

/**
 * @since 0.3.0
 * @deprecated 0.7.0
 */
function image_by_custom_field( $args = array() ) {
    return get_the_image_by_meta_key( $args );
}

/**
 * @since 0.4.0
 * @deprecated 0.7.0
 */
function image_by_the_post_thumbnail( $args = array() ) {
    return get_the_image_by_post_thumbnail( $args );
}

/**
 * @since 0.3.0
 * @deprecated 0.7.0
 */
function image_by_attachment( $args = array() ) {
    return get_the_image_by_attachment( $args );
}

/**
 * @since 0.3.0
 * @deprecated 0.7.0
 */
function image_by_scan( $args = array() ) {
    return get_the_image_by_scan( $args );
}

/**
 * @since 0.3.0
 * @deprecated 0.7.0
 */
function image_by_default( $args = array() ) {
    return get_the_image_by_default( $args );
}

/**
 * @since 0.1.0
 * @deprecated 0.7.0
 */
function display_the_image( $args = array(), $image = false ) {
    return get_the_image_format( $args, $image );
}

/**
 * @since 0.5.0
 * @deprecated 0.7.0 Replaced by cache delete functions specifically for the post ID.
 */
function get_the_image_delete_cache() {
    return;
}

?>
